Comparison of Antioxidant Activities of Different Colored Wheat Grains and Analysis of Phenolic Compounds

Extracts from six wheat varieties (three purple, one yellow, two red, and one white) were evaluated and compared for their antioxidant capacities against oxygen radical and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Phenolic composition in the extracts was examined by high-performance liquid chromatography and mass spectrometry. The results showed that Charcoal purple wheat had remarkable antioxidant activity (up to 6899 mu mol/100 g) followed by Red Fife wheat and yellow Luteus wheat. White AC Vista wheat, due to its lowest phenolic content, exhibited the weakest antioxidant property. The major phenolic composition identified in wheat grains consisted of phenolic acids, flavones, flavonols, and anthocyanins. The former three components were detected in all of the wheat varieties, whereas anthocyanins were identified only in purple wheat. Therefore, anthocyanins could be the major compounds distinguishing purple wheats from other colored wheats with high antioxidant activity.