黑豆酸奶发酵微生物鉴定与发酵特性研究
Identification and Characteristics of Lactic Acid Srains for Back Sybean Yghurt Frmentation
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摘要: 利用形态学观察、生理生化方法对黑豆酸奶发酵菌株FJAT-7926和FJAT-7928进行分类鉴定。2株菌的菌体均为杆状,无芽孢,革兰氏阳性,过氧化氢酶阴性。菌株FJAT-7926的生理生化特征与植物乳杆菌Lactobacillus plantarum一致,菌株FJAT-7928的生理生化特征与干酪乳杆菌Lactobacillus casei基本一致。对菌株的16S rDNA基因进行扩增、克隆测序、分子系统发育树分析,结果与生理生化鉴定结果一致。2个菌株对豆类基质进行混合发酵,能形成色泽均匀、风味独特、营养合理的黑豆酸奶,凝乳时活菌数达4.95108cfumL-1,pH值4.28,滴定酸度71.3T,蛋白含量1.62 ghg-1,可见菌株FJAT-7926和FJAT-7928适合作为黑豆酸奶的混合发酵菌种。Abstract: Two lactic acid strains FJAT-7926 and FJAT-7928,which had been screened as promising fermentation agents for bean yoghurt beverage,were identified and characterized in the present work.Observation under scanning and transmission electron microscope showed that both strains were rod-shaped,gram-negative and catalase-negative without spores.According to their physiological and bio-chemical properties,FJAT-7926 and FJAT-7928 were similar to Lactobacillus plantarum and Lactobacillus casei,respectively.The similarities were also indicated with phylogenetic tree of FJAT-7926 and FJAT-7928 based on their 16S rDNA sequences.In the soybean yoghurt prepared by co-fermentation of the two lactic acid strains on bean mild,the viable cell number of the bacteria strains were 4.95108cfuL-1.The pH value,acidity,content of protein of the soybean yoghurt were 4.28,71.3 and 1.62 gg-1,respectively.