Characterization of anthocyanins in novel Chilean maqui berry clones by HPLC–DAD–ESI/MSn and NMR-spectroscopy

摘要

Highlights ? Qualitative and quantitative analyses of anthocyanins in novel Chilean maqui berry clones. ? Major maqui anthocyanins were shown to be 3,5-O-diglycosylated by NMR spectroscopy. ? Delphinidin 3-O-β-glucoside-5-O-β-glucoside represented the major anthocyanin. ? Diglycosylated anthocyanin levels were higher than those of mono-substituted ones. ? The presented findings may be suitable for future commercial purposes of the berry. Anthocyanins in two Chilean maqui berry (Aristotelia chilensis (Mol.) Stuntz) clones named Luna Nueva and Morena were isolated and characterized by a core-shell column-based HPLC–DAD–ESI/MSn method and 2D–NMR spectroscopy, focusing on the yet not fully elucidated glycosylation pattern of the aglycones. For the first time, 2D–NMR spectroscopic data unambiguously showed that the major maqui anthocyanins were delphinidin 3-O-(2″-O-β-xylopyranosyl-β-glucopyranoside)-5-O-β-glucopyranoside and delphinidin 3-O-β-glucopyranoside-5-O-β-glucopyranoside. Among these pigments, the latter represented the most abundant anthocyanin in Luna Nueva (59% of total anthocyanin content, TAC) and Morena (50% of TAC). TAC was significantly higher in Luna Nueva (14.6g/kg dry weight, DW) than in Morena (12.8g/kg DW). In both samples, relative proportions of diglycosylated anthocyanins (84% of TAC) exceeded those of mono-substituted anthocyanins (～16%). The provided information about the position of glycosylation may be relevant for assessing color stability of maqui anthocyanins in future food applications.