Calcium chelating agents, such as sodium hexametaphosphate (SHMP), can be added to milk protein solutions to aid in rehydration; however, this leads to a concomitant increase in solution viscosity due to micelle swelling/dissociation. Crosslinking casein proteins 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 milk protein concentrate (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 rehydration particle size, compared to powders without SHMP addition, indicating increased particle swelling due to increased water absorption. (C) 2020 Elsevier B.V. All rights reserved.