Study On The Protective Agent Of Staphylococcus Xylose Dry Powder And Its Application In Fermented Sausage

Staphylococcus xylose is one of the indispensable strains in commercial meat starters.Because of its good fermentation and flavor characteristics,it is favored by consumers.The development of high-activity Staphylococcus dry powder starter is not only conducive to large-scale industrial production of fermented meat products,but also can reduce the use of imported starters by domestic companies.Taking Staphylococcus xylose as the research object,the protective effects of different protective agents on the strains were studied,the protective agent formula was optimized,and a highly active dry powder starter was prepared.Finally,the dry powder starter was used in fermented sausages to study its effect on sausage quality.The specific research content and research results are as follows:1.Preparation of dry powder starter of Staphylococcus xyloseTaking Staphylococcus xylose as the research object,the culture conditions of the strain were determined to be 37℃,16 h;the centrifugal collection conditions of the cells were 6000 r/min,10 min;and 10%concentration of skim milk was used as the suspension matrix.Through the response surface test,the concentration of each component of the compound protective agent was determined to be:trehalose(14.19%),sucrose(11.49%),sorbitol(3.25%),and the freeze-drying survival rate reached 87.49%.2.Study on the protective effect of different protective agents on Staphylococcus xyloseIn the process of freeze drying,adding protective agent can significantly improve the survival rate of freeze-dried Staphylococcus xylose(P<0.05),the protective effect of different protectants on Staphylococcus xylose was different:using a single protective agent,the concentration of 3%sorbitol protection effect is best,add the protection of the composite protective agent effect is significantly higher than add the effect of single protective agent(P<0.05).The GC-MS experiment showed that the treatment group with added protectant could better maintain the fatty acid composition of the cell membrane,and the cell activity was significantly higher than that of the treatment group with no protectant(P<0.05),and the unsaturation of the treatment group with composite protectant was significantly higher than that of the group with no protectant and that of the single protectant(P<0.05).Through SEM and TEM observation,it can be found that the protective agent can fully wrap Staphylococcus xylose,and form a protective layer outside the cell,so as to maintain full cell,smooth surface and intact cell membrane.3.Application of Staphylococcus xylose starter in sausage after freeze-dryingStaphylococcus xylose dry powder starter was used in fermented sausage.The sausage fermented by inoculation of non-protectant dry powder starter(S1),composite protectant dry powder starter(S2)and liquid starter(S3)was treated as the experimental group,and the naturally fermented sausage(CK)was treated as the control group.The fermentation lasted for 28 d.The results showed that compared with natural fermentation(CK),inoculated Staphylococcus xylose fermented sausage could significantly reduce the pH value of sausage.Increase the hardness and mastication of sausage,decrease the value of L*,increase the value of a*/b*(P<0.05),so as to improve the texture and color of sausage.Reduce the fat oxidation of sausage;It also contributes to the formation of flavor components and improves the sensory quality of sausage finishing.There was no significant difference in quality between the dry powder starter and the liquid starter of the compound protectant(P>0.05),so it could be used in production.