The effect of different cooking methods on the antioxidant activity of wild Swiss chard (Beta vulgaris L. var. cicla)

Abstract

This study aimed to investigate the effects of different cooking methods (boiling for 5 min and 8 min, microwave cooking for 3.5 min and 6.5 min, and stir-fry for 5 min and 10 min) on wild chard's antioxidant activity and total phenolic content. It was determined that the total phenolic content [1 552.00 ±Â 299.82 mg GAE·(100 g)–1, GAE – gallic acid equivalents] increased in 3.5 min in the microwave [2 611.33 ±Â 311.76 mg GAE·(100 g)–1] and 5 min in stir-frying [2 434.33 ±Â 197.75 mg GAE·(100 g)–1] compared to the raw chard samples (P < 0.05). Two different antioxidant activity determination methods [2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP)] were used in the study. In both methods, it was determined that antioxidant activity decreased in the 10-min application of stir-frying. In contrast, the antioxidant activity increased by applying 3.5 min and 6.5 min in the microwave (P < 0.05). As a result, it was found that the antioxidant activity and total phenol content of wild chard changed when the cooking method and time were changed.