A comparative study on antioxidative activity and polyphenol content of colored kernel rice

Abstract

Six rice cultivars (two red rice, two purple-black rice and two white rice) were compared for their antioxidative activities and differential distribution of active substances. Ethanol extracts prepared from red and purple-black hulled rice exhibited remarkably high superoxide anion-and radical-scavenging activities compared with those from white hulled rice. In addition, these activities were localized mostly in pericarp and testa, namely, rice bran. Colored rice contained polyphenols much more abundantly than white rice and their contents were mutually related to their antioxidative potencies. Spectrophotometric analyses showed that the major active substances in red rice and purple-black rice were tannin pigments and anthocyanin pigments, respectively.