STRUCTURE-FORMING PROCESSES IN CA2-INDUCED WHEY-PROTEIN ISOLATE COLD GELATION()

The structure-forming process of Ca2+-induced whey protein isolate (WP I) gels was studied, at 24 degrees C, in the presence of 10 and 120 mM CaCl2. Pre-heating WPI suspensions (10% protein) at 90 degrees C dram atically increased specific viscosity, but did not change the number o f accessible sulfhydryl groups, compared to pre-heating at 70 degrees C. The most important factor governing the process appeared to be CaCl 2 concentration, rather than the reactive sulfhydryl groups. At 10 mM CaCl2, the increase in aggregate size and network connectivity over ti me was achieved by clustering of adjacent aggregates. At 120 mM CaCl2, the increase in aggregate size and connectivity was by enlargement of the aggregates which formed connected paths and filled up interstitia l spaces. (C) 1998 Elsevier Science Ltd. All rights reserved.