Polyphenol profiles and in vitro digestive enzyme inhibitory activities were compared between cocoa extracts from unfermented beans (UB), fermented beans (FB), unfermented liquor (UL), and fermented liquor (FL). Total polyphenols, total flavanols, and individual flavanols were significantly different between UB/FB and UL/FL. All extracts effectively inhibited α-glucosidase (lowest IC50 = 90.0 μg/mL, UL) and moderately inhibited α-amylase (lowest IC50 = 183 μg/mL, FL) and lipase (lowest IC25 = 65.5 μg/mL, FB). Our data suggest that fermentation does not reduce α-glucosidase inhibition, while roasting may enhance inhibition. For α-amylase, both fermentation and roasting improved inhibition. Finally, for lipase, both fermentation and roasting attenuated inhibition. Conclusive correlations between inhibition and mDP, total polyphenol, and flavanol contents were not found. Our data suggest that enzyme inhibition activities of cocoa are not uniformly reduced by polyphenol/flavanol losses during fermentation and roasting. This paradigm-challenging finding suggests other cocoa constituents, potentially formed during processing, contribute to digestive enzyme inhibition.
Keywords: diabetes; flavan-3-ols; glucose; lipase; procyanidins; α-amylase; α-glucosidase.