Effect of cooking on the antioxidant properties of coloured peppers

• Published in: Food chemistry Vol. 111; no. 1; pp. 20 - 28
• Main Authors: Chuah, Ai Mey, Lee, Ya-Chi, Yamaguchi, Tomoko, Takamura, Hitoshi, Yin, Li-Jun, Matoba, Teruyoshi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.2008; [Amsterdam]: Elsevier Science; Elsevier
• Subjects: antioxidant activity; Antioxidant properties; Ascorbic acid; Biological and medical sciences; boiling; Capsicum annuum; carotenoids; color; colored varieties; Cooking; cooking quality; food analysis; food composition; Food industries; free radical scavengers; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; heat treatment; leaching; microwave cooking; Pepper; peppers; Radical scavenging activity; stir frying; Total polyphenol content; Total polyphenol content; Radical scavenging activity; Antioxidant properties; Cooking; Ascorbic acid; Pepper; Antioxidant properties;Pepper;Cooking;Radical scavenging activity;Ascorbic acid;Total polyphenol content; Heat treatment; Polyphenol; Vegetables; Bell pepper; Antioxidant; Properties
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2008.03.022

Pepper ( Capsicum annum L.) has long been recognized as an excellent source of antioxidants, being rich in ascorbic acid and other phytochemicals. This study was conducted to investigate the effect of different cooking methods on the antioxidant properties of coloured peppers. Six varieties of peppers were subjected to different cooking methods, such as microwave heating, stir-frying and boiling in water, for 5 min individually. The cooked and raw peppers were analyzed for radical-scavenging activity (RSA) and total polyphenol content (TP) using 1,1-diphenyl-2-picrylhydrazyl–high-pressure liquid chromatography (DPPH)–HPLC and Folin-Ciocalteu methods, respectively. The samples were also evaluated for ascorbic acid content (AsA) by HPLC. Total carotenoid content was determined spectrophotometrically. Results suggest that there is no significant ( P > 0.05) difference in RSA, TP, AsA and total carotenoid contents between the cooked and raw peppers when processed for 5 min. However, the cooked peppers show marked differences ( P < 0.05) in the RSA, TP and AsA when cooked for 5 min in boiling water with further reduction observed after boiling for 30 min. This may be due to the leaching of antioxidant compounds from the pepper into the cooking water during the prolonged exposure to water and heat. Therefore, it is vital to use less water and cooking time and also to consume the water used for boiling so as to obtain the optimum benefits of bioactive compounds present in peppers. It is concluded that microwave heating and stir-frying without using water are more suitable cooking methods for pepper, to ensure the maximum retention of antioxidant molecules.