BREAKING STRESS AND SYNERESIS OF RENNIN CURDS FROM RECONSTITUTED SKIM MILK FROZEN CONCENTRATE

Skim milk was concentrated to 17-18% solid non-fat (SNF) by reverse osmosis and then stored at -20 +/- 2 degrees C. Samples were thawed, reconstituted, and manufactured into rennin curds. Breaking stress and syneresis of curds increased with calcium or magnesium, and decreased as pH values increased. Breaking stress and syneresis of curds prepared from skim milk reconstituted from a frozen concentrate (SMRFC) were lower than of curds from raw or heated skim milk. The formation of curds results from a three-dimensional network of protein chain and clusters, and the addition of calcium chloride resulted in partial disintegration of the micelle, producing larger particles. Curds from raw milk showed more protein aggregatiom curds from SMRFC, and also had a more open matrix.