高效降解胆固醇菌株的筛选及其在食品中的应用

Highly Efficient Cholesterol-degrading Bacterium Separating and Screening and Their Application in Food Key LabI

目的:为开发低胆固醇系列食品,从多种富含胆固醇的动物性发酵食品中分离、筛选高效降解胆固醇的菌株。方法:将采集的25种样品,选择培养基Ⅰ连续传代培养,通过比较胆固醇降解率和酶活力,筛选出降解胆固醇能力较高的菌株,并研究其酶学特性。结果:筛选出的红球菌(Rhodococcussp.)R14-2和短杆菌(Brevibac-teriumsp.)R22-4对胆固醇底物溶液的降解率分别为97.5%和94.7%;对鲜肉糜中胆固醇的降解率分别为41.3%和40.5%,并在低温(0～10℃)时仍表现出一定的酶活性;将这两种菌株的粗酶液应用于乳、蛋及香肠制作中,降胆固醇效果明显且未见有不良风味。结论:利用酶法生物降解食品中胆固醇,不仅产物单一,而且对食品风味、营养的影响较小,适于开发低胆固醇系列食品。

Objective： Highly efficient cholesterol-degrading bacterium were separated and screened to exploit a series of lower cholesterol food of animal origin. Methods： The 25 kinds of food samples collected were continuously cultivated in selective medium I. The separated bacterium were screened through comparing their rates of cholesterol-degrading and enzyme activities, and enzymology characteristic was primarily studied. Results： Rhodococcus sp. R14-2 and Brevibacterium sp. R22-4 with high activity of degrading cholesterol had been screened. Their degradation rates of cholesterol substrate liquid and cholesterol of fresh meat were 97.5%, 94.7%, 41.3% and 40.5%, respectively. And their enzymes keep some activities at low temperature （such as 0-10℃） . When the fermented liquid of R14-2 and R22-4 were applied to milk, egg and sausage making, they had been obviously represented activities of degrading cholesterol, meanwhile, had not an bad effect on their tastiness. Conclusions： it is fit for exploiting lower cholesterol food to decrease food cholesterol by enzyme, it not only bring single component, but also have less effect on flavor and nutrition.