Abstract:

Grains with black color are considered benefit to human’s health. Several cultivars or lines of wheat with black grain have been successfully bred in China. The antioxidation capacities of wheat grains with different colors were characterized by using active oxygen resistance reactivity units (AORRU), superoxide anion resistance reactivity units (SARRU) and total antioxidant reactivity units (TARU) as antioxidation indices. The relationships between antioxidation indices of wheat grains and the corresponding concentrations of pigments and flavonoid compounds as well as antioxidant enzyme activities were also investigated. The results indicated that blue, black purple, dark purple and purple wheat grains were significantly higher in the levels of AORRU, SARRU and TARU than white and red wheat grains. Their concentrations of antioxidants such as total flavonoids, amino acids, vitamin C and carotenoids, and activities of antioxidases such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were also higher than common white or red wheat grains. Grain pigment content, total flavonoid content, total amino acid content and SOD activity showed significant positive correlations to the three antioxidation indices at P≤0.05 or P≤0.01, while vitamin C content and carotenoid content showed significant positive correlations to one or two of the three indices at P≤0.05 or P≤0.01. It was concluded that the pigments, flavonoids, SOD, vitamin C and amino acids are the main substances those confer distinguished antioxidation capacities of blue, purple black, dark purple and purple wheat grains as compared with common white and red wheat grains.

Key words: Wheat, Antioxidant activity, Antioxidant, Grain pigment, Flavonoids