Determination of oligomeric proanthocyanidins and their antioxidant capacity from different chocolate manufacturing stages using the NP-HPLC-online-DPPH methodology
Cocoa beans are a well-known source of antioxidant polyphenols. Especially individual oligomeric proanthocyanidins demonstrated a significant contribution to the total antioxidant activity of cocoa compared to monomeric compounds. An NP-HPLC-online-DPPH assay was developed for separating the homologous series of oligomeric proanthocyanidins and the simultaneous assessment of their antioxidant capacity in relation to the degree of polymerization (DP). The present study describes the influence of the different stages of a lab -scale chocolate manufacturing process on the content of oligomeric proanthocyanidins and their antioxidant capacity. The sum of the total proanthocyanidin content (Sigma DP1-DP13) decreased from 30 mg epicatechin equivalents per gram non-fat dry matter in raw fresh cocoa beans to 6 mg epicatechin equivalents per gram in the final chocolate. The antioxidant capacity decreased accordingly from 25 mg epicatechin equivalents per gram nonfat dry matter in raw fresh cocoa beans to 4 mg/g in the final chocolate product. (C) 2016 Elsevier Ltd. All rights reserved.