title: Optimized antioxidant peptides fractions preparation and secondary structure analysis by MIR.
abstract: The soybean protein was hydrolyzed by Alcalase Food grade (FG) 2.4 L and the optimal hydrolysis parameters of strongest antioxidant capacity of peptides were obtained using response surface methodology (RSM). The effects of reaction temperature, pH value and ratio of enzyme/soybean protein powder ([E/S]) on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) of the peptides was well fitted to a quadric equation with high determination coefficients. The hydrolysate with optimal DPPH was predicted to be obtained at: temperature of 50°C, pH value of 10.32, and [E/S] ratio of 12%. The hydrolysates were separated by the ultrafiltration membranes in the cut-off MW at 1kDa, 3kDa, 10kDa and 30kDa and molecular weight cut-offs (MWCO) I-V were determined antioxidant activity. And secondary structures of those fractions were investigated by mid-infrared spectroscopy (MIR).
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University, Changchun 130062, PR China.
authors.forename: Songyi
authors.initials: S
authors.lastname: Lin
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Yong
authors.initials: Y
authors.lastname: Pang
authors.forename: Haiqing
authors.initials: H
authors.lastname: Ye
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.forename: Jingbo
authors.initials: J
authors.lastname: Liu
authors.forename: Gregory
authors.initials: G
authors.lastname: Jones
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000037:antagonists & inhibitors / Q000737:chemistry; D005163:Factor Analysis, Statistical; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010851:Picrates / Q000037:antagonists & inhibitors / Q000737:chemistry; D011492:Protein Hydrolysates / Q000737:chemistry*; D017433:Protein Structure, Secondary; D059748:Proteolysis; D030262:Soybean Proteins / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013381:Subtilisins / Q000737:chemistry*; D013696:Temperature; D014462:Ultrafiltration
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D011492:Protein Hydrolysates; D030262:Soybean Proteins; C004931:1,1-diphenyl-2-picrylhydrazyl; D013381:Subtilisins