Screening Of Lactic Acid Bacteria In Traditional Sausage And Optimization Of Fermentation Technology With Compound Fermentation Agent

Lactobacillus is one of the most widely recognized probiotics in nature.Lactic acid bacteria are widely used in the production of fermented meat products,which can not only ensure food safety but also give food good flavor.Traditional fermented meat products have unique flavor and texture,and contain many kinds of probiotics which are easy to ferment.The fermented meat products are artificially fermented,and their nutrition and flavor are single.In this study,lactic acid bacteria were isolated from natural fermented meat products and identified by 16 S r RNA sequence homology analysis.The identified lactic acid bacteria were inoculated into the sausage to explore the fermentation technology of the sausage and analyze the influence of lactic acid bacteria on the physicochemical properties of the fermented sausage.The results are as follows:(1)97 strains of bacteria were isolated from 30 naturally fermented meat products and 53 strains were identified to be Gram-positive by Gram staining.According to the results of physiological and biochemical identification,six strains were screened out as experimental strains of fermented meat products.Total genomic DNA was extracted from 6 suspected strains by CTAB method.DNA concentration was determined by micro-UV spectrophotometer.DNA was amplified by PCR.The amplified PCR products were analyzed by agarose gel electrophoresis.Bright bands were found at 1500 bp.By 16 S r RNA homology analysis,6 suspected strains were found to be Lactobacillus plantarum.(2)Through orthogonal experiment,the optimum addition of salt and sugar in pickling period was determined as follows: nitrite 0.015%,salt 3.0%,glucose 2.5%.The best flavor formula is pepper powder 0.30%,garlic powder 0.18%,MSG 0.25%.Sensory evaluation was 59.8 after drying and ripening.The optimum fermentation conditions were as follows: Lactobacillus plantarum 107 CFU / g,fermentation temperature 28 C,fermentation time 28 days,fermentation humidity 94%.Thiobarbituric acid(TBA)value and volatile base nitrogen(TVB-N)were within the safe range when lipase,flavor protease and acidic protease were 0.10%,0.020% and 0.015% respectively.(3)The number of Lactobacillus in fermented sausages inoculated with Lactobacillus plantarum was always higher than that in the control group,and the p H value was 4.8 at the end of fermentation,which was maintained in the international standard range;the water activity value was 0.791,which was lower than that of the control group;the content of non-protein nitrogen was 0.67%,which was significantly higher than that of the control group;the free amino acids were mainly in days.Aspartate,glutamate and isoleucine were the main amino acids,and some of them were lower than the control group.The color,flavor,texture and appearance of the experimental group were better than the control group.In this study,Lactobacillus suitable for sausage fermentation was screened,and the optimal fermentation process was determined.The sensory and physicochemical properties of sausage were preliminarily identified,which provided a theoretical basis for the selection of starter for meat products and the optimization of fermented meat products.