Cacao roasting process

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... 

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. 

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. 

Maillard reactions can be involved in the manufacture of foods in at least three quite different ways. First, there is the unconscious role played in the development of flavor in such traditional processes as the roasting of coffee and cacao beans, the baking of breads and cakes, and the cooking of meats. Second, there is the deliberate use of Maillard technology in the production of artificial (or engineered) foods and flavors. Third, there are the efforts to inhibit undesirable results of Maillard reactions in food processing today. 

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. 

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). 

Watterson, J.J., Miller, K.B., Fuijanic, J.J., Stuart, D.A. Process of producing cacao flavor by roasting combination of amino acids and reducing sugars. US Patent, 1997, 5,676,993, assigned to Hershey Foods. 

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