Physicochemical properties and residual antigenicity of transglutaminase cross-linked sodium caseinate hydrolysates

Transglutaminase (TGase) cross-linked sodium caseinate (NaCN) was hydrolysed with Alcalase, Corolase 7089, Promod 144MG (papain) and Corolase PP. NaCN hydrolysates were also generated with these food-grade proteolytic preparations and subsequently cross-linked. The contribution of the order of partial TGase cross-linking and proteolysis to the properties of the resultant NaCN hydrolysates was studied. At essentially similar degree of hydrolysis (DH) values, the order of cross-linking and hydrolysis did not appear to affect the physicochemical (reversed-phase and gel permeation) profiles of the hydrolysates. Furthermore, TGase cross-linking, and the order of enzymatic modification (cross-linking/hydrolysis) did not significantly (P>0.05) alter the residual antigenicity properties of NaCN or of high DH (>18%) hydrolysates. Under the experimental conditions, it was not possible to determine if cross-linking affected the extent of hydrolysis. Overall, these results indicate that DH was considerably more important than cross-linking in determining the physicochemical and residual antigenicity properties of the hydrolysates.