Total phenolic content and antioxidant capacity of rice grains with extremely small size

Abstract

Whole cereal grains have been received increasingly attention by consumers due to their potential health benefits because of their antioxidant capacity, which is probably derived from their high contents of phenolics, flavonoids and other phytochemicals. Here, we reported the contents of phenolics and flavonoids in different rice genotypes with grain size ranging from extremely small to normal size. The smaller grains had higher phenolic content, flavonoid content and antioxidant capacity than the normal and larger grains. The phenolic content had positive correlation with the flavonoid content (P<0.001) and the antioxidant capacity (P<0.01). The phenolic and flavonoid content had negative correlation with grain length, grain length to width ratio and 100-grain weight (P<0.01), but had no relationship with grain width and grain thickness. Thus, the phenolic content could be indirectly predicted by grain length and 100-grain weight. New rice varieties high in antioxidant levels could be obtained by breeding for extremely small grain rice.   Key words: Phenolics, flavnoids, antioxidant capacity, rice grains.