Composition and Structure of Anthocyanins in the Periderm and Flesh of Sweet Potatoes

Abstract

Thirteen anthocyanins were isolated from the periderm of 'Beniaka' and 'Beniazuma' sweet potatoes (Ipomoea batatas L.). By means of absorption spectra, HPLC, 1H-NMR and FAB-MS analysis, the structures of major anthocyanins were identified as:cyanidin-3-diglucoside-5-glucoside, peonidin-3-diglucoside-5-glucoside, p-hydroxybenzoyl-cyanidin-3-diglucoside-5-glucoside, p-hydroxybenzoyl-peonidin-3-diglucoside-5-glucoside, caffeoyl-p-hydroxybenzoyl-cyanidin-3-diglucoside-5-glucoside, caffeoyl-p-hydroxybenzoyl-peonidin-3-diglucoside-5-glucoside, and caffeoyl-peonidin-3-diglucoside-5-glucoside.
The anthocyanins contained in the flesh of 'Yamagawamurasaki' and 'Tanegashimamurasaki' sweet potatoes, were acylated with cinnamic acid derivatives. The analyses revealed that the compositions of anthocyanins differed from those found in the periderm.