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

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-,beta-xylopyranosyl-beta-glucopyranoside)-5-O-beta-glucopyranoside and delphinidin 3-O-beta-glucopyranoside-5-O-beta-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 (14.6 g/kg dry weight, DW) than in Morena (12.8 g/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. (C) 2017 Elsevier Inc. All rights reserved.