Polyphenolic content and composition and antioxidative activity of different cocoa liquors

Abstract

Cocoa liquor used in the confectionery industry comes from a wide range of geographical areas and may have different chemical compositions, sensory properties, and nutritional values. We found it interesting to study the polyphenolic content and composition of cocoa liquors for their potential use in industrial production. Six defatted samples originating from different countries were extracted with aqueous methanol (70%, v/v), and the polyphenolic profiles were determined using RP-HPLC method. According to our results, all samples of cocoa liquors have similar polyphenolic profiles, however, quantitatively varied. In the samples, about 13 compounds were identified by comparison of their retention times and UV spectra, and the quantified peaks were (+)-catechin, (–)-epicatechin, (–)-gallocatechin, (–)-epigallocatechin, caffeic acid derivative, caffeine, and theobromine. Also, several peaks were identified as oligomeric procyanidins. The free-radical scavenging activity was determined by the DPPH• (1,1'-dipheny-2-picrylhydrazyl) and Oxygen Radical Antioxidant Capacity (ORAC) assays. The order of antioxidant activity of the cocoa liquors studied was the same with both methods (Madagascar > Mexico > Ecuador > Venezuela > Sao Tome > Ghana samples). In addition, correlation between the antioxidant capacity and polyphenolic content was also determined, a high correlation coefficient having been obtained by both methods (<i>R<sup>2<Isup> = 0.9868 for DPPH, and 0.9375 for ORAC).