Model Proteolysis of β-Casein with Immobilized Trypsin and Its Technological Significance
Immobilized enzymes were used as a model system to study proteolytic processes which occur in milk during processing. The properties of milk depend on the protein composition, especially on the hydrophobic caseins. β-casein is about 30% and γ-casein up to 10% of the total casein. The γ-caseins are fragments of β-casein, as derived from sequence analysis (1) . During storage of raw milk at 4°C the γ-casein fraction increases steadily, resulting in irreversible changes of technological properties. During our research we isolated and characterized two serine proteinases, associated with the casein micelles, showed the high specifity of these enzymes for β-casein degradation (2) , and did further characterization using immobilized trypsins.