Dissolution of bovine serum albumin hydrogels in alkali

Heat-induced protein gelled deposits, occurring during dairy processing, are industrially cleaned with caustic-based solutions. In order to develop general dissolution mechanisms of protein hydrogels, in analogy to general gelation mechanisms for globular proteins, different protein systems must be characterized. We report the first characterization of the dissolution behaviour of heat-set pure bovine serum albumin (BSA) hydrogels. At low alkali concentrations (<0.2 M NaOH), the formed BSA gels were dissolved as observed for whey protein mixtures or pure β-lactoglobulin gels. The key rate limiting step is suggested to be the destruction of inter-protein non-covalent interactions. At higher NaOH concentrations (>0.2 M) the dissolution rate of BSA gels was fairly constant, unlike seen before. Activation energy estimations of the rate yield very low value in certain conditions, again unlike seen before. It is suggested that mass transfer limitations occur during dissolution due to the large BSA size.