Influence of Certain Salts, Whey Protein, and Heat Treatment Upon the pH and Rennet Curd Tension of Casein Sols

Abstract

Using a 3% casein sol, addition of NaCl, Na3PO4, MgSO4 and sodium citrate reduced the curd tension. Heating (62.2 or 71.1[degree]C for 30 minutes) reduced the pH of all sols used except those containing high levels of sodium citrate. Heating (62.2 or 71.1[degree]C for 30 minutes) increased the curd tension of 3% casein sols containing 0.18 to 0.3% sodium chloride. Heating for 30 minutes at 62.2[degree]C increased the curd tension of casein sols containing sodium citrate or tribasic sodium phosphate. Casein sols containing whey protein plus added salts formed clots more nearly resembling a normal clot of skimmilk, and were found to be more heat-stable when adjusted to pH 6.50 than when adjusted to 6.10.