Extraction and characterization of antioxidant from cocoa by-products

Antioxidative properties of extracts from six types of cocoa by-products have been studied. Seven different solvents differing in polarity were used to extract the antioxidants from cocoa by-products. Out of 42 different extracts tested, twelve extracts from cocoa powder, natural cocoa powder, cocoa nib and cocoa shell exhibited strong antioxidant activities using a diene conjugation formation method. The characterization studies done indicated that increasing extract concentration resulted in increased antioxidant activities at all the levels studied, namely 1000, 2000 and 3000 ppm. Methanol proved to be the best solvent in extracting antioxidants from cocoa by-products, followed by mixtures of chloroform, ether and dichloroethane and mixtures of chloroform, methanol and dichloroethane. The antioxidative activities of the extracts were found to be stable at temperatures below 50 degrees C and exhibited highest activity at neutral and alkaline pH. It appeares that flavonoid compounds may be responsible for the antioxidative activities in cocoa by-products and complete elucidation of the active compounds is in progress. (C) 1998 Elsevier Science Ltd. All rights reserved.