Effect of phosphatase/transglutaminase treatment on molar mass distribution and techno-functional properties of sodium caseinate

Sodium caseinate was enzymatically dephosphorylated by alkaline or acid phosphatase prior to incubation with microbial transglutaminase. It was demonstrated that a higher degree of protein cross-linking by transglutaminase was achieved in dephosphorylated sodium caseinate than in non-dephosphorylated sodium caseinate. During transglutaminase treatment, about 70% protein polymers >200.000 g/mol were produced from untreated sodium caseinate, but about 90% protein polymers >200.000 g/mol from dephosphorylated sodium caseinate. Phosphatase/transglutaminase-treated sodium caseinate exhibited techno-functional properties similar to transglutaminase-treated sodium caseinate, but performed improved interfacial stabilisation behaviour as well as higher viscosity. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.