Secondary Phase and Mechanism of Enzymic Milk Coagulation

Immobilized enzymes were used as tools to study the secondary phase apart from the enzymic phase of milk coagulation. Skim milk, after passing through a column of pepsin or rennet bound to porous glass, was subjected to changes in pH, temperature, and dilution, and their effects on rate of coagulation were studied. The secondary phase exhibited a high temperature coefficient (Q10) of 11 to 12 between 20 C and 50 C and a 30-fold decrease in eoagulatiort time when the pt! of the secondary phase was lowered from 6.7 to 5.6. When fresh sklmmilk was added in increasing amounts to the treated effluent skim milk prior to assay, the entire mix.re coagulated with proportionally longer coagulation times indicating that r~ot all of the x-casein need be enzymically attacked for coagulation but only enough to initiate aggregation of micelles. TREATED MtLY, FLUIDIZED BED ~" ~"~ ~,cTo~ ~ ~i