酵子中产蛋白酶细菌及其对馒头品质的影响

EFFECTS OF PROTEASE PRODUCING BACTERIA ISOLATED FROM JIAOZI ON THE STEAMED BREAD QUALITY

利用采自商丘的酵子样品分离产蛋白酶的细菌,通过脱脂牛奶培养基筛选后共得到15株,综合比较各菌株透明圈与菌落的直径比(HC)值以及蛋白酶活力的大小,发现3号菌的HC值和蛋白酶活力均最大,分别为4.0和48.95 U/m L,因此确定其为实验菌株.考察3号菌株对馒头品质的影响时,检测到面团中的蛋白酶活力明显提高,可增至3.16 U/m L,且发现馒头的硬度、胶性和咀嚼性有所提高,而比容和白度均有所降低.

The present study to examine the effects of protease producing bacteria,which was isolated from Jiaozi,on the quality of steamed bread. 15 protease-producing bacterial strains were isolated from the samples of Jiaozi collected from Shangqiu. After screened by milk plate and Folin-phenol methods,strain 3 was selected because of the highest HC value and protease activity,which was up to 4.0 U/m L and 48.95 U/m L,respectively.And then the effects of strain 3 on the quality of steamed bread were evaluated. The results showed that the protease activity in the dough increased significantly,up to 3.16 U/m L and the hardness,gumminess and chewiness of the bread were improved,while the specific volume and whiteness were decreased after strain 3addition. The reason might be that the protease could function in the formation of peptides and amino acids,so as to improve the flexibility and extensibility of the dough,so that improve the quality of the steamed bread.