Effect of dipotassium phosphate addition and heat on proteins and minerals in milk protein beverages.

Our objective was to determine the effects of dipotassium phosphate (DKP) addition, heat treatments (no heat, HTST: 72°C for 15 s, and direct steam injection UHT: 142°C for 2.3 s), and storage time on the soluble protein composition and mineral (P, Ca, K) concentration of the aqueous phase around casein micelles in 7.5% milk protein-based beverages made with liquid skim milk protein concentrate (MPC) and micellar casein concentrate (MCC). MPC was produced using a spiral wound polymeric membrane and MCC was produced using a 0.1µ ceramic membrane by filtration at 50°C. Two DKP concentrations were used (0 and 0.15% wt/wt) within each of the 3 heat treatments. All beverages had no other additives and ran through heat treatment without coagulation. Ultracentrifugation (2 h run at 4°C) supernatants of the beverages were collected at 1, 5, 8, 12 and 15 d storage at 4°C. P, Ca, and K concentrations in the beverages and supernatants were measured using inductively coupled plasma spectrometry. Protein composition of supernatants was measured using Kjeldahl and SDS-PAGE. MCC and MPC beverages with 0.15% DKP had higher (P < 0.05) concentrations of supernatant protein, Ca, and P than beverages without DKP. Protein, Ca, and P concentrations were higher in MCC supernatant than in MPC supernatant when DKP was added, and these concentrations increased (P < 0.05) over storage time, especially when lower heat treatments (HTST or no heat treatment) had been applied. DKP addition caused the dissociation of α

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© 2023, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).