The effect of alkalization on the bioactive and flavor related components in commercial cocoa powder

Abstract

The influence of alkalization on the bioactive components, volatile flavor compounds, and flavor related components in cocoa powder was studied. It indicated that the content of both methylxanthines and flavan-3-ols reduced as the degree of alkalization increased. Higher degree of alkalization decreased the total polyphenols content. More than 80 volatile compounds in the cocoa mass after alkalization were found in our study. Acetic acid, which was the predominated acid in cocoa powders before alkalization, was greatly decreased by 67.15%, while d-limonene was increased to 31.4% after heavy alkalization. Less nitrogen-containing heterocyclics were found after alkalization treatment, suggesting that interactions may occurred between polyphenols and aroma compounds pyrazines in cocoa powders. Amino acids analysis indicated that saccharide binding was preferred on hydrophobic amino acids. Under varying alkalizing conditions, fructose content reduced significantly except for the one with the addition of glucose. Results showed that the polyphenols, theobromine, caffeine, amino acids as well as the volatile compounds changed through alkalization, leading to unique flavor and color to the end products.