Evaluation of Potato Varieties with High Antioxidant Activities by Measuring Phenolic Acids in Different Tuber Parts

초록

Potato is a valuable source of antioxidants in the human diet and their genetic variability exists for antioxidant activity. This study was carried out to define selection criteria for potato varieties and breeding clones with high antioxidant levels as measured by 1,1-diphenyl-2-picryl-hydrazyl methods. There were significant differences in antioxidant activities among potato genotypes. Radical scavenging activities (RC50) of 29 potato genotypes ranged from 64.8 to 493.6 gmL1. We further analyzed the antioxidant activities in three different sections including cortex, perimedullary, and pith tissue were separately measured for five selected potato varieties. At least, two-fold higher antioxidant activity for cortex tissue (5 mm-thick of periderm tissue with skin) was found in all five Valley potatoes, compared to that in Atlantic. Very low antioxidant activity was detected in perimedullary and pith tissue of all potato varieties, except for Bora Valley, which had purple flesh. Based on the varieties tested, purple skinned varieties showed higher antioxidant activity than red skinned tubers, while tubers with yellow skins showed the lowest antioxidant activity. The levels of three major phenolic compounds such as chlorogenic, caffeic, and ferulic acids were highly correlated to RC50 values for cortex tissue as well as whole tubers. Although chlorogenic, caffeic, and ferulic acids were the major phenolic acids contributing to the total antioxidant activity of potato tubers, caffeic acid was the most effective compound contributing to the total tuber antioxidant activity based on RC50 values.

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