Glycosylation and cross-linking of casein catalyzed by transglutaminase in presence of glucosamine was studied in this work. When the concentration of casein was fixed at 3% (w/v) and glucosamine added to the final concentration of 3 mol glucosamine /kg casein, the content of glucosamine conjugated in the modified casein product was used as an index, the pH of reaction system, addition level of transglutaminase, reaction temperature and time were studied by single factor experiments. The optimal modification conditions final selected were as fellow: a pH of 7.5, enzyme addition level of 10 kU/kg casein, temperature of 37 ℃ and reaction time of 4 h. Compared to the original casein and the cross-linked casein by transglutaminase, the modified casein product exhibited markedly improved emulsifying and gelation properties; moreover, its digestibility in vitro wasn't impaired upon this modification. Our results indicated that glycosylation and cross-linking of casein catalyzed by transglutaminase could improve these important properties of casein.%在氨基葡萄糖存在的条件下,利用转谷氨酰胺酶(EC 2.3.2.13)对酪蛋白进行糖基化交联修饰.以修饰酪蛋白产物中氨基葡萄糖的导入量为指标,采用单因素试验分别考察反应体系pH值、酶添加量、反应温度和时间对修饰反应的影响.优化后的适宜修饰条件为:酪蛋白底物质量浓度为30 g/L,氨基葡萄糖添加量为3 mol(每kg酪蛋白中)、pH值为7.5、酶添加量为10 kU(每kg酪蛋白中)、反应温度为37 C、时间4h.与酪蛋白和转谷氨酰胺酶促交联的酪蛋白相比,修饰酪蛋白产物的乳化性质和胶凝性质得到显著改善,并且体外消化性能未受到影响,表明转谷氨酰胺酶催化的糖基化交联修饰可以用于改善酪蛋白的这些功能性质.
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