Ultraviole Ray Mutagenesis Screening Cholesterol-degrading Strain And Its Application To Fermentative Beef Sausage

Cholesterol is a necessary nutritional ingredient for man, and diseases caused by excess cholesterol are threatening human health. Some researches indicate that the content of cholesterol in diet is positively correlated with the content cholesterol in blood. Therefore, it has been a hot topic to study the approach of lowering the content of cholesterol in food for medical science and food nutrition field constantly.Meat products are indispensable delicious foods in our lives, they can offer many kinds of nutrients. Nevertheless, high content of cholesterol in meat products hindered people to enjoy the food. In order to help people to enjoy the meat products without afraid of bad effects of cholesterol, we screened a strain by ultraviolet mutagenesis from traditional fermentative meat product which can degrade cholesterol, and enhanced the ability of cholesterol degradation, and applied it into the processing of fermentative beef sausage, finally obtained low-cholesterol fermentative beef sausage sausage.Results showed that the lactobacillus M1 which ws separated and screened from traditional fermentative meat product was suitable for meat product processing and with cholesterol degradation rate of 24.60%. It was characterized by physiological and biochemistry functions and PCR technology, this strain was definited as Lactobacillus. plantarum. In order to increase the cholesterol degradadition rate, the screened strains were ultraviolet mutated, with the ultraviolet mutated time set at 100s. After 3 grounds mutagenesis, a strain(M1-UVs29) obtained from 2 ground mutagenesis were the best strain with degradadition rate higher than orginal strains. Passage experiment showed that its heritage of M1-UVs29 was stable compared with origin strains, and the salt endurance,nitrate enduranced and bacteriostasis increased than origin strain.Acute poison experiment were carried out for the new strain, and the result showed that LD50 for female and male mouse were more than 15000mg/kgBW, accordingly the M1-UVs29 culture fluid was determined innocuity.To improve the taste of fermentative , high performance cholesterol degradation M1-UVs29 and Brewer's yeast were applid in producing fermentative beef sausage with low cholesterol content. Single factor experiments were carried out to study 4 factors including the ratio of M1-UVs29 and brewer's yeast,innoculation amount,fermentation temperature,fermentation time. Based on single factor experiments, D-Satur Design were used to optimize the experiment, took cholesterol degradation and organoleptic investigation as the target index, built a mathematical model according to the regression analysis, the optimized parameters including: ratio of Brewer's yeast to M1-UVs29 were 1:2, inoculation 0.9%, fermentation temperature 28℃, fermentation time 24h. Under these technology parameters, the degradation rate of cholesterol was 37.06%, sensory evaluation scored 82.01, the microorganism index was correspond to the government standard, and the shelf life was prolonged than non-fermented sausage, the nutrition value was improved.