Showing papers in "Journal of the American Oil Chemists' Society in 1972"
TL;DR: In this article, changes in various structural units present in surfactants strongly affect the interfacial properties shown by these materials, such as surface tension reduction, micelle formation, wetting, foaming and defoaming, detergency, and dispersion of solids.
Abstract: Changes in the various structural units present in surfactants strongly affect the interfacial properties shown by these materials. Such properties as surface tension reduction, micelle formation, wetting, foaming and defoaming, detergency, and dispersion of solids all show marked changes with variations in both the hydrophilic and hydrophobic portions of the surfactant molecule, reflecting the processes occurring on a molecular level. Changes in these properties caused by such factors as the length and nature of the hydrophobic group, branching or unsaturation in the hydrophobic group, the nature of the hydrophilic group and its position in the molecule, and the presence or absence of an ionic charge are described and explained in terms of the molecular processes involved.
160 citations
TL;DR: In contrast to the singleβ′-form generally attributed to such triglycerides, at least two intermediate endotherms were found for most samples between the least stable (α) and most stable (β) polymorphs as discussed by the authors.
Abstract: The polymorphism of 13 single acid triglycerides with acyl group chain lengths ranging from 16–22 was studied by differential scanning calorimetry. In contrast to the singleβ′-form generally attributed to such triglycerides, at least two intermediate endotherms were found for most samples between the least stable (α) and most stable (β) polymorphs. For saturated triglycerides, two versions of the familiar “tuning fork” model meet theβ′-form requirement of alternate fatty acid chains in planes perpendicular to each other. The detection of three intermediate endotherms for triolein, tri-cis-1 1-octadecenoin and trierucin (and possibly also trilinolein) may be rationalized by assuming that the segments of polymethylene chains on either side of double bonds may zigzag in different planes. Four exceptions for which no evidence was found forβ′-forms are tri-cis-6-octadecenoin, tri-cis-6-hexadecenoin, tri-trans-6-octadecenoin and trielaidin. Three of these exceptions contain Δ6-acyl groups and have in common segments with even numbers of methylene groups on either side of the double bonds. These same three triglycerides also have a shorter than usual polymethylene segment between the ester linkages and the double bonds and a longer than usual distance from the double bonds to the terminal methyl groups. Tri-trans-6-octadecenoin and trielaidin are exceptional in still another way. Only they and are exceptional in still another way. Only they and trierucin exhibited significant nonconformity with an empirical relationship between melting points and heats of fusion ofβ-forms. Otherwise, all points in a plot of the former physical constants vs. the latter closely fit a smooth curve, the positive slope of which gets larger as the X-axis values, i.e., melting points, increase.
111 citations
TL;DR: A significant negative correlation was found between oleic and linoleic acid content and there was no correlation between oil content and iodine value of the oil.
Abstract: The quantity and quality of oil was studied in 721 introductions of sesame seed. The mean oil content was 53.1% and the iodine value 117.4. The mean per cent fatty acid composition was: palmitic 9.5, stearic 4.4, oleic 39.6 and linoleic 46.0. The oil was clear, colorless in 47.4% of the samples and light green in 37.2%. The remainder of the oil samples were dark green or brown. Short plants tended to have colorless oil while tall plants had light green oil. Early plants had a higher seed oil content. Earliness, yellow seed color and large seed size were associated with lower iodine value. A significant negative correlation was found between oleic and linoleic acid content. There was no correlation between oil content and iodine value of the oil.
106 citations
TL;DR: In this paper, the unsaponifiables isolated from olive, corn, wheat germ and Vernonia anthelmintica oils were found to be effective in protecting safflower oil from oxidative polymerization during heating at frying temperature.
Abstract: Addition of certain vegetable oil unsaponifiables to safflower oil protects it from oxidative polymerization during heating at frying temperature. The unsaponifiables isolated from olive, corn, wheat germ andVernonia anthelmintica oils were found to be effective. The fraction responsible for this effect is largely sterol in nature. Although the common plant sterols show no antioxidant activity, the 4-α-methyl sterols function well. The sterols fromVernonia oil, which contain no 4-α-methyl group, are also active. It appears that an isofucosterol side chain may be the structural feature required to obtain this protective effect.
95 citations
TL;DR: In this article, a new method was presented for determining thecis/trans isomer content of edible vegetable oils based on the intensities of Raman lines near 1656 and 1670 cm−1.
Abstract: A new method is presented for determining thecis/trans isomer content of edible vegetable oils. The intensities of Raman lines near 1656 and 1670 cm−1 are associated with thecis andtrans configuration, respectively. A precision of ca. 1% can be obtained in thecis/trans isomer analysis of binary mixtures of methyl esters and triglycerides of monoenes and dienes and of hydrogenated vegetable oils. The spectroscopic data also provide the iodine value of vegetable oils or isolated fractions with precision for a single determination of ca. 1%.
92 citations
TL;DR: Physical and chemical properties of 80 samples of Canadian yellow unrefined beeswax have been determined as mentioned in this paper, and the results showed that the results were very similar to those of U.S. beewax and were within the specifications of National Formulary XIII.
Abstract: Physical and chemical properties of 80 samples of Canadian yellow unrefined beeswax have been determined. Mean values were: melting point, 64.3 C; acid value, 18.7; ester value, 72.6; ratio number 3.89; saponification cloud point 62.5 C; and hydrocarbon content, 15.3%. There was no significant variation due to geography or climate. Values were very similar to those of U.S. beeswax and were within the specifications of National Formulary XIII, except that 21 samples had ester values in the range 70–72. A more accurate specification for ester value would be 70–77 instead of 72–77. Hydrocarbons, free fatty acids and long chain esters were analyzed by gas liquid chromatography, and the limiting values found make possible improved detection and estimation of adulterants. The upper limits for C16 and C18 acids were 5.8 and 3.3%, respectively, of the total free acids.
85 citations
TL;DR: In this article, the results were in good agreement with given hydrophilic lipophilic balance (HLB) values for various commercial nonionic surfactants by means of high resolution NMR.
Abstract: Hydrophilic lipophilic balance (HLB) values for various commercial nonionic surfactants have been determined by means of high resolution NMR. The results are in good agreement with given HLB values. The method is rapid, nondestructive and requires only small samples.
71 citations
TL;DR: In this paper, a possible decomposition product of oils containing unsaturated fatty acids with the double bond pattern ω3,6,9 or ω 3, 6,9, etc., is 2-trans,4-cis,7-decatrienal.
Abstract: A possible decomposition product of oils containing unsaturated fatty acids with the double bond pattern ω3,6,9 or ω3,6,9, etc., is 2-trans,4-cis,7-cis-decatrienal. It has therefore been investigated whether this trienal is present in strongly autoxidized linolenic acid, soybean, linseed and fish oils. Via a degassing technique the carbonyls from the samples of oils heated in a closed system under nitrogen were collected and separated as their 2,4-dinitrophenylhydrazones (DNPHs) by thin layer chromatography (TLC). The presence of 2-trans,4-cis,7-cis-decatrienal in the samples was positively established by TLC, UV absorption and mass spectroscopy of its DNPH. All analytical data established the complete identity of the isolated DNPH with a synthesized 2,4,7-decatrienal-DNPH. The free aldehyde obtained on hydrolysis of the alkatrienal-DNPH in question had the same flavor as authentic 2-trans,4-cis,7-cis-decatrienal, having a fish or rather a whale oil flavor.
68 citations
TL;DR: This paper showed that the oleic acid content of safflower seed oil can be increased by modifying genes and the major geneol, though probably not above 85% in the wild.
Abstract: Current research on the fatty acid composition of the seed oil of safflower (Carthamus tinctorius L.) has shown the following: (1) there is a possibility that the oleic acid content can be increased above 80%, though probably not above 85%, by use of modifying genes and the major geneol; (2) wild species do not look very promising as a source of genes for modifying fatty acid composition; (3) commercially grown high linoleic and high oleic types are temperature stable; (4) an experimental type with about equal amounts of oleic and linoleic acids is responsive to temperature, with high temperature increasing oleic acid and low temperature increasing linoleic acid; and (5) stearic acid in another experimental type with higher levels of stearic acid (5–10%) is reduced by low temperatures.
68 citations
TL;DR: Sesame meal is a valuable supplement for food and feeds because of the high methionine content of its protein relative to other oilseed proteins as discussed by the authors, and the production of sesame seed in the U.S. has been small but is expected to increase with success in the development of nonshattering varieties.
Abstract: Because of its good taste and outstanding stability, sesame oil has long been one of the most desirable edible vegetable oils. Sesame meal is a valuable supplement for food and feeds because of the high methionine content of its protein relative to other oilseed proteins. Production of sesame seed in the U.S. has been small but is expected to increase with success in the development of nonshattering varieties. Current information on the composition, properties, processing and use of sesame is discussed.
68 citations
TL;DR: Long chain N-acylglutamic acid was prepared in a high yield by a reaction of glutamic acid with fatty acid chloride in a mixed solvent of water and a water miscible organic solvent.
Abstract: Long chain N-acylglutamic acid was prepared in a high yield by a reaction of glutamic acid with fatty acid chloride in a mixed solvent of water and a water miscible organic solvent such as acetone, methyl ethyl ketone, dioxane, tetrahydrofuran,t-butyl alcohol or cyclohexanone. In this reaction the composition of the mixed solvent influenced the yield of N-acylated glutamic acid and the best yield was obtained when the reaction was carried out in the mixed solvent comprising 30–60% v/v of the organic solvent. Long chain N-acylaspartic acid was also obtained in a high yield by the same method. As the other method to obtain N-lauroyl-D L-glutamic acid, it was examined that N-acyl-α-aminoglutarodinitrile which was obtained by a reaction of α-aminoglutarodinitrile with fatty acid chloride was hydrolyzed with an aqueous alkaline solution. The salts of long chain N-acylglutamic acid are known as the surface active agents that react mildly on the human skin.
TL;DR: The null hypothesis that each of the true unknown distribution functions was negative binomial was not rejected at the 5% significance level for all 29 comparisons and the functional relationship betweenk andm was indicated to be:k=(2.0866+2.3898m) × 10−6.
Abstract: Suitability of the negative binomial distribution for use in estimating the probabilities associated with sampling lots of shelled peanuts for aflatoxin analysis has been studied. Large samples, called “minilots,” were drawn from 29 lots of shelled peanuts contaminated with aflatoxin. These minilots were subdivided into ca. 12 lb samples which were analyzed for aflatoxin. The mean and variance of these aflatoxin determinations for each minilot were determined. The shape parameterk and the mean aflatoxin concentrationm were estimated for each minilot. A regression analysis indicated the functional relationship betweenk andm to be:k=(2.0866+2.3898m) × 10−6. The observed distribution of sample concentrations from each of the 29 minilots was compared to the negative binomial distribution by means of the Kolmogorov-Smirnov test. The null hypothesis that each of the true unknown distribution functions was negative binomial was not rejected at the 5% significance level for all 29 comparisons.
TL;DR: In this article, rigid urethane foams were prepared from hydroxymethylated linseed oil and its esters of glycerol, trimethylolpropane and pentaerythritol.
Abstract: Rigid urethane foams were prepared from hydroxymethylated linseed oil and its esters of glycerol, trimethylolpropane and pentaerythritol. These polyols were made by selective hydroformylation with a rhodium-triphenylphosphine catalyst followed by catalytic hydrogenation with Raney nickel. Although the hydroxymethylated linseed monoglyceride by itself yielded a satisfactory foam, better foams were made from all hydroxymethylated linseed derivatives when blended with a low-molecular weight commercial polyol. Linseed-derived foams were compared with foams from equivalent formulations of hydroxymethylated monoolein and castor oil. Hydroxymethylated products yielded polyurethane foams meeting the requirements of commercial products with respect to density, compressive strength and dimensional stability.
TL;DR: A wide range of flavor profiles can be produced via control of enzyme, fat and processing prior to and subsequent to enzyme modification as mentioned in this paper, including margarine, imitation dairy products, confections and prepared foods.
Abstract: Technology has been developed for the production of flavor systems via controlled enzyme modification of fats. Lipases and esterases from various sources are used. Fats modified include milk fat and meat fats. A wide range of flavor profiles can be produced via control of enzyme, fat and processing prior to and subsequent to enzyme modification. Applications for the flavor systems include margarine, imitation dairy products, confections and prepared foods.
TL;DR: The results obtained indicate that lipid soluble bromine and arseno organic compounds are characteristic components of marine animal and marine plant oils (seaweed) and that the bromines are not localized in any particular compound or type of compounds.
Abstract: Samples of marine and terrestrial oils of both plant and animal origin have been analyzed for arsenic and bromine content Two oil samples (cod liver oil and oil extracted from mackerel fillets) were fractionated on silica gel columns and bromine was determined in the different fractions The results obtained indicate that lipid soluble bromine and arseno organic compounds are characteristic components of marine animal and marine plant oils (seaweed) The results also show that the bromine is not localized in any particular compound or type of compounds The bromine-containing compounds seem to be relatively stable, but the arseno-containing compounds are not When oils containing arsenic and bromine were saponified, some of the arsenic and bromine compounds were found in the fatty acid fraction while others appeared in the water soluble fraction
TL;DR: In this paper, the authors identify as many as possible of the monomeric products that form when fats are heated in the air, and the most abundant components of the non-urea-adductable fraction (DNUA) of the esters were octadecenoate and octadecarienoate which had not been removed completely by urea adduction.
Abstract: Although animal studies have shown that the chemical reactions occurring in fats during frying do not make them unsuited for food use, questions continue to arise about the products of these reactions and their significance. The purpose of this work was to identify as many as possible of the monomeric products that form when fats are heated in the air. Cottonseed oil was kept at 182 C for six 8 hr days; then it was converted to methyl esters. The distillable, non-urea-adductable fraction (DNUA) of the esters was separated into 96 fractions by gradient elution chromatography on silica gel. Each fraction was analyzed by gas liquid chromatography (GLC). One hundred thirty-six components were observed, corresponding to 0.42% of the fat. Many of the components were isolated by preparative GLC. Fifty-one were partially or completely characterized. The most abundant components of the DNUA were octadecenoate and octadecadienoate which had not been removed completely by urea adduction. Esters of alicyclic fatty acids made up 34% of the characterized material. These cyclic materials are probably responsible for the toxic effects that have been seen when DNUA was isolated and fed to rats at high dietary levels. Many of the other components appear to be of little biological interest. No components present in substantial amounts remain uncharacterized.
TL;DR: In this paper, different malonaldehyde-amine condensation products were tested for their relative color contribution to the thiobarbituric acid (TBA) test, an indicator for oxidative rancidity of polyunsaturated lipids.
Abstract: Different malonaldehyde-amine condensation products were tested for their relative color contribution to the thiobarbituric acid (TBA) test, an indicator for oxidative rancidity of polyunsaturated lipids The open chain mono- and disubstituted malonaldehyde (M) addition products (R-N=CH-CH=CHOH and R-N=CH-CH=CH-NH-R) gave complete (100%) recovery ofM on a mole basis When theM residue was incorporated into cyclic products which formed between the ureido- or guanidino- substituents of α-amino acids such as citrulline or arginine andM, recovery ofM by the TBA color test was 30% and 6%, respectively Products, from imine-amine type interactions, containing theM residue as in pyrazoline or pyrazole ring systems, released from 4% to noM
TL;DR: Analysis of chemical, physical and organoleptic properties indicate that dehulled sunflower kernels can be used in various food products and are more flavorful after storage for four weeks than similarly treated chips fried in cottonseed-corn oil mixtures.
Abstract: The sunflower,Helianthus annuus, is a crop which has been neglected in American agriculture. Sunflower oil from seed grown in the northern U.S. typically contains 70% linoleic acid and has a high ratio of polyunsaturated to saturated fatty acids. This makes it desirable as an edible oil in light of evidence linking saturated fats to high blood cholesterol and incidence of heart disease. In contrast sunflower oil from seed produced in the South generally contains 40–50% linoleic acid. Preliminary studies indicate that southern oil with a lower content of linoleic acid is slightly more stable than northern oil. The effect of planting dates, location and environmental temperatures on the fatty acid composition of northern and southern sunflower oils is reported. Studies also show that potato chips fried in sunflower oil are more flavorful after storage for four weeks than similarly treated chips fried in cottonseed-corn oil mixtures. Sunflower protein is highly digestible (90%) and possesses a high biological value (60%). Protein isolates prepared by the conventional method of extraction are greenish in color due to oxidation of chlorogenic acid. However research underway indicates that development of a nearly white isolate is possible. Analysis of chemical, physical and organoleptic properties indicate that dehulled sunflower kernels can be used in various food products. Defatted meal also can be used as a partial wheat substitute in bread and other bakery products.
TL;DR: The physicochemical properties of long chain N-acylglutamic acids (AGA) and their sodium salts (AGSn) are described in this paper, where the solubility, Krafft point, pH value, critical micelle concentration, surface tension and foaming power are measured.
Abstract: The physicochemical properties of long chain N-acylglutamic acids (AGA) and their sodium salts (AGSn) are described. The solubility, Krafft point, pH value, critical micelle concentration, surface tension and foaming power were measured. The properties of the optically active AGA or AGSn differed from those of the corresponding racemates, especially in solubility. The monosodium salts generally had high Krafft points, but monosodium N-oleoylglutamate had a low Krafft point. The monosodium salts hydrolyzed in the diluted aqueous solution to liberate the AGA. The aqueous solutions of the monosodium salts had low surface tensions and good foaming properties. The disodium salts were highly soluble in water, while surface tensions and foaming properties were inferior to those of the corresponding monosodium salts.
TL;DR: In this paper, the types of antioxidants currently available for food fats and oils are listed, and theoretical and practical aspects of selecting the proper ones for various food uses are reviewed, considering the relative potencies, modes of application, regulations governing use, and some of the more prominent problems encountered in their commercial applications.
Abstract: Types of antioxidants currently available for food fats and oils are listed, and theoretical and practical aspects of selecting the proper ones for various food uses are reviewed. Consideration is given to relative potencies, modes of application, regulations governing use, and some of the more prominent problems encountered in their commercial applications. A brief look is taken into future needs and possible developments with fat and oil antioxidants.
TL;DR: In this article, an aqueous process was investigated for the recovery of oil and food grade protein from fresh coconuts, which was related to three critical unit operations: separation of oil from the fiber, destabilization of an oil-in-water emulsion, and recovery of a protein product that is low in oil content.
Abstract: An aqueous process was investigated for the recovery of oil and food grade protein from fresh coconuts. Efficient recovery of oil, which is very important for economical reasons, was related to three critical unit operations: separation of oil from the fiber, destabilization of an oil-in-water emulsion, and recovery of a protein product that is low in oil content. The material balance is reported for a laboratory process that satisfactorily separates oil and breaks the emulsion, and data are shown which has led to a process for recovery of a protein with low oil content.
TL;DR: In this paper, the important reactions of carbon monoxide with unsaturated fatty derivatives that are reviewed in this paper include hydroformylation (the oxo reaction), Koch carboxylation and Reppe carbonylation.
Abstract: The important reactions of carbon monoxide with unsaturated fatty derivatives that are reviewed in this paper include hydroformylation (the oxo reaction), Koch carboxylation and Reppe carbonylation. With oleic acid as a substrate, the products are C19 bifunctional compounds e.g., formyl- or carboxy-stearic acid. Double bond isomerization before carbon monoxide addition is characteristic of these catalytic reactions; additionally, rearrangement to introduce methyl branching occurs in the Koch carboxylation. Isomerization does not occur when a rhodium-triphenylphosphine catalyst replaces cobalt in the oxo reaction. Properties of the C19 dicarboxylic acids differ and depend upon method of preparation: Many areas of application have been reported for C19 compounds-lubricants, plasticizers, polyurethanes, epoxy resins, leather and other coatings, unsaturated polyester resins and transparent polyamide plastics.
TL;DR: In this paper, eight varieties of peanuts were grown under measured field conditions, and seed obtained at five successive harvest dates and separated into three maturity levels were analyzed for fatty acid composition of oil.
Abstract: Eight varieties of peanuts were grown under measured field conditions. Seed obtained at five successive harvest dates and separated into three maturity levels were analyzed for fatty acid composition of oil. Mature peanuts were mostly higher in stearic (18:0) and oleic (18:1) acids, and lower in linoleic (18:2), arachidic (20:0) and behenic (22:0) acids. Oleic-linoleic ratios, which are correlated with oil stability, were higher in mature peanuts.
TL;DR: There is no research known at this time with the objective of altering amino acid distribution in soybeans, but interest in changing composition of soybeans focuses on linolenic acid in the oil.
Abstract: Interest in changing composition of soybeans focuses on linolenic acid in the oil. Available germ plasm includes no lines with less than about 3.5% linolenic acid in the oil. Some breeding lines have been obtained with iodine values of about 115, reflecting higher oleic acid and somewhat lower than normal linoleic and linolenic acid levels. Radiation and other mutagenic agents have been investigated to a limited extent for potential usefulness in inducing a mutation in the direction of low linolenic acid. No such mutant has yet been found, and the task of identifying one is formidable. There is no research known at this time with the objective of altering amino acid distribution in soybeans.
TL;DR: There is a 2- to 3-fold variation in the lipoxygenase activity of the soybean lines tested, which is influenced by the genotype of the maternal parent.
Abstract: Treatment of soybean seeds with x-rays has been successful in increasing the incidence of low-linolenic-acid soybean strains both in pure breeding lines and crosses of low-linolenic-acid lines. The incidence of strains high in oleic acid also is increased by x-ray treatment. A procedure for measuring the lipoxygenase content of seed is described. There is a 2- to 3-fold variation in the lipoxygenase activity of the soybean lines tested. The lipoxygenase activity of soybean seed is influenced by the genotype of the maternal parent.
TL;DR: In this article, a rhodium and triphenylphosphine catalyst system was used to hydroform safflower and linseed oils and their methyl esters, which resulted in a mixture of formylstearate, formyloleate, and diformyl stearate.
Abstract: Soybean, safflower and linseed oils and their methyl esters were effectively hydroformylated with a rhodium and triphenylphosphine catalyst system. The product from safflower methyl esters, hydroformylated at 100 C and 1000 psi synthesis gas (H2 + CO), proved to be a mixture of formylstearate, formyloleate and diformylstearate. At 150 C and 15 00 psi synthesis gas the formyloleate was hydrogenated and the product formed was a mixture of mono- and diformylstearates. The unsaturated monoformyl fraction (100 C) was tentatively identified as a mixture consisting mainly of methyl 9(10)-formyl-cis-12-and methyl 12(13)-formyl-cis-9-octadecenoates. The saturated monoformyl fraction (150 C) was a more complex isomeric mixture of methyl formylstearate. The diformyl fractions from hydroformylated safflower and linseed esters were identified as mixtures consisting mainly of 9,12-(10,13)- and 10,12-(11,13)-diformyloctadecanoates. When hydroformlyation of polyunsaturated fats was interrupted,cis-unsaturated formyl oils resulted.
TL;DR: Nuclear magnetic resonance (NMR) method for the quantitative analysis of cyclopropenoid fatty acids (CPFA) in lipids is described, with good accuracy at CPFA concentrations of 1% to 100%.
Abstract: Nuclear magnetic resonance (NMR) method for the quantitative analysis of cyclopropenoid fatty acids (CPFA) in lipids is described. Good accuracy is obtained at CPFA concentrations of 1% to 100%. At a CPFA concentration of 10%, NMR is accurate to 0.5%. The position of absorption of the two ring methylene hydrogens is solvent dependent.
TL;DR: In this article, general classifications of food emulsifiers are presented, and their functions are discussed. Examples of many food products are given, and recommended emulsifier usage levels are presented.
Abstract: General classifications of food emulsifiers are presented, and their functions are discussed. Examples of many food products are given, and recommended emulsifier usage levels are presented. Some of the food applications cited include: cakes, icings, toppings, bread, sweet goods, frozen desserts, coffee whiteners, peanut butter, margarine and confectionery coatings.
TL;DR: Gas liquid chromatographic analysis of unfractionated beeswax (treated with diazomethane) using Dexsil 300 as liquid phase gives a good separation of hydrocarbons, free fatty acids as methyl esters, and long chain monoesters as mentioned in this paper.
Abstract: Gas liquid chromatographic analysis of unfractionated beeswax (treated with diazomethane) using Dexsil 300 as liquid phase gives a good separation of hydrocarbons, free fatty acids as methyl esters, and long chain monoesters. These components can be estimated using internal standards and together account for ca. 65% of the wax. Petroleum hydrocarbon or fatty acid adulterants can be detected. Unsaturated hydrocarbons are partially resolved from the corresponding saturated compounds.
TL;DR: In this article, the effect of fermentation and roasting on certain chemical properties related to flavor in chocolate is reviewed, focusing on monocarbonyls, headspace volatiles, pyrrole aldehydes and alkyl pyrazines.
Abstract: More than 300 volatile compounds have been identified in roasted cocoa beans and its products, making chocolate one of the most complicated natural flavors. Most beans, after harvesting, are subjected to a fermentation that is an important step in the formation of flavor precursors. Roasting is essential to the development of chocolate flavor both with respect to the loss of undesirable volatiles and the generating of key aroma compounds. Flavor is modified to meet demand using blends of beans and through variation in roasting conditions and the mechanical treatments employed to process beans into chocolate liquor and coating. The effect of fermentation and roasting on certain chemical properties related to flavor in chocolate is reviewed. Particular attention is given to monocarbonyls, headspace volatiles, pyrrole aldehydes and alkylpyrazines.