Cacao fermentation

Knapp, A., Cacao Fermentation, Bale, Sons and Curnow, London, 1937. 

DKP Formation in Model Peptide Systems. The fact that DKPs are formed at relatively lov temperatures suggested that catalyzed peptide decomposition occurs in the weakly acidic milieu produced by cacao fermentation. Reactions of simple peptides were followed at 0.02 M (initial concentration) in refluxing acetic acid (120°C) to simulate the interior of a bean during roasting (Table II). 

Forsyth, W. G. 1949. A method for studying the chemistry of cacao fermentation. Nature 164, 25. 

Knapp, A. W. 1937. Cacao Fermentation. Bale, Sons and Cumow, Ltd., London. Knapp, A. W., and Heame, J. F. 1939. The presence of leuco-anthocyanins in Criollo cacao. Analyst 64, 475. 

Schwan, R.F., Vanetti, M.C.D., Silva, D.O., et al. (1986) Characterization and distribution of aerobic, spo-e-forming bacteria from cacao fermentations in Bahia. J Food Sci 51, 1583-1584. 

After the ripe pods are harvested, they are cut open and the beans and adhering pulp are removed for fermentation. It is during the process of fermentation that cacao acquires much of its characteristic flavor and aroma. Fermentation soon occurs due to the high sugar content of the pulp and the presence of microorganisms. The sugars are converted to alcohols and finally to acetic acid, which drains off. The acetic acid and heat formed... 

Composition of Unfermented and Fermented Cacao Beans (Percent by Weight)... 

Although low levels of methylxanthines have been detected in the leaves and flowers of T. cacao, the primary storage location is within the seed or bean.16 The cocoa bean is the major natural source of the methylxanthine theobromine, but contains only small amounts of caffeine. Theophylline has been detected in cacao beans, but at such low concentrations that its presence generally is ignored. Together, theobromine and caffeine account for up to 99% of the alkaloid content of T. cacao beans. Alkaloid content is affected by genetic makeup, maturity of beans at harvest, and fermentation process. Analytical methodology also is partially responsible for some of the disparity in methylxanthine values since many early methods were unable to separate theobromine and caffeine. 

In live cocoa seeds, the methylxanthines are localized in polyphenolic storage cells. Bean death, which occurs 24 to 48 h after initiation of fermentation, triggers diffusion of the methylxanthines from the nib to the shell. The early studies of Humphries state that cacao cotyledons lose about 40% of their theobromine during fermentation.17 According to Knapp and Wadsworth, the loss of theobromine and caffeine becomes significant on the third day when the methylxanthines begin to diffuse into the shell.18 This migration continues until the concentration of the methylxanthines in nibs and shell are almost equal. 

After fermentation, cacao beans are dried and then transported to the factory for roasting. The ultimate purpose of roasting is to develop desirable bean flavor and aroma, as well as the necessary texture for later grinding. As shown in Table 4, the methylxanthine content of cacao beans was not found to change significantly during the roasting process.5-24 26... 

This chapter has compiled and evaluated information on the methylxanthine composition of cocoa and various chocolate foods and beverages, as well as the consumption pattern for these commodities. Cacao is the major natural source of the xanthine base theobromine. Small amounts of caffeine are present in the bean along with trace amounts of theophylline. Numerous factors, including varietal type and fermentation process, influence the methylxanthine content of beans. 

The cacao plant, Theobroma cacao, is the source of chocolate which is well known and highly prized in international commerce. The cacao pods contain beans which are fermented and pressed to provide a brown liquid which is the raw material for chocolate. The press cake is ground and sold as cocoa and it also provides a brown colorant. The pods, beans, shells, husks and stems have also been suggested as colorants. They contain a very complex mixture of acyl acids, leucoanthocyanins, flavonoid polymers, tannins, and catechin-type polymers.33... 

Jacquet, M., Vincent, J.C., Rios, G.M. and Gibert, H., Fermentation of cocoa beans in a triple phase fluidized bed. Cafe Cacao The, 25 (1981) 45-54. 

Although cocoa as a drink is now rather unfashionable, it provides the raw material for the manufacture of chocolate and is commercially very important. Cocoa (or cacao) is derived from the roasted seeds of Theobroma cacao (Sterculiaceae), a tree widely cultivated in South America and West Africa. The fruits develop on the trunk of the tree, and the seeds from them are separated, allowed to ferment, and are then roasted to develop the characteristic chocolate flavour. The kernels are then separated from the husks, ground up, and processed in various ways to give chocolate, cocoa, and cocoa butter. 

There is no evidence that any of the manufacturers of cocoa and chocolate have adapted any part of the Maillard technology to their manufacturing processes. There are at least two reasons for this. First, the standard processes, as applied to beans of good quality, produce excellent products. Second, while the work just reviewed has given us a rather clear outline as to how chocolate aroma is developed in the roasting of fermented beans, the research work has not yet been done, or reported, that would serve as a basis for improving the industrial processing of cacao beans. 

Chocolate has antioxidant properties for low-density lipoproteins and hence could prevent heart disease. Foods and beverages derived from cocoa beans have been consumed by humans since 460 a.d. Cocoa pods from the cocoa tree (Theobroma cacao) are harvested and the beans removed and fermented. Dried and roasted beans contain about 300 chemicals including caffeine, theobromine, and phenethylamine. Chocolate liquor is prepared by finely grinding the nib of the cocoa bean and is the basis for all chocolate products. Cocoa powder is made by removing part of the cocoabutter from the liquor. Bittersweet chocolate, sometimes called dark chocolate, contains between 15 and 60% chocolate liquor, the remainder being cocoa butter, sugar, and other additives. Milk chocolate is the predominant form of chocolate consumed in the U.S. and typically contains 10 to 12% chocolate liquor. 

Besides their general flavor forming potential peptides are also reported to be unique precursors of composite food aromas. Peptides formed in the fermentative stage of cacao processing have been linked to roast generated chocolate aroma (5). Also, a methionine rich polypeptide has been associated vith roasted peanut volatiles (15). 

The composition of the aroma of coffee is extremely complex with more than 900 compounds determined146,147 (see Chapter 3.25). The aroma of tea is greatly influenced by the degree of fermentation (green tea148 and black tea149 to mention a representative example) (see Chapter 3.23). Research of cacao mass volatiles using AEDA was also conducted (Table 16).150... 

Another source of important and valuable papers has been the annual conferences held in London since 1945 by the Cocoa, Chocolate, and Confectionery Alliance, which has concentrated its endeavors on investigations of the agricultural problems of cacao, its extension to new areas of the world, the pests, diseases, and hazards to which cacao seems an easy victim, the specific problems of cacao viruses and their hosts, rehabilitation of devastated areas, improvement in cacao quality by dissemination of new methods of fermentation, drying and grading of the commercial supply of raw cacao, research on the soil, and investigation of insecticides, trace minerals, sunlight, rainfall, and fertilizers (22). 

Cacao liquor is prepared by fermenting and roasting cacao beans (Theobroma cacao L.). There are many reports on the antioxidant and related biological activities... 

Theobromine (3,7-dimethylxanthine, 3,7-dihydro-3,7-dimethyl-lW-purine-2,6-dione). C7H,N402, Mr 180.17 formula, see under theophylline. Monoclinic, bitter tasting needles, mp. 357 °C, sublimes at 290-295 °C, soluble in hot water, alkali hydroxides, concentrated acids, moderately soluble in ammonia, poorly soluble in cold water and alcohol. With acids T. forms salts which decompose in water detection by the murexid reaction. T. is the main alkaloid of cocoa (Theobroma cacao, 1.5-3 wt.-%), from which it is obtained - especially from the husks in which it accumulates during fermentation. The typical bitter taste of cocoa is the result of interactions between T. and the pip-erazinediones formed in the roasting process. T. has diuretic, vasodilatory, and stimulating effects on cardiac muscle. The activities are weaker than those of the structurally related caffeine (a methylation product of T.) with which it co-occurs in cola nuts. For further pharmacological properties, see table under theophylline. 

Cacao, from Theobroma cacao (and related species of the Sterculiaceae), is derived from the seed, which is fermented and roasted. These seeds contain 0.9-3% theobromine (31) and the husks 0.2-3%. The genus Theobroma is native to the New World but is extensively cultivated in several tropical areas, especially West Africa. 

Isobutyl-2-methoxypyrazine (41) is a major odor component of Capsicum annuum. P3nazines that lack the 2-me-thoxyl substituent are partially responsible for the odor of fermented and roasted coffee and cacao (Nahrstedt, 1982 Rothschild et al., 1984). 

Forsyth, W. G. 1952b. Cacao pol3rphenolic substances. 2. Changes during fermentation. Biochem. J. 61, 516. 

Seeds of Theobroma cacao are worldwide in use for production of cocoa butter and confectionary products. The production of raw cocoa from fresh seeds is based on a complex fermentation process, which leads to the aroma precursors. This process enhances the amount of peptides and free amino acids in the seeds, but it also reduces the amount of phenolic compounds, especially the proantho-cyanidins. These antioxidative compounds are mostly composed of catechin and epicatechin monomers and oligomers up to decamers. The fermentation has to take into account that both factors, production of aroma precursors as well as... 

The compounds found in fermented and dried raw cacao, the basis for chocolate production, differ considerably from the compounds present in fresh-harvested cocoa seeds. The transition of fresh seeds to raw cocoa takes place in the... 

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