TITLE:
Effect of Home-Cooking Methods on Phenolic Composition and Antioxidant Activity of Sweetpotato (Ipomoea batatas (L.) Lam.) Cultivars Grown in Egypt
AUTHORS:
Ateea A. Bellail, Omayma E. Shaltout, Mohammed M. Youssef, Ahmed M. A. El Gamal
KEYWORDS:
Sweetpotato; Total Phenolics; Antioxidant Activity; Chlorogenic Acid; Thermal Processing; HPLC
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.3 No.4,
April
18,
2012
ABSTRACT: Four sweetpotato (Ipomoea batatas (L.) Lam.) cultivars grown in Alexandria, Egypt, including Monofya 6, Monofya 66, Abeeis, and Beauregard were cooked using four different home-cooking methods (boiling, baking, microwaving, and deep-frying). The antioxidant contents (total phenolics by Folin-Denis, and individual phenolic acids by HPLC) as well as the antioxidant activity determined by reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) were measured in this study. Results indicated that total phenolic contents of raw flesh tissue by Folin-Denis ranged from 0.53 to 0.87 mg chlorogenic acid equivalent (mg ChAE)/g dry weight basis (dw). The RP ranged between 0.1 and 0.25 mg ChAE/g dw, DPPH and ABTS radical scavenging activities varied from 1.10 to 1.72 and 0.85 to 1.51 μmol trolox equivalent (TE)/g dw, respectively. Thermal processing significantly (P ≤ 0.05) increased the total phenolic content, as well as individual phenolic acids and antioxidant capacity of all the cultivars under study. In this respect, deep-frying exhibited the highest increment among the four processing methods. The most abundant individual phenolic acids in processed flesh roots tissues were chlorogenic acid followed by 3,5-dicaffeoylquinic acid. Total phenolic contents were highly correlated with RP, DPPH, and ABTS, also the correlation between the DPPH and ABTS values were significantly high.