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Functional properties of a cross‐linked soy protein–gelatin composite towards limited tryptic digestion of two extents
Author(s) -
Sheng WenWen,
Zhao XinHuai
Publication year - 2013
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.6276
Subject(s) - gelatin , soy protein , chemistry , hydrolysis , emulsion , composite number , rheology , ingredient , trypsin , digestion (alchemy) , absorption of water , dynamic mechanical analysis , enzymatic hydrolysis , chromatography , food science , materials science , composite material , organic chemistry , enzyme , polymer
BACKGROUND Both enzymatic cross‐linking and hydrolysis are used to treat food proteins for functionality modification. The present study aimed to reveal the impact of limited tryptic digestion on some functional properties of a cross‐linked composite generated from soy protein isolate and gelatin by transglutaminase . RESULTS The composite was digested by trypsin for 1.5 and 4 h to produce two hydrolyzed composites with degrees of hydrolysis of 1% and 2%, respectively. Electrophoretic and chemical analysis showed that only part of the composite was degraded, and the gelatin fraction in the composite was more sensitive to tryptic digestion than the soy protein fraction. The hydrolyzed composites exhibited higher protein dispersion index at pH 4.5 or 7.0 and surface hydrophobicity, better digestibility in vitro , emulsifying property and oil absorption capacity, but lower water holding capacity and rheological properties (apparent viscosity, storage and loss modulus) than the composite. Compared to soy protein isolate, the hydrolyzed composites had better rheological properties, and higher water‐holding capacity and emulsion stability index . CONCLUSION The applied tryptic digestion conferred some improved properties on the hydrolyzed composites compared with the composite or soy protein isolate, and has potential for obtaining a new functional ingredient for processed foods. © 2013 Society of Chemical Industry