Compositional and antioxidant properties of anthocyanin-rich products prepared from purple wheat

Abstract

Demands for anthocyanin-rich ingredients are steadily growing due to their positive functions in human health and food coloration. Commercially available purple wheat was evaluated as a source of functional ingredients based on anthocyanin composition and antioxidant properties. Anthocyanins were concentrated in the bran fraction by about 2-fold and then the bran was further processed into anthocyanin-rich powder using ethanol extraction and column purification. Batch studies showed that anthocyanin concentration factor increased by about 81- to 135-fold in the powder depending on batch size. Characterization of anthocyanins with a triple quad mass spectrometry showed a complex anthocyanin profile with 5 pigments making up 93-96% of the total anthocyanin content. These pigments were cyanidin-3-glucoside, cyanidin-3-(6-malonyl glucoside), cyanidin-3-rutinoside, peonidin-3-glucoside and peonidin-3-(6-malonylglucoside) but their concentrations varied between bran and powder. The purple wheat bran and powder exhibited exceptional antioxidant capacity based on scavenging of DPPH, ABTS and peroxyl radicals holding a promise as functional ingredients.

Keywords: Anthocyanin composition; Anthocyanin-rich powder; Purple wheat; Wheat bran.