嗜热链球菌产乙醛关键功能基因在发酵乳后熟期动态表达分析  

Dynamic expression analysis of key functional gene of acetaldehyde production of Streptococcus thermophilus in after-ripening period of yogurt

作　　者：乌仁图雅[1] 于洁[1] 王宏梅[1] 秦艳婷[1] 德亮亮 刘文俊[1] 张和平[1] 孟和毕力格[1] 

机构地区：[1]内蒙古农业大学,乳品生物技术与工程教育部重要实验室,呼和浩特010018

出　　处：《食品科技》2014年第7期11-16,共6页Food Science and Technology

基　　金：国家高技术研究发展计划项目(2011AA100902);国家自然科学基金青年基金项目(31301518);内蒙古自然科学基金项目(2013MS1206)

摘　　要：研究3株具有不同产乙醛特性的嗜热链球菌，在发酵牛乳后熟期（贮藏初期0-48h）内，采用乙醛试剂盒测定发酵乳乙醛含量，并选取嗜热链球菌中与乙醛形成相关的功能基因pdc（Pyruvate decarboxylase）、ald（Acetaldehyde dehydrogenase）、pfl（Pyruvate formate-lyase）及lid（Lactate dehydrogenase）进行q—PCR定量分析；结合发酵乳乙醛含量的表型数据，阐明这些基因对发酵乳乙醛含量的影响。结果表明，3株嗜热链球菌中pdc、ald及pn基因表达量随着乙醛含量的增加而升高，促进发酵乳乙醛生成；而11d基因在不同菌株中有明显的表达差异，为高、中产乙醛菌株提供了乙醛的生成前体物丙酮酸，而低产乙醛菌株中，将大量丙酮酸催化生成了乳酸，从而使得发酵乳乙醛含量较低。In this study, the acetaldehyde content of 3 different acetaldehyde production characteristic strains of Streptococcus thermophilus were measured during the period of after-ripening of yogurt using the acetaldehyde kit. And then, 4 key functional genes related to acetaldehyde formation were selected to perform quantitatively analysis of gene expression by using q-PCR. Finally, Combine with the acetaldehyde content of fermented milk phenotypic data, clarify the influence of those genes expression on the acetaldehyde content of the fermented milk. The result showed that, in the 3 strains of Streptococcus thermophilus, the expression of pdc （Pyruvate decarboxylase）, aid （Acetaldehyde dehydrogenase） and pfl （Pyruvate formate-lyase） increased with the accumulation of production of acetaldehyde, from which we can presume that the expression of these gene promote the formation of acetaldehyde. Gene lid （Lactate dehydrogenase） which catalyzed reversible reaction the pyruvate and lactate has significant expression differences in strains, which provides acetaldehyde precursors pyruvate for high, middle acetaldehyde yielding strains, in low acetaldehyde yielding strain the expression of gene lid decreased with the increasing of acetaldehyde production, catalyzed a large amount of pyruvate to lactic acid, thereby low acetaldehyde content of such fermented milk.

关 键 词：嗜热链球菌 乙醛 发酵乳后熟期 相对定量-PCR(q-PCR) 

分 类 号：TS201.3[轻工技术与工程—食品科学]