谷氨酰胺转胺酶对搅拌型酸奶品质的影响

Effect of transglutaminase on the quality of stirred yoghurt

因为谷氨酰胺转胺酶对乳蛋白有交联作用,所以在酸奶制作中加入谷氨酰胺转胺酶可以提高酸奶的品质,将0.2g/L牛乳的谷氨酰胺转胺酶使用不同的添加方法(对酶灭活和不灭活)应用到酸奶制作中,通过酸奶硬度、持水力、流变特性、乳酸菌等指标的变化及综合感官评价,评定谷氨酰胺转胺酶的最适添加方法。结果表明两种不同的酶添加方法都可以减弱酸奶后酸化,提高酸奶硬度、持水力和剪切应力。TGase酶与发酵剂同时加入显著提高了酸奶的理化特性(p<0.05),硬度在第21d达到最大,与对照组相比提高8.48g,持水力随贮存时间的延长,不断增大,增幅为5.41%。在贮存后期TGase酶活力减弱,对酸奶的质构无不良影响,而且这种方法不需要额外的酶反应时间,热处理工序及设备,符合实际生产的需求。

The crosslinking of milk protein by transglutaminase,so it was applied in yoghurt processing to improve texture properties. The enzyme was added to yoghurt-milk at different production steps （inactive enzyme and not inactive enzyme） at 0.2g/L milk. The optimum adding method of transglutaminase was decided through the change of hardness,water holding capacity,the rheological characteristics,starter bacteria and comprehensive sensory evaluation. The result showed that two treatment methods of enzyme could reduce the post acidification of yoghurt during storage,improve hardness,water holding capacity and shearing stress. TGase was added together with starter culture could improve the physical and chemical properties more significantly（p〈0.05）. Compared with the control group,haedness had the maximum and increased 8.48g in the first 21 days. With storage time increasing ,water holding capacity was increased ,an increase of 5.41%. As a result of the residual activity of TGase drastically reduced during yoghurt storage,had no passive effect on yogurt quality. This method did not require additional enzyme reaction time,the heat treatment step and equipment, So it was the best way to acquire economic benefits.