INFLUENCE OF THE REACTION CONDITIONS ON THE CHEMICAL PHOSPHORYLATION OF MILK-PROTEINS

The optimal and mildest possible conditions for the phosphorylation of whole casein and beta-lactoglobulin have been established. They allow to displace the phosphorylation equilibria towards either dominating polymers or phosphorylated monomeric forms of studied milk proteins as well as a mixture of both. The studied reaction conditions and factors included the reaction medium, type of base, time, POCl3 molar ratio, diverse phosphorylating agents, protein concentration, reaction sequence and chemical protein premodifications. Use of semiorganic conditions in the presence of an organic base such as the tertiary amine (TEA) resulted in cross-linked phosphorylated protein polymers especially at high molar ratios of POCl3 (400-800). Mostly monomeric phosphorylated proteins were obtained in aqueous conditions using POCl3 at low molar ratio (100) neutralized by tertiary amines.