Antioxidant activities and contents of phytochemicals in methanolic extracts of specialty rice cultivars in Korea

Rice is an important agricultural commodity and a major staple food in Asian diets. The aims of this study were to investigate the antioxidant activities and phytochemical contents of methanolic extracts from specialty rice cultivars and to determine if there is any correlation between antioxidant activity and phytochemical content. Our results indicate that methanolic extracts from different rice cultivars contain different levels of phenolics, anthocyanin, carotenoids, γ-oryzanol, and vitamin E. Black rice cultivars such as 'Heugkwang', 'Heugseol', and 'Heugjinju' contained higher phytochemical contents compared to other cultivars. In contrast, the cultivars 'Segyejinmi', 'Cheonseok', 'Hanareum', and 'Dasan 1' contained significantly higher levels of γ-tocotrienol compared with other cultivars. The black rice cultivars also showed higher antioxidant activities. Phenolic content was positively correlated with DPPH and ABTS radical scavenging activities and reducing power. The results could have a direct impact on rice consumption by enhancing consumer awareness of health benefits of the rice.