【作者】 李静；

【导师】 武运；

【作者基本信息】 新疆农业大学 ， 食品科学， 2012， 硕士

【摘要】 本研究对新疆哈萨克族传统发酵酸马奶中的酵母菌进行分离鉴定,对部分菌株进行了5.8S rDNA系统发育分析,对酸马奶中抑菌酵母菌菌株进行筛选,并对酸马奶发酵工艺进行研究,试验结果如下：1.从新疆伊犁昭苏、南山、水西沟采集的新疆哈萨克族自制酸马奶中,分离出酵母菌34株。经传统形态学及生理生化鉴定,鉴定结果为Schizosaccharomyces1株,Sehizoblastosporion1株,Torulopsis1株,Saccharomycodes1株,Kloechera9株,Kluveromyces5株,Dekker8株,Trichosporon3株,Hansenula2株,Brettanomyces3株。对菌株12号的5.8SrDNA序列进行同源性分析,鉴定结果为：菌株12与标准菌株HQ396523.1同源性达到96.7%,为Kluveromyces的Kluveromyces marxianus,结果与传统鉴定一致。2.从上述34株菌中选取10株代表菌株进行5.8S rDNA序列分析,代表菌株与NCBI数据库中比对菌株的相似度均大于99%,具有较高的相似度,其中菌株12与标准菌株HQ396523.1Kluveromyces marxianus的平均相似度为99%,菌株鉴定结果与传统生理生化鉴定结果保持一致。3.根据5.8S rDNA序列系统发育分析,判定菌株12与标准菌株HQ396523.1的分支遗传距离最近,为同一支系,菌株16号为12号菌株的下属分支。4.通过牛津杯法,从己分离的34株酵母菌中,筛选出2株对人肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)枯草芽孢杆菌(Bacillus subtilis)具有抑菌活性的菌株,其中菌株16号抑菌活性最强,以大肠杆菌(Escherichia coli)为指示菌,在pH值3-7具有抑菌效果,说明该酵母菌有较强的抑菌性,且具有较广的抑菌谱。5.采用响应面法确定发酵酸马奶的最佳工艺参数,结果表明,乳酸球菌接种量2%,乳酸杆菌接种量2%,酵母菌接种量4%,乳酸发酵8h,酒精发酵48h,混合发酵72h,感官评分可达89分。6.将发酵成熟的酸马奶进行安全性分析,结果表明,发酵酸马奶感官指标、理化指标及卫生指标等均符合安全食用标准；发酵酸马奶中具有人体所需的17种氨基酸,说明酸马奶具有很好的营养价值。更多还原

【Abstract】 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.更多还原