title: Effects of domestic cooking methods on polyphenols and antioxidant activity of sweet potato leaves.
abstract: In this study, effects of boiling, steaming, microwaving, baking, and frying on proximate composition, total and individual polyphenol contents, and antioxidant activity of sweet potato leaves were investigated. An increase of 9.44% in total polyphenol content was observed after steaming, whereas decreases of 30.51, 25.70, and 15.73% were noted after boiling, microwaving, and frying, respectively. Decreases of 63.82 and 32.35% in antioxidant activity were observed after boiling and microwaving, respectively, whereas increases of 81.40, 30.09, and 85.82% in antioxidant activity were observed after steaming, baking, and frying, respectively. Eight phenolic compounds were identified in sweet potato leaves. The correlation analysis between content of individual phenolic compounds and antioxidant activity suggested that antioxidant activity could be mainly attributed to 4,5-di-O-caffeoylquinic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 3,4,5-tri-O-caffeoylquinic acid. It was suggested that steaming is a preferred method to maintain polyphenols and antioxidant activity of sweet potato leaves.
authors.affiliation: Laboratory of Food Chemistry and Nutrition Science, Institute of Agro-Products Processing Science and Technology, Chinese Academy of Agricultural Sciences , and Key Laboratory of Agro-Products Processing, Ministry of Agriculture, No. 2 Yuan Ming Yuan West Road, Haidian District, Beijing 100193, People's Republic of China.
authors.forename: Hongnan
authors.initials: H
authors.lastname: Sun
authors.forename: Taihua
authors.initials: T
authors.lastname: Mu
authors.forename: Lisha
authors.initials: L
authors.lastname: Xi
authors.forename: Zhen
authors.initials: Z
authors.lastname: Song
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003296:Cooking / Q000379:methods*; D006358:Hot Temperature; D027723:Ipomoea batatas / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D059808:Polyphenols / Q000032:analysis*; D011801:Quinic Acid / Q000031:analogs & derivatives / Q000032:analysis; D013227:Steam
chemical_list: D000975:Antioxidants; D059808:Polyphenols; D013227:Steam; C472707:caffeoylquinic acid; D011801:Quinic Acid
keywords: ORAC assay; RP-HPLC; antioxidant activity; caffeoylquinic acids; domestic cooking; phenolic acids