Solubility and Hydrolyzability of Films Produced by Transglutaminase Catalytic Crosslinking of Whey Protein

Abstract

Transglutaminase was used to crosslink covalently concentrated protein solutions of α-lactalbumin and β-lactoglobulin and a 1:1 (wt/wt) mixture of these two proteins to form gels. These gels were dehydrated to produce films. Solubility of films incubated at room temperature for 24 h in buffered solvents indicated a significant relationship with glycerol concentration in the film mixture and with the pH of the buffered solvent. The films were insoluble in SDS and β-mercaptoethanol. A significant relationship between solubility of all films and guanidine hydrochloride and urea in the solvent was observed. Films incubated with the proteolytic enzymes trypsin and α-chymotrypsin produced a significant correlation between film hydrolyzability and incubation time. Utilization of transglutaminase-crosslinked whey protein as a film or food-coating material should consider the pH and the enzymic nature of the coated food surface. © 1993, American Dairy Science Association. All rights reserved.