Our recent study found that antioxidative activity of phenolic compounds extracted from germinated chickpea was boosted in both in vitro assays and oil-in-water emulsions [ Xu et al. Food Chem. 2018 , 250 , 140 ]. The purpose of this study was to elucidate the mechanism by which germination enhances the antioxidative activity of the phenolic compounds extracted from chickpea. Liquid chromatography coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS) and size-exclusion chromatography with multiangle-light-scattering and refractive-index detection (SEC-MALS-RI) were employed to evaluate the phenolic composition of soluble phenolic compounds (free and bound) and molar masses of soluble bound phenolic compounds, respectively, over 6 days of germination. According to principal-component analysis of the interrelationship between germination time and phenolic composition, it is revealed that protocatechuic acid 4- O-glucoside and 6-hydroxydaidzein played a pivotal role in the soluble free phenolic compounds, whereas gentisic acid and 7,3',4'-trihydroxyflavone were important in the soluble bound phenolic compounds. Molar masses of soluble bound phenolic compounds were increased after 6 days of germination. Protective and dual antioxidative effects were proposed to explicate how the antioxidative activity of soluble bound phenolic compounds in oil-in-water emulsions was improved with germination.
Keywords: antioxidative activity; chickpea; germination; molar mass; phenolic compounds.