Immobilized Pepsin Treatment of Skim Milk and Skim Milk Fractions

Columns and batch reactors of pepsin immobilized on glass were used to study the mechanism of enzymic clotting of milk. A linear relationship existed between nonprotein nitrogen release and the logarithm of coagulation time of skim milk within limits tested. A nearly linear relationship was found between the logarithm of nonprotein nitrogen release and increase in curd tension of skim milk. Ultracentrifuged skim milk supernate treated with immobilized pepsin caused skim milk or washed micelles to clot. The coagulation time for treated skim milk, treated micelles, treated ultracentrifuged skim milk supernate plus micelles, and treated ultracentrifuged skim milk supernate plus skim milk decreased as the contact time with immobilized pepsin on glass was increased.