title: Effects on DPPH inhibition of egg-white protein polypeptides treated by pulsed electric field technology.
abstract: BACKGROUND
  Egg-white protein polypeptides are potentially used as a functional ingredient in food products. In this study, the effects on DPPH inhibition of egg-white protein polypeptides ranging from 10 to 30 kDa treated by pulsed electric field (PEF) technology were investigated.
  
  
  RESULTS
  2, 2-Diphenyl-1-picrylhydrazyl (DPPH) inhibition (%) was used to evaluate the antioxidant activity of polypeptides. In order to develop and optimize a pulsed electric field (PEF) mathematical model for improving the antioxidant activity, we have investigated three variables, including concentration (6, 8 and 10 mg mL(-1)), electric field intensity (10, 20 and 30 kV cm(-1)) and pulse frequency (2000, 2350 and 2700 Hz) and subsequently optimized them by response surface methodology (RSM). The concentration (8 mg mL(-1)), electric field intensity (10 kV cm(-1)) and pulse frequency (2000 Hz) were found to be the optimal conditions under which the DPPH inhibition increased 28.44%, compared to the sample without PEF treatment. Both near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyze the change of functional groups.
  
  
  CONCLUSIONS
  The results showed that PEF technology could improve the antioxidant activity of antioxidant polypeptides from egg-white protein under the optimized conditions.
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University, Changchun, 130062, People's Republic of China.
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Bolong
authors.initials: B
authors.lastname: Liu
authors.forename: Songyi
authors.initials: S
authors.lastname: Lin
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Jingbo
authors.initials: J
authors.lastname: Liu
authors.forename: Gregory
authors.initials: G
authors.lastname: Jones
authors.forename: Hsiang-Chi
authors.initials: HC
authors.lastname: Huang
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000378:metabolism; D004032:Diet; D004527:Egg Proteins / Q000494:pharmacology*; D004560:Electricity; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D010455:Peptides / Q000494:pharmacology*; D010851:Picrates / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D004527:Egg Proteins; D010455:Peptides; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl