title: Comparative composition and antioxidant activity of Peptide fractions obtained by ultrafiltration of egg yolk protein enzymatic hydrolysates.
abstract: The objective of the study was to compare the antioxidant activity of two distinct hydrolysates and their peptide fractions prepared by ultrafiltration (UF) using membranes with molecular weight cut-off of 5 and 1 kDa. The hydrolysates were a delipidated egg yolk protein concentrate (EYP) intensively hydrolyzed with a combination of two bacterial proteases, and a phosphoproteins (PPP) extract partially hydrolyzed with trypsin. Antioxidant activity, as determined by the oxygen radical absorbance capacity (ORAC) assay, was low for EYP and PPP hydrolysates with values of 613.1 and 489.2 µM TE×g-1 protein, respectively. UF-fractionation of EYP hydrolysate increased slightly the antioxidant activity in permeate fractions (720.5-867.8 µM TE×g-1 protein). However, ORAC values were increased by more than 3-fold in UF-fractions prepared from PPP hydrolysate, which were enriched in peptides with molecular weight lower than 5 kDa. These UF-fractions were characterized by their lower N/P atomic ratio and higher phosphorus content compared to the same UF-fractions obtained from EYP-TH. They also contained high amounts of His, Met, Leu, and Phe, which are recognized as antioxidant amino acids, but also high content in Lys and Arg which both represent target amino acids of trypsin used for the hydrolysis of PPP.
authors: Institute of Nutraceuticals and Functional Foods (INAF), Department of Food Science and Nutrition, Université Laval, Québec, QC, G1V 0A6, Canada. bertrand.chay-pak-ting.1@ulaval.ca.
authors: Bertrand P
authors: BP
authors: Chay Pak Ting
authors: Department of Food Science, University of Guelph, Guelph, ON, N1G 2W1, Canada. ymine@uoguelph.ca.
authors: Yoshinori
authors: Y
authors: Mine
authors: Research Laboratories, Taiyo Kagaku Co, Ltd., 1-3 Takaramachi, Yokkaichi, Mie 510 0844, Japan. ljuneja@taiyokagaku.co.jp.
authors: Lekh R
authors: LR
authors: Juneja
authors: Research Laboratories, Taiyo Kagaku Co, Ltd., 1-3 Takaramachi, Yokkaichi, Mie 510 0844, Japan. tokubo@taiyokagaku.co.jp.
authors: Tsutomu
authors: T
authors: Okubo
authors: Institute of Nutraceuticals and Functional Foods (INAF), Department of Food Science and Nutrition, Université Laval, Québec, QC, G1V 0A6, Canada. sylvie.gauthier@fsaa.ulaval.ca.
authors: Sylvie F
authors: SF
authors: Gauthier
authors: Institute of Nutraceuticals and Functional Foods (INAF), Department of Food Science and Nutrition, Université Laval, Québec, QC, G1V 0A6, Canada. yves.pouliot@inaf.ulaval.ca.
authors: Yves
authors: Y
authors: Pouliot