Antioxidant activity of peptide fractions from whey protein hydrolysates as measured by electron spin resonance

• Published in: Food chemistry Vol. 113; no. 1; pp. 196 - 201
• Main Authors: Peng, Xinyan, Xiong, Youling L., Kong, Baohua
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2009; [Amsterdam]: Elsevier Science
• Subjects: Antioxidant activity; Antioxidant peptide; electron paramagnetic resonance spectroscopy; Electron spin resonance; enzymatic hydrolysis; enzymes; food analysis; food composition; free radical scavengers; peptide fractions; peptides; protein hydrolysates; subtilisin; whey protein; Whey protein isolates; Whey protein isolates; Electron spin resonance; Antioxidant activity; Antioxidant peptide
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2008.07.068

Whey protein isolate (WPI) was hydrolysed for 0.5–8
h using Alcalase, and the 5-h hydrolysate, identified to possess the strongest reducing ability, was subjected to column fractionation and antioxidant activity assays. Sephadex G-10 gel filtration chromatography of the 5-h hydrolysate yielded four fractions (I, II, III and IV) that were composed of peptides of >40
k, 2.8–40
k, 0.1–2.8
k, and <0.1
k, respectively. Fraction III exhibited the strongest free radical scavenging effects, which was evidenced by the electron spin resonance (ESR) of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH
) and of trapped hydroxyl (
OH) and superoxide (
O
2
-
) radicals. The results indicated that antioxidant activity of whey protein hydrolysates depended on peptide molecular weight, with peptides of 0.1–2.8
k possessing the strongest radical scavenging activity.