Neutral Proteinase And Starter Lactic Acid Bacteria Cell Immobilization On Sodium Alginate And Its Effect On Accelerating Ripening Of Cheese

The ripening of cheese is a long and costly process, which leads to inventory cost added. Therefore, accelerated ripening of cheese is widely concerned. The study investigated the technology of neutral proteinase and starter lactic acid bacteria cell immobilized on sodium alginate and its effect on accelerating ripening of cheese.Results from neutral proteinase immobilized on sodium alginate showed that the immobilized technology of neutral proteinase was viable, sodium alginate as the material. The effective encapsulation and the activity of enzyme could amount to 97.5%, 3600U/g respectively on the condition of 3.0% sodium alginate, 1:2(v/v) ratio of enzyme level and sodium alginate level, 2.5h gelation time and 3.0% CaCl2 solution. The optimum temperature and pH value of immobilized enzyme were 50℃,7.5 respectively, which were all higher than the free one. Furthermore, the stabilities of heat, pH value and storage were higher too.Results from starter lactic acid bacteria cell immobilized on sodium alginate showed that the optimum culture medium and culture time were removed milk culture medium and 8h respectively. The optimum conditions selected for the immobilization were 1:2(v/v) ratio of lactic acid bacteria level and sodium alginate level, 2.0% sodium alginate, 40 ℃ reaction temperature, 3.0% CaCl2 solution, 0-4 ℃ cross linking temperature for 2.0h and 1.0~1.5mm beads diamum. The stabilities of immobilized lactic acid bacteria did improve than the free one.The variation of proteolysis and liposis could reflect the effect of immobilized neutral proteinase on cheese ripening, WSN, TCASN and PTASN as the proteolysis index, and acid value (ADV) as the liposis index, and both together regarded as ripening index. The results showed that WSN, TCASN and PTASN increased steadily as the ripening period advanced for all cheese treatments. However, cheeses added of enzyme had no obvious effect on accelerating only if the level of enzyme was high enough. The cheese contained 1000U/g immobilized neutral proteinase in cheese particles had more pronounced amounts of WSN, TCASN and PTASN than control batch. The effect of...