The Precursors of Chocolate Aroma: Production of Reducing Sugars during Fermentation of Cocoa Beans

Abstract

SUMMARY— The sucrose in fresh cocoa beans is hydrolyzed to glucose and fructose during fermentation and the rate of the reaction confirms the possible inclusion of reducing sugars among the precursors of chocolate aroma. The optimal concentration of reducing sugars in the bean is reached at about the same time as maximal flavor development, and coincides approximately with the peak in amino acid concentration. An objective method for assessing the “Degree of Fermentation” of cocoa beans has been proposed and tested.

Changes in free amino acid, peptide-N, sugar and pyrazine concentration during cocoa fermentation

“…In contrast, fructose, glucose, mannitol, inositol and total reducing sugars increased after the death of the beans and reached a maximum concentrations after 4 days of fermentation ; thereafter, their concentrations were decreased slightly until the end of the fermentation. Similar results were observed by Rohan and Stewart (1967b). Reineccius et al (1972a) and Berbert (1979).…”

“…Changes in peptide-N during cocoa fermentation were carried out by Biehl and Passern (1982) and Biehl et al (1985), whereas Lopez et al (1978), Reineccius et al (1972a) and Rohan and Stewart (1967b) studied the changes in sugars. During this fermentation process, the activity of microorganisms on the cocoa pulp will produce alcohol, acetic acid, lactic acid and generate heat that causes bean death.…”

Influência da fermentação e secagem de amêndoas de cacau no teor de compostos fenólicos e na aceitação sensorial

“…Com isso, é provável que, durante a secagem artificial, tenha ocorrido migração de gordura dos cotilédones para a testa (LOPEZ;QUESNEL, 1973;STEWART, 1967). Cabe destacar que, nas indústrias processadoras de cacau, a testa é descartada ou, em alguns casos, utilizada como combustível de caldeiras ou adubo.…”

“…Por outro lado, não deve ser efetuada de forma demasiadamente rápida, com o emprego de temperaturas elevadas, para evitar a migração de manteiga de cacau para a testa (película que envolve a amêndoa) e afetar o desenvolvimento do sabor característico de chocolate. Muitas das reações bioquímicas iniciadas na fermentação continuam na secagem (ROHAN; STEWART, 1967;LOPEZ;QUESNEL, 1973). Jinap, Thien e Yap (1994) avaliaram o efeito da secagem na acidez e no teor de ácidos graxos voláteis em amêndoas de cacau, não sendo observadas, por equipe de provadores treinada, diferenças sensoriais significativas entre os produtos obtidos da secagem natural e artificial.…”

Comparison of enzyme activities involved in flavour precursor formation in unfermented beans of different cocoa genotypes

“…6,8,9 Cotyledon invertase is another important enzyme during fermentation, responsible for hydrolysis of sucrose into glucose and fructose. 2,7,10 During roasting, these¯avour precursors participate in Maillard reactions to form the typical cocoa¯avour volatiles. 4 During the fermentation process, substrates become accessible to the enzymes as a result of subcellular changes.…”