THE EFFECT OF COOKING ON TOTAL POLYPHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF SELECTED VEGETABLES

Abstract

The aim of this study to investigate the effect of different cooking methods (boiling, steaming, stir-frying, and microwaving) on the total polyphenolic content and total antioxidant activity of selected vegetables (beet, red cabbage, broccoli, white cabbage, black radish, kale, turnip, and red radish) from Turkey. A wide variation on total phenolic content was observed in raw vegetables, ranging from 44.94 +/- 0.47 (beet, Beta vulgaris L. subsp. vulgaris) to 350.94 +/- 5.18 (red radish, Raphanus sativus L.) g gallic acid equivalent/mg of sample. Considering uncooked vegetables, the order of total antioxidant activity determined by -carotene bleaching assay was beet > red cabbage > broccoli > white cabbage > black radish > kale > turnip > red radish. In DPPH center dot assay, kale had an exceptionally high antioxidant activity followed by red cabbage, broccoli, turnip, black radish, beet, white cabbage, and red radish.