Abstract
Black-purple rice is becoming popular with health conscious food consumers. In the present study, the secondary metabolites in dehulled black-purple rice cv. Asamurasaki were analysed using HPLC-PDA-MS2. The seeds contained a high concentration of seven anthocyanins (1400 mu g/g fresh weight) with cyanidin-3-O-glucoside and peonidin-3-O-glucoside predominating. Five flavonol glycosides, principally quercetin-3-O-glucoside and quercetin-3-O-rutinoside, and flavones were detected at a total concentration of 189 mu g/g. The seeds also contained 3.9 mu g/g of carotenoids consisting of lutein, zeaxanthin, lycopene and beta-carotene. gamma-Oryzanol (279 mu g/g) was also present as a mixture of 24-methylenecycloartenol ferulate, campesterol ferulate, cycloartenol ferulate and beta-sitosterol ferulate. No procyanidins were detected in this variety of black-purple rice. The results demonstrate that the black-purple rice in the dehulled form in which it is consumed by humans contains a rich heterogeneous mixture of phytochemicals which may provide a basis for the potential health benefits, and highlights the possible use of the rice as functional food. (C) 2013 Elsevier Ltd. All rights reserved.