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Caseinate–gelatin and caseinate‐hydrolyzed gelatin composites formed via transglutaminase: chemical and functional properties
Author(s) -
Luo ZhenLing,
Zhao XinHuai
Publication year - 2015
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.7042
Subject(s) - gelatin , tissue transglutaminase , hydrolysis , sodium caseinate , chemistry , materials science , chemical engineering , composite material , food science , enzyme , organic chemistry , engineering
BACKGROUND Treatment of food proteins by enzymatic crosslinking and other reactions can confer modified properties on the treated proteins. Bovine gelatin and hydrolyzed bovine gelatin were used to generate two caseinate‐based composites via transglutaminase, and potential useful properties to food processing were investigated for both composites. RESULTS Caseinate–gelatin and caseinate‐hydrolyzed gelatin composites contained 33.4 and 10.3 g kg −1 protein of 4‐hydroxyproline, respectively. Caseinate conjugation with gelatin and hydrolyzed gelatin resulted in two composites with stronger absorption at five wavenumbers during Fourier transform–infrared analysis, demonstrating that they were rich in hydroxyl and carboxyl groups. Both composites exhibited higher viscosity values in aqueous dispersions, lower thermal stability (i.e. higher mass loss) during thermogravimetric analysis and worse emulsifying properties than original caseinate, owing to conjugation and crosslinking via transglutaminase. However, confocal laser scanning microscopy ( CLSM ) analysis revealed that both composites actually had better emulsion stability after 2 weeks of storage. CONCLUSION The composites generated were different in chemical characteristics and better in viscosity and emulsion stability than original caseinate. They might have potential as protein thickeners and emulsifiers. CLSM is a better technique to assess emulsion stability of food proteins than the classic turbidity method. © 2014 Society of Chemical Industry