Compositional characterization study on high -molecular -mass polymeric polyphenols in red wines by chemical degradation

In this study, purified high-molecular-mass polymeric polyphenols (PHPPCs) were first isolated by solid phase extraction combined with semi-preparative HPLC from red wine. Different chemical degradation methods (NaOH, HCl and benzyl mercaptan degradation) were used to decompose the PHPPCs into low molecular weight fragments. The chemical structures of the degradation fragments were verified by HPLC/UPLC−DAD and HPLC-FT-ICR-MS. The results showed that three proanthocyanidins, five proanthocyanidins benzylthioether, quercetin and fifteen anthocyanins were detected by degradation in the presence of benzyl mercaptan. Nine bound phenolic acids were found by NaOH degradation and twelve bound amino acids were proved by HCl. Among these different fragments detected,delphinidin-3-O-glucoside pyruvic adduct, four acylated anthocyanins, four hydroxyphenyl pyranoanthocyanins, quercetin, protocatechuic acid, vanillic acid, and cinnamic acid were first found in the PHPPCs. For the first time amino acids as constitutive units of polymeric polyphenols in red wines were verified. Based on the degradation fragments, the possible structural skeleton of PHPPCs in red wine was postulated.Graphical abstract
Source: Food Research International - Category: Food Science Source Type: research