Soluble and insoluble-bound fractions of phenolics and alkaloids and their antioxidant activities in raw and traditional chocolate: A comparative study

Abstract

Raw chocolate, produced with unroasted cocoa beans, is a novel food product. In this study, phenolics and alkaloids present in the soluble and insoluble-bound forms were identified and quantified by UPLC. The antioxidant activity was investigated by ABTS, DPPH, ORAC, and FRAP assays. Formulations with raw chocolate showed higher contents of many compounds in the soluble form (e.g. epicatechin, catechin, protocatechuic acid, and all alkaloids) in comparison with those found in traditional formulations and this translated to higher antioxidant activity (up to 56%, ORAC assay) than that in the latter samples. Traditional chocolates showed a higher amount of catechin released from the insoluble-bound fraction. Quantification of insoluble-bound theophylline (up to 96% insoluble-bound) and protocatechuic acid (up to 91% insoluble-bound) was critical. This is the first screening of the soluble and insoluble-bound antioxidants in both traditional and raw chocolate, therefore may help in carving their potential health claims as functional foods.