ความสัมพันธ์ของปริมาณแอนโทไซยานินต่อปริมาณโพลีฟีนอล และความสามารถในการต้านปฏิกิริยาออกซิเดชันในข้าวสีและไม่มีสีสายพันธุ์ต่างๆ

Abstract

Anthocyanin, total polyphenol content and antioxidant activities of fifty-one Thai rice cultivars were investigated. The antioxidant activities were evaluated using three different assays; ferric reducing antioxidant power (FRAP), 2,2-azino-bis-(3-ethylbenzothi azoline-6-sulphonic acid) diammonium salt (ABTS) radical cation and oxygen radical absorbance capacity (ORAC) assays. The total polyphenol content (TPC) and anthocyanin content varied significantly and ranged from 0.194-8.702 and 0.001– 6.676 mg/g (dry wt), respectively. The extracts from pigmented rice exhibited higher TPC, anthocyanin content and antioxidant activities than did the non-pigmented varieties. Among them, glutinous dark rice (GDR) had the highest levels of TPC and anthocyanin content and exhibited the greatest antioxidant activities. The significant correlation coefficient was also noted between TPC, anthocyanin content and all three antioxidant assays ranged from 0.758-0.943 indicating that TPC in rice genotype were responsible for the antioxidant activities. These results revealed that the anthocyanin content and total polyphenol content as well as antioxidant activities in non-pigmented rice lower than pigmented rice cultivars.