Screening Of Lacticacid Bacteria And The Influence On Characteristics Of Mutton Dry Fermented Sausage

To screen out the potential strains used as starter culltures for fermented sausage, theprocessing and functional characteristics of lactic acid bacteria isolated from traditionalsausages of different areas in Inner Mongolia were studied. After producing mutton dryfermented sausage by single selected strains or the combination of selected strain andpapain, the microbial, physiochemical, flavor and sensory properties of fermented sausageunder processing and storage conditions were tested. Moreover, the influence oflactobacilli and papain on the quality of mutton dry fermetned sausage was evaluated. Theresults showed that:Eight lactobacilli strains which possess the required fermented properties of startercultures used for meat products were screened out from Inner Mongolia traditionalsausages. Through morphous, physiological, biochemical characteristics and16S rDNAsequence analysis, these eight strains were identified as five strains of Lactobacillusplantarum, three strains of Lactodacillus curvature All the selected strains can expressstrong growth adaptability under different conditions with various temperature and pHvalues. The growth of X3-2B, X3-3B, X3-4B and X3-5B at25,30,37℃were significantlyhigher than those at other temperatures （P<0.05）. Moreover, the growth of these fourstrains under pH4.5,5.5and6.5were significantly higher than that of other strains（P<0.01）. All the selected strains can reduce the pH value of various culture media to4.2within24h. The survival rate of X3-3B and X3-2B in artifical gastric juice weresignificantly higher than that of other strains （P<0.05）. The bile salt resistance ability ofX3-2B and X3-5B were the highest. The cholestero removal rate of X3-2B wassignificantly higher than that of other strains, with68.92%. Moreover, X3-2B and X3-5Bexpressed strong inhibitory effect on the growth of E. coli and Staphylococcus aureus.Therefore, it is concluded that X3-2B is suitable to act as starter culture for the productionof fermented sausage. Mutton dry fermented sausage was produced by X3-2B or thecombination of X3-2B and papain, with the products without LAB starter culture as controlgroup. The results showed that the viable count of lactobacilli in trial groups weresignificantly higher than that of control group during processing and storage of mutton dryfermented sausage. However, their total viable counts were significantly lower than that of control group （P<0.05）. pH value, Aw, nitrite content and TVBN of trial groups weresignificantly lower than those of control group. But their texture and color weresignificantly higher （P<0.05）. There were no significant difference between the group ofX3-2B and X3-2B with papain. Thus X3-2B had a significant impact on thephysicochemical properties of mutton dry fermented sausage, and adding papain had nosignificant effect on it.There were small molecule protein bands appeared in trail groups during drying andmaturity stage, and small molecular protein bands disappeared during storage; Releaseamount of free amino acid of trial groups were significantly higher than control groupduring the processing and storage, and X3-2B+papain group was higher than X3-2Bgroup; Species and contents of flavor substances in each group were：X3-2B+papaingroup> X3-2B group> control group; sensory evaluation score of trial groups weresignificantly higher than that of control group.It was concluded that the addition oflactobacilli could obviously promote the formation of mutton flavor characteristics of dryfermented sausage, and papain can enhance this effect.