Phytochemical content and antioxidant activity of colored and non-colored Thai rice cultivars

Abstract

Rice is one of the important foods of the world. Particularly, countries in Asia are popular eating rice daily food rather than in order regions of the world. Rice is sources of many bioactive non-nutrient compounds, known as phytochemicals. This study aimed to determine phytochemicals value such as, total phenolic compound, total anthocyanin, phytic acid, gamma (γ)-oiyzanol composition and antioxidant activity of rice seed extracts of twelve colored and non-colored native Thai rice cultivars in Surin province, Thailand. The results showed that methanolic extracts of those rice seeds produced the highest extraction yield (5.45%). The colored cultivar 53 showed the highest Total Phenolic Content (TPC) and anthocyanins content by Folin-Ciocalteu method and pH-differential, respectively (7.40 mg Gallic Acid Equivalent (GAE)/100 g and 1045.12 mg malvidin/100 g, respectively). Moreover, there is a similarity in the γ-oiyzanol content which detected by HPLC, colored rice seed extracts was statistically significant higher (p<0.05) than those non-colored. There were 4 major components of oryzanol (cycloartenol ferulate, 24-methylene cycloartenol ferulate, campesteiyl ferulate and β-sitosteryl ferulate) which were successfully identified. Anti oxidant activity of rice crude extracts was examined by DPPH scavenging method. Colored rice seed cultivar number 98 showed the highest activity (IC50 = 0.545 mg mL-1). While, phytic acid content in non-colored-rice seed cultivar number 236 showed the highest content (9.94 mg/100 g). From these results suggested to the potential of Thai rice seeds which may be further developed in food industry, cosmetic and health product. © 2012 Asian Network for Scientific Information.