Total phenolic contents of 20 varieties of black rice and antioxidant activities

Polyphenols from 20 black rice varieties were separated with ultrasound-assisted ethonal methods. The total polyphenolic content was evaluated by Folin-Coleau method. The antioxidant activities were analyzed with potassium ferricyanide, ferric reducing-antioxidant power ( FRAP) and 1, 1-diphenyl-2-picrylhydrazyl ( DPPH) methods, respectively.Correlation analysis was carried out between total polyphenolic content and antioxidant capacities determined by different methods.The results showed that the total polyphenolic content and antioxidant capacity differs among black rice varieties. The total polyphenolic content was among ( 2.305 ± 0.035) and ( 4.842 ± 0.030) mg/g.The elected five rice varieties possessed higher polyphenolic content and higher antioxidant capacities. Through the correlation analysis, it was found that the antioxidant capacity and polyphenols contents showed a significant positive correlation ( R²> 0.900, p < 0.01) . The study provides an important reference value and scientific basis for the comprehensive selective breeding and development and utilization of black rice varieties.