Cocoa flavor components

More than 300 compounds had been identified in cocoa volatiles, 10% of which were carbonyl compounds (59,60). Acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2-methylbutanal, phenylacetaldhyde and propanal were products of Strecker degradation of alanine, valine, leucine, isoleucine, phenyl-acetaldehyde, and a-aminobutyric acid, respectively. Eckey (61) reported that raw cocoa beans contain about 50-55% fats, which consisted of palmitic (26.2%), stearic (34.4%), oleic (37.3%), and linoleic (2.1%) acids. During roasting cocoa beans these acids were oxidized and the following carbonyl compounds might be produced - oleic 2-propenal, butanal, valeraldehyde, hexanal, heptanal, octanal, nonanal, decanal, and 2-alkenals of Cg to C-q. Linoleic ethanal, propanal, pentanal, hexanal, 2-alkenals of to C q, 2,4-alkadienals of Cg to C-q, methyl ethyl ketone and hexen-1,6-dial. Carbonyl compounds play a major role in the formation of cocoa flavor components. 

Cocoa flavor. Some of the over 500 known volatile components of C. f. are already present in raw cocoa, but most are formed after diying and roasting (at 110-130 °C), mainly by Maillard or Strecker reactions from amino acids, peptides, and sugars resulting from anaerobic fermentation. C. f. is not determined by one impact compound but is rather a composition of various aromas caramel-like ( maltol, Furaneol , and 2-hydroxy-3-methy 1-2-cyclopenten-1 -one), flowery ( linalool, 2-phenylethanol, phenylacetaldehyde). 

Kadow, D., Bohlmann, J., Phillips, W., and lieberei, R. (2013) Identification of main fine or flavor components in two genotypes of the cocoa tree (Theobroma cacao I..). J Appl Bot Food Quat 86, 90-98. 

It is a complex mixture of acetone-insoluble phosphatides that consists chiefly of phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl inositol combined with various amounts of other substances such as triglycerides, fatty acids, and carbohydrates. Refined grades of Lecithin may contain any of these components in varying proportions and combinations depending on the type of fractionation used. In its oil-free form, the preponderance of triglycerides and fatty acids is removed and the product contains 90% or more of phosphatides representing ah or certain fractions of the total phosphatide complex. Edible diluents, such as cocoa butter and vegetable oils, often replace soybean oil to improve functional and flavor characteristics. Lecithin is only partially soluble in water, but it readily hydrates to form emulsions. The oil-free phosphatides are soluble in fatty acids, but they are practically insoluble in fixed oils. When ah phosphatide fractions are present, Lecithin is partially soluble in alcohol and practically insoluble in acetone. 

If only a few specific components need be quantified, the analysis time can be considerably shortened. Dong and DICesare (50) developed an high speed isocratic reverse phase separation for 2,5-dimethyl-4-hydroxy-3(2H)-furanone. This compound is commonly known as pineapple ketone and can be quantified in food flavoring products using one of the new 3x3, C-18 columns in as little as 2 minutes. Other workers (51J have used rapid gradients (6 min.) to separate caffeine, trigonelle and theobromine in coffee and cocoa products. 

The authors observed that an exhaustive list of all the chemicals present in coffee flavor had not yet been compiled, but they believed they had identified the components that are present at the higher ratio of weight, and those which principally control the odor note. Most of the substances identified were well-known compounds present in other roasted products as well, for instance in caramel sugar, cocoa, baked bread and—partially—even in wood tar. However, some of the chemicals detected were new and, obviously, characteristic of roasted coffee. Traces of methyl mercaptan, which was already known at that time and which smells even worse, were also detected in coffee aroma. Commenting on this observation, Reichstein and Staudinger note that it is generally known that many popular raw materials and synthetic perfume compounds owe their characteristic note, which is extremely pleasant to the olfactory sense, to their content of small quantities in additives which carry a rather unpleasant odor in themselves but prove very attractive in thinned solutions and in admixture with other oils. The authors tried to reconstitute coffee aroma, and only by combining over 40 of the substances extracted from coffee... 

The odor is powerful, choking when undiluted, but becomes tolerable in extreme dilution, almost pleasant fruity, fermented with a peculiar note resembling that of roasted cocoa or coffee (Arctander, 1967). For Motoda (1979), it is apple or malt. Fors (1983) mentions other odor descriptions as burnt, sickly for GC eluates, musty, fruity aromatic at 100°C becoming burnt cheese at 180°C. It is described as fermented, pungent, fruity at a sniffing port in a headspace/GC analysis of freshly roasted coffee (Holscher and Steinhart, 1992a). Like C.ll, it is a key component in a brew with a high aroma impact (Pollien et al., 1998). The flavor of the (R)-isomer is chocolate-like (Chemisis, 1971). 

Because they are biochemically similar to zygotic embryos (3,4), somatic embryos also present an opportunity for vitro production of numerous secondary plant products which are associated with seeds. For example, essential oil, flavor, and aroma components found in seeds of celery (5), cocoa (6,7), and oil palm (8) are produced by somatic embryos. The ability to control and develop this process may permit more economical and reliable production of certain plant products on an industrial level. 

Occurrence The main component of rose absolute and rose water occurs in small amounts in many flavors and essential oils, e. g., beer, cocoa, and tea flavor, as well as geranium, neroli [see orange flower absolute (oil)], and ylang-ylang oil. Frequently, P. occurs in glycosidic form. ... 

The major analytes of coffee include caffeine, chlorogenic acids, and flavor and volatile aromatic components. The major analytes in cocoa are me-thylxanthines, mainly theobromine and trace amounts of caffeine, cocoa fat, and lipids. Other analytes of interest in cocoa are tannins, pigments, and aroma components. The major analytes of tea are the methylxanthine alkaloids, including caffeine and theophylline, polyphenols (catechins, tannins, and related flavanols), and volatile and aromatic components. Analysis of black tea would also include theaflavins and thearubigens, which are oxidation and condensation products of polyphenols. 

Quality evaluation of cocoa bean and cocoa powder is by visual inspection for contamination, moldiness, and by aroma/flavor and tasting. Physical analysis of cocoa bean and cocoa powder includes analysis for total moisture (< 8%) and fat (<55%). Additionally, the quality of cocoa is characterized by the iodine number (degree of unsaturation of the fatty acid components), unsaponifiable matter, and GC analysis (for volatile and aroma components). 

It is noteworthy that it took 40 scientists working since 1920 to segregate out the 80 chemical components of apple flavor. Cocoa has been found to have over 125 basic chemical elements, and coffee has nearly 200. 

Cocoa powder is used extensively as a flavor or nutrient component in nonalcoholic beverages, ice cream, cakes, biscuits, and others. 

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