title: Antioxidant activity of some protein hydrolysates and their fractions with different isoelectric points.
abstract: Antioxidant activities of commercially available enzymatic hydrolysates of milk and plant proteins were examined. Among them, soy protein and wheat gluten hydrolysates showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and antioxidation activity against linoleic acid oxidation in emulsion systems. Peptide fractions with higher antioxidant activities than crude enzymatic hydrolysates of gluten and soy protein were prepared without toxic solvents and reagents. Peptides in these plant protein hydrolysates were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without adding chemically synthesized carrier ampholytes, which is termed autofocusing. The acidic fractions from both protein hydrolysates showed stronger DPPH radical scavenging activities than the basic fractions, while the basic fractions strongly suppressed 2,2'-azobis (2-amidinopropane) dihydrochloride-induced oxidation of linoleic acid in an emulsion system. These acidic and basic peptide fractions would be useful to examine the mechanism underlying the antioxidant activities of peptides in food.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamo Kyoto 606-8522, Japan. ohiolove@kpu.ac.jp
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Park
authors.forename: Megumi
authors.initials: M
authors.lastname: Morimae
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Kenji
authors.initials: K
authors.lastname: Sato
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001713:Biphenyl Compounds; D005983:Glutens / Q000737:chemistry* / Q000494:pharmacology*; D007526:Isoelectric Point; D015227:Lipid Peroxidation / Q000187:drug effects; D010851:Picrates; D011492:Protein Hydrolysates / Q000494:pharmacology*; D030262:Soybean Proteins / Q000737:chemistry* / Q000494:pharmacology*; D014908:Triticum / Q000737:chemistry
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D011492:Protein Hydrolysates; D030262:Soybean Proteins; D005983:Glutens; C004931:1,1-diphenyl-2-picrylhydrazyl