Pyrazines formation in cocoa beans: Changes during fermentation

Fermentation of cocoa beans led to the formation of 2-methyl-, 2,5-dimethyl-, 2,6-dimethyl-, 2,3-dimethyl-, 2,3-5-trimethyl- and 2,3,5,6-tetramethylpyrazine. No pyrazines were detected in unfermented cocoa beans. Tota pyrazines (437.53 mu g/100g), tetramethyl-(295.56 mu g/100g), trimethyl-(126.07 mu g/100g) and 2,5-dimethylpyrazine (6.01 mu g/100g) reached maximum concentrations on the 4th day of fermentation. The formation of total pyrazines and trimethylpyrazine was more influenced by an increase in the aeration time, whereas that of the tetramethylpyrazine was dependent on fermenting mass. Optimum conditions for maximum formation of total pyrazines, trimethyl- and tetramethylpyrazine could be achieved at fermenting mass of 85-88 kg and an aeration time of 5.5-5.7 min.