Isolation And Identification Of Yeast And Analysis The Safety Of Koumiss In Xinjiang

In this study, the isolation and identification of yeasts in Xinjiang fermented koumiss,5.8S rDNA phylogenetic analysis of some strains, screening the koumiss antibacterial yeast strains, and acid the mare’s milk fermentation process, the test results were as follows:1.34strains of yeasts were isolated from koumiss which was gathered from places such as Yili Zhaosu, Nanshan, Shuixigou, in Xinjiang. According to the morphological characters, physiological and biochemical properties,1strain was identified as Schizosaccharomyces;1strain was identified as Sehizoblastosporion;1strain was identified as Torulopsis; and1strain was identified as Saccharomycodes;9strains were identified as Kloechera;5strains were identified as Kluveromyces;8strains were identified as Dekker;3strains were identified as Trichosporon;2strains were identified as Hansenula;3strains were identified as Brettanomyces.Use5.8Sr DNA sequence analysis and phylogenetic tree strains on the12th, the identification of molecular biology, the identification results:strains12and the standard strain HQ396523.1homology of96.7%, for Kluveromyces Kluveromyces marxianus, and traditional Identification results were consistent with that5.8Sr DNA sequence analysis of the accuracy of yeast identification.2.10representative strains were selected from the34bacteria for5.8S rDNA sequence analysis, the similarity of the comparative strains and strains in the NCBI database were greater than99%, the average similarity of strain12and standard strain HQ396523.1Kluveromyces marxianus was99%, the isolates were identified with the traditional physiological and biochemical identification results are consistent.3. According to the phylogenetic analysis of5.8S rDNA sequence, the strain of12was a monophyletic group with HQ396523.1Kluveromyces marxianus, and with a department of the credibility of96%; strains12was a large branch of the strains,and strains16was belonged to strains12.4. Use the Oxford cup method to separated2yeasts from the34yeasts, which can suppress the activity of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, the strains16had strongest antibacterial activity. Use E.coli as indicator bacteria, experience showed that the yeast has good antibacterial effect when the pH value with3to7.5. Use the response surface method to detennine the best technology of the fennented koumiss, results showed that the Lactococcus lactis inoculum size was2%, Lactobacillus inoculum size was2%, yeast inoculum size was4%, lactic acid fermentation time was8h, alcohol fermentation time was48h, mixed fennentation time was72h; Sensory scores can up to89points.6. Analysis the security of koumiss when it mature.The results showed that the acid, koumiss sensory indicators, physical and chemical indicators was adhere to safe food standards, and it had17amino acids, that human body needs, it showed that the koumiss has some nutritional value.