Study On The Screening And Application Of Strains Of Fermented Mutton

Mutton,as an excellent meat,is a kind of nutritious food with high protein and low cholesterol.Due to its warm nature,it has health care functions such as replenishing empty qi,warming,tonifying kidney and helping fire,raising gallbladder and eyesight,benefiting spleen and stomach,and benefiting lung and helping qi,etc.At present,with the improvement of people’s consumption level,mutton consumption demand further expanded,showing a steady growth trend.However,the consumption of mutton in China is mainly cold meat,and the deep processing of mutton is relatively less.In this experiment,the optimum lactic acid bacteria for fermented mutton was screened out from the traditional dong acid meat,and then mixed with appropriate amount of sacrilomyces cervix,the fermentation process parameters were optimized,and the shelf life of fermented mutton products was predicted.This paper mainly studies from the following aspects:1.Screening,identification and safety evaluation of lactic acid bacteria in dong acid meatBased on dong acid meat products as the research object,adopts the traditional acid in the meat microorganism separation method of dong fermentation lactic acid bacteria,and for this reason the sifting for lactic acid bacteria fermented meat,identified are:sausage Lactobacillus(Lactobacillus farciminis strain)S26,plant Lactobacillus(Lactobacillus plantarum strain)S42 and lactic acid bacteria(Pediococcus acidilactici strain)S53.Then safety evaluation was carried out to explore whether they had resistance to antibiotics and whether they had plasmid and hemolysis.The results showed that these three strains had no resistance to most antibiotics and no plasmid and hemolysis.At the same time,the growth and acid production energy of the three strains were studied,and it was found that the three strains grew well and produced acid quickly,and the pH could be reduced to about 3.5 within 24 hours.Moreover,the antagonistic test showed that there was no antagonistic resistance among the three strains,which could be used for mixed bacteria fermentation of mutton.2.Study on the mixture proportion of fermented mutton strainsIn view of the single flavor of mutton fermented by a single lactic acid bacteria,the selected lactic acid bacteria and laboratory preserved Saccharomyces cerevisiae were used as experimental strains in this study.With sensory score and pH value as reference indicators,yeast was added to the mutton fermented by lactic acid bacteria.Through mixed fermentation,the flavor of mutton fermented was improved,the quality was improved,and the types of mutton processed products were enriched The effects of single lactobacillus fermentation and compound fermentation of Lactobacillus and Saccharomyces cerevisiae on the quality of fermented mutton were compared.The optimum mixing ratio of Lactobacillus and Saccharomyces cerevisiae was determined by single factor and orthogonal test.The results showed that the mixed fermentation effect of Lactobacillus and yeast was better,and the optimal mixed proportion of Lactobacillus sausagei S26,Lactobacillus plantarum S42,Lactococcus lactis S53 and Saccharomyces cerevisiae was 2:4:3:2.At this time,the sensory score of fermented mutton was 83.75,and the pH value was 4.30.3.Optimization of mutton fermentation processAccording to the optimal mixing ratio of lactic acid bacteria and Saccharomyces cerevisiae,sensory score and pH value as reference indexes,mutton was fermented.Through single factor and response surface experiments,the effects of fermentation temperature,fermentation time,inoculation amount and meat size on the quality of fermented mutton were explored,and the optimal technological conditions of fermented mutton were determined.The results showed that the optimal fermentation parameters were:fermentation temperature 28℃,fermentation time 20 hours,inoculation amount 1.0%,the size of meat 3 cm square,the sensory score of fermented mutton was 88.5,pH value 4.4.4.Shelf life prediction of fermented muttonTaking the mutton fermented under the above optimal fermentation conditions as the research object,through the study of the quality change of the fermented mutton under different storage temperature conditions,the total number of colonies,pH,water content,texture,brightness value L*,sense organs,thiobarbituric acid(TBARS)of the fermented mutton in different storage time were measured,and the TBARS was used to predict the quality of the fermented mutton products in 4℃,25℃,37℃.The results showed that the sensory quality of fermented mutton products at different storage temperature decreased with the prolongation of storage time.The sensory rejection degree of fermented mutton products stored at 4℃ reached at 62 days,and that of fermented mutton products stored at 25℃ and 37℃ at 18 days and 15 days,respectively.The TBARS value of fermented mutton products increased gradually with the increase of time,and the rising rate was 37℃>25℃>4℃.The Pearson correlation coefficient between sensory score and TBARS of fermented mutton at different storage temperature is greater than 0.9,so TBARS is selected as the key factor of shelf-life prediction model.Combining with Arrhenius equation,the shelf-life prediction model about the relationship between the change rate constant(k)of TBARS and storage temperature(T)is established,and the shelf-life prediction model is as follows:t=lnA-laA0/3.52×103×exp(-3.11×103/273+a)In the prediction model,the activation energy Ea was 25.8846 kJ/mol,and the preexponential factor k0 was 3.52×103.The predicted shelf life of fermented mutton stored at temperatures of 4℃,25℃ and 37℃ is 59 days,19.7 days and 14.08 days respectively,which is more consistent with the measured value of 62 days,18 days and 15 days.