Effects of pH, CaCl2 and Soy Protein on [Ca2+] in Reconstituted Nonfat Dry Milk and on Rennet-Induced Coagulum Properties

Increasing CaCl2 and lowering pH caused a significant increase in [Ca2+] in reconstituted nonfat dry milk (RNDM), while the addition of soy protein caused a significant reduction in [Ca2+]. Lowering pH greatly increased rennet-induced coagulum firmness in RNDM and slightly increased it in RNDM-soy protein mixtures. Added CaCl2 increased coagulum textural parameters and syneresis in both systems. The extent to which these properties were increased was higher in RNDM than in the coagulum containing soy protein depending on the time after rennet addition and the amount of CaCl2 added. The first increment of CaCl2 added had the highest effect in improving textural properties and increasing syneresis.