Abstract
Anthocyanins are economically valuable phytochemicals of significant relevance to human health. Multiple fruit and vegetable sources for industrial-scale anthocyanin purification exist, however, each source has distinct anthocyanin levels and profiles conferred by modifications to the central anthocyanidin core. In this study, we assessed three purple-fleshed and one orange-fleshed cultivars of sweet potato, with the goal of studying their anthocyanin yield and diversity when this warm-weather crop is grown in cooler, northern latitudes. Comparison of multiple anthocyanin extraction methods revealed acidified ethanol extraction of lyophilized roots as the optimal method, producing a high, average yield of ∼800 mg anthocyanins/100g dry weight. Mass spectrometric analysis of sweet potato extracts identified eighteen high-confidence anthocyanins – all derived from peonidin and cyanidin cores – contributing to over 90% of the total anthocyanin signal. The concentrations of different anthocyanins were variable between the three purple-fleshed cultivars, while low anthocyanin accumulation was observed in the orange-fleshed cultivar. Further assessment of the untargeted high-resolution mass spectrometry data using MS/MS molecular networking revealed existence of low-abundance anthocyanins with delphinidin and pelargonidin cores, as well as over 250 peaks comprising of potential anthocyanins and flavonoids. These results provide a comprehensive insight into anthocyanin yields of purple-fleshed sweet potato grown in the northern latitudes and reveal the large diversity of anthocyanins and flavonoids in this popular crop.
Competing Interest Statement
The authors have declared no competing interest.
