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

Xinyan Peng, Youling L. Xiong, Baohua Kong

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237 Scopus citations


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 >40k, 2.8-40k, 0.1-2.8k, and <0.1k, 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{radical dot}) and of trapped hydroxyl ({radical dot}OH) and superoxide (O2{radical dot} -) radicals. The results indicated that antioxidant activity of whey protein hydrolysates depended on peptide molecular weight, with peptides of 0.1-2.8k possessing the strongest radical scavenging activity.

Original languageEnglish
Pages (from-to)196-201
Number of pages6
JournalFood Chemistry
Issue number1
StatePublished - Mar 1 2009

Bibliographical note

Funding Information:
This study was a joint project between Northeast Agricultural University (China) and University of Kentucky (USA), which was supported by a grant from the Natural Science Foundation of Heilongjiang Province for overseas collaboration (Grant No. ZJN0605-01), and by a grant from the 863 Plan of Ministry of Science and Technology of China (Grant No. 2008AA10Z315).


  • Antioxidant activity
  • Antioxidant peptide
  • Electron spin resonance
  • Whey protein isolates

ASJC Scopus subject areas

  • Analytical Chemistry
  • Food Science


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