Effect of whey protein dispersions on syneresis of curd

The influence of adding whey protein dispersions (WPD) and deproteinated whey (DPW) on syneresis of renneted skim milk was studied. Protein dispersions, prepared by heating whey at 95 °C and pH 4.6 for 5 min, were added to reconstituted skim milk at 5 levels between 4.95 and 20.64%. WPD was homogenized as required. Volume of whey released at pH 6.26 and 6.5 was measured as a function of time. Relative to skim milk, whey volumes were lower with additions of WPD and higher with additions of DPW. Homogenization of WPD did little to alter whey yield. At 2.5 h after cutting the curd, more whey was released at low pH (6.26) than at pH 6.5. This seemed to account for the lower protein content of curd processed at low pH compared to high pH. Minor differences were observed for specific combinations of whey protein dispersions and deproteinated whey, pH and time. Thus whey from cheese manufacturing can be incorporated into cheese as whey protein dispersions. If moisture levels of the cheese are controlled by duration of syneresis, attention to additives and pH are necessary for accurate timing to optimize cheese texture.