Residual Milk Coagulants in Whey — Their Inactivation and Effects on Ultrafiltration Flux and Nitrogen Yields

Abstract

Ten commercial milk coagulants were used to produce Cheddar cheese wheys. Wheys were then concentrated fourfold by ultrafiltration following pasteurization, separation, and prewarming. Fluxes were monitored. Wheys, final concentrates, and pooled permeates were tested for total nitrogen, nonprotein nitrogen, and fat. Wheys and concentrates were also tested for residual milk clotting activity. Residual activity was observed in the wheys and concentrates originating from the unmodified proteases of Mucor miehei and Mucor pusillus but not from the two modified proteases of Mucor miehei, an Endothia parasitica protease, two bovine pepsins, a bovine pepsin-swine pepsin blend, a Mucor pusillus-swine pepsin blend, or calf rennet, which served as the control. No significant differences in flux or nitrogen yields were observed.