Impact of New Milk Clotting Enzymes on Cheese Technology

Veal rennet now plays a minor role in United States cheese production, reflecting an inadequate and continually decreasing supply. Rennet has been supplanted principally by rennet-pepsin blends which also usually contain bovine pepsin, and by fermentation-derived rennets. The description, classification, and specification of rennets and swine pepsin are included in the First Supplement to tbe Food Chemicals Codex, 2nd ed. A wide array of techniques for differentiating milk clotting enzymes has been published; however, none of these techniques is employed interlaboratory. All commercially marketed milk clotting enzyme preparations incorporating various rennets or rennet-pepsin blends generally exhibit satisfactory performance during the cheesemaking process. Cheese yields with various commercial milk clotting enzyme preparations are comparable. Utilization of fermentation-derived rennets in long-hold cheese is limited by their alleged implication in the protein related defects of short acid body and astringent or bitter flavor. The greater thermostability of Mucor-derived rennets combined with the relatively high carryover into the whey poses concern for the whey processing industries.