Water sorption and hydration properties of high protein milk powders are influenced by enzymatic crosslinking and calcium chelation

Abstract

Calcium chelating agents, such as sodium hexametaphosphate (SHMP), can be added to milk protein (MPC) solutions to aid in rehydration; however, this leads to a concomitant increase in solution viscosity due to micelle swelling/dissociation. Crosslinking casein proteins in MPC using transglutaminase (TGase) can help retain casein micelle structure and maintain low viscosity. This study aimed to determine the water sorption and hydration properties of MPC powders, as influenced by the crosslinking of milk proteins and the addition of SHMP. Crosslinked casein protein (TG-MPC) powders without SHMP addition had improved wettability, water sorption and water diffusion compared to the non-crosslinked control (C-MPC) powder. All powders containing SHMP were found to have increased water sorption compared to control powders without SHMP addition. Powder dissolution data showed that increasing SHMP content increased powder particle size, compared to powders without SHMP addition, indicating increased powder particle swelling due to increased water uptake.