The Art of Perfumery
THE ROOTS AND THE EVOLUTION OF PERFUMERY
Although history attributes the first perfume container to the period of Darius III (4th century bc) the roots of perfumery reach much deeper into the past.
The first human beings had to rely on their sense of smell to survive forcing them to recognize the various scents nature provided: animals of course but also plants flowers trees fruits grains roots and resins. Their awareness of olfactory abilities had awakened.
Since odours have a tremendous influence on flavour people applied their olfactory abilities to the preparation of meals to perfume their food even before the term had been created to communicate such impressions.
Condiments spices and herbs whose properties they eventually discovered just like those of grains fruits and bark rapidly extended their olfactory know how. To improve their diet they extracted oil from oleogenous grains and fate perhaps lending a hand they macerated vegetable and herbaceous ingredients into it. These ingredients gave their properties and odours to the oil. It is safe to say that the first rose oil probably dates back somewhat further than we might expect.
Usefulness not being dissociated from pleasure nutritional or therapeutic values it was easy to move to adornment perhaps even before the idea of religious offerings was born because feminine seduction no doubt goes back to Eve. The first representatives of Homo sapiens were so observant and sensorially awake by necessity that they probably benefited and took pleasure from everything derived from these fragrant materials.
Before he even knew how to make fire man had already learned from natural fires that heat transformed the odour and flavour of vegetables and flesh. After the art of making fire was discovered initial applications were no doubt of a culinary nature. However the fragrant smoke of burning herbs rising to the sky could only trigger the spirit of those first religious practitioners . . . How not to associate smoke and odour? Per fumar perfumer would one day become the term perfume.
Mastering fire and all the progress it engendered pottery among other skills led to the construction of the first distillation equipment. The remains of one still were found in Mesopotamia and are said to be 5000 years old. In other words the Arabs actually did little more than rediscover the alembic.
Used in metaphysics in Syria and Egypt as well as for religious purposes in India scents and fragrances except for a few historical setbacks would become invaluable. Having discovered the antiseptic values of fragrant balms and resins the Egyptians embalmed their most famous dead the pharaohs.
In the Middle and Far East the first application of fragrances in daily life took the form of beauty products rather than perfumes. Ointments creams and make up preceded the use of odorants simply for their fragrance.
Thanks to perfumed oils and later to alcohol a good extraction solvent and a practical vehicle for the first perfume mixtures the era of smelling good had begun. But perfumery as it is known today was still far away.
In fact for several centuries olfactory practices were limited to simple mixtures to recipes. The 18th and 19th centuries were years of excess of terror and conquering wars followed by the pretentious and ridiculous refinements of the Muscadins. Only the end of the 19th century saw the birth of real perfumery the result of an evolving industry: the production of odorous substances by chemical reactions. These odorous compounds added to the old recipes transformed them by setting new fragrant accents often strong and long lasting leading to unprecedented combinations. Later it would be discovered that some of these new fragrant components were actually hidden in highly complex natural essences from which they could not always be extracted individually. Now available in isolated form they offer completely different possibilities than when drowned in a natural substrate such as an essential oil or an absolute.
Thle growing list of chemically defined odorous substances allowed man to enrich simple recipes and to create real formulae which gave way to original olfactory forms invented by formulators.
These formulators had worked with odorous materials of natural or synthetic origin much in the same way that musicians work with tones or painters with colours. They had combined specific properties of their materials to create a completely new form and not a mere addition to existing forms. With their material they had composed the olfactory composition. This stage represents the beginning of perfumery as it is known today it has existed for just one century.
Of course perfumery passed through various stages during the past 100 years: craftsmanship industrialization and commercialization. It had to modernize and evolve under tho diverse forces of a changing world. These factors need to be mentioned here in order to understand better the current situation in perfumery worldwide.
Modern perfumery therefore was born at the very end of the 19th century the initial compositions combining for the first time both natural raw materials and synthetic chemicals. I will only cite the most famous the still very much alive Jicky created in 1889 whose incredible centennial was smothered by the clamours of a bicentennial. What a pity!
The real champion the mastermind of this contemporary olfactory composition. Francois Coty also gifted in marketing and sales helped perfumery leave the first stage of rough sketches to enter the world of fine arts. He revolutionized not only compositions but also bottles packaging and sales methods. He was the first and probably the only real professional in perfume marketing.
Origan and Chypre were the glorious masterpieces which Coty revealed to his contemporaries. And Muguet des Bois introduced in 1936 two years after his death but unmistakably one of his creations was the most beautiful floral evocation ever cultivated on this theme at a time when resources were limited.
Stimulated by his example his peers eventually surpassed each other each through his own ingenuity each faithful to his own taste. Guerlain Houbigant (Parquet Bienaime) and Caron (Ernest Daltroff) became renowned for their creations. In each of these perfume houses the owners were tasteful and perceptive composers exercising complete initiative and responsibility from concept to sale. Success was the sanction of united action. Unfortunately these qualities were not transmittable and the future of these houses would suffer the consequences.
After World War I having seen the success of perfumers renowned fashion designers wanted to exploit this success to stabilize precarious fashion revenues. The first Coco Chanel following the failure of Poiret was exceptionally fortunate to stumble upon Ernest Beaux who had worked for the Rallet Perfumery in Russia before 1914 and had subsequently moved to La Bocca Cannes France in 1917.
Beaux had created a perfume for Rallet which under the label of Rallet no. 1 had been a failure. Rallet offered it to Coco Chanel and was her supplier during the initial years. Its launching in 1922 or 1923 as No. 5 by Coco Chanel (a novice in this field and with limited resources) was far from spectacular. The real introduction was made by the powerful Wertheimer Group (Parfums Bourjois) which took over the activities of Parfums Chanel. Beaux finally a member of the Chanel group would be the author of several other masterpieces.
Fashion designer Jeanne Lanvin also tried her luck with a modest perfume My Sin in 1925. She as well would meet a great perfumer who would conjure the most spectacular tetralogy in the history of perfumery: Arpege Scandal Rumeur and Pretexte.
Designers Marcel Rochas and Christian Dior followed the footsteps of their two colleagues and also tasted the sweetness of success. In these four cases when the designer was no longer pulling all the strings the composition of the perfumes was ensured by true professionals and their distribution was controlled either by the fashion designers or by professionals like Bourjois. The break with tradition was therefore limited and all artistic objectives were maintained.
However the diversity of new brands introduced by amateurs not familiar with the clever nuances in perfumery and financed by groups who did not respect the ideals of true perfumery triggered dramatic changes. Perfume was no longer a respected work of art. It had been reduced to a commercial product sold under the most lucrative of conditions. Its production was given to the highest bidder without setting any aesthetic priorities marketing being the choice method to impose it on the public. The entire system was based on this principle putting a rein on the creative wave of parfums a risque as they were called by the new people in charge. However the real risk lies in launching any old product it is an established fact that nine launches out of ten are a failure.
Today perfumery is uprooted. Only a revolution can redeem it.
THE PART OF HEDONISM
Hedonism is attributed to the School of Cyrene which was established by Aristippe (around 435 350 bc) a contemporary of Plato and a follower of Socrates. The School was continued by his daughter Arete and his grandson Aristippe the Young known as the Metrodidacte who because of his contacts with the Sophistes and their cynicism may very well have systematized his grandfathers principles.
This philosophical doctrine which aimed for an ethic was founded on the ideal of immediate impressions. It advocated the search for pleasure while avoiding pain and preferred intensity to quality. Pleasure was always something good even if its origin engendered shame.
The philosophy of (immediate) pleasure is the negation of all arduous training either in sports or the arts of any intellectual effort of any creative constraint of any devotion implying sacrifice or of any generous altruism.
Those who would place perfume under the sign of hedonism would arbitrarily limit it to sensual and possibly vulgar aspects completely neglecting the sensory aesthetic quality which has essentially characterized the great perfumes of the 20th century.
For most hedonism translates into pleasant sensations. In terms of olfactory sensations a distinction must be made between the perception of the layman of the perfumer and even of the experienced amateur. The fact that to ordinary mortals some odours are considered pleasant and others unpleasant can be attributed to a lack of education and to an innate taste which impedes the layman from making an objective and technical judgement on the value and usage of odours. However after a short but inevitable emotional reaction the motivated and experienced perfumer no longer distingui shes between pleasant and unpleasant smells. This is like the music composer who considers notes to be elementary forms which can be combined into intricate music. The composer no longer judges the notes but the rapport he has created between them. The same applies to perfumers. This is one reason why 1 studied Kant who so eloquently distinguished between things pleasant and things aesthetic.
The perfumer judges odours in terms of quality intensity and duration of perceptibility. The latter must be distinguished from intensity even though duration is defined as intensity in time. Volatility is the fourth important component which plays a considerable role in the genesis of a composition because without volatility there would be no perfume. I have stated the above by convention because these attributes arise not from odours (pheno menon of conscious ness) but from the stimulus which determines them or more precisely from the reaction between the odorous molecule and the receptive macromolecule to which it will bind. This reaction triggers a change of the normal potential in the living cells which translates into electric impulses a set of waves which are decoded by the brain. The consciousness of odours is born.
Perfumery Applications: Functional Products
Cleanliness has been an on going pursuit of mankind for centuries. The earliest mention of soap for cleaning purposes appeared in the second century ad. A great deal has happened since then as the human race became quite serious about getting and remaining clean. This seriousness is probably the genesis of the age old adage Cleanliness is next to Godliness.
Not until the early part of this century was there anything but soap available for cleaning one s body or the clothes on it and it was a rather crude soap at that. As the years progressed however a variety of cleaning products started appearing for a yet unsophisticated and undemanding consumer.
The evolution began with a small selection of washing products for personal use as well as clothes in the 1920s and 1930s. These early products were unperfumed and allowed the soap base odor to linger on the skin and cloth. By the 1940s simple perfumes started to make their way into functional products. These perfumes for the most part relied on citronella thyme and iemongrass oils along with isolates and chemicals such as bornyl acetate camphor diphenyl oxide and terpinolene.
Although it appeared that the perfumery development of functional products was destined for fast growth. World War 11 stunted the growth of this industry as it did others as it caused monumental shortages of raw materials. It was not until the 1950s therefore that the business got rolling again.
The industry was up and running. The 1950s brought us expanded palettes of raw materials through the production of greater numbers of synthetic products called aromatic chemicals which later became known simply as aroma chemicals. The fragrance industry expanded to meet the growing need of cleaning products manufacturers who were now creating new products at a quickened pace. All the new products were aimed at the consumers so they could keep their personal environments their wearing apparel and themselves clean.
Now the fun began because along with this unprecedented growth came a completely new segment of the industry creative perfumery for household products. Perfumers were not only required to become more and more imaginative they were also faced with the challenge of mastering and manipulating raw materials through hostile base environments.
FRAGRANCING OF FUNCTIONAL PRODUCTS
By the mid 1970s the fragrancing of functional products became a very important part of the industry contributing significantly to the growth and profits of fragrance suppliers ultimately losing their stepchild image to the fine fragrance creators.
During that same decade we witnessed the larger fragrance supply houses establish creative departments of perfumers whose sole responsibility was to work in the functional products area. Suppliers with research capabilities to develop new aroma chemicals were feeding the creative efforts of the perfumery. Voluminous and tedious stability studies of fragrance raw materials produced results which often gave direction to the research laboratory efforts to find new aroma chemicals which answered specific stability and creative needs.
At the close of the 1970s the work emanating from the research facilities of household products manufacturers produced aggressive bases which were fraught with problems that the household products perfumer had to face problems which carried into the next decade. Examples included solubilities active integrity oxygen and chlorine bleaches encapsulated chlorine fabric conditioners enzyme additives and so on.
As if this were not enough the perfumer had then to consider linear fragrance diffusion and longevity for perfuming the environmental air fresheners with emphasis on continuous action. These various mechanisms created problems related more to the physical aspects of the chemistry of fragrance materials than to the interaction of a product s base nature with the fragrance itself.
The household products perfumers needed to address all of these various criteria for their fragrance creations often learning something from one product base and applying it to another. At all times the tenets adhered to with each project were raw material stability availability and cost and the marriage of these three to produce a fragrance which would aesthetically send the appropriate signal about the product to the consumer.
The specific problems encountered by the perfumer when presented with the challenge of fragrancing functional products a category which can be further subdivided into cosmetic and household products.
Not all great fragrance ideas for functional products are born independently in the mind of the perfumer. Rather they are inspired by what has gone before or what is currently in the marketplace in an upscale way. Fine fragrances have in recent years been a source of ideas which inspire the creation of a functional product perfume. This process is known as the trickle down effect. Although a tried and true method of developing new functional products perfumes it has several obstacles that must be overcome before a successful transfer of a fine fragrance theme to a functional product can be accomplished.
Successful fine fragrances can create a polarizing effect among consumers causing a love/hate feeling toward the fragrance. Functional products on the other hand particularly the household ones cannot afford this love/hate reaction from consumers because they must be acceptable to a broad cross section within the consumer market. Therefore the unique combinations which give birth to the couturier fragrance theme have to be modified tamed and massaged by the functional perfumer to broaden the fragrance profile for greater consumer acceptance. Of course there are always exceptions to this successful translation of polarizing fragrances to those which trickle down almost exactly intact giving consideration to cost stability and availability.
A more recent introduction by Dior Poison has already made its way into a room air freshener and prognosticators see this as on the way for fabric softeners.
Line extensions of couturier fragrances into functional cosmetics is the first and the most obvious example of the trickle down effect although not representative in the truest sense of this phenomenon. Today it is expected that the lead fragrance note in the perfume or cologne will be carried throughout all the products in the line of the same name. Trickle down in the present sense is from couturier perfume to hair spray deodorants bar soaps detergents fabric softeners etc. In attempting to adapt a fragrance theme for functional products perfumers must consider the following factors.
Acceptability of couturier theme in product category.
Technical considerations of matching diffusion stability of both odor and color are of paramount importance. Substitution of raw materials is almost always necessary.
Costs and availability of aroma chemicals and natural materials.
Need for fragrance materials to comply with the IFRA and RIFM safety guidelines.
Aroma chemicals create the palette for today s modern perfumer that makes it possible to translate couturier perfumes into other products. Cologne (notes) have found stability and musk notes do not discolor these are just two examples of how aroma chemical developments in the last 30 years have become the key to the expanding world of fragranced products.
Hair products such as shampoos and hair sprays have provided fertile areas for the trickle down effect. The desired residual character of the couturier fragrances is easily translated to these products. Popular types in shampoos are derived from fragrances like Chloé Chanel No. 5 Charlie and Lauren. Major hair spray products utilize the fragrance types of Anais Anais L Air du Temps and Chanel No. 5.
Several of the top beauty complexion soap bars in the world have been inspired by Arpége Chanel No. 5 Chamade and Cabochard.
Detergent products and cleansing products in general place too many constraints on the perfumer trying to translate a couturier fragrance for the end use. Usually the base odor indicative of the active ingredient and pH considerations dictate the direction of fragrances in the products. This however does not preclude the perfumer from being inspired by a couturier theme and using it as a starting point modifying the theme until all constraints are dealt with successfully usually producing a fragrance which bears slight resemblance to the original idea.
However this does not dissuade the perfumer from saying the creation is of a certain couturier type taking into consideration all the aforementioned reasons to make changes in the odor profile.
Defying the natural order of things there are also two variations of the trickle down theory: those that trickle up and trickle across. An example of the up phenomenon is the Youth Dew bath oil by Estee Lauder which became the inspiration for the perfume oil. Another example of bath oil to perfume is Dioressence by Dior. Though these examples are rare they do happen giving credence to the trickle up state of creativity and inspiration.
Trickle across has one famous example the Johnson & Johnson Baby Powder fragrance a powdery rose accord which far overshadows all others and probably has become the most overdone fragrance type of the past three decades. This fragrance implies on the very first whiff softness and babies. All perfumers even those with moderate experience know how difficult if not impossible it is to change the mind set of marketers and product formulation chemists away from the J&J type when discussing fragrancing baby products bathroom deodorants or any other product which might demand a powdery fragrance type. The marketing request is usually for something new and different but which smells like J & J Baby Powder. There is a fear of limited product acceptance by the consumer if it does not have familiar notes which can always be related back to the Baby Powder note.
The popularity of J&J Baby Powder fragrance making it one of the all time classic blends has been said to be responsible for Ombre Rose Baby Soft and Sweet Honesty all perfume/cologne fragrances which are examples of the trickle up theory.
Fruity notes did not always enjoy the prestige of being the lead notes of many couturier fragrances as found in today s markets. Rather these notes were complete fragrances themselves used particularly in the USA as strong masking agents and most effective in public lavatories. These fragrances which bordered on flavors with their intensity were discharged into the atmosphere through mechanical means or continuous action para blocks.
It was only in the late 1960s and early 1970s that fruity fragrances began to gain respectability in their own right by providing a whole new range of odor concepts for functional products. Shampoos by the dozens had myriad fruity notes espousing their different claims on the hair.
This fruity era trickled across to many different product areas. The natural fragrances picked up along the same lines giving way to vegetable and other food like fragrances.
The fruity notes have trickled up to modify and lead the couturier palettes of aldehydic florals chypre spicy woody etc.
The fruity notes have also trickled down to detergents and fabric softeners leaving their imprint of residual quality along with richness and masking power.
Today the trickle down phenomenon is occurring more quickly than it did in the past. The sophisticated demands of the customer for more upscale fragrances in the functional products area along with the availability of a greater range of aroma chemicals yielding increased stability and creativity in more product bases have made this possible. As mentioned. Poison has already been translated to a room freshener.
Today s functional products perfumer has much to be inspired by to enhance his creativity but he needs the knowledge and experience to make successful fragrance translations.
The first group of functional products to be considered is line extensions to perfume/cologne. While these do present problems they are not as severe or seemingly insurmountable as those in the household products area.
Cost stability and color are the prime considerations when making line extensions. Costs ot extensions are proportionately less than the cologne oil. Some guidelines are as follows: the bath fragrance might be 60 75% of the cost of the cologne the talc hair products baby lotions and deodorants at 50% of the cologne with the soap interpretations coming in the 30 40% of the original cost.
Initially as a fact finding experiment the cologne oil should be incorporated into all bases at appropriate levels while the perfumer using his experience examines the formula for obvious necessary modifications for cost and compatibility. The first exercise involving the cologne oil will help to narrow down the potential problems such as coloration and discoloration. Frequently one lower cost version may work in two or three line extensions. Therefore fragrances developed from modified cologne oils for line extensions are usually more intense and used at higher levels than those in non line extension consumer products. Fragrances which are lower cost versions of cologne oil and which work in more than one line extension may tolerate the use of solvents to adjust costs where necessary.
Origin of Natural Odorants
Only substances that have a molecular weight below about 400 and an appreciable vapor pressure at room temperature can be perceived as having odor. The spectrum of odorants is thus limited to relatively small neutral organic compounds including undissociated acids and nitrogenous bases. Relatively few organic acids are sufficiently volatile to contribute to natural aromas. Acetic (vinegary) propionic (goaty) butyric (spoiled butter) and lactic (sauerkraut) acids are odorous at relatively high concentration.
Historically aroma research was largely directed toward the isolation identification and cataloging of specific odor producing constituents from the complex mixtures produced by nature. This work continues and many important aromas from foodstuffs beverages smoking materials and flowers have only recently been separated and the constituents positively identified. The cost of natural isolates coupled to the often difficult separation of the desirable component(s) has stimulated the development of chemical syntheses of many substances from more abundant raw materials including petrochemical feedstocks. Synthetically derived fragrances in many cases have superseded those produced oy living organisms.
The more recent emphasis on natural as opposed to artificial ingredients has however refocused attention on the origin of natural odorants and on the possibility of improving biological methods for the production of these materials. Recent advances in analytical techniques and instrumentation the use of radiolabeled tracers the development of instructive biomimetic syntheses and chemical model reactions and the exploitation of cell free enzyme systems have greatly facilitated our understanding of the origin of natural odorants via the enzymatic and occasionally non enzymatic processes that occur in microbial animal and plant cells. Of the natural fragrances those of plant origin are certainly the most structurally diverse. In spite of this diversity and the potential biogenetic possibilities most odor bearing compounds appear to be formed by way of relatively few often overlapping metabolic pathways that form the subject of this chapter.
PRODUCTS OF LIPID AND AMINO ACID METABOLISM
Aliphatic aldehydes ketones lactones and related compounds are among the most widely distributed of natural odorants and are often major contributors to fruit aromas. Many such compounds associated for example with the essence of banana apple and pear are neither produced during growth nor present at harvest. Rather they arise during a short ripening period marked by a climacteric rise in respiration and the onset of cellular catabolic processes. The biogenesis of a large number of these volatile aliphatic types can be rationalized by invoking a reasonably small number of metabolic pathways in which non volatile fatty acids and amino acids serve as the most important precursors.
Aroma bearing aliphatic compounds are considered to be produced via three major pathways: (1) Lipoxygenase catalyzed conversion of polyunsaturated fatty acids into C6 and C9 aldehydes and related substances and into C12 and C9 oxo acids (2) conversion of fatty acids via a and b oxidation into short chain acids aldehydes and ketones and related metabolites (3) conversion of amino acids to their corresponding Cn 1 acyl derivatives via trans amination and oxidative decarboxylation.
The major fatty acids of plant glyceryl lipids are the even numbered saturated derivatives from C12 to C18 and the unsaturated C18 derivatives (oleic Linoleic and linolenic acids) all of which are products of primary metabolism derived via the well known acetyl coenzyme A malonyl coenzyme A pathway. Free fatty acids exist at very low levels in intact plant cells and must first be released from the corresponding glycerides and phosphoglycerides by enzymatic hydrolysis (i.e. by the action of lipases and phospho lipases). Unsaturated fatty acids (primarily linoleic and linolenic) may then become substrates for lipoxygenase this enzymatic oxygen insertion reaction ultimately leading to the formation of C9 and C13 hydroperoxides. The lipoxygenase reaction mimics radical initiated autoxidation however the enzymatic process is both regio and stereo specific the selectivity depending on the enzyme source. Hydroperoxide lyases then cleave these reactive compounds the cleavage of the C9 hydroperoxide leading to unsaturated C9 aldehydes and 9 oxononanoic acid and the cleavage of the C13 hydroperoxide leading to C6 aldehydes and the corresponding 12 oxododecenoic acid. Lyase activity has been demonstrated in a variety of plants including cucumber tomato pear and apple. The lyase from pear fruit is specific for the C9 hydroperoxide whereas that from tomato fruit is specific for the C13 hydroperoxide. The lyase from cucumber fruit accepts both isomers.
Hexanal and trans 2 nonenal originate from linoleic acid (C18:2) as illustrated in Fig. 1 while trans 2 hexenal and nonadienal arise from linolenic acid (C18.3). Alcohols are derived from these aldehydes by the action of alcohol dehydrogenase(s). The C6 aldehydes and alcohols are largely responsible for the characteristic odor of green leaves and they contribute to the aroma of a variety of fruits. The 3 enals are converted by an isomerasc to the conjugated 2 enals. Such isomerization of (3Z) hexenal to (2E) hexenal yields leaf aldehyde . The former provides leaf alcohol upon reduction. Nonenal and nonadienal and their derived alcohols have been described as melon cucumber or violet like. Species dependent variations in the type and quantity of available fatty acids and the specificity of lipoxygenases lyases isomerases and dehydrogenases are responsible for the diverse mixtures of C6 and C9 aliphatics encountered in plant volatilcs.
An alternative means of generating volatile chain shortened products from the fatty acids of fruits and vegetables is the b oxidation pathway. This general scheme is initiated by conversion of the fatty acid to the corresponding acyl coenzyme A derivative by the action of acyl thiol ligases (acyl Co A synthetase acyl thiokinase). The acyl chain then undergoes sequential desaturation at C2 C3 hydration of the double bond to the C3 (b) hydroxy derivative and oxidation to the corresponding C3 (b) ketoacyl chain. In the final step of this sequence the enzyme thiolase with the assistance of coenzyme A cleaves the b keto derivative to yield acetyl coenzyme A and the acyl coenzyme A with the chain now shorter by two carbons. Repetition of the b oxidation cycle would ultimately cleave the chain to acetate units. Both saturated and unsaturated chains may be oxidized by this route although in the latter case the participation of ancillary reduction and/or isomerization step(s) is required to convert unsaturated chains to normal b oxidation intermediates. The resulting chain shortened fatty acyl coenzyme A esters may be reduced to the corresponding aldehydes by the action of acyl coenzyme A reductases and the aldehydes in turn converted to alcohols by dehydrogenases. The alcohols thus formed may be esterified with acyl coenzyme A derivatives by the action of transacylase. A generalized scheme for these transformations is provided in Fig. 2 in which the production of such compounds as ethyl octanoate and octyl acetate is illustrative of the diverse set of volatile metabolites which could be so generated.
Odd chain products are formed from the more common even chain fatty acids by the process of a oxidation in which flavin dependent enzymes decarboxylate the fatty acid via the a hydroperoxy intermediate to yield the aldehyde shortened by one carbon. Reduction of the aldehyde may occur and the resulting alcohol may enter the esterification cycle as illustrated. Alternatively oxidation of the aldehyde to the acid could lead to the production of odd chain esters including propionates and valerates.68 It is obvious that the combination of a and b oxidation when coupled to reduction and esterification steps is capable of generating an extremely wide and complex range of volatile odor bearing metabolites.
β Oxidation and alternate modes of lipid oxygenation are also thought to be involved in the production of additional odorants in plants including the methyl ketones and lactones.
Fig. 2. Pathway for the biosynthesis of short chain aldehydes alcohols and esters from acyl CoA.
Aliphatic methyl ketones are characteristic of the essential oil of rue (Ruta graveolens). Most prominent are 2 nonanone and 2 undecanone (and the corresponding secondary alcohols) which are considered to arise from C10 and C12 acyl chains in the course of b oxidation. Thus following conversion to the b ketoacyl chain decarboxylation yields the odd chain methyl ketohe. The g and d lactones characteristic of pineapple peach apricot strawberry mango and coconut undoubtedly arise from intermediates of fatty acid b oxidation or the biosynthetic elongation process. It seems likely that C4 unsaturated chains undergo hydration of the double bond or epoxidation and reduction to give the C4 and C5 hydroxyacyl chains which are subsequently lactonized to the corresponding g and d lactone. Macrocyclic lactones such as those found in galbanum angelica root and ambretre seed are probably formed by w (or w 1) hydroxylation of the corresponding odd or even acyl chain followed by internal esterification via a transacylase type enzyme. The aroma producing phthalides (bicyclic g lactones bearing a fused cyclohexane ring) typical of the essential oils of certain Umbelliferae are probably formed by the polyketide pathway rather than by oxidative modification of normal fatty acids.
Short branched chain aldehydes alcohols and esters are also important aroma compounds of ripening fruits and vegetables produced during the climacteric rise in respiration. Such branched chain derivatives arise from branched amino acids by transamination and oxidative decarboxylation to the shortened acyl coenzyme A derivative. Cellular levels of free leucine and valine may increase several fold during the climacteric period and may serve as precursors of 3 methylbutyl and 2 methylpropyl derivatives respectively. The aroma of field ripened tomatoes is attributed to esters of 3 methyl 1 butanol derived ultimately from leucine. Thus leucine amino transferase converts the amino acid to the a keto acid (a ketoisocaproic acid) which is decarboxylated to 3 methylbutanoyl CoA. The coenzyme A ester may either be a substrate for transacylation or be reduced to the corresponding aldehyde and alcohol (isoamyl alcohol). Valine and isoleucine may be transformed to branched esters aldehydes and alcohols by the same general pathway and alanine and aspartic acid are similarly metabolized by mitochondrial transaminases.
Jasmone was discovered as a principal aroma constituent of jasmine in 1899. This cyclopentenone derivative has a fruity celery like odor which upon dilution becomes sweet floral and blends well with all floral scents. Of the numerous compounds in jasmine flower oil Jasmone methyl jasmonate and jasmine lactone are thought to carry the principal jasmine fragrance while comprising but a very small fraction of the fresh weight of the flowers.
All proposed biosynthetic schemes for the formation of jasmonoid compounds begin with polyunsaturated fatty acids. The extensive studies by Vick & Zimmernan have led to a proposal for the formation of jasmonic acid which serves as a plant growth regulator (promotes senescence). This pathway begins with the C13 hydroperoxide derivative of linolenic acid (via lipoxy genase see above) which is dehydrated (via hydroperoxide dehydrase of the chtoroplast) to a short lived allene oxide. The latter may undergo hydrolysis to ketols or spontaneous rearrangement and cyclization to 12 oxo 10 15 phytodienoic acid a key intermediate of the pathway which by reduction of the endocyclic double bond and b oxidative carboxyl end shortening yields jasmonic acid Methylation of this product presumably by S adenosylmethionine could provide methyl jasmonate.
Products of Natural Origin
INTRODUCTION CONCRETES, ABSOLUTES
The diversity of the natural products used in perfumery is very considerable. From remote antiquity until the end of the nineteenth century i.e. 1880 90 the perfumery industry had used only natural products for its perfumes. The development of organic chemistry by French and German scientists created an important dye industry and then the synthetic odorants industry these two industries had many points of contact.
Advances in synthetic chemistry had major repercussions on perfumery and marked the beginning of a new epoch. The enthusiasm resulting from obtaining odours similar to those of certain flowers led at one time to the belief that synthetic products could entirely take the place of natural products. Many perfumers took this view but those of the French school were always able to observe and retain in perfumes a balance between the relative proportions of natural and synthetic products. This resulted for a long time in the superiority of French perfumes to the others quite apart from the influence of the artistic aspect of the Paris atmosphere and of French art in general. The Grasse natural essential oil industry exerted a far reaching influence in the same direction.
The years went by and successes with artificial perfumes which indeed contained a proportion of natural products such as Chuit s Dianthine brought the synthetics into fashion again.
This later on prompted Hubert Fraysse who presides over the destinies of Synar6me to say: It is now possible to dispense almost entirely with natural essential oils.
It is undeniable that the methods of analysing essential oils had undergone considerable development with the introduction of spectrography mass spectrography gas chromatography etc.
Max Stoll commented in 1962 upon the complexity of the composition of a natural essential oil and taking by way of example an absolute oil of jasmin which had been very fully analysed he reported that 14 different alcohols had been identified in a large portion of that absolute oil and in a far smaller portion by weight 28 to 29 alcohols had been found which it was not possible to identify. The lecturer added: No chemist in the world would tackle such a problem.
For those who know as a true perfumer does the influence of tiny quantities of certain products in a composition it will be realised that it is very difficult to replace in a high grade perfume a natural product by an artificial one. Perfumers know moreover that lavender is greatly improved by a trace of phenylethyl alcohol. A trace of tincture of ambergris improves Bulgarian rose. The merest suggestion of a certain lactone often improves a lily of the valley. And so on. The consequences of this extreme complexity of natural perfumery materials may be summarised as follows:
It is practically impossible to produce a perfect reconstitution of a natural essential oil by means of synthetics. (Many reconstitutions are nevertheless used for part or even total replacement of excessively expensive natural products. Such reconstituted or artificial oils are economically important and tend to improve in quality as time goes on and research expands. They may be purchased as such as is often the case or in some cases are made by the perfumer himself.)
The mellowness which exists in natural essential oils can only be obtained in compositions provided that very many component substances are used especially in the nature of olfactory analogues. This runs counter to the theory which claims that a perfume must consist of a small number of components: unless of course one endeavours to produce more or less diagrammatic perfumes.
Apart from what this analysis of natural products teaches us the fact cannot be overlooked that the latter have various other properties that are favourable to their use in perfume compositions. Thus they produce homogeneity round off the note temper the harshness of synthetics etc.
Greater persistence may be imparted to perfumes containing naturals but much depends of course on the quantity used as well as the type.
Distilled essential oils and those obtained by expression from the peel of citrus fruits etc. all possess terpenes to a greater or lesser degree and these play a very important part in perfumes by exercising an exalting effect. In the special language of the perfumer: ils poussent le parfum (they push or boost the perfume).
It is true that deterpenated or terpeneless essential oils are also valuable because they can be employed in larger quantities in alcoholic solution.
A very important requirement for natural products is quality. How is it to be ensured? There is of course the physical and chemical standards for each of them but these are only an indication the final decision remaining with olfactory analysis.
How is it possible to know the olfactory quality for each of the natural essential oils? Although the faculty of judging olfactory purity and quality may to some extent be inherent it is one that must be adequately trained and exercised for it depends above all upon a well stored reliable and discriminatory odour memory.
We consider elsewhere the actual training of the perfumer but here may be noted just a few points which have to be taken into consideration when examining natural perfumery raw materials:
The custom more or less permissible of making mixtures which physical and chemical analysis may or may not detect and which olfactory analysis can readily detect.
For a determined natural product olfactory analysis recognizes the origin of the product. For instance a Grasse Jasmin as distinct from an Italian jasmin or the jasmin of one supplier from that of another firm.
The tastes and preferences of a perfumer play a part here. Thus one perfumer will look in a jasmin for the fresh part the sharp top note while another will seek rather the warm rather jam like and sometimes indoloid note.
Thus a young perfumer who wishes to know the raw materials olfactorily must have available for his education the largest possible number of products.
We have touched on the problem of the adulteration of natural products and it has to be admitted that sometimes certain inexperienced buyers make trouble for themselves. What is a seller to do who offers a true natural jasmin absolute for which the incompetent buyer refuses to place a large order saying that the jasmin is 25 per cent too expensive and that he has had offers at the lower price? The seller will almost certainly submit a fresh sample which will be 30 per cent cheaper and has been arranged accordingly. This happens more often than might be imagined.
These examples would suggest that the purchase of odorants should be made by a highly experienced perfumer or perfumery buyer. All too often the general management of a perfumery concern tends nowadays to make the buying department for perfumery raw materials independent of the technological side doubtless in order to avoid any understanding if one may use the phrase developing between buyer and seller. It is doubtful however whether the gains made by this division of power outweigh the losses. Buying usually suffers when left to the relatively unskilled: there is a loss of immediacy opportunity and time. The perfumer moreover is deprived of vital contact with an important source of information if someone else in the firm and not he habitually interviews the sellers representatives for it is they who are in touch with the perfumery world of all his competitors. It should never be forgotten that the perfumer bears responsibility for the creation of the perfume and the continuity of its quality and he ought therefore to live in the full atmosphere of perfume and fashion unimpeded by an excess of ill considered restrictions.
The natural odorants that are employed in perfumery can be assigned to seven categories viz.:
Concrete oils (concretes).
Absolute oils (absolutes).
Essential oils derived from the distillation of flowers leaves roots and fruits.
Essential oils obtained by expressing fruits.
Aromatic odorants obtained by the fractional distillation etc. of certain essential oils.
Odorants (such as tinctures) of vegetable or animal origin.
Products in the form of resins and balsams.
We refer elsewhere to the conventional use of the smelling slip (mouillette) for the purpose of olfactory examination. For the comparison and selection of competitive samples of any specific essential oil or other odorant the smelling slip is once again indispensable.
Concretes and absolutes are sometimes loosely designated natural flower oils in order to distinguish them from the distilled and expressed essential oils . They are obtained by different processes. For example the flowers leaves roots etc. are subjected to a kind of extraction by hydrocarbon solvents which dissolve the waxes containing the odorous principles from the flowers. The hydrocarbons are then eliminated by evaporation under reduced pressure so that the heat does not affect the product so obtained which is called concrete oil or simply a concrete.
In all these very delicate processes the constant care is to heat as little as possible in order not to impair the product. Flowers for extraction are gathered very early in the morning.
The concrete of the flowers so treated has the appearance of a more or less solid wax. It is insoluble in water and virtually insoluble in alcohol. However it is possible to make tinctures with it i.e. to dissolve by mixing in the cold state the odorous principles contained in the concrete by using enclosed blade mixers and 95° alcohol for a considerable number of days (about a month). An odorous product of great fineness is obtained displaying marked fidelity to the perfume of the flower. This is quite sensational particularly with jasmin and certain great perfumes owe part of their fame to this practice which is moreover of very great antiquity.
A variation on the process was devised circa 1950 by the chemist Louis Romagnan. It was based on ultrasonics and the energy which the latter liberate by their intense vibratory movements producing a series of pressures and decompressions ringing about the bursting of the cells which liberates the esential oils contained in those cells. The oils are then recovered but not apparently without some difficulty. One well known Grasse house has shown particular interest in the process. It seems quite possible a priori that an adequate medium may be found for each type of product and that this will facilitate the recovery of the essential oils suspended in the supporting liquid. This process has at least the potential advantage of doing away with malodorous solvents and of obtaining concretes or absolute oils that have not been overheated.
These are generally obtained by extracting the concretes with alcohol then eliminating the alcohol at reduced pressure. The product so obtained is entirely soluble in alcohol and often has the consistency of honey.
The concrete is subjected to extraction by alcohol by heating to the lowest possible temperature in mixers. The product is then concentrated and the alcohol evaporated by heating to a low temperature and at low pressure. A so called absolute essential oil is obtained which will be termed commercially: ether type.
However the various extremely delicate operations of heating even slightly do not improve the quality and that is why in the case of jasmin the tincture has a remarkable and irreplaceable bouquet. Thus every firm making natural raw materials jealously guards the secret of its treatments processes and operations which constitute the differences from the products of other firms. The precaution of not heating the extraction products in order to retain their freshness of odour has encouraged research workers to find new processes.
A few years ago a process was invented and perfected by Eugene Meunier on behalf of Messrs P. Robertet & Cie who registered the name of Butaflor for all the absolutes obtained by this method. The process is a low temperature one and consists of passing a stream of butane gas (boiling point 0 5°C) through a kind of tube in which the flowers are placed whose perfume is to be extracted. The absolute so obtained tends to be relatively light coloured and true to type but in some cases it may not be entirely soluble in alcohol. This process first made it possible to obtain commercially interesting absolutes of lilac and lily of the valley.
A very old process is that of the pomades. There were two ways of carrying it out:
The process of maceration in the hot state which consisted of melting an odourless fat and allowing the flowers to be macerated in it the fat or oil being kept at a medium temperature for the fat to be liquid without excessive heating. The fat absorbs the perfume. In the past forms of alcoholate were prepared by extracting these pomades with alcohol in the cold state. Pomade washings (lavages de pommade) were obtained which showed their concentration according to the number they bore.
Then extractions of these pomades with alcohol were carried out to obtain concentrated solutions and the alcohol was evaporated in order to produce the absolute essential oils ex pomade.
Not all flowers can be treated by this process but only those which are not too delicate: the flowers of Cassie farnesiana rose orange blossom mimosa hyacinth carnation etc.
The process of maceration in the cold state or enfleurage.
In this process fat or oil is also used. It involves coating the glass plates of glazed wooden frames with a fat or oil. Inside these frames (termed cadre or chassis) on the part coated with fat are placed the flowers. The frames are stacked on one another so as to obtain a hermetic seal and they are allowed to stand for 24 hours so that the effluvia liberated dissolve in the fat or oil.
The flowers that have given up their perfume are removed and replaced by fresh ones. This operation is repeated until the fat or grease is saturated with perfume. The perfumed fats are treated with alcohol and by increasing these extraction operations followed by chilling and filtration an alcoholic solution is obtained which is subsequently concentrated by evaporation to yield the absolute enfleurage essential oil.
The flowers that have given up the greater part of their perfume in the frames still contain perfume. They are treated with volatile solvents (petroleum ether or benzene) so that products are obtained which bear the name of absolute ex chassis ether type or absolute ex chassis benzene type.
The flowers treated by this process are those which are the most delicate but which in spite of all continue to live and yield perfume after they have been cut. These include jasmin tuberose jonquil narcissus and mignonette.
The fats used are lard or vegetable fat. Pork lard is best and it is preferably deodorized. In these processes a small amount of fat is always carried along by the alcohol. In the past this habitually gave when used in perfumes a liquid that was very slightly cloudy and which had to be chilled and filtered.
It is at present possible to obtain extremely odourless fats some of them synthetic. On the other hand there were once certain perfumers who were not opposed to the odour sui generis of these fats which contributed a very slight suggestion of rancio (to use the special term adopted by perfumers in the early part of this century).
Essential Oils derived from Distillation
This process is applied to flowers leaves stalks herbs roots and even to certain fruits.
There are three main ways of obtaining these products:
Distillation in a still with naked flame. This was the former process. It continued to be practised for a long time at artisan level in Bulgaria concurrently with the steam process to obtain essential oil of rose. The essential oil of Bulgarian rose obtained by this process then bore the name of Bulgarian peasant rose (Rose Bulgare Paysanne) to distinguish it from that obtained by the steam processes.
It should be noted that the latter were introduced by the French (A. Verley Gamier Hasslauer et al.) and also by a few Germans. These were the processes and equipment used at Grasse with which the French had great experience.
In naked flame distillation water was placed in the still along with the ingredients to be distilled. It was heated to boiling point the steam passed through a cooled coil and at the end of the coils the water and the essential oil were collected. After a certain rest time the latter floats on the surface (except in the case of a very few oils of higher specific gravity) and is separated from the water.
This process is still used for certain plants for which distillation on the spot is more advantageous. These include lavender lavandin rosemary spike thyme etc. and in this way the products treated have the advantage of being fresh and undried.
The second process is to have large cylindrical stills heated by coils in which steam circulates. It makes it possible to heat more regularly and to avoid the heat surges inevitable with naked flame stills. Water is placed in the still with the raw materials from which it is desired to obtain the essential oil. It is heated and the steam is collected in more or less the same way as in the naked flame process.
This process is the same as the previous one but a stream of live steam is passed to the still which carries the essential oils along more quickly. In certain cases a partial vacuum is produced which makes it possible to heat to a lower temperature and to obtain finer products.
In addition to leaves stems and roots citrus fruits are sometimes treated in this way i.e. the peel of lemons and oranges. The essential oils obtained in this way are generally less fine and are above all used in the food and beverage industries. Some perfumers nevertheless prefer even for fine perfumes the distilled essential oil of West Indies lime to that of expressed lime as the odour of this distilled essential oil is more characteristic finer and more interesting in use than that obtained by expression.
Essential Oils Obtained by Expression
The fruits that yield their essential oils by expression are the citrus fruits or Hesperidaceae as they are termed in France (i.e. the fruit of the garden of the Hesperides islands which are supposed to have been located near the Cape Verde or Canary Islands).
These fruits include: lemons sweet and bitter oranges mandarins bergamots citrons limes from Italy or Africa the highly perfumed West Indian lime and the shaddock or grapefruit.
All these fruits whose essential oil is contained in the peel can be simply squeezed out as they are. The whole of the juice of the fruit is thus collected together with the floating essential oil. The drawback is that the juice is always acid and considerably impairs the essential oil.
Probably the best processes are those in which the peel only is abraded to liberate the essential oils contained in its cells. The oldest process now obsolescent if not obsolete involved soaking up the essential oil with a sponge after making incisions in the rind. A number of mechanical processes have since been patented and used to obtain citrus peel type essential oils economically and of good quality.
Isolates etc. from Essential Oils
These products are midway between the natural products and the pure synthetic products. An example will better show what is meant. From the natural essential oil of Brazilian bois de rose is extracted linalool of which it contains up to 90 per cent. This natural organic product has a sweet odour which is pleasant and recalls the odour of the parent oil a slightly rosy and at the same time woody odour.
This is a very important ingredient in perfumery which lacks the dryness and harshness of the products of pure chemical synthesis. That is why in our opinion it should not be assigned to the class of synthetic products but to a kind of special synthetic natural class.
The problem of the pure and entire synthesis of the different aromatic products outside the chemical difficulties is governed by the cost of the synthetic product in relation to the same product obtained by extraction from the natural essential oil or by a modification of the natural product.
Take the example of linalyl acetate obtained from bois de rose linalobl and entirely synthetic linalyl acetate. It has to be admitted that for the perfumer of the two linalyl acetates that having bois de rose as its origin is far superior while the other tends to suggest terpinyl acetate.
It has often been an advantage in a complicated structural formula having part of its chain existing in nature to take this part and construct the rest from it. However as the organic chemicals industry is developing more and more day by day the possibilities of integral synthesis are becoming ever more numerous.
This will not prevent the use in high class perfumery of isolates etc. obtained from natural products. Sometimes even exceptional products are found e.g. a special bergamot linalyl acetate derived from bergamot oil and having a distinct but subtle odour variation all of its own.
However there is a whole class of products derived for different reasons from essential oils and these are the deterpenated essential oils. Over forty years ago a perfumery chemist who caused a great stir at the time conducted considerable publicity for deterpenated essential oils in the sole French perfumery journal that existed in those days. According to him all the essential oils should be done away with and replaced by the corresponding terpene free essential oils. The latter are more soluble in alcohol than those which are not deterpenated and it is therefore possible to concentrate more in a weakly alcoholic solution. But that is not the only criterion. The terpenes present in normal essential oils play a part when incorporated in an alcoholic perfume that is far from negligible and appears to exalt the perfume as a whole. This is due in part at least to the fact that in the scale of volatilities terpenes are an important link between the alcohol itself and the low boiling esters etc.
The example has very often been cited of a perfume made with natural essential oils and the same perfume made with deterpenated essential oils. Taking into account differences in strength that made with natural non deterpenated essential oils is often greatly superior. Moreover what can a terpeneless oil of lemon mean to a perfumer when the natural essential oil contains 90 per. cent terpenes? On the other hand some well produced terpeneless oils undoubtedly deserve a place on the perfumer s shelves.
It has been frequently stated that perfumes made with terpeneless products deteriorate less rapidly but perfumers are not in entire agreement on this point.
Deterpenation is carried out by fractional distillation at reduced pressure. It is also effected by appropriate solvents and other more recent methods.
Natural Odorants as Tinctures
Some natural products are frequently employed in the form of tinctures based on their more or less prolonged maceration in 95° alcohol which is initially used hot or cold. Commonly found in this category is animal musk ambergris civet and castoreum but other materials may also be treated in this way e.g. patchouli leaves vetiver root oakmoss. The corresponding essential oils and/or absolutes are in most cases also available. Infusions are similarly prepared by means of such treatments as processing in 95° alcohol in a heated closed container fitted with reflux cooling equipment.
Flavoring Vegetable Protein Meat Analogs
Meat Analogs can be defined as products nutritionally equivalent to their biological counterparts however they do not contain meat proiein or meat by products. They are developed to have the appearance texture and flavor of their meat counterparts. The proteins in meat analogs are derived from vegetable dairy and other non meat sources. On the other hand meat extenders are normally vegetable proteins added to processed meats to supply nutritional and functional properties.
Worthington Foods was the modern day pioneer in the fabrication of meat analogs with the introduction in June 1962 of SOYA MEATR a canned chicken analog. These meat analogs were based on the Robert Boyer patent which employed the use of spun soy fiber from soy isolate to impart a meaty texture.
Consumers are motivated to purchase fabricated foods for many reasons but the principal factors are nutrition health convenience economy and variety. The finished meat analog must meet the consumer s expectations in taste aroma texture and appearance.
In the early 1970 s government and industry sources indicated highly optimistic projections for sales of meat analogs. This optimistic forecast was based on significant improvement by 1985 in the flavor texture and overall nutritional composition of these products. However sales of this magnitude never materialized.
There are many factors which influence the sales forecast for meat analogs. The poor flavor and texture of soy protein based analogs along with the inherent flatulence factor were major drawbacks in early fabricated food products. Significant improvements in the texture appearance nutrition and flavor have occurred over the last ten years and further improvements are being made. However improved meat flavor for meat analogs would definitely increase consumer acceptance. Consumers expect meat analogs to taste like their meat counterparts. When this criteria is met sales of meat analogs will become a significant factor in the food processing industry.
The flavoring of meat analogs include the following topics: A) development of characteristic meat flavors B) properties of meat analogs as compared to meat and C) the application of meat flavors in meat analogs concerning ingredients and processing. Flavoring meat analogs involves two related major problems namely developing characteristic meat flavors and the application of these flavors in the analogs.
DEVELOPMENT OF CHARACTERISTIC MEAT FLAVORS
The flavor of meat is attributed to a complex mixture of compounds produced by heating a heterogeneous system containing non odorous precursors which can develop volatile compounds non volatile compounds with taste properties potentiators and synergists. An approach to the development of meat flavors involves the tollowing investigations.
The isolation and identification of volatile flavor compounds found in processed meat.
The identification of flavor precursors in meat and their role in flavor development.
The role of biological processes in the development of meat flavor.
The study of model systems that produce desirable meat type flavours.
Combinations of above.
These are very complex investigations due to physical and chemical properties size and chemistry of the compounds. New analytical techniques have been developed to pursue these investigations. In the last 20 years there has been a tremendous advance in the understanding of meat flavor technology. To date the majority of investigations by government universities and industry have been concerned with the basic understanding of the flavor of beef pork and poultry.
Dwivedi summarized the volatile compounds identified in Beef and Pork. In beef he lists 6 acids 31 aldehydes 3 esters 1 ether 2 pyroles 25 alcohols 23 ketones 19 hydrocarbons 12 benzene compounds 11 lactones 8 furans 53 sulfur compounds and 37 nitrogen compounds. The compounds listed from pork are similar in number and type. Chang characterized lactones furanoids sulfur compounds and pyrazines as compounds which may be important contributors to meat flavor.
One would think there would be more characteristic meat flavors available from this type of investigation. However as compared to fruit dairy and nut type flavors meat flavor has not been found to contain a single predominant characterizing volatile compound. In addition since the flavor of meat is the result of thermal processing the typical flavor varies depending upon the degree and length of heating. This also adds to the complexity of flavor characterization. Just the number of volatile compounds identified poses a development problem.
Mabrouk lists the aqueous meat flavor precursors which encompass fifteen classes of organic compounds.
His work indicates that the overall impression of cooked meat is the result of these organic precursors. Of the twenty three amino compounds identified and quantified in beef extract he concluded that Methionine and Cysteic Acid are the most important amino acids contributing to meat flavor. It is generally agreed that the development of volatiles responsible for typical meaty flavor is the result of non enzymatic browning reactions. These volatile flavors are produced mainly from reactions of reducing sugars with amines amino acids peptides and proteins.
It is uncertain what significant effect lipids have on the development of meat aroma however it appears to be important in identifying overall characteristic meat flavor. Flavor components are formed as a result of thermal oxidation of lipid constituents.
Many of the meat flavor precursors found in meat are the result of biochemical reactions catalyzed by enzymes. Dwivedi reviewed anti and post mortem enzymatic factors relating to the development of meat flavor precursors. Post mortem tissue proteins degrade to release amino acids by the action of microbial proteases. In addition other precursors such as peptides nucleotides and carbohydrates also result from biochemical reactions. These precursors are important taste compounds. and also develop volatile compounds upon heat processing.
Cultures and lipolytic enzymes have been used for decades for developing the characteristic flavor of sausage. Free fatty acids liberated from sausage lipids by lipase provide the substrate for the development of carbonyl compounds. These free fatty acids and carbonyl compounds are important in characterizing dry sausage.
Studies of model systems containing precursors identified in meat and systems containing compounds that may produce desirable meaty aromas and flavor have been investigated. Shibamoto et al studied the reaction of D Glucose Hydrogen Sulfide and Amnonia. Fifty one compounds were identified the main constituents being thiophenes furans pyrazines and thiazoles. Twenty four of these compounds were also identified in heated beef. By varying the levels and ratios of reactants the reaction products will vary in concentration and composition. This example demonstrates the utility of this approach in developing meat flavors.
Many patents have been issued covering the use of certain chemicals in meat flavor formulations. In addition patents covering flavor formulations utilizing maillard and other reactions producing meaty compounds have been issued over the last 15 years.
Even though meat has been intensely investigated using modern technology characteristic meat flavors have not been developed to satisfaction for meat analogs. One of the reasons may be that the majority of the investigations concern beef pork and poultry whereas meat analogs utilize other types of meat flavors as found in Table 2. Many of these meats are combi nations of various cuts and types of meats fats and spices. In addition many home made recipes add to the complication of characterizing these processed meats. One of the major flavor differences between meat and meat analogs is the development of characteristic meat aroma upon consumer processing. This is caused by the level and type of flavor added and the inherent chemical properties of meat analogs.
To date the development of characteristic meat flavor includes the combined use of volatile compounds maillard and other selected reactions precursors and enhancers and biological processes. Meat flavors for analogs must not only supply the characterizing flavor of the meat they must also mask the flavor of the analog ingredients. Analogs that contain spicy flavors such as sausage and hamburger are somewhat easy to flavor as compared to analogs that contain delicate flavors like ham.
Flavor Aspects of Chocolate
The delicate flavor of a chocolate bar is due to the summation of skillful techniques. Fundamental knowledge has been gained until now on several unit operations which play an important role in flavor development and in the final texture of the chocolate bars.
Flavor precursors .are developed in the cocoa beans during the fermentation and the drying steps. Several analytical indices allow to follow changes in composition induced by these operations: several ratios such as catechins/soluble tannins glucose+fructose/sucrose and soluble nitrogen/total nitrogen were shown to present useful indices. Varietal differences and changes in protein during pod ripening and fermentation were characterized by detailed amino acid analysis. Histological changes during cocoa fermentation show a transformation of phases so that at the end of the operation hydrophilic cytoplasmic constituents are included in a continuous lipidic phase. Classes of flavor precursors developed during this process were shown to include carbohydrates flavonoids catechins phenolic acids and amino acids.
The flavor of cocoa is developed during a roasting step where beans are submitted to a mild heat treatment. Main reactions during the roasting step involve Maillard reactions Amadori rearrangements and Strecker degradations. Pyrazines are particularly generated during the thermal process and their content was shown to vary according to the importance of the roasting temperature. Roasting of thin layers of cocoa mass allow to characterize more precisely the importance of time/temperature treatment in developing optimal cocoa flavor. Free amino acids undergo also a Strecker degradation leading to carbonylic compounds which themselves may react to give aldol condensation products. The presence of 5 Methyl 2 phenyl hexenal an important flavor contributor can be such wise explained. Some volatile sulphur derivatives may be attributed to the thermal decomposition of methyl S methioninesulphonium salt present in raw cocoa. Important taste contributors to the bitterness of cocoa are also developed by thermal cyclisation of peptides which play a synergic role with theobromine.
Various chromatographic techniques were used for characterizing the complex volatile mixture which contains important flavor contributors to cocoa aroma in a recent review we mention the use of differential gas chromatographic techniques which allow to select constituents involved in specific flavors of cocoa beans from various origins. More elaborate mathematical methodology allows to select important flavor contributors by taking into consideration sensorial evaluation data. For routine quality control simpler methods can be used one of them relies on measuring the ultraviolet absorption of steam distillates and allows to characterize the degree of desodorization of cocoa butters the quality of milk chocolate samples and of various ingredients.
Roasted cocoa nibs are then milled the resulting cocoa liquor can be characterized by using the same quality indices as those used for roasted cocoa beans. The cocoa liquor crystal sugar and milk solids are then mixed and refined together various technological processes are used for this operation. Continuous lines are now in use so that mixing comminuting and flavor development are optimized. Future perspective in chocolate technology also involves multistage comminution of chocolate mass.
To obtain a smooth flavor of chocolate bar a last refining step called conching is applied during which some volatile constituents are lost and various aggregates are dispersed so that the viscosity of chocolate mass is reduced the optimal conching time can be determined by the time at which lowest yield value is obtained. During the first 24 hours of conching strong changes in physical and sensory properties are observed but the particle size distribution of solid particles is determined by the anterior milling and refining operations. This particle size distribution plays a considerable role in assessing chocolate bar acceptance to the consumer. Granulometric analytical methods reviewed and correlation experiments showed the importance of particle size distribution in deter mining preferences of a taste panel.
The conched chocolate mass is then submitted to a temper ing operation during which a suitable crystalline form of polymorphic cocoa butter is favoured. This operation can be analytically followed by applying a differential micro calorimetric method. This precrystallization step will ensure a correct hardness to moulded chocolate bars.
All these physico chemical methods are however not sufficient for determining the overall quality of chocolate bars which can be only assessed by sensory evaluation. Trained taste panel judgements may be expressed under the form of flavor profiles. These judgements can then be submitted to multidimensional classification using for instance the principal component analysis. Other statistical methods can also be applied. These mathematical methodologies allow to characterize the censorial quality of chocolate bars.
The Aroma of Various Teas
Tea is one of the most popular beverages and there are many types and grades of teas available in the market of the world.
The starting material for tea manufacture is the tender rapidly growing shoot tips of tea plant (tea flush) or tender young leaves.
Various teas are broadly classified by the manufacturing process i.e. fermented tea (black tea) partially fermented tea (oolong tea and pouchong tea) and non fermented tea (green tea).
The high acceptability of tea may be due to many factors but one of the most contributory factors seems to be its aroma.
Tea aroma is determined by the quality of tea flush as well as the conditions of manufacturing process. The quality of tea flush is largely influenced by the season the geographical location and the variety of tea plant Camellia sinensis.
An amazing complexity of tea aroma components has been shown. They analyzed an aroma concentrate from black tea by capillary column gas chromatography and found that black tea aroma contains about three hundred different compounds.
In order to find out the most important constituents which are responsible for the tea aroma characteristics a number of research has been carried on and the investigations are gradually focused on a miner component. Thus the total number of compounds identified related with tea aroma arised to almost 300 up to date as shown in Table 1. Here it may be said that the compound which first reported year is later the amount supposed to be smaller.
Although such a numerous compounds have been identified from tea aroma real contributory components which determine the aroma character of various teas seemed to be not so large number.
This paper deals with the aroma characteristics of several distinctive teas such as Sri Lankan (Ceylon) flavory black tea Keemun black tea pouchong tea lotus tea and Japanese green tea (Sen Cha) and roasted green tea.table 1. Aroma constituents of Tea.
Manufacturing process of black tea: withering à rolling à fermentation à drying.
Withering is the preliminary step to rolling resulting in a desired loss of water a flaccid condition of the leaves which they can stand rolling without breaking. The wither is judged by loss weight (35 40%) softness and an agreeable fruity aroma developed during withering.
The object of the rolling is to impart the characteristic twist break the leaf cells and expose the juice to the air starting the oxidation of the cell sap. Generally the withered leaves are rolled twice the first rolling requires about 50 minutes after that the leaves are sifted and the finer leaves are brought into fermenting room while the coarser rolled again continuing for 40 minutes with increasing pressure.After the second rolling the leaves are separated by screen and brought in fermentation process.
The leaves brought into the fermenting room are spread evenly in shallow trays in 5 cm deep and the room temperature should be kept around 25°C and the relative humidity over 95%. During fermentation oxidation of the components in tea leaves bring about chemical changes which largely determine the flavor strength body and color of its infusion.
Drying process has two purposes the one is stopping the fermentation and the other is the reduction of water content to 4 5% at which level the tea can be stored safely.
Green Tea (Sen Cha)
Manufacturing process of Sen cha: steaming à primary heating and rolling à rolling à secondary drying à final rolling à final drying.
The first step of the Sen Cha manufacturing is steaming by which the oxidizing enzyme in the leaf is inactivated and the green color of leaf can be maintained. In the primary heating tea roller tea leaves are agitated and dehydrated by hot air introduced by fan from a furnance and taking out when the loss of weight reached 48%. Then the leaves are rolled under pressure for 10 minutes without heating and after taken out the lumps should be broken. The object of this rolling is to break the leaf cells and enable to dissolve the content of the leaves easily when brewed.
By secondary drying in the tea roller (a trough placed over a heater) the leaves are reduced 68% of their weight for about 20 minutes.
Final rolling is performed in the final tea roller here the tea leaves are twisted under pressure and dried with the help of the heater beneath the trough. After about 35 minutes the tea leaves is taken out from the final tea roller the tea leaves are dried again with hot air at about 65°C for reducing the moisture to 3 4%.
The highest quality of pouchong tea is made only from the variety Chin shin oolong. The tea flush is subjected first to withering by sun light for 5 20 minutes then withering indoors for 2 4 hours before the usual process of manufacturing of pan fired green tea (Chinese green tea). The first step of pan fired green tea manufacture is parching in a pan at higher temperature about 230°C for 8 10 minutes. Then continue heating in the pan such a way that 150°C 10 min. 110°C 15 min. 100°C 30 min. 80°C 60 min. with repeating turn over the leaves. By this process the tea has a curly form.
AROMA COMPOSITION OF VARIOUS TEAS
Flavory Ceylon Black Tea
In Sri Lanka (Ceylon) there are two well defined seasons during which Ceylon tea flavor is outstanding. These are Jan. / Feb. in the Dimbula District and July/Aug. /Sept. in the Uva District.
Composition of the Top Note Aroma. Generally tea is evaluated its quality first by topnote of aroma which arises from tea infusion.
Fresh unblended black tea produced during the flavory season in Uva District was used for our investigation.
Aroma concentrate which had a typical topnote or first perceptible characteristic note of aroma from the tea infusion was prepared from the tea by relatively short time steam distillation (15 min.) followed by isopentane extraction.
The aroma constituents were identified by combined gas chromatography mass spectrometry (GC MS) and IR.
A total of 57 compounds wore identified and approximate composition of the topnote aroma was determined as shown in Table 2.
Besides the constituents listed in Table 2 twelve miner components were recognized but not identified.
Although there are still unidentified important components which will contribute to topnote aroma of flavory Ceylon tea composite mixture of identified components prepared based on the quantitative data in Table 2 seemed to improve the flavor of commercial instant black tea to some extent.
Wine is the result of the transformation of a natural product the grape by alcoholic fermentation. It is quite remarkable to note that with this one term we group a variety of products whose organoleptic characteristics or flavor are extremely different for instance there is little resemblance between a Champagne and a fine Bordeaux red wine or between a Sherry a Port wine and a Moselle wine.
Another characteristic of vinicultural production unlike that of any other food or drink is the vast hierarchy of quality and price that exists differentiating the various types of production on one hand and wines of the same type on the other.
This diversity of course expresses differences in chemical composition responsible for the differences in odor and taste but they are not always easily distinguished by classical analyses. PEYNAUD points out the example of two wines having pratically the same basic analysis (alcohol acidity extract...) although the price of one (Medoc grand cru classé) was twenty times higher than the other (ordinary table wine) an even larger scale of prices can exist.
In order to interpret the differences in odor and in taste which justifies such a large price range it is necessary to explain the composition of wine and the causes of its modification in more detail. Numerous natural factors are involved in the constitution of wine: a) particular properties of the variety b) the state of maturity c) eventual intervention of parasites which develop on the grape particularly Botrytis cinerea the fungus which causes rot d) conditions of the alcoholic fermentation by yeast e) in certain cases the intervention of malic acid fermentation by lactic acid bacteria f) and interventions always to be feared of chemical or bacteriological spoilage.
Thus we understand the complexity of the chemical composition of wine a product which has probably given rise to a greater amount of research and analytical study than any other food or drink. Although our knowledge is still very fragmentary we will try to indicate the current ideas concerning the taste and aroma of wine.
THE TASTE OF WINE
The equilibrium of tastes
The four basic tastes are found in wine a) the acid taste comes from the numerous organic acids whose free functions correspond to 100 meq/1 (N/10) b) the sweet taste which is found even in wines which contain no sugar is due to the alcohol and glycerol (8 to 10 g/l) c) the salty taste is due to 2 to 4 g/l of mineral salts d) the bitter taste comes primarily from the phenolic compounds and tannins (2 to 4 g/l in red wine).
The quality of wine depends on the harmony of these different tastes one should not dominate the others. In particular the acid and bitter tastes should be balanced by the sweet taste the only one which is pleasant by itself. In wines which contain no sugar the alcohol plays an important role a solution of 30 g/l of ethanol has a sweet taste much like a solution of 20 g/l of saccharose a slightly alcoholic solution of saccharose is sweeter than a similar solution in water.
With red wine a demonstration can be given by separating the alcohol through vacuum distillation or by steam distillation the distillate has a mellow taste truly sweet which couples with the vinosity of the alcohol the stongly acidic and bitter residue is entirely undrinkable.
This equilibrium helps explain why red wine rich in tannins and thus in bitterness cannot tolerate as high a level of acidity as can white wine whose level of tannins is low.
Wine also has a relatively high level of acidity with a pH between 2.8 and 3.8 it is the most acidic of all fermented drinks this acidity is linked to a relatively strong acid found in the grape tartaric acid. Such acidity is tolerable only because it is counterbalanced by the sweet taste of the alcohol since wine is also the most alcoholic of all fermented drinks reciprocally the alcohol is tolerable because of wine s high acidity. Moreover wine owes its microbiological stability to its acidity and alcohol content which permit certain conservation without the use of highly specific techniques.
The Suppleness Index
It follows from the preceeding ideas that wines especially red wines must be supple that is they should not have an excessively bitter or acid taste. It was thus found necessary to define a suppleness index which is explained with examples in table 1 an increase in the value of the index corresponds to an increase in the sensations of volume softness and fullness of body characteristics highly desirable in red wines.
This suppleness index constitutes a relatively unique attempt to translate organoleptic qualities by a relation which combines several elements of the chemical composition. The index could be improved upon as it remains relatively imprecise yet little work is being done in this field. Of course it is not true that an increase of alcohol or a decrease of acidity would improve quality in every case these variations rapidly become excessive and the suppleness index is valid only within a certain compositional range. In addition the units employed are certainly not the best possible an increase in acidity of 1 g/1 probably has more effect on the decrease of sup pleness than a decrease in alcohol of 1° GL. Also the total quantity of acid is not the only factor involved in wine flavor the pH is involved as well as the nature of acids for instance succinic acid has a characteristic vinous taste.
The hardness of red wines which is the opposite of suppleness depends upon additional compositional elements particularly the level of acetic acid andethyl acetate. When present in excessive quantities these compounds are an indication of bacterial development and give wines particular organoleptic characteristics which reduce their quality. Even below the organoleptic perception threshold (on the order of 1 g/1 for acetic acid and 150 mg/1 for ethyl acetate) these compounds especially the latter intervene in sensory evaluation particualrly on the aftertaste they reinforce the impressions of hardness and burning the suppleness index should take these compounds into account as well.
Influence of phenolic compound structure (tannins)
Table 1. The Suppleness Index and Examples of its Application
Another important element in the suppleness of red wines as well as in their general composition is the presence of phenolic compounds or more specifically tannins these compounds are involved in the taste not only by their quantity but also by their nature which is not taken into account by the suppleness index.
Tannins are formed by the condensation of 2 to 10 elementary flavan molecules (catechins). The polymerization level affects the tannins capacity to combine with the proteins this capacity governs all of their properties in particular astringency results from a loss of the saliva s lubricating effect by denatuation of its proteins. Thus as an example a tannin composed of 2 flavan dimers will not have the same properties organoleptic in particular as a tannin composed of 1 tetramer even though the total weight remains the same.
The polymerization of flavans can set off several mechanisms which lead to tannins with different properties. Other molecules as well (anthocyanins mineral salts polysaccharides) can intervene in the structure of these tannins table 2 gives a recent classification developed by GLORIES. Each class of phenolic compounds has its own organoleptic properties thus explaining the enologist s evaluation which differentiates the good tannins which give both body and a certain mellowness to the wine and the bad tannins which give wine an agressive astringency. A precise chemical interpretation of these sensory differences remains to be done they are related to the different tannin structures which cannot be distinguished by traditional analytical methods. High quality vine varieties cultivated in reputed vineyards are distinctive precisely because they produce grapes rich in good tannins this characteristic dominates the tasting of fine red wines the variations between vintage years as well concern a modification of tannins linked to the climatic conditions during ripening.
SULFUR CONTAINING COMPOUNDS
U.S. Patents 4 080 367 March 21 1978 and 4 134 901 January 16 1979 both assigned to Lever Brothers Company describe food flavoring substances which can impart to food a savory flavor of roast or fried meat. These compounds have the following formulas in which Y is either a sulfur or oxygen atom and R1 and R2 are hydrogen or an alkyl or hydroxy alkyl group having 1 to 9 carbon atoms.
Examples of compounds of this class are: 4 mercapto 5 methyl 2 3 dihydrothio phene 3 one and 4 mercapto 5 ethyl 2 3 dihydrofuran 3 one.
Examples of compounds of this class are: 3 mercapto 5 methyl 4 5 dihydrofuran and 3 mercapto 2 5 dimethyl 4 5 dihydrothiophene.
Examples of compounds of this class are: 4 mercapto 5 methyl tetrahydrothio phene 3 one and 4 mercapto 2 5 dimethyl tetrahydrofuran 3 one.
Examples of compounds of this class are: 3 mercapto 2 methyl tetrahydrothiophene (cis and trans) and 3 mercapto 5 ethyl tetrahydrofuran (cis and trans).
Examples of compounds of this class are: 3 mercapto 2 methyl 2 3 dihydrothiophene and 3 mercapto 2 5 dimethyl 2 3 dihydrofuran.
The flavoring characteristics of compounds satisfying the above five general formulae and their tautomers were found to he particularly interesting in the case where R1 and R2 represent a hydrogen atom a methyl group or a hydroxymethyl group.
Compounds like structure (1) except that the 4 position has a hydroxyl rather than a mercapto group which may be used as starting furanone compounds to be reacted with hydrogen sulfide are for example 4 hydroxy 5 methyl 2 3 dihydrofuran 3 one 4 hydroxy 2 5 dimethyl 2 3 dihydrofuran 3 one and 4 hydroxy 2 methyl 5 ethyl 2 3 dihydrofuran 3 one. Preferred examples of the pyrones which may be reacted with hydrogen sulfide are: 3 hydroxy 2 methyl 4 pyrone (maltol) and 3 hydroxy 2 ethyl 4 pyrone.
As an illustration of suitable quantities of the flavoring substances that may be added to specified types of foodstuff as little as 1 to 10 ppm w/w is sufficient to impart a pleasant roast meat flavor to soups which are bland or otherwise lightly flavored. On the other hand when incorporating a similar roast meat flavor to already flavored foodstuffs such as those based on vegetable protein it may be necessary to incorporate larger amounts for example from 600 to 8 000 ppm w/w of the flavoring substance in order to obtain a desirable flavor.
Example 1: Preparation of 4 Hydroxy 5 Methyl 2 3 Dihydrothiophene 3 one 140 g of commercially available 1 butyn 3 ol (BP 107°C at atmospheric pressure) were treated in an aqueous solution with 200 g of a 30% formaldehyde solution in the presence of 10 g CuCI and refluxed for 50 hr. The resulting 156 g (70%) of 2 pentyn 1 4 diol (BP 115°C at 2.5 mm Hg) were isolated by evaporating off the water and distilling the residue.
50 g (0.5 mol) of 2 pentyn 1 4 diol were dissolved in 250 ml of dry pyridine. The solution was stirred and cooled to 10°C in an ice salt mixture. With stirring a cold solution of 286 g (1.5 mols) of p toluene sulfonyl chloride in 550 ml of dry dichloro methane was added dropwise under exclusion of atmospheric moisture from the dropping funnel in such a manner that the temperature did not exceed 5°C. After completion of the addition (about 1.5 hr) stirring at 0ºC was continued for 5 hr and water (30 ml) was added in portions at intervals of 5 min with stirring and cooling so that the temperature did not rise above 5°C.
10 g of the yellow oil thus obtained (pentane 2 3 dione 1 4 dithioacetate) were dissolved in 1 500 ml of 0.5 N aqueous hydrochloric acid and stirred for 1.5 hr at 95°C. After cooling the reaction mixture was extracted five times with chloroform the combined extracts were washed with water dried with anhydrous sodium sulfate and evaporated to dryness affording a syrup which crystallized on standing. After recrystallization from dichloromethane white crystals of 4 hydroxy 5 methyl 2 3 dihydro thiophene 3 one were obtained MP 152° to 153°C yield = 40%.
Example 2: A_beef flavored composition was prepared by adding 250 ml of water to a mixture of 5.7 g of 4 hydroxy 5 methyl 2 3 dihydrofuran 3 one and 25.0 g of cysteine and heating the mixture at about 100°C for 2½ hr. The resuiting mixture was cooled and quantities of between 0.2 and 2.0 ml of the reaction mixture were sprayed over 100 g portions of dehydrated textured vegetable protein containing no meat. An excellent roast meat flavor was thereby imparted to this material as assessed by eleven out of a total panel of twelve expert tasters.
Dextrin maltose was added to a portion of the flavored mixture which resulted from the reaction described above in an amount which provided a composition containing about 70 pbw of dextrin maltose to each part of the substance calculated on a solid basis. The composition was freeze dried and a beef flavored product was obtained.
Example 3: A mixture of 1.5 g of 4 hydroxy 5 methyl 2 3 dihydrofuran 3 one and 1.5 g of cysteine in 30 ml of water was heated at about 100°C for 2½ hr. To the resulting solution was added 33 g of maltodextrin. The solution thus obtained was carefully freeze dried. The powder obtained was used as a good beef flavor in soup or gravy.
Example 4: 6.3 g of 3 hydroxy 2 methyl 4 pyrone 10.5 g of sodium sulfide (Na2S.9H2O) and 100 ml of water were heated together in a round bottomed flask at 100°C for 2½ hr.
To the reaction mixture was added 117 g of maltodextrin. The resulting solution was spray dried immediately. The powder thus obtained proved to have a good beef flavor.
Example 5: A mixture of 5 g 4 hydroxy 5 methyl 2 3 dihydrothiophene 3 one (cf Example 1) 0.5 g of hydrogen sulfide and 50 ml of water were heated in an autoclave for 4 hr at 100°C and was subsequently allowed to cool. A product with a roasted meat flavor was obtained which was diluted to a volume of 1 liter forming a liquid meat flavor.
One liter of water was added to the mixture and the whole was boiled for 5 min. The soup so obtained was divided in two portions of 500 ml. In the first portion 150 mg of maltodextrin was dissolved and in the second portion 150 mg of the flavor powder prepared according to Example 3.
Both soups were assessed in a paired comparison test by a panel consisting of 8 persons. The soup containing the flavor powder had a characteristic beef flavor and was preferred by 7 out of the 8 testers.
Furyl Alkyl Disulfides
Reproduction of sweet meat roasted meat liver flavors and aromas and hydrolyzed vegetable protein like flavors and aromas has been the subject of the long and continuing search by those engaged in the production of foodstuffs e.g. luncheon meats such as liverwurst sausages. The severe shortage of foods especially protein foods in many parts of the world has given rise to the need for utilizing nonmeat sources of proteins and making such proteins as palatable and as meat like as possible. Hence materials which will closely simulate or exactly reproduce the flavor and aroma of roasted meat products (e.g. roast beef like) and liver products are required.
Moreover there are a great many meat containing or meat based foods presently distributed in a preserved form. Examples include condensed soups dry soup mixes dry meat freeze dried or lyophilized meats packaged gravies and the like. While these products contain meat or meat extracts the fragrance taste and other organoleptic factors are very often impaired by the processing operation and it is desirable to supplement or enhance the flavors of these preserved foods with versatile materials which have sweet meat roasted meat and/or liver taste and aroma nuances.
U.S. Patent 4.098 310 July 4 1978 assigned to International Flavors & Fragrances Inc. have provided certain 3 furyl alkyl disulfides for altering the organoleptic properties of foodstuffs. These compounds have the formula:
Fragrances-Floral and Fruity
U.S. Patent 4 066 710 January 3 1978 assigned to Givaudan Corporation describes octadiene olfactory derivatives having the general formula.
In the foregoing reaction scheme 2 7 dimethyl 1 3 7 octatriene of formula II is converted into the sulfone of formula III using an excess of sulfur dioxide in the presence of about 1% of a polymerization inhibitor for example hydroquinone 3 tert butyl 4 methoxyphenol 2 6 di (tert butyl) 4 methylphenol (BHT) etc. After removal of the excess sulfur dioxide this sulfone of formula III is hydrated at the terminal double bond for example by the action of 40 to 60% aqueous sulfuric acid expediently at temperatures of 10° to 25°C. The resulting product of formula IV is neutralized (e.g. with sodium hydroxide) and separated with a solvent (e.g. benzene).
The removal of the SO2 protecting group and concommi tantly the reintroduction of the conjugated double bond can be carried out by heating the compound of formula IV expediently in a vacuum and at temperatures 120° to 130°C.
It has proved advantageous to carry out the heating of the compound of formula IV in the presence of 1 to 2% of a high boiling organic base for example tri ethanolamine or a tertiary amine such as a trialkylamine (e.g. trimethylamine). Inorganic compounds which have a weak basic reaction (e.g. calcium carbonate) can also be used.
The esterification of the resulting alcohol (2 7 dimethyl 5 7 octadien 2 ol) can be carried out according to known methods expediently by reacting the alcohol with a compound yielding the desired C1 5 alkanoyl group especially using an appropriate acid anhydride such as acetic anhydride in the presence of a base (e.g. pyridine sodium acetate etc). A corresponding acid halide can however also be used for this esterification.
The octadiene derivatives of formula I possess particular odorant properties. They can accordingly be used in the perfume industry for the manufacture of perfumes and perfume products for example for the perfuming of soaps solid and liquid detergents aerosols and cosmetic products of all kinds such as toilet waters ointments face milks make ups lipsticks bath salts and bath oils. In the finished perfumes or perfumed products the content of the octadiene derivatives can lie within wide limits for example between 1% (detergents) and 20% (alcoholic solutions). In perfume bases or concentrates the octadiene derivatives can of course also be present in amounts greater than 20%.
These octadiene derivatives provide in general a flowery especially lavender like odor without a fatty note. The free alcohol namely the octadiene derivative of formula I in which R represents a hydrogen atom possesses outstanding fragrance qualities the odor thereof being pleasantly flowery (reminiscent of lavender) linalool like piquant earthy slightly metallic and long lasting. The compositions which contain this alcohol have a powerful fresh action the alcohol being especially suitable for flowery woody or hesperidine notes.
The octadiene derivative of formula I in which R represents an acetyl group possesses a natural flowery fruity green slightly woody odor which is somewhat reminiscent of grapefruit and neroli and which is vetiverlike in the background. Compositions containing this octadiene derivative accordingly havo a very natural action.
The ethers of formula I especially the methyl ether are readily volatile compounds and they can accordingly be used in perfume compositions especially for head notes.
The octadiene derivatives of formula I can be advantageously incorporated into odorant compositions of the flowery type. Such compositions thereby acquire strength and cohesion and are thus modified in an advantageous manner.
The following examples illustrate typical odorant compositions containing the octadiene derivatives provided by this process.
U.S. Patent 4 077 916 March 7 1978 assigned to Fritzsche Dodge & Olcott Inc. have found that desirable perfume compositions can be made which contain from 0.1 to 1% by weight hexyloxy acetronitrile and at least 1% by weight of a perfume component which modifies the olfactory properties of the hexyloxyacetonitrile. The hexyloxyacetonitrile may be incorporated in the perfume composition in the form of a solution of dipropylene glycol. Desirably the compositions contain at least 0.1% by weight of hexyloxyacetaldehyde dimethyl acetal.
The hexyloxyacetonitrile utilized in these perfume composi tions is unique in its olfactory properties. This nitrile has a flowery herbaceous slightly fatty odor reminiscent of irone. One of its outstanding characteristics is its diffusing odor. Thus it is readily perceived and recognizable even from a distance. Its lasting power as determined from a smelling blotter is limited to 7 to 8 hours. Accordingly it can be used advantageously to give top notes to perfume compositions. It blends well with other perfume components to improve and give character to the total odor profile.
The hexyloxyacetonitrile may be used in a great variety of perfume compositions such as rose jasmine chypre lavender and phantasy bouquet. In such compositions it may be used in various concentrations to achieve a desired effect. Consequently hexylo xyacetonitrile is a valuable addition to the arsenal of aroma chemicals.
The hexyloxyacetonitrile may be produced by the method described in U.S. Patent 3 132 179 which employs the hexylo xyacetonitrile as a pharmaceutical intermediate.
U.S. Patent 3 132 179 describes a procedure for the production of hexyloxyace tonitrile involving a two step method chloro methylating n hexanol to chloro methyl n hexyl ether and reacting the ether with cuprous cyanide in accordance with the following reaction scheme:
Alternatively the hexyloxyacetonitrile may be produced by liberating hexyloxy acetaldehyde from one of its acetals such as its dimethylacetal reacting the hexyloxyacetaldehyde with hydroxy lamine to obtain hexyloxyacetaldehyde oxime and dehydrating hexyloxyacetaldehyde oxime for example with acetic anhydride to obtain the hexyloxyacetonitrile.
U.S. Patent 4 092 362 May 30 1978 describes a process for the production of 2 n pentyl 3 (2 oxopropyl) 1 cyclopentanone and also perfume formulations containing this substance.
2 n pentyl 3 (2 oxopropyl) 1 cyclopentanone is a valuable odoriferous substance possessing a particularly fragrant magnolialike aroma. The production of 2 n pentyl 3 (2 oxopropyl) 1 Cyclopentanone is accomplished by hydrolyzing and decarboxylating a compound of the formula
The hydrolysis and decarboxylation is conveniently carried out at a temperature of from 120° to 300°C preferably from 140° to 250°C under substantially neutral conditions.
The reaction is conveniently effected using the same weight of water as of 2 n pentyl 3 (2 oxopropyl) 1 Cyclopentanone. The reaction is normally effected in an autoclave from which the air is first purged.
The reaction conditions for this step are those of a conventional Michael condensation. The group R is conveniently an alkyl group and preferably a lower alkyl group having from 1 to 5 carbon atoms for example methyl or ethyl. 2 n pentyl 3 (2 oxopropyl) 1 cyclopentanone and its stereoisomers have a very strong odor of magnolia. Thus the compound can be used for the preparation of perfumes as well as for the preparation of perfumed products for example solid and liquid detergents synthetic washing agents aerosols or cosmetic products of all kinds. These odorant compositions may conveniently contain from 1 to 20% by weight preferably 5 to 10% by weight of 2 n pentyl 3 (2 oxopropyl) 1 cyclopentanone.
Substituted 1 Alkenynyl Cyclohexanols
U.S. Patent 4 088 681 May 9 1978 assigned to BASF Aktiengesellschaft Germany have obtained the 1 alkenynyl cyclohexanols of the general formula:
These compounds of Formula (1) have a fresh woody and tart coniferous odor and can be used as constituents of scent compositions or to improve the odor of industrial products. Furthermore they offer a new and economical method of obtaining the b damascones which are popular scents since they can be converted simply by heating in the presence of acids to the corresponding b damascones.
In the process for the manufacture of these substituted 1 alkenynyl cyclohexanols of Formula (1) cyclohexanones of the general Formula (2):
The cyclohexanones of Formula (2) required as starting materials for the process are conventional compounds which may be manufactured by alkylating cyclohexanones or hydrogenating cyclohexanones which in turn may be manufactured from aliphatic ketones and a b unsaturated carbonyl compounds.
Enynes of Formula (3) which are preferable for use in the process are vinylacetylene and methylbutenyne.
The enynes of Formula (3) need not be employed as such. Instead of using the enynes in the presence of a strongly basic condensing agent the active salts of the enyne may be used directly. This is very advisable for example when using the unsubstituted enyne of the Formula (3) since vinylacetylene itself is difficult to handle. In that case sodium vinylacetylide for example is used it can be obtained simply by the action of sodium on 1 4 dichloro 2 butene in liquid ammonia.
Example 1: A solution of CH3MgCI in tetrahydrofuran (THF) is prepared by passing methyl chloride into a suspension of 19 g of Mg filings in 500 ml of (THF). 50 g of methylbutenyne are added dropwise thereto in the course of 50 minutes at 0°C. The reaction mixture is then stirred until the evolution of gas has ceased. 105 g of 2 3 6 trimethylcyclohexanone are then added dropwise at room temperature and while cooling and the reaction mixture is left overnight while being stirred in order to complete the reaction.
120 ml of water are then added dropwise and the organic phase is decanted concentrated and subjected to fractional distillation. 93.5 g (61% of theory) of 2 3 6 trimethyl 1 (3 methyl but 1 yn 3 en 1 yl) cyclohexanol of boiling point 72°C/0.1 mm Hg are obtained. The spectroscopic data confirm the structure.
Fragrance note: fresh herbaceous.
Example 2: 28 g of 2 2 6 trimethyl cyclohexanone are added dropwise to a suspension of sodium vinylacetylide (prepared from 25 g of 1 4 dichlorobut 2 ene and 15 g of Na in liquid ammonia) in 200 ml of THF while cooling and the reaction mixture is stirred overnight at room temperature. 50 ml of water are then added the aqueous phase is extracted with ether and the resulting organic phase is dried and concentrated. Subsequent fractional distillation gives 5.5 g of unconverted trimethylcylohexanone and 20.7 g (corresponding to 68% of theory based on ketone converted) of 2 2 6 trimethyl 1 (but 1 yn 3 en 1 yl) cyclohexanol of boiling point 62° to 63°C/0.3 mm Hg and refractive index nD25 1.4982. Fragrance note: fresh tart woody coniferous.
U.S. Patent 4 119 575 October 10 1978 assigned to Monsanto Company have found that a specific class of compounds having characteristic aromas which are useful in the preparation of fragrances are represented by the structural formulas:
R represents hydrogen or alkyl having from 1 to 6 carbon atoms D and E each independently represent hydrogen or alkyl having from 1 to 6 carbon atoms provided that the sum of the carbon atoms in D and E does not exceed 6 provided that in the bicyclo compounds at least one of A B C D or E must be an alkyl m is an integer 1 through 8 F and G represent hydrogen or alkyl having from 1 to 3 carbon atoms X represents l (CH2)p J wherein p is an integer 0 through 2 and I and J each independently represent hydrogen or methyl provided that if p is 0 then m must be greater than 2 provided that the sum of the carbon and oxygen atoms in the compound is no greater than 23.
Example 1: 4 4 6 Trimethylbicyclo(4.2.0) Octane 2 ol - To a 2 liter 3 necked flask fitted with a mechanical stirrer addition funnel reflux condenser and drying tube was added 15 g (0.39 mol) of sodium borohydride and 500 ml 2 propanol. To this solution was slowly added 218.6 g (1.317 mols) of 4 4 6 trimethylbicyclo [4.2.0] octane 2 one in 50 ml of 2 propanol. After 2 hours about 200 ml of water was added. The mixture was stirred an additional 1 hour then about 35 ml concentrated hydrochloric acid was added. After another 1 hour of stirring 400 ml of toluene and 500 ml of water were added.
The layers were separated and the organic layer was washed three times with 100 ml of water. The combined water layers were extracted with toluene. The toluene layers were combined and dried over potassium carbonate. The solution was concentrated in vacuo and the residue distilled through a 25 cm Vigreux column to yield 215.8 g (1.284 mols 97.5% yield) of 4 4 6 trimethylbicyclo [4.2.0] octane 2 ol IR: 3360 cm 1. The aroma of the compound had camphor minty patchouly and woody notes.
Example 2: 5 5 7 Trimethyltricyclo [6.4.0.02 7] Dodecane 3 ol To 7.0g (0.19 mol) of sodium borohydride in 400 ml of isopropyl alcohol in a 1 liter round bottomed flask equipped with magnetic stirrer reflux condenser and drying tube is added 140 g (0.636 mol) of 5 5 7 trimethyltricyclo[6.4.0.02 7] dodecane 3 one in 100 ml of isopropyl alcohol. The mixture is stirred for about 15 hours and then 300 ml of a saturated aqueous sodium chloride solution containing 70 ml of concentrated hydrochloric acid is cautiously added. The entire mixture is transferred to a 1 liter separatory funnel and the layers are separated.
The aqueous layer is extracted three times with 100 ml of petroleum ether. The organic layers are combined extracted three times with 100 ml of water dried over magnesium sulfate and concentrated in vacuo to yield the product as a viscous oil. 127.5 g of 5 5 7 trimethyltricyclo [6.4.0.02 7] Idodecane 3 ol was recovered (0.572 mol 90% yield). IR: 3380 cm-1 BP 104º to 110°C/0.2 mm. This compound had a sandalwood aroma.
Perfumes and perfumed products are part and parcel of our everyday life. The demand worldwide for perfumes is enormous and constantly on the increase. At present over 300000 tonnes of aroma chemicals and perfume oils valued at over 5000 million US dollars are used for cosmetics washing and cleansing agents and other products. The perfume industry has become a major business.
While in earlier times perfumes were blended and their virtues extolled by priests alchemists apothecaries perfumers or even charlatans since the mid 19th century the production of perfumes has gradually become manufacturing in character and is now largely automatic and computer controlled.
PERFUME OIL FORMULA
Perfume oils are homogeneous clear mostly yellow tinted and often very complex mixtures of natural and synthetic fragrances. Currently about 20 30% of the demand for perfume oils in terms of quantity is covered by natural substances and 70 80% by synthetic products. In terms of numbers there are well over 3000 different mostly liquid and non crystalline fragrances. Perfume oils generally consist of 20 to 200 different components.
Compared with earlier times it is far more expensive to mix perfume oils because of this increased variety of substances and the vast number of complex perfume oil formulas from the many products to be perfumed.
In all perfume houses the perfume oil formulas are among the best kept secrets and represent the know how. They play a major role in the success of the companies. Therefore access to the formulas is strictly controlled and numerous safety provisions are incorporated. Earlier formulas were kept in safes but now in the age of computers formula safety is provided by card readers passwords user IDs and the like. The metering and mixing processes naturally represent a risk in the security system. However careful selection of mixing staff and suitable coding of the individual fragrances and formulas minimize the risk. The expanding use of computer control in compounding also increases formula safety.
MANUFACTURE OF PERFUME OILS
The manufacture of perfume oils means metering of the individual components in accordance with the formula followed by blending for homogenization.
In view of the wide variety of individual substances and perfume oil formulas the latter should be devised in such a way as to provide a logical sequence of products to be metered one after the other. The following method has proved successful:
Addition of products with low volatility in liquid form
Dissolution possibly under heat
Cooling as required
Addition of more volatile substances (aldehydes esters etc.)
Incorporation of crystalline substances and resins (in some cases it may be wise to add these substances at the beginning).
In the current state of the art there are basically two different types of metering volumetric and gravimetric metering.
Volumetric metering devices work on the principle of displacement. The metering flow or quantity is not measured out produced by reproducible drive parameters. There is usually a relatively simple relationship between metering flow and drive parameters.
Some of the many volumetric metering devices include oval wheel meters and metering pumps for liquids and screw type metering devices and star feeder devices for solids.
In gravimetric processes the metering flow weight is constantly measured and indicated.
Since density fluctuations have an effect in all metering methods with mass measurement gravimetric metering is the most accurate.
Volumetric appliances may fit the bill in a large number of cases especially when no special demands are made. However gravimetric methods have so far been preferred for metering perfume oil components.
In the production of perfume oils accurate metering of the individual mostly high quality components is the decisive criterion for quality and hence a guarantee of constant product composition.
Weight is therefore the essential factor for quality assurance and materials handling.
The individual components are weighed by hand. In the past mechanical scales (indicator scales) were used which did not permit data input and recording. In recent years however electronic scales have taken over. Depending on the procedure the weighing system is fixed or mobile.
The scales are installed and the individual components are brought from storage to the scales. Streamlining is provided in the form of rows of battery tanks for frequently used aroma chemicals with feed pipes to the weighing station (product to scales).
The scales are mobile and are moved to the individual storage containers which are also suitably arranged in battery tank rows (scales to product).
Automatic Metering on a Production Scale
The complexity leads automatically to thoughts of how the conventional metering process can be made easier.
A first step towards automation was to control the weighing system with punched cards. The aroma chemicals flowed from the storage containers to the central metering stations and metering was controlled in accordance with the given formula by punched cards on which the component data were printed in the form of punch holes. This process has now been superseded by the rapid development of microprocessor technology.
The electronic scales thus form the heart of the system and together with control mechanisms and computers provide the basis for a wide variety of tasks which go well beyond the simple recording of weight. The use of electronic weighing systems can be seen from two main viewpoints. On the one hand weight and the respective operating data are to be determined and further processed. On the other there is the weight dependent control of the metering processes.
As a basic parameter weight guarantees
Correct composition of the individual substances in terms of quantity
Control and monitoring of material consumption
Logical control of sequences.
Basic parameters for the design of an automatic metering station are the required throughput (size and number of batches) and the requisite weighing accuracy for the individual components. The time needed to make up a batch is known as the lead time which is determined by the number and duration of weighing operations and the need for weighing accuracy.
Electronic control is the brain of the installation. It controls and monitors the process sequence and organizes the logging.
Selection of automated equipment will depend by and large on data volume the requisite memory capacity and tae operating system.
While process control and interlock circuits in metering installations are mostly achieved with the aid of programmable logic controllers (PLC) process computers with and without external data memory ate used for formula management on screen dialogue and extensive recording.
Depending on the production standard there are quite different ideas on equipment set up and operating systems for weighing devices with integrated or dislocated metering controls.
The main function groups of metering control are:
Nominal/actual comparison for coarse/fine metering per component with tolerance control and metering time monitoring
Metering sequence control
Keys for functions data formulas
Data interfaces for peripheral equipment e.g. electronic data processing printer remote indicators
Not so long ago it was fashionable in some circles to decry flower perfumes. Why it was asked should a woman want to smell of flowers? The exclusion of flower perfumes from perfumery has been taking place over a long period... The flower perfume is dead one writer asserted. His subsequent observations however tended to modify this initial impression because he went on to praise some forgotten garden scents gave suggestions for their formulation and recommended their potential use as background odours in more sophisticated fantasy perfumes.
Despite any extravagant statements to the contrary flowers and their perfumes are still of very considerable and even basic importance to the perfumer. In the first place they are a stimulus a point of reference and a source of pleasure and invaluable information. In the second some of them are still irreplaceable raw materials despite any disadvantage that may attach to them in respect of scarcity or cost. And in the third place many flower notes or floral accords form part of the essential structure of even the most advanced and up to date fantasy perfumes. The fashionable woman may not wish to smell like a flower but neither is she improved by smelling like a crude mixture of synthetic chemicals or like a civet cat a musk deer or a dish of overripe peaches. The finished perfume is after all a balanced blend of rather widely different odorants and in it the floral note still plays a vital and even a dominant part.
We shall be giving in this chapter for each flower mentioned a list of constituents used in its reproduction including some that may be thought of as tricks of the trade although the main object will always be to approach the true note of each flower. Secondly we shall give one two or more complete formulae by way of illustration. Here it is necessary to point out that such formulae can only be considered as the sum of the actual materials used in preparing them in the first place and that subsequent reproduction must involve olfactory adjustments in order to give the desired result.
We shall start with the more familiar perfumes based on flower notes.
Rose notes vary considerably one from another. In addition to the basic components mentioned below under Red Rose. Damascene Rose and Centifolia Rose we find some important auxiliary notes in the naturally occurring esters as well as in a few aldehydes and acetals. Many other odorants also enter in relatively small amounts but with significant effect into the composition of specialised rose notes e.g. those of the tea rose Banksiana Zephyrine Drouhin and Marechal Niel types.
Red Rose. This is usually considered to be the truest and finest type of rose odour. Its main constituents are rhodinol phenylethyl alcohol alpha ionone (as used by Coty in his Rose Jacqueminot) and the very useful nerol. A more flowery effect is obtained by the addition of rose absolute and Bulgarian otto. Zdravetz or Bulgarian geranium oil can when obtainable impart a much appreciated green note.
Rose damascena. Among natural essential oils this is represented by Bulgarian rose. The basis of this odour is given by rhodinot phenylethyl alcohol geraniol ex palmarosa oil and cinnamic alcohol always in association with certain natural essential oils and esters.
Rose centifolia. The main constituents here are citronellol geraniol phenylethyl alcohol and rhodinol together with smaller amounts of adjuncts which give it a slightly sharp note such as C9 aldehyde citral etc.
Tea Rose. The basic components are citronellol phenylethyl alcohol and geraniol. The accessories that impart its special character include guaiyl acetate menthone and tuberose absolute.
Rose Marechal Niel. In nature this is a yellow rose with a very special perfume. Basically one uses geraniol ex palmarosa oil citronellol and synthetic geraniol in association with isoeugenol benzoin and sandalwood oil etc.
White Rose. Here the base is rhodinol phenylethyl alcohol benzyl alcohol and linalool (to give it the slightly acidulated note by which it is identified). The blend is rounded off with a little bergamot phenylethyl acetate etc.
In all matters relating to rose perfumes one has to take into consideration the part played by Bulgarian Rose. This note is often required but unfortunately the widespread use of Bulgarian oil of rose in its pure state is limited by considerations of cost. This necessitates research into compositions de coupage i.e. diluents or extenders and these must be the best possible for the purpose. By using certain raw materials judiciously one can in fact arrive at some very interesting extenders which will blend well with the natural oil giving an excellent quality of end product at a reasonable price. The raw materials in question are relatively few in number. One thinks of: phenylethyl alcohol oil of geranium such as the Geranium incolore de Grasse geraniol rhodinol 1 citronellol and very small quantities of nerol and farnesol.
A formula is given below. This is a convenient point to emphasise that no formula can be better than the type and quality of its individual constituents. It is therefore essential for perfumers to make their own trials and adjust their final formulae accordingly.
Some readers may be surprised to note the recurrence in certain of these formulae of branded specialities usually made by some of the leading supply houses. We make no apologies for these inclusions because they are in fact justified. Some are used because they contain new synthetic bodies that are not obtainable on the market in the pure state while others are the result of the highly skilled blending of standard ingredients that it would be extremely difficult and time consuming to copy.
In this way one has at hand three different rose formulae all of a tonality approaching that of the Bulgarian Rose but each at a different price level. Formulation over a reasonably wide price range is thus facilitated.
Where socialities are cited under the names of specific firms this simply means that no one firm makes and criers exactly the same end product as the others. In each case one must take into account the fact that chemicals included in a process as trace impurities are not likely to be present in exactly the same pattern or proportions in a competitive product.
Examples of special shades of odour even among standard chemicals are provided for example by Givaudan s Laurine which is a hydroxycitronellal with a note of its own often in great demand and Lorcna of Firmcnich which though a nerol is yet distinguishable from other nerols.
A footnote to rose compounding: modern perfumery now also makes use with restraint of rose oxide.
Rose and jasmin are still the most important flower notes used in perfumery. Singly or together they provide a conventional floral background for a great diversity of perfumes. Oil of jasmin has been the subject of much analytical research and on this basis it is possible to devise a wide range of formulae for jasmin artificial. Among the basic components one may note benzyl acetate amyl and hexyl cinnamic aldehydes benzyl alcohol formate salicylate and other esters indole and derivatives phenylethyl alcohol dimethyl benzyl carbinyl acetate hydroxycitronellal linalool linalyl acetate ester? of propionic and butyric acids Peru balsam etc. To sweeten formulae for artificial jasmins that may be somewhat crude and synthetic use can be made of jasmin absolute chassis which is the absolute obtained by petroleum ether or benzene extraction from jasmin flowers that have previously been treated by the enfleurage process but which have nevertheless retained some of their perfume. This must not be confused with the actual absolute of jasmin d enfleurage.
It is a principle in fine perfumery that natural materials should be used to sweeten and soften the odours of synthetic blends. When costing considerations prevent the more liberal use of naturals the result of judiciously incorporating even small quantities will usually prove conclusive.
This composition has a rather fresh note that facilitates its use in numerous combinations both with other jasmin components and in perfumes where a sharp and fresh jasmin note contributes to the overall odour.
The Production of Natural Perfumes
The perfume in the plant
Natural perfumes one of the most marvelous phenomena of plant metabolism probably reach their highest degree of excellence in the fragrance exhaled by fresh flowers. This fragrance is due to the minute traces of essential oil which exist in the petals sometimes in the free state as in rose and lavender and occasionally in the form of a glucoside which under favourable conditions is decomposed in the presence of an enzyme or ferment as in jasmin and tuberose. The existence of a volatile oil however is by no means confined to the inflorescence but frequently occurs in other parts of the vegetable organism.
For example it is found in the
Flowers of cassie carnation clove hyacinth heliotrope mimosa jasmin jonquille orange blossom rose reseda violet and ylang ylang.
Flowers and leaves of lavender rosemary peppermint and violet.
Leaves and stems of geranium patchouli petitgrain verbena and cinnamon.
Barks of canella cinnamon and cassia.
Woods of ceda linaloe and santal.
Roots of angelica sassafras vetivert.
Rhizomes of ginger orris and calamus.
Fruits of bergamot lemon lime and orange.
Seeds of bitter almonds anise (both kinds) fennel and nutmeg.
Gums or Oleo resinous exudations from labdanum myrrh olibanum Peru balsam storax and tolu.
Then again different varieties of plants produce aromatic bodies of slightly dissimilar odour as is shown by the numerous roses such as the red rose the white rose and the Marechal Niel while yet again the same plant grown under different conditions and in different soil will often yield an essential oil of entirely different bouquet as is demonstrated by the lavender of Norfolk and of France or by the geranium of Vallauris and of Bourbon.
All these remarkable variations present a problem which has for many years been studied by numerous distinguished scientists among whom may be mentioned Mer Mesnard Maquenne Tschirch Dr Eugene Charabot and his co workers Messrs. Gatin Hebert and Laloue.
The theories advanced by some of these earlier workers concerning the formation of the essential oil in the plant is worthy of note.
Merthought starches and cellulose were the starting point in resin formation preceded by that of essential oils.
Tschirch one of the greatest authorities on resins agree that the formation of the oil preceded that of the resins in the cell but that they were produced from materials accumulated in the membrane of the cells bordering on the secreting canal.
Mesnard at an earlier date however was of the opinion that essential oils were degradation products of chlorophyll. In the flower they are localised in the cells of the internal surface of the epidermis where by photosynthesis the chlorophyll is converted into essential oils etc.
Maquenne more recently thought perseite and other polyhydric alcohols containing more than six OH groups were the starting point in the formation of aromatic terpenes.
All these workers considered the essential oils to be excretory products formed during the metabolism of substances which functioned in the life of the plant. They considered further that their property of odour had a distinct relationship to the functions of insects and of animals but very little to that of life in the vegetable kingdom.
Charabot and Laloue in the course of experiments conducted over a number of years were able to show that in many cases the essential oil did in fact originate in the chloroplast and resulted from the assimilative work of the chlorophyll.
Concerning the formation of individual constituents of essential oils the following are the generally accepted views:
Alcohols formed first in the chloroplast.
Esters by the action of acids on the alcohols in the chloroplast.
Hydrocarbons by dehydration of alcohols in the chloroplast.
Terpene alcohols by isomerization.
Acids from the decomposition of proteins or from the oxidation of carbohydrates.
Aldehydes from the rapid oxidation of alcohols principally in the inflorescence. Action hastened during fecundation and growth of fruit.
Ketones probably in the same way as the aldehydes.
Phenols either from the splitting up of proteins or of aromatic acids.
The problem of the evolution of these odoriferous constituents of the vegetable kingdom embraces the following points:
The formation and circulation of the odoriferous consti tuents.
Their evolution and the mechanism of that evolution.
The creation of the perfumes themselves.
Their physiological influence on the plant.
In a communication to the Academie d Agriculture de France Dr Charabot elaborated these points most clearly by considering the perfume first in the case of the whole plant and then in the case of the flower only.
He says: When the plant is examined the odoriferous materials only appear in the young organs and continue to form and accumulate with decreasing activity until blossom time by diffusion they go from the leaf to the stalk and thence to the flower.
During the process of fecundation a certain quantity of essential oil is consumed by the inflorescence and as a practical consequence the gathering of perfume producing plants should be made just before fertilisation is accomplished. Once this process is complete the fragrant principles redescend into the stem and diffuse into the other organs that migration being stimulated by drying of the inflorescences which increases the osmotic pressure and partially precipitates the less soluble products.
In considering the flower only it is known that certain varieties (after collection) produce fragrant bodies when placed in such a condition that their vital functions may still be exercised while in other cases the flower contains all its odoriferous principles in the free state and it is impossible for it to produce new fragrant materials even though it be still living.
The conclusions arrived at by Dr Charabot after a study of the evolution of odoriferous compounds and of their mechanism are as follows: The esters so frequently found in essential oils are formed in a particularly active manner in the green part of the plant by the action of acids on the alcohols. This phenomenon characteristic of the chlorophyll region is influenced by an agent probably a diastase of reversible action which functions as a dehydrating body. The influences capable of modifying the plant in order to adapt it to an intense chlorophyllic action at the same time aid the formation of esters this being favourable to the mechanical elimination of water.
Thus the functions of chlorophyll tend to acquire a new significance not only do they assure the fixation of carbonic acid gas by the vegetable tissues not only do they in assisting transpiration effect the circulation of the liquids which bring and distribute the materials necessary to the mineral nutrition of the plant but they also during the assimilation of carbon actively assist condensation enabling the transformation of a simple chemical body into one of those innumerable complex substances the study of which has puzzled the shrewdest chemist.
When the alcohol is in the proper state to easily lose the elements of water it gives birth to the esters and the corresponding hydrocarbon at the same time or briefly put the first transformation takes place in the chlorophyll region by way of dehydration.
On the appearance of the flowers (those organs in which the fixation of oxygen by the tissues is particularly intense) it is possible that the alcohols and their esters are converted into other oxygenated products the aldehydes or ketones with at the same time the liberation of the energy necessary for fecundation.
A large number of odoriferous materials varying greatly in their functions and their chemical structure may be produced by the splitting up of glucosides. When the generality of such a mechanism is admitted it is easy to give an explanation of the observed facts relating to the formation of odoriferous materials and to their sudden appearance in this or that part of the vegetable organism. If the glucoside which is formed in the green part of the plant immediately encounters a medium whose conditions are favourable to its decomposition the essential oil appears there at once and begins to circulate to perform evolutions and to play its part. In other cases the glucoside will only meet the ferment capable of splitting it up in the flower. Only after having circulated in the plant and reached the flower being modified more or less the whole way will the glucoside be able to liberate the constituents of the essential oil. The flower only will then be odoriferous. The formation in certain flowers of new quantities of essential oil in proportion to the quantity of essence removed is explained by the phenomenon of chemical equilibrium resulting from the reversible reaction.
The production of essence ceases when the state of equilibrium is attained. But when the odoriferous material is removed in proportion to its formation the reaction of division can go on until the whole of the glucoside is decomposed. From these conclusions it will be easy to understand their application in the extraction of flower perfumes especially by enfleurage.
With regard to the physiological influence of the aromatic materials it was assumed formerly that they were of little use in the vegetable organism. It has been noticed by Dr Charabot and his co workers that on the contrary they can be employed by the plant especially when the latter is sheltered from the light and does not assimilate the carbonic acid gas of the air with the same power. They participate in a normal manner in the work of fecundation and of the formation of the seeds during which time they are partially consumed. Other hypotheses put forward to account for the part played by the essential oils in the life of the plant are as follows:
Ciamician and Ravenna think they may act as hormones and thus act as excitants in the fecundation of the flower.
Pokorny considers them to be waste products because they are generally toxic both for lower organisms and for higher plants. Tschirch thinks they are waste products from which the resins are formed and are therefore incapable of circulation again in the plant.
Frisch takes the view that odour is more effective than colour for attracting pollen laden insects but that the essential oil has other functions is not disputed.
The suggestion that the volatile oil may be a protecting agent against plant parasites will not hold water because unfortunately odoriferous species are just as much subject to invasion as non odorous plants.
Before leaving the subject of plant metabolism let us take a concrete example of the marvelous changes which occur in the composition of an essential oil namely that which is produced by the orange plant. If an essential oil is distilled from the inflorescences when they are in full flower and before fecundation has taken place the product will have a comparatively high content of esters and other oxygenated bodies and be relatively low in terpenes.
If the orange flowers are fertilised and the fruit allowed to develop slightly an essential oil is obtained on distillation that contains much less oxygenated constituents and a larger proportion of terpenes than the oil distilled from the fresh flowers.
Again supposing the fruit is allowed to become fully grown and the essential oil expressed from the mature peel it will be found that the oxygenated constituents have decreased to an almost negligible percentage and their place has been taken by terpenes.
Monographs on Flower Perfumes
Acacia is the name of an extensive genus of trees and shrubs of the N.O. Leguminosae varying in habit from heath like shrubs to lofty trees and widely spread throughout the tropical and sub tropical regions of both hemispheres. The inflorescences take the form of compact globose heads or spikes of various colours generally white pink or yellow the latter being the predominant colour in the Australian species.
In India the genus is represented by about eighteen species of trees of various sizes distributed throughout the country some attaining a height of 100 feet especially in the forests of Pegu and Prome. In Western Asia and Africa the genus is represented by gum yielding species such as A Arabica and A Senegal which are small sized thorny trees of forbidding aspect and frequently occupying large tracts of desert country. Other species of acacia are also common in the West Indies and tropical America where they are valued for their timber. In Australia this genus is profuse and as many as 300 different species are recorded several of which are of great commercial value as the bark is used for tanning. Among the more important of these are Acacia decurrens known as the black wattle in Victoria and Tasmania A. dealbata the silver wattle and A. pycnantba the broad leaf wattle. In southern Europe and western Syria the genus is represented by A. Julibrissin and A. Farnesiana. In this country the south of France and northern America the trees generally but erroneously referred to as acacia are Robinia pseudacacia having aromatic white flowers which appear during May and June and impart a pleasant odour to the avenues and gardens they adorn. Originally a North American species the tree was introduced into Britain some 250 years ago and is today much admired. It attains a height of 40 or 50 feet and averages 2½ feet in diameter.
Several acacias possess sweet scented flowers and of these (with the exception of A. Farnesiana and A. dealbata which will be dealt with in separate monographs) the more important are A. biflora and A. bastulata. The odour of the former recalls the coconut while that of the latter resembles hawthorn but as far as is known neither have been turned to practical account for the extraction of their perfume in Europe. In Australia however there is a perfume known as wattle blossom obtained from the flowers collected after sundown. It is prepared by macerating them in olive oil which when saturated is extracted with strong alcohol. The odour of the flowers of Robinia approximates more nearly to that of the A. bastulata and will therefore be taken as the standard flower for its synthetic prototype.
The flowers of Robinia pseudacacia have been subjected to an examination by F. Elze who extracted the blossoms with a readily volatile solvent and obtained a very dark coloured oil with a peculiar basic odour which when diluted repro duced the natural flower fragrance. This oil contained 9 per cent of ester calculated as methyl anthranilate. In alcoholic solution it gave a clearly perceptible blue fluorescence and on dilution with ethereal sulphuric acid yielded this substance. The following further constituents were also identified: indole heliotropin benzyl alcohol linalol and a terpineol. In addition aldehydes and ketones with a decided odour of peach and probably also nerol are present.
Acacia perfumes as distinct from those of cassie and mimosa are characterised by an intense flowery fragrance that is reminiscent of a blend of hawthorn with orange blossom. A rich bouquet may be obtained by combining these already compounded oils or if a basic note is required on which to build the perfume it may be secured by mixing anisic aldehyde with methyl anthranilate in the ratio of 4 to 6. But since the latter is rather harsh a part of it may be replaced with advantage by methyl naphthyl ketone in which case the note may be rounded off by the following vital constituents:
Top notes. Benzyl acetate Linalol Terpineol Bergamot Methyl cinnamate and French petitgrain. Middle notes. Clove Ylang Jasmin Rose and Neroly. Basic notes. Musk ketone Santal and Vetivert.
The Greek philosopher Theophrastus in his Enquiry into Plants VI 6 2 states that the gillyflower (? stock) is sweet scented but that the carnation and wallflower are scentless from which it is evident that this flower was known in the fourth century B.C. There appears to be no clear record of the introduction of the carnation into Britain some writers stating that it came from Germany and others that it was imported from Italy and the shores of the Mediterranean. There is no doubt however that the spicy fragrance of the flower has been appreciated for centuries throughout Europe and was very much favoured in the time of Queen Elizabeth.
The clove pink Diantbus caryopbylus of which the carnation is a variety is a grass leaved herbaceous plant of the N.O. Caryophyllaceae. The origin of the name clove is worthy of mention. It is derived from the French word clou English clout a nail from the imaginary resemblance of the clove flower to the head of a nail. Tournefort a French botanist who died in 1708 is supposed to have given it the specific name Caryopbyllus on account of its similarity to some of the short leaved species of the genus C arex and its allies. The word Caryopbyllus is also applied to the molucca clove although there is no likeness between the two nevertheless Tournefort s name of Caryopbyllus aromaticus was adopted by early botanists for this well known spice. This consists of the dried unexpanded flower buds of a tree of the N.O. Myrtaceae which is now known as Eugenia caryopbyllata.
There are over fifty species of Dianthus with numerous varieties believed by some horticulturists to exceed 2000 and including carnations pinks picotees and sweet williams. Some of the well defined species are:
Cbinensis beautiful but inodorous.
Barbatus the sweet william.
Hortensis the garden pink.
Plumarius tiit pheasant s eye.
Deltoides am D. Caesius both commonly occur wild.
Carnations are grouped by florists according to markings of the flower as follows
Bizarres spotted or striped with several shades (usually three).
Fancies with markings on coloured grounds.
Flakes of two colours striped longitudinally.
Picotees with tinted petal edges.
Selfs of one colour.
On referring to the catalogues of any of the well known horticulturists there will be found hundreds of these varieties of carnations and like roses they are known by all sorts of fancy names. From the point of view of odour however white carnations are generally to be preferred to red ones. Along the French and Italian Rivieras very large tracts of land are devoted to the cultivation of these exquisite flowers. Visitors will have noticed them in particular near Nice and Antibes and also near Venti miglia Bordighera and San Remo. The blossoms begin to appear as early as September and continue until July. The major portion of them are sold as cut flowers and sent to Paris and London. As an indication of the importance of this business it is interesting to note that a substantial number of carnations are sold annually by French growers and a lesser amount by the Italians.
The carnation has developed its rich spicy odour with cultivation although it is a peculiar fact that horticulture is responsible for many beautiful forms which are almost devoid of perfume. In the wild state it seldom possesses either of these qualities and is occasionally found growing on dry soil.
Although as stated above large quantities of carnations are grown in the south of France by far the greater proportions are sold for decorative purposes. In certain parts of the Var near Grasse the flowers are grown especially for perfumery purposes. Those of importance are white pink and red and yellow and red. The harvest takes place in June and the blossoms are picked after exposure to about three hours of brilliant sunshine. The perfume is then at its maximum fragrance. It is extracted nowadays almost exclusively by means of volatile solvents. About 500 kilos of flowers yield 1 kilo of concrete. This has rather high wax content and the yield of absolute is in the region of 10 per cent only. This has a waxy odour of heavy carnation type and is eminently suited for sophisticated perfumes. In Holland a quantity of carnations are grown for perfumery purposes and are extracted by volatile solvents.
To distillation 1000 kilos of carnation flowers yield 30 grams (0.003 per cent) of a pale green solid having an intense odour resembling that of the nine and ten carbon atom aldehydes. On extreme dilution this develops the true flower odour.
The chemistry of carnation flower oil has not received much attention probably owing to its meagre yield. However it has been studied by Glichitch who isolated from the distilled extract 31 per cent of stearophene which appeared to be identical with heptacosane. He removed traces of an aldehyde when the residual oil had an odour reminiscent of cinnamyl and citronellyl acetates. Treff and Wittrisch experimented upon clove pink blossoms grown at Groba. in Saxony. They extracted 2.840 kg of flowers with petroleum ether and obtained a yield of 8.0 kg = 0.289 per cent of solid extract. This was treated with alcohol to remove inodorous matter yielding 2.5 kg 0.088 per cent of pure extract. This was finally steam distilled to yield 122.65 grams = 0.00432 per cent.
Carnation perfumes are based largely upon the isolates and synthetics derived from clove oil of which eugenol is much favoured owing to its fragrant peppery character. Salicylates are also indispensable constituents and the vital natural ingredients are the rose alcohols ylang and Peru balsam reinforced with either orris absolute or carrot seed oil.
Acacia Farnesiana is a small tree whose origin appears to be uncertain. It is said to be a native of San Domingo and became naturalised in Europe in the Farnesian gardens at Rome about 1656 but this date is probably incorrect since it is referred to by the author of a book published in Rome in 1625 entitled Albini Hort. Fantesiana. About 1764 Linnaeus in Honrt Upalensis described and named it Mimosa Farnesiana which was afterwards by Willdenow placed in his genus Acacia.
Fragrant waters have been in use since the days of Theophrastus and are believed to have hygienic qualities not possessed by ordinary handkerchief perfumes. It is difficult to explain their nomenclature especially since they are generally made with weak alcohol but as the diluent usually consists of rose or orange flower water it may be that this to some extent at any rate accounts for their designation.
Another distinction is however noticeable in nearly all modern formulae and this is the absence of any flower extract the principal constituents being either distillation or expression products. In the formulae which follow it will be noticed that the citrus oils play an important part even in lavender water where the best effects are obtained by the liberal use of bergamot oil in conjunction with of course either English or French lavender oil.
Honey water was probably the earliest member of this series and is said to have been used by the ancient Greeks as a tonic for the hair. In later years it was prepared by distilling a mixture of honey gum arabic and water and was employed as a lotion for the face which it made white and fair . Nearly all modern formulae are based on the product originated by George Wilson who manufactured it for King James II.
Grind the musk and ambergris in a glass mortar and afterwards put all together into a large matrass and let them circulate three days and three nights in a gentle heat let them cool. Filter and keep the water in bottles well stoppered.
Honey water was popularised by Sir Erasmus Wilson who prescribed it as a hair wash. The following formula will make a pleasantly perfumed product such as is in demand today:
This may be prepared as described under eau de Cologne when an excellent product will result but if distilling apparatus is not available the whole should be macerated at least six months and afterwards filtered.
Hungary water is another eau de toilette of comparatively ancient origin and was prepared mainly from rosemary. The fresh herb was taken and distilled with spirit variations being sometimes made by the addition of lemon lavender or orris. There is very little call for this product today but as it may be of interest the following formula is appended:
Eau de Cologne
Of all the toilet waters sold to the public none are so popular as eau de Cologne for it is known universally. There appears to be some doubt as to the actual origin of this perfume and according to one version ir was invented at Milan by Paul de Feminis who manufactured it at Cologne in 1690. This gentleman is stated to have given the formula to his nephew Jean Antoine Farina who commenced to make it at Paris in 1806 and the manufacture of this particular eau de Cologne is supposed to be continued there today by a well known firm. Another version and probably the correct one appeared in a well known English periodical many years ago. According to this account J. M. Farina who was the veritable inventor of what he called Kolnisches Water or as it is much more elegantly designated in its French synonym eau de Cologne was an Italian by birth born at Santa Maria Maggiore in the valley of Vigezza district.Domo d Ossola in the year 1685. He had emigrated to Cologne however and became a naturalised German changing his first name to Johann at a somewhat early period. Certainly he was in business opposite the Julich s Place in the year 1709 for his commercial books back to that date are still in the possession of the firm. Kolnisches Wasser is among the entries at that period so that the perfume has been in existence certainly since that date. In 1726 the trade was flourishing for in that year he sent for his brother John Baptist from Italy who became his partner. The latter died in 1732 and John Maria who was unmarried found himself again alone. Then he sent for the son of John Baptist who was also his own godson and was luckily named John Maria from Italy and gave him a partnership. In 1766 the original old gentleman died and left the concern exclusively to this John Maria the second. This one lived till 1792 after which his three sons John Baptist John Maria and Charles Antony Hieronymus reigned in his stead. The middle one of these who was obviously intended to be the survivor of them all perversely died first and so for a moment the famous name was lost to the firm. But the other brothers both named their eldest sons John Maria/ and these ultimately succeeded to the proprietorship of the business. The son of John Baptist died in 1833 but the other John Maria became head of the house. His son who was also named John Maria was actively associated with the senior Mr. Farina in the conduct of the business. The word Farina appears on several makes of eau de Cologne and this is not surprising since the name is a common one in Italy. At the present time there are two or three perfumers in Cologne who claim to be the original makers of this favourite toilet water. There is one characteristic about all the old fashioned eau de Colognes which is that they represent a type being more or less citrusbouquets blended with rosemary or lavender. They possess a refreshing and incomparable fragrance which is typical of all the constituents.
The purity and source of the alcohol employed as a solvent for the oils is a factor which contributes materially to the odour of the finished perfume and a perfectly neutral and highly rectified potato spirit is undoubtedly the most useful for this purpose. If this should not be available a treble distilled molasses or grain alcohol will make a good substitute. The mere traces of oenanthic ether which are present in these specially prepared raw materials appear to blend well with the oils and slightly modify their odour. The oils used should be selected from the few rather than the many possibles and may include neroli petitgrain lemon orange and bergamot with the judicious additions of lavender and either rosemary or thyme.
Distillation also plays a most important role in the manufacture of de luxe products but the oil of neroli should always be added afterwards. This process has a very subtle influence upon the fragrance of the constituents and an entirely different and finer product results. The reasons for this peculiar change can only be conjectured but that some molecular reconstruction of the essential oils takes place on distilling appears to be most probable. When distilling apparatus is not available the oils should be dissolved in the strong alcohol and the water added little by little. The mixture is then placed aside in tanks when certain terpenes are precipitated. This process may be hastened by freezing and immediate filtration yields a brilliantly clear liquid which will not cloud under any conditions. A reference to the odour classification which follows will suggest other basic notes together with a long list of all aromatics that may be used in the creation of this complex. There are a few firms who still use rectified spirit for their toilet waters but with the availability of better quality alcohol in Britain a different complexion has been placed upon the manufacture of all perfumery. For the succeeding formulae the oils are merely added direct to the alcohol. Since the cost factor is of minor importance maturing of the finished product for any period may be resorted to.
Products which closely resemble the original may be made as follows:
Beverage Flavourings and their Applications
Our requirement for liquid refreshment is as longstanding as the origins of the species homo sapiens. An examination of Figure 1 shows that at relatively low levels of fluid loss e.g. 3% impaired performance results. A 20 30% reduction in capacity for hard muscular work occurs with a moisture/fluid loss of 4% heat exhaustion at 5% hallucinations at 7% and circulatory collapse and/or heat stroke at 10% fluid loss. The required fluid intake for the average person in the arid areas surrounding the Red Sea is a staggering 8 litres per day.
With the very existence of life depending on our fluid intake why do we not simply take water alone? The first reason is that water alone is not readily taken into human body systems as it requires a certain level of carbohydrate and salt for rapid transfer across the brush border of the gut. The second reason is that water alone is uninteresting and unquenching in taste.
The importance of fluid intake at the correct osmotic pressure (a measure of tonicity and hence compatability with body fluids the desired goal being isotonicity) is at the very origin of hum nutrition. What was the reason for the original manufacture of local wines ut alcohol contents of approximately 5% in the tropical subtropical and arid areas of the world? It was simply to use the preservation properties of alcohol as a means of keeping grape juice from degrading to a non potable state. In the process rehydration fluid (water) was held in a microbiologically stable and acceptable state suitable for use over extended periods of time. This was the origin of the category of food products that has the universally accepted nomenclature beverages.
In the early days of wine production it was found that by using different grape juices and fruit juices in varying proportions a multitude of completely different tastes was achievable. The occasional use of only small quantities of certain fruits vegetables or herbs with strong characters (e.g. mango or thyme) in the blend of juices to be fermented would result in a completely different taste of the finished wine. This was probably the first regular use of the application of food flavourings to beverages.
Any substance which when added to a beverage in quantities lower than 50% of the total volume causes the flavour of the whole product to assume its own character may technically be called a flavouring. However we will consider such flavourings only in passing and concentrate our discussions on intense relatively low volume use flavours one of the problems when trying to discuss the composition and appli cation of food flavourings to beverages is the number and diversity of beverage industries around the world. An overview of some of the major sectors of these industries is presented in this chapter.
The composition of either naturally occurring or synthetically produced flavouring material must now be examined closely for compatibility with the category of beverage that requires flavouring. For example some of the most effective and readily available natural flavouring materials are citrus essential oils released from the peel of citrus fruits during processing for juice extraction. These oils as obtained from the fruit are almost insoluble in aqueous and aqueous sugar containing beverages are generally soluble in high alcohol containing beverages and have limited solubility (but greater miscibility) in aqueous beverages with sugar contents higher than 60%. These solubility/miscibility characteristics are predictable from an examination of the composition of the oils which shows a very high water insoluble tcrpcnc content. The composition of both lemon and orange oils is given together with information on essential extraction requirements in Appendix I.
The best beverage composition for the natural whole citrus oil which has been neither solubilised nor processed is thus a high alcohol containing beverage with a high sugar content. This is usually called a liqueur. Many famous names in this beverage category are renowned for their strong fresh authentic citrus characters that would be almost impossible to obtain via any other flavour route since the other methods which we shall consider for the processing of these and other such essential oils result in a diminution in authenticity of character unless this is compensated for in other ways.
Types of Flavourings for Beverages
Just as there are broad compositional categories for beverages so it is with flavourings for beverages. They result from either the form in which the concentrated natural or synthetic flavouring exists or result from the method or methods used to extract or manufacture the flavouring.
When the flavourist is compounding a flavour he will start with an array of flavouring components of either natural or synthetic origin. These components will have different physical performance characteristics of dispersibility and solubility as well as individual flavour effects and interactive properties with other components. For natural flavouring materials these properties will in part be the result of the method of extraction and solvents used and will fall into three broad categories or types which then result in two basic performance properties:
Oil soluble flavourings subdividing into type by solvent
Water soluble flavourings
Mixtures of (a) and (b) for performance reasons and generally operating at the limits of technical acceptability of the beverage application
The synthetic components will also carry with them performance characteristics which may be categorised in a similar way.
Methods of Extraction, Solubilisation and Concentration of Flavourings
Since water (a lone) soluble flavourings are by far the smallest category for the flavouring of beverages it would seem sensible to consider these before oil soluble and mixed solvent flavourings. Their acceptability and ease of use in the aqueous non alcoholic beverage category and industry (as defined in this chapter) would make them the preferred route for flavour application if it were not for the limitation they impose on flavour range and intensity. The biggest and most widespread extraction and use of water soluble flavourings is instant coffee.
Extraction of Coffee Flavour and Manufacture of the Instant Product
Instantly soluble coffee is prepared in a series of column extractors in which the finely ground roast beans are extracted with counter currents of water under pressure at 175°C (350°F) for a period of about 4 h. This results in an almost complete recovery of soluble solids from beans and gives about 45 50% of extract. The initial concentrate is then either spray dried to give the familiar free flowing powder or freeze dried and agglomerated to give a product looking more like ground coffee. To improve the freshly perked or filtered coffee aroma about 0.2% of recovered coffee oil is incorporated into the product by either spraying onto the surface of the powder or by incorporation into the concentrate prior to freeze drying. The resulting products are packed under inert gas into glass jars to protect flavour freshness and intensity during storage prior to use.
In this example of what appears on the surface to be a fully water extracted and soluble flavouring system we can already see that certain very important and significant volatile (taste and in particular aroma) components are lost if only the water extract alone is used. This is because when any flavour extraction is carried out at temperatures of 100°C and above (at atmospheric pressure) any essential oils and dependent upon temperature resinous materials will be volatilised and carried over in the steam released. The effectiveness of this volati lisation which must be compensated for when formulating the finished beverage will be dependent upon the particle size of the material under extraction since this has to be small enough to allow good steam penetration. This can be seen even more clearly in the next most commonly perceived water soluble or extracted group of flavourings concentrated fruit compounds and flavouring extracts where the flavour of the fruit is divided unequally between the juice and the volatile and oil components.
Flavourings Extracted from Harvested Fruits
Fruits are the matured ovary of the plant or tree and may be with or without seeds and sometimes with the flower still attached. The wall of the fruit developed from the wall of the ovary is called the pericarp and may be either dry or fleshy it is this edible fleshy part which forms most of the varieties we call fruits . Nuts are also fruits and they will be covered separately for their application to beverages and in particular the manufacture of cola nut extracts and flavourings. Botanically fruits may be classified as in Appendix II.
This is the type of classification and way of thinking about fruits that a beverage formulator will pursue as it follows the perception and requirements of the consumer. A flavourist however will be more interested in the value diversity and intensity of the flavouring materials as library items from which to draw when compounding flavourings. He or she may be less interested in the replication of the whole fruit flavour in the finished beverage this being the job of the applications technologist. The processing of fruit for the purpose of extracting juice is a complex area of technology involving the use of enzymes preservatives different expression techniques de activation of natural enzymes heat processing and flavour retention collection and recovery techniques. A very full account of fruit processing has been also been given by Tressler and Joslyn and will only be covered in outline here as far as it relates to flavour extraction formulation beverage application and their intera ctions.
Very little flavouring which may be obtained from natural materials for beverages can be extracted and dissolved by water alone. In citrus fruits the juice cannot possibly be characteristic of the whole fruit since so much of the character is contained in the oil component in the peel.
In so called berry fruits the method of hot enzyming and extraction ensures that the volatile organic components will be lost during concentration in the steam/water phase unless steps are taken to recover them. The characteristic volatile aroma that is responsible for the flavour profile of most freshly pressed juices is present at levels typically around only 700 parts per million and considerably less in heat treated juices. In the extraction of flavouring materials from the juicing process it is intended that no components of potential value are wasted and that the valuable non aqueous phase materials are collected. These components are insoluble and form an unstable emulsion when applied to most liquid beverages.
Extraction and Use of Oil Soluble Flavourings
In this section discussion is restricted to the methods of their application to beverages and where necessary (e.g. cola nut extract) specific methods of extraction which result in products compatible with aqueous and aqueous sugar containing beverages in addition to beverages containing less than 20% alcohol.
The flavouring of confectionery
The principal ingredient in all confectionery is sugar (sucrose) which in its refined form has little flavour apart from its inherent sweetness. Raw (unrefined) sugar has its own particular flavour. Other important carbohydrates used in confectionery are corn syrup invert sugar and dextrose which are added mainly to control or prevent crystallisation. The texture of the confection may be altered by their use and this property is used by confectioners to manufacture many varied products.
Other ingredients such as gums pectin gelatine starch milk butter other fats and cocoa do most to give special textures although it must not be forgotten that air and water probably have the greatest effect in confectionery. Other ingredients which also play a part include liquorice honey nuts coconut raw sugar (molasses) malt extract dried fruit fruit and fruit juices. These ingredients are added usually for their flavouring properties or for their contribution to the eating quality mouthfeel or nutritional value of a confection. Some products owe their total appeal to these added ingredients. The flavour industry also provides extracts concentrates and flavourings to suit requirements for all these confectionery types.
Temperature and cooking (or heating) times also play an important role in determining final taste and texture as they have a significant effect on flavour and flavour develop ment.
Figure 1. shows temperature bands for producing various confectionery types. The apparently large range is normal and takes into account recipe differences and texture required. Lower boiling temperatures enable crystallisation to occur and a variation even as small as 0.5°C can make a significant difference to the texture of most types of confectionery.
Typical composition and procedures for the various types are outlined but no account has been taken of water since it is used mainly to dissolve sugar or other ingredients or to disperse gums. It is then removed by boiling or drying. The role of flavourings is also discussed.
Basic Confectionery Types, Recipes, Inherent Flavours
High Boilings (Hard Candy)
Candy is a collective U.S. name for sugar confectionery whereas in the United Kingdom it describes a special crystallised type.
If natural colourings are used generally many times more is required.
Manufacturing method: Sugar is dissolved in water and corn syrup added. The mixture is boiled to the required temperature for example 147°C for a 60/40 sugar/corn syrup mix and cooled. Acid flavouring and colouring are then added and the resultant material moulded by various means to make the finished confection. In large scale production liquid corn syrup is metered into sugar solution and cooked in a microfilm cooker (so called because a thin film of syrup is heated and brought to the required solids content under reduced pressure in the shortest possible time). Apart from being energy efficient no browning occurs and therefore little or no cooked flavour is apparent. This syrup is fed into a mixing chamber where calculated quantities of flavouring colouring and acid are added by means of dosing pumps. The ingredients are then mixed and formed into a ribbon for cooling. The mass is finally transferred onto sizing rollers prior to spinning to a rope and moulding. On a small scale the batch is boiled in a pan which may also have a facility to remove final amounts of water by vacuum. At the temperature required the product is transferred to a cooling table (confectioners slab which has the facility to have hot or cold water passed through it) where the batch is cooled. When the correct temperature is reached as determined by the viscosity of the mass rather than any other factor the flavouring colouring and acid are added folded in and the confection finished as before or passed through drop rollers. Drop here means the shape of the sweet (e.g. pear drops).
Another type of high boiling (candy) which should be mentioned is the deposited type where the cooked flavoured acidified and coloured syrup is held at high temperature in special hoppers and deposited into metal moulds prior to cooling and wrapping. The acid used has to be buffered to prevent inversion of sugar whilst the colouring and flavouring used must be specially selected lo withstand the extra heating necessary. Invert sugar is produced by the addition of acid into the boil or by long slow cooking. Excessive inversion leads to stickiness or even a product that will not solidify. While some confections have invert sugar added because it controls the crystallisation of super saturated sucrose solutions it is usually added as commercially available material or as golden syrup treacle or honey. Any additional production of invert sugar during cooking needs very careful control and buffer salts are added to adjust the pH and consequently the rate of inversion.
Using the same recipe pulled sugar work (seaside rock figured lollypops satins) can be made. Their manufacture necessitates pulling the previously boiled flavoured coloured and acidified sugar/corn syrup mixture on a machine or over a hook to incorporate air. When moulding (to make fancy shapes or to build up letters) is complete the batch has to be kept hot for a considerable time and this inevitably leads to deterioration of the flavour. For this reason heat stable flavourings or lower quality products without fine topnotes which would be lost may be utilised. One way of introducing fine flavours into boiled sugar is to prepare delicately flavoured centres. Fruit pulps may be used to produce jams nut pastes may be prepared or whole nuts used as well as all kinds of fillings based on chocolate. They are introduced into the boiled sugar rope by means of a centre pump. The high boiled casing then protects and encloses the lower boiled portion enabling its finer flavour to be retained.Very many different confections are made using these same basic ingredients some boiled to the higher temperature range (e.g. satins) while those boiled to lower temperatures are allowed to crystallise (e.g. Edinburgh rock).
Looking at variations on plain boiled sugar as described the addition of fat is perhaps the most obvious. Traditionally this fat was butter which imparts a smooth mouthfeel excellent taste and is self emulsifying. Butterscotch is made by the addition of 4% or more of butter solids and the flavour of this product is developed by exposing the raw materials to the high temperature of manufacture.
Manufacturing method: Sugars and corn syrup are dissolved and boiled together until a temperature of about 145°C is reached. Butter is then added and gently incorporated to preserve as much of its flavour as possible. The batch is then boiled to the final temperature of 145 160°C. Where higher temperatures are preferred special arrangements for direct heating (gas) may have to be made since they are often too high for steam heated equipment. The mass is then cooled and flavouring incorporated before the product is cut and wrapped. Generally lemon usually in the form of lemon oil is added since it is said to neutralise the greasy effect of fat. Vanilla flavourings are often used to enhance the character of the product and butter flavourings are popular too as they increase the overall buttery taste. Flavourings of commerce intended for this confection generally contain all these components in carefully balanced amounts.
Variations on butterscotch recipes would be to alter the proportion of white to brown sugar (or the replacement caramelised syrups which are available). If the higher boiling temperatures are used to achieve a special cooked flavour and texture invert sugar has to be either added or made during production in replacement for all or part of the corn syrup. The inclusion of invert sugar in one form or another results in a much less viscous batch and higher temperatures are required to reach the same solids content. The amount of butter may be varied or replaced totally or partially with other fats. Butter has natural emulsifying agents present so if other fats are used an emulsifier usually lecithin or glyceryl monostearate (GMS) has to be added in order to ensure proper dispersion of fat through the batch.
2. Buttermint confectionery. Incorporation of air either by means of pulling or the addition of frappe will result in Buttermint types or Mintoes two typical compositions are as follows.
Method of manufacture: Sugar syrup and corn syrup are heated to about 130°C when butter (or other fats with emulsifiers) are added. The mass is reboiled to 138°C allowed to cool and peppermint oil mixed into the batch which is then pulled to the correct consistency spun into a rope formed and wrapped. Frappe is made by beating egg albumen (10%) or gelatine (5%) into previously warmed corn syrup. Both these materials have to be dispersed in minimal amounts of water before addition.
Manufacturing method: Sugar and corn syrups are warmed to 140°C. Fat and lecithin are then added and when dispersed the frappe and peppermint oil are carefully stirred in. The mass is allowed to cool and finished as usual. The heat of the batch will expand air entrapped in the frappe and care must be taken to avoid its loss by excessive handling. To avoid inconsistent batches it is necessary to control the temperatures used as well as manufacture of the frappe.
The quality of peppermint oil used in this type of product is important an oil without harsh top notes will enhance the smooth character of the confection. This may be a natural American oil (e.g. from Mentha piperita) or an oil from China or Brazil (Mentha arvensis) which will have been dementholised at source and subsequently rectified to remove the harsher top notes and undesirable residues. Alternatively a mixture of the two may be used. Most essential oil and flavour houses have suitable blends to offer. Butter flavourings may also be added especially when not all the fat used is butter. These are often made with a vanilla background which accentuates the smooth character of the confection together with diacetyl and butyric acid. Both these substances are naturally present in butter and increasing the proportion of them boosts the final flavour considerably and replaces processing losses. It should be noted they are available as both natural and synthetic materials. Butter esters i.e. obtained from butter may also be used Composite flavourings based on peppermint vanilla and butter are also available.
Flavourings for bakery and general use
Bakery products are in general based on three major ingredients and a number of minor but nevertheless extremely important components.
Flour is in most cases the major ingredient and is usually derived from wheat. It may be whole wheat as in the case of wholemeal flour or part of the wheat berry as in white flour. It can be of different grades depending on its protein content: high protein (11% +) for bread making and low (approx 9%) for cakes and biscuits. In addition flour can be treated in various ways to increase the amount of damaged starch cells a factor which in turn increases its water holding power. It is also possible to treat flour with oxidising agents (typically ascorbic acid) either to increase the apparent strength of the protein fraction or as is the case in the Chorleywood Breadmaking Process to reduce the time required for fermentation when used in conjunction with mechanical development. It is also a requirement in law that white flour is nutritionally supplemented with calcium and iron plus vitamins. None of these processes have effects likely to. cause major flavour problems. Anyone interested in understanding more about flour and its properties should read Modern Cereal Chemistry or some of the other major works on the subject.
There are of course other cereals that can be used rye oats and maize being the most common. Rye is of particular interest in that it was normal in continental practice to produce a rye sour by a long period of fermentation which gives the product a particular flavour and helps to improve keeping properties of the bread. It is possible to reproduce this effect and its shelf life improvement by the use of flavourings and chemical additions. By this means the risk inherent in long fermentation periods of the culture of undesirable microbiological organisms is avoided. The practice of sour dough systems is now little used as it is being replaced by flavourings or specially prepared dried sours made under strictly controlled conditions.
Sugars are the second major ingredient to be found in most bakery formulae. There are many different sugars that can be used.
Sucrose is the most common both in granular form or as a ground powder it is also available in its partly refined stage as brown sugars the best known of which is probably demerara.
Molasses or its partly refined stage golden syrup is another sweetening ingredient manufactured as a by product of sugar manufacture it is used not only for its sweetening property but as a flavouring in many products.
Dextrose is produced by the acid or enzymic conversion of starch derived from maize or as a by product of protein extraction from wheat flour. It is typically available either as a component of liquid glucose syrup or as a powder (dextrose monohydrate). The liquid syrup is supplied with different levels of conversion of starch to sugars which is measured as dextrose equivalent (DE). The syrup is sold within a range of solids (72 84%) depending on its intended end use.
Invert sugar is a product of acid or enzyme treatment in this case the substrate is sucrose. It has many properties similar to glucose and is often used in formulae for its ability to act as a humectant. We must also consider honey in this group it is used as a flavouring ingredient as well as a sweetener. There are many honey types all of which have different flavours characterised by the flowers visited by the bee at the time the honey was produced.
Other bulk sweeteners fructose and polyols such as sorbitol are used to make products suitable for diabetics as they do not require the human digestive system to provide insulin.
Fats are the third major ingredient. They are derived from animal and vegetable sources and have to undergo several purification steps before being suitable for bakery use. The processes of filtration colour and flavour removal fractionation and hydrogenation allow the manufacturer to produce tailor made fats for the particular application. The very special flavour characteristics of butter that are changed during the baking process must also be considered. These are the target of much research in the flavour industry the results of which have produced some excellent flavourings which can add a special note to many baked products.
Liquids are one of the minor but very important ingredients in bakery formulations and are normally added in one or more of many forms including egg milk and water. The prime function of liquid is to bind all the various additions of the formulae holding them together in the early stages of the baking process. Later as the temperature rises a secondary function of the protein fraction of egg coagulates to produce structure. Free liquid then enters the starch grain of the flour and allows gelatinisation to take place again adding to the structure of the product. The retention of moisture in the finished item is important in its taste sensation when eaten. Lack of moisture can for example make a cake unacceptable whilst too much of it can make a biscuit equally unpleasant to eat.
Gases producing the effect of aeration are another minor but important ingredient.
Mechanical aeration although not strictly an added ingredient can be produced by beating or whisking and here egg has a very important role in baked products in that it can hold air in its protein structure. Fat of the correct type will entrap air when beaten. Aeration can also be produced by chemical and biochemical components.
Chemical aeration is possible using ammonium carbonate which on heating decomposes to produce ammonia carbon dioxide and water. Unfortunately ammonia tends to re dissolve into any available water in the product and is therefore not acceptable in high moisture products such as cake. It does form a very useful aerating ingredient for biscuits and low moisture items. Sodium bicarbonate upon heating will release some carbon dioxide however the reaction can be made to produce more carbon dioxide when used in conjunction with a variety of acids. Although chemical residues remain after both reactions they are considered acceptable tastes in powder aerated products. The common acids used are:
Cream of tartar
Acid sodium pyrophosphate
Calcium hydrogen phosphate
Glucono delta lactone
Glucono delta lactone is preferred in that it produces the minimum after taste. Biochemical aeration by the use of yeast usually the specially cultivated variety(Saccharomyces cerevisiae) is the prime source of biochemical aeration although it is possible to take advantage of the yeast spores floating in the air or found on the surface of fruits. There are obvious risks in using these so called wild yeasts as they can be a very unreliable source of aeration and so are little used.
Yeast breaks down the available carbohydrates by the use of enzymes in a fermentation process which produces carbon dioxide gas and a large range of other organic chemicals including ethyl alcohol pyruvic acid and acetaldehyde some of which can then go on to further reactions. Many of the chemicals produced have flavour and it is this complex combination which gives bread its unique taste.
I hear that you are experts in dairy flavourings. Well I need a cheese flavouring of general Cheddar type with a hint of Blue a sort of buttery creamy background and perhaps a slight Swiss fruitiness. I want to use it in a low fat cheese sauce for a low calorie fish and pasta frozen ready meal designed for both microwave and conventional oven preparation. The flavouring must be a powder with no added flavour enhancers like monosodium glutamate and it cannot be artificial in fact the Marketing Department would prefer it to be totally natural. And by the way the finished product is to be sold throughout Europe and Scandinavia.
The above transcript of a hypothetical call from a development technologist in a food company is sadly not as typical as the flavourist might hope. All too often the flavour requirements are much less tangibly defined the end product and processing are not revealed and the legal and marketing implications of the target market are not clear. This makes the job of the flavourist trying to satisfy customers flavour needs much more difficult. It is very important that the flavourist engages the customer in dialogue about his or her flavour needs. Only then can the flavourist use broad experience to help to satisfy those needs.
The basic areas of knowledge which the experienced dairy flavourist draws upon to understand and fulfil the flavour needs of today s demanding food development technologist. It has been written mainly for the flavourist venturing into dairy flavour types for the first time but should prove of interest to all interested in other flavourists views. It is not highly technical but gives the basics which help to build up a feel for dairy flavours.
You may be surprised by the breadth of information about different types of real cheeses butters and other dairy products. Such an understanding is vital to the process of defining the flavour target and the target must be adequately defined if you are to have any chance of reproducing the flavour in a processed food product.
All dairy products start out as milk their flavour components tend to be similar the secret of their varied and unique characters is in the balance of those components.
History of Animal Milks as a Human Food Source
The earliest domestication of animals is believed to have been about 6500 BC and with this came the widespread consumption of animal milks by man. It is highly likely that the practice had begun long before this time with the milk of wild animals hunted for their flesh. The nature of milk itself with the influence of weather probably gave rapid rise to a range of dairy products and this formed the basis of the wide range of milk products we have come to know today. We should be grateful that early man discovered the variety of possible dairy products before he devised refrigeration a process which might have prevented many of them from developing!
The Development of Flavour in Dairy Products
Although there are significant species variations animal milks are generally oil in water emulsions containing varying quantities of triglyceride fats with the characteristic milk protein casein (plus other proteins at much lower levels) the milk sugar lactose and a broad range of vitamins and minerals. In short they contain just the necessary mix of nutrients to ensure the healthy development of the juvenile of the species until it is able to digest other foods.
These macroscopic components are not solely responsible for the varied flavours we associate with dairy products. They provide the raw materials for the development of an immense variety of aromatic compounds. Degradation of the protein lactose and fat components directly yields many aroma compounds some more desirable than others! But the great variety in dairy product flavours would not occur without the action of a range of microorganisms which selectively act on the raw milk to give compounds responsible for the familiar flavour characters. Further chemical interaction between these compounds increases the range of chemical species which contribute to dairy flavours.
Differences between the milks of different species manifest themselves mainly as differences in lactose protein and fat levels and in particular in differences in the chemical composition of the fat triglycerides. This in turn gives rise to differences in the types and balance of small aromatic molecules liberated in degradation processes. Thus there is significant variation in flavour between dairy products derived from milk of different species despite the broadly similar reactions taking place.
As in many areas of flavour science understanding of dairy product flavours has advanced tremendously in the last 30 years. This has been largely driven by the increasing availability of instrumental analytical techniques which allow detailed examination of the low level components of complex mixtures. Gas chromatography and mass spectrometry have revolutionised the study of all flavours and of dairy flavour in particular. Together these two techniques enable separation and identification of components in extracts from dairy products. However they do not indicate which components are the most important contributors to the overall flavour of the dairy product. For this the trained human nose is still the most reliable if not the only means of analysis. Sometimes the nose can usefully be used as an aroma specific detector for the gas chromatograph indicating which components should be further studied by mass spectrometry and other techniques. The result can be a list of the key compounds which together characterise the flavour of the product under study. But even this is of little use to the flavourist unless the compounds are available or could be made available within commercial cost restraints. So although analytical information is of great help the skill and experience of the flavourist remains paramount in the development of commercially viable flavourings.
The Development and Uses of Dairy Flavourings
Dairy flavourings are used throughout almost all sectors of the manufacturing food industry from snack foods through to alcoholic beverages from sugar confectionery to ready meals from dairy products even to specifically non dairy foods. The range is extremely wide and this demands a certain approach from the dairy flavourist. It is vital to obtain as much information as possible about the application the customer has in mind. At a minimum each of the following considerations should be addressed.
A flavourist must be a jack of all trades expert in whatever discipline is required! Intermittently and concurrently the skills of chemist artist food technologist designer marketeer consumer and even psychoanalyst may be needed in order to identify and satisfy the customer s needs. The customer has an idea of what he wants the marketing department sets a brief the food technologists research the practicalities. Ideally the flavourist works alongside this whole process to achieve the desired flavour profile.
Flavourists can obviously benefit from a detailed knowledge of the compounds responsible for flavour in real dairy products but this is only a part of the story. The inherent flavour of the product will greatly affect the emphasis of the required flavouring. Many of the components of the real thing will be technically unavailable or commercially unusable. The flavour of the real thing may not even be what the customer really needs! Before commencing development work on any project flavourists should satisfy themselves that they fully understand the customer s needs. The best way to do this is to question the customer directly. Such a direct approach is rarely rejected as most food product developers realise this is the most effective way for them to achieve their goals.