Investigating the solubility and rheology of milk protein powders is of great interest because they are commonly used in research or industrial applications as substitute for fresh milk concentrates. The solubility of skim milk (SM), milk protein concentrate with 50% and 85% protein (MPC50, MPC85) and micellar casein powder (MC) was evaluated at variable temperatures (4, 20 and 50 degrees C) and their resulting rheological profile was compared to freshly produced samples. Powder composition impacts the powder aggregate's size. Increasing the casein content combined with a lactose reduction decreases the powder dissolving ability leading to bigger particles, higher shear stresses and stronger shear-thinning. Highly concentrated protein powders like MPC85 and MC required a high pressure homogenization step to disintegrate all powder aggregates to single particles, i.e., to casein micelle size. If the rehydration conditions were adapted to the powder type, fresh concentrates were completely substitutable with reconstituted concentrates regarding their rheology. (C) 2020 Published by Elsevier B.V.