曹瑛瑛¹，曹 磊²，张忠明^1*，王 莹¹，汪 月¹，文鹏程¹，刘红娜³，乔海军⁴，张卫兵^1*

（1.甘肃农业大学食品科学与工程学院，甘肃兰州 730070；

2.兰州资源环境职业技术学院气象学院，甘肃兰州 730030；

3.西北民族大学生命科学与工程学院，甘肃兰州 730030；

4.甘肃农业大学理学院，甘肃兰州 730070）

摘要：为了揭示地衣芽孢杆菌凝乳酶的凝乳性能，在不同pH的脱脂乳中加入凝乳酶，分析凝乳过程中浊度、粒径、粘度和流变学性质的变化规律。结果表明：随着凝乳pH降低，脱脂乳浊度显著降低（P＜0.05），凝乳pH越低浊度增长率越高，凝乳pH为5.2时在凝乳15 min内浊度增长率高达100.30%。随着时间的延长酪蛋白胶束尺寸不断增加，凝乳pH为5.8时酪蛋白胶束中位径D50增加值最大，为58.699 μm。凝乳pH越低，脱脂乳粘度增长越快；凝乳前10 min内，不同pH条件下粘度分别增长了13.11、11.16、9.88、6.02、1.17、1.13倍。流变学性质表明，在pH 5.2~6.7范围内，凝乳pH越低凝乳时间越短；在凝乳pH 5.8时所形成的凝胶强度最大，最大储能模量值达到101.34 Pa。相关性分析表明凝乳pH与浊度、粒径、粘度、储能模量值呈显著负相关（P＜0.01）。本研究发现改变凝乳pH对凝乳过程的影响显著，试验结果可为地衣芽孢杆菌凝乳酶的应用提供理论依据。

关键词：地衣芽孢杆菌；pH；凝乳性能

中图分类号：Q814.9    文献标识码：A    文章编号：1674-506X（2020）06-0014-0008

Study on the Coagulation Properties of Rennet from Bacillus licheniformis D3.11 at Different pH Conditions

CAO Ying-ying¹, CAO Lei², ZHANG Zhong-ming^1*, WANG Ying¹, WANG Yue¹, WEN Peng-cheng¹, LIU Hong-na³, QIAO Hai-jun⁴, ZHANG Wei-bing^1*

（1.College of Food Science and Engineering, Gansu Agricultural University, Lanzhou Gansu 730070, China;

2.College of Meteorological, Lanzhou Resources and Environment Voc-Tech College, Lanzhou Gansu 730030, China;

3.College of Life Science and Engineering, Northwest Minzu University, Lanzhou Gansu730030, China;

4.College of Sciences, Gansu Agricultural University, Lanzhou Gansu 730070, China）

Abstract：In order to reveal the coagulation properties of rennet from Bacillus licheniformis, the rennet was added into skimmed milk with different pH, and the variation of viscosity, turbidity, particle size and rheology properties in the process of coagulation was analyzed. The results showed that as the pH decreased, the turbidity of skim milk decreased significantly (P＜0.05). The lower the pH of curd, the higher the turbidity growth rate. The turbidity growth rate was as high as 100.30% within 15 minutes of the curd at pH 5.2. The size of the casein micelles continued to increase with the prolongation of the time, and the maximum increase in median diameter D50 of casein micelles at curd pH 5.8 is 58.699 μm. The lower the curd pH, the faster the viscosity of skim milk rises. During the first 10 minutes of curd, the viscosity increased by 13.11, 11.16, 9.88, 6.02, 1.17, 1.13 times under different pH conditions. The rheology properties showed that within the range of pH 5.2 ~ 6.7, the lower the curd pH, the shorter the curd time; The gel strength formed at curd pH 5.8 is the largest, and the maximum storage modulus reaches 101.34 Pa. Correlation analysis showed that the curd pH was significantly negatively correlated with turbidity, particle size, viscosity, and storage modulus values (P＜0.05). This research showed that changing the curd pH had a significant effect on the curd process, and the experimental results could provide a theoretical basis for the application of rennet from Bacillus licheniformis.

Keywords：Bacillus licheniformis; pH; coagulation properties

doi：10.3969/j.issn.1674-506X.2020.06-003

收稿日期：2020-05-06

基金项目：国家自然科学基金项目（31760466，31960486，31560442，21864002）；企业研究转化与产业化专项（2018-SF-C29）

作者简介：曹瑛瑛（1995-），女，硕士研究生。研究方向：乳品微生物。

*通讯作者

引文格式：曹瑛瑛,曹磊,张忠明,等.不同pH条件下地衣芽孢杆菌凝乳酶的凝乳性能研究[J].食品与发酵科技,2020,56(6):14-21.