Screening Of Cholesterol-reducing Bifidobacterium In Vitro

Serum cholesterol levels are considered the main factors induce cardio-cerebral vascular diseases. At the same time, the human total cholesterol concentration has a close relationship with the dietary lipids intake, thus reducing the cholesterol level in food relates to human health.Large number of studies abroad found that Bifidobacterium can reduce the cholesterol level in fermented food and the human body. Meanwhile, in Europe and Japan already have a market with the complementary products of lactic acid bacteria to reduce serum cholesterol and low cholesterol content of food, but in China research in this area is relatively small. The purpose of this study is to be efficient in vitro screening of Bifidobacterium cholesterol and increase its survival rate of freeze-drying preservation, the main research contents and results are as follows:Firstly, determination of nine food-grade laboratory preservation of Bifidobacterium in vitro cholesterol-lowering ability, of which five degradation rates over 50%. The strains for the unknown.Bifidobacterium were preliminary identified as B.animalis.Secondly, nine Bifidobacterium were tested the tolerance of the human gastrointestinal system experiment and the intestinal colonization experiment. The results showed that the nine subject strains are able to survive at pH2 buffer 2.5h; of which seven tested bacteria can survive concentrations of 0.3% bile salts 24h; and nine tested bacteria cell adhesion better than those of commercial strains B.lactics Bb1.2. Thus, Select NO.6 strains for future dairy probiotics and functional development of the potential strain.Thirdly, the formula of protective additive was optimized to suitable for NO.6 bifidobacterium.The optimum cryoprotectants formula for bacteria was determined by monofactorial experiment and the orthogonal trial as:whey powder 40%, trehalose 10 %, vitamin C 1%, saccharose 1.5%. In that condition, the survival rate can achieved above 90 percent.