酪蛋白与明胶的酶促交联与产物的流变学性质

Transglutaminase-induced cross-linking of casein and gelatin and rheological properties of the products

利用转谷氨酰胺酶对酪蛋白和明胶进行酶促混合交联。在酪蛋白与明胶比例为4︰1(质量比)时,以交联产物中羟脯氨酸质量分数为指标,采用单因素试验研究酶添加量、反应时间和温度对交联反应的影响。优化后的适宜交联条件为:底物质量浓度固定为50 g/L,酶添加量为每克蛋白质20 U,反应时间为4 h,温度为45℃。SDS-聚丙烯酰胺凝胶电泳分析表明产物中含有蛋白质聚合物。与原料酪蛋白、转谷氨酰胺酶促交联的酪蛋白相比,所得到的产物的分散液表观黏度和黏弹性均有显著的改变,表明转谷氨酰胺酶催化的酪蛋白和明胶混合可以用于改善其流变学性质。

Cross-linking of casein and gelatin catalyzed by transglutaminase was studied in this work.When the ratio of casein to gelatin was fixed at 4∶1（w/w） and the content of hydroxyproline in the obtained product was used as index,the addition level of transglutaminase,reaction temperature and time were studied by single factor experiments.The optimal cross-linking conditions obtained were that protein concentration was fixed at 5%（w/v）,enzyme addition level was 20 U/g proteins,reaction time was 4 h and reaction temperature was 45 ℃.SDS-PAGE analysis demonstrated that some protein polymers existed in the obtained product.Compared to casein and transglutaminase-induced cross-linked casein,the dispersion of the obtained product exhibited markedly improved apparent viscosity and viscoelastic behaviors.Our result indicated that cross-linking of casein and gelatin could improve their rheological properties.