一株适宜于Kefir发酵的优良酵母菌的筛选与鉴定  

Screening and identification of an excellent yeast strain suitable for Kefir fermentation

作　　者：肖冉 惠明[1,2] 田青 XIAO Ran;HUI Ming;TIAN Qing(College of Biological Engineering,Henan University of Technology,Zhengzhou 450001,China;Henan Provincial Engineering Laboratory of Preservation and Breeding of Industrial Microbial Strains,Zhengzhou 450001,China)

机构地区：[1]河南工业大学生物工程学院,河南郑州450001 [2]工业微生物菌种保藏与选育河南省工程实验室,河南郑州450001

出　　处：《河南工业大学学报（自然科学版）》2023年第2期56-63,共8页Journal of Henan University of Technology：Natural Science Edition

基　　金：河南省重大科技专项课题(181100211400-8-2)。

摘　　要：为制备开菲尔(Kefir)新型发酵剂,发掘一株产气适中、耐受性高、使发酵乳具有沙口感且风味独特的酵母菌,利用YPD培养基从甜瓜曲中分离纯化出4株产香酵母菌,分别编号为TN_(1)、N2、Z2、HX。通过耐酸、耐酒精及耐高温试验对4株酵母菌进行初筛、复筛,使用固相微萃取-气质联用色谱(SPME-GC-MS)对其中两株发酵乳香气物质成分进行主成分分析,并将最终得到的菌株进行分子生物学鉴定。结果表明:4株酵母菌中TN_(1)、N2耐受性高,生长迅速,发酵性能较佳;TN_(1)发酵牛奶产生的香气物质种类最多,典型味物质的含量适中,产生的香气更佳,更适合后续Kefir酸乳的开发;结合TN_(1)菌株的分子生物学分析结果,该菌株与NRRL Y-12632菌株同源性为100%,将TN_(1)鉴定为酿酒酵母(Saccharomyces cerevisiae)。研究结果为开发Kefir发酵乳发酵剂奠定了基础。Commercially available Kefir fermented milk does not have the taste of traditional kefir milk like champagne.In order to develop a pure Kefir fermented milk and prepare a new type of kefir starter culture,an excellent yeast strain is required to be selected with a moderate production of bubbles and resistance to high acidity and high temperature.In addition,such strain should have the unique flavor of Kefir milk that ordinary single lactic acid bacteria fermented yogurt does not have.Four aroma-producing yeast strains were isolated and purified from melon koji(a natural starter used to ferment sourdough steamed bread)by YPD medium,which were numbered TN_(1),N2,Z2 and HX,respectively,to conduct subsequent experiments.The preliminary screening of four isolated strains resistant to acid,alcohol,and high termperature was carried out.Through solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS),the aroma components in the fermented milk fermented by the two yeasts obtained from the previous experiment were used as evaluation indexes,and the aroma components were rescreened.A strain with the best aroma content,type and flavor was selected.The final strain was identified by molecular biology.The results showed that after comprehensive evaluation of various indicators,the growth,tolerance,and fermentation performance of TN_(1) and N2 in the four yeast strains were better.In comparison with N2 strain,TN_(1) strain produced the most kinds of aroma substances,the content of typical flavor substances of which was moderate.The aroma of TN_(1) strain had wheat alcohol aroma,rose aroma and cream aroma,which was better than the other strains.Through PCA analysis,the data were reduced in dimension,and the difference of key flavor substances between TN_(1) and N2 was more intuitive and convenient.Therefore,TN_(1) was more suitable for the subsequent development of Kefir yogurt.In combination with the molecular biological analysis results of TN_(1) strain,the homology between the strain and NRRL Y-12632 strai

关 键 词：酿酒酵母 开菲尔 风味物质 生物学鉴定 

分 类 号：TS201.3[轻工技术与工程—食品科学]