Red Pericarp Advanced Breeding Lines Derived from Oryza Rufipogon × Oryza Sativa: Physicochemical Properties, Total Antioxidant Activity, Phenolic Compounds and Vitamin E Content

Two new red pericarp transgressive variants (advanced breeding lines from BC2F7 generation) with high yield, derived from a cross between the wild relative, O. rufipogon Griff. and O. sativa subsp. indica cv. MR219, were analysed to determine their proximate composition, total antioxidant activity, phenolic acid composition and tocochromanol content in comparison with two commonly consumed rice varieties, MR219 (brown coloured) and Thailand rice (red coloured). The red pericarp variants were not significantly different in grain quality related traits. For fat content, neither variant showed any significant difference to the recurrent parent MR219, however for amylose content they possessed lower levels compared to MR219 but for both traits results were comparable to Thailand red rice. Variants G33 and G37 produced significantly (p<0.05) higher total phenolic content (0.49 and 0.51 mgGAE/g, respectively) than the white control sample, MR219 (0.32 mgGAE/g) but lower than Thailand red rice (1.59 mgGAE/g) (p<0.05). Ferric-Reducing Ability Power (FRAP) was significantly (p<0.01) higher in both variants compared to MR219 but lower than in Thailand red rice. For DPPH0 radical scavenging, both variants were not significantly different from both controls. Caffeic and ferulic acid detected in all samples were in higher amounts compared to the other compounds and hydroxycinnamic acids were considered as the main phenolic acids. Across all samples, the content of total E vitamin was higher in G37 and (-tocotrienol, which was the most abundant tocol. In conclusion both red pericarp variants can be used in cultivar development program for red rice with high nutritional value.