摘要
[目的]为低乳糖乳制品的工业化生产提供技术支持。[方法]以阳离子交换树脂D151为载体，采用吸附交联法对黑曲霉乳糖酶进行固定化，进而研究了固定化乳糖酶的酶学特性。[结果]固定化乳糖酶和游离酶的最适温度分别为60和70℃。在低于50℃的条件下对固定化乳糖酶和游离酶进行保温处理，酶活力没有损失；在高于50℃的条件下对固定化乳糖酶和游离酶进行保温处理，其酶活力呈现下降趋势，且固定化乳糖酶的活力下降更为迅速。固定化乳糖酶和游离酶的最适pH值分别为4．5和4．0，其pH值稳定范围分别为2．5—4．5和5．0～7．0。pH=6．5时，固定化乳糖酶和游离酶的活力分别为其最适pH值下的87．5％和3．8％。固定化乳糖酶和游离酶的半衰期分剐为24和9d。[结论]在牛奶的天然pH值下，固定化乳糖酶比游离酶更适用。
[ Objective ] The purpose of the study was to provide technical support for the industrial production of low lactose dairy products. [ Method] With cationic exchange resin DlSl as vector, the lactase from Aspergillus niger was immobilized by absorption - crosslinking method and then the enzymatic properties of immobilized lactase were studied. [ Result ] The most suitable temperatures of immobilized and free lactase were 60 and 70 ℃ resp. In the thermostatic treatment at the temperature below 50 ℃, the activities of immobilized and free lactase got no loss. In the thermostatic treatment at the temperature above 50 ℃, the activities of immobilized and free lactase showed decreasing trend and that of immobilized lactase was decreased more rapidly. The most suitable pH values of immobilized and free lactase were 4.5 and 4.0 resp. and their stable ranges of pH were 2.5 -4.5 and 5.0 -7.0 resp. When the pH value was 6.5, the activities of immobilized and free lactase were 87.5% and 3.8% of that at their most suitable pH value. The half-life periods of immobilized and free lactase were 24 and 9 d resp. [ Conclusion] At the natural pH value of milk, the immobilized lactase was more suitable than free lactase.
出处
《安徽农业科学》
CAS
北大核心
2010年第2期904-905,909,共3页
Journal of Anhui Agricultural Sciences
基金
河北省农副产品加工重大攻关专项(03220173D)
关键词
乳糖酶
酶学性质
游离酶
固定化酶
Lactase
Enzymatic properties
Free enzyme
Immobilized enzyme
