Effects of Different Cooking Methods on the Antioxidant Properties of Red Pepper (Capsicum annuum L.)
The effect of various cooking method and cooking times on the antioxidant properties of red pepper.
We investigated the effect of various cooking methods (boiling, steaming, stir-frying, and roasting) and three cooking times (5, 10, and 15 min) on the antioxidant properties of red pepper. Raw and cooked peppers were measured for proximate composition, ascorbic acid (AsA) content, total carotenoid content (TCC), total polyphenol content (TP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities. Results showed that the proximate composition, AsA content, TCC, TP, and antioxidant activities were significantly (p<0.05) affected by the cooking procedure; the loss rate varied among individual compounds. Boiling and steaming significantly reduced AsA content (24.3~66.5%), TP (13.9~ 54.9%), and antioxidant activity (21.7~60.5%) in red pepper, while stir-frying and roasting slightly reduced AsA content (2.7~25.9%), TP (1.8~4.9%), and antioxidant activity (4.9~17.9%). The highest loss was observed after boiling, followed by steaming, roasting, and stir-frying. Stir-frying and roasting better preserved AsA content, TCC, TP, and antioxidant activity. In conclusion, dry-heat cooking methods such as stir-frying and roasting may be preferred to retain the nutrient compositions and antioxidant properties of red pepper.
In our study, the four different cooking processes (boiling, steaming, stir-frying, and roasting) changed the proximate composition, ascorbic acid (AsA) content, total carotenoids content (TCC), total polyphenol (TP), and antioxidant activities of red peppers. Boiling and steaming significantly decreased the AsA content, TP, and antioxidant levels compared with the other cooking methods. The contents of red peppers decreased with prolonged cooking times. Moreover, antioxidant activities were less dependent on the AsA content and TP levels of red peppers. Stir-frying and roasting preserved the nutrient compositions, antioxidant components, such as AsA content, TCC, and TP levels, and antioxidant activities in red peppers than boiling and steaming. These results may contribute to consumers’ knowledge when choosing cooking practices that retain the nutritional quality of peppers. However, this research has a limitation, in that only red pepper was evaluated. Therefore, further study using other foods is needed to validate matrix effects.