Evaluation of bitterness and astringency of polyphenolic compounds in cocoa powder

Total polyphenols, tannins, (-)-epicatechin and colorimetric fractions were determined in six samples of three batches of cocoa beans subjected to various stages of fermentation (1-8 days), in 36 samples of non-alkalinized low fat cocoa powder and 15 samples of instant cocoa powder. The physico-chemical data obtained were related to sensory evaluation and submitted to analysis of variance, multivariate distribution (Mahalanobis distance) and Pearson Chi-squared test. From the results obtained, we can infer that optimally fermented cocoa samples have a maximum total polyphenols of 58 mg g-1, a tannins of 31 mg g-1, and a (-)-epicatechin of 3 mg g-1. Correspondence was not found between colorimetric fraction values and sensory data. These parameters are related to the sensory properties of cocoa and can be used to confirm deficiencies. © 1997 Published by Elsevier Science Ltd