摘要
酸奶中的乳酸菌能将大分子蛋白质分解成人体易吸收的小分子营养物质,这对人体具有很重要的保健功能,然而酸奶的后酸化问题不仅严重影响风味,还大大缩短了酸奶的货架期,阻碍了我国酸奶行业的发展。研究证明,控制保加利亚乳杆菌在酸奶发酵后期的生长代谢,是解决酸奶后酸化的关键。本文在研究模式菌株保加利亚乳杆菌ATCC 11842在复原脱脂乳培养基中生长和产酸特性的基础上,利用半定量RT-PCR技术,分析酸奶后酸化中保加利亚乳杆菌不同时期关键基因表达的差异,选取后酸化过程中表达变化明显的丙糖异构酶基因,通过对该基因的过量表达,探究该基因在酸奶后酸化过程中的功能。结果表明,大多数关键基因受到后酸化的影响而上调或下调,其中丙糖异构酶基因过量表达后影响菌株产酸和生长。
The proteins can be enzymatic hydrolysis into small molecules of nutrients which are easy absorbed by human by lactic acid bacteria in yoghurt. However the post-acidification of yogurt not only seriously affects the flavor,also greatly shortens the shelf life, which hinders the development of the yogurt industry in China. Previous studies indicated that controlling the growth of Lactobacillus delbrueckii subsp. bulgaricus in the late fermentation stage is the key to solve this problem. In this study, we detected the growth and characteristics of acid-producing of the model strain Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 cultivating in RSM. When the strain fermented in skim milk,the expression of the key genes in different fermentation periods was analyzed by the semi-quantitative RT-PCR technology. The tpi A gene was selected which expression level is significantly different and through over-expression of the gene,its function related to yogurt postacidification was explored. The results showed that most of the key genes were up-regulated or down-regulated by the effect of post-acidification, and over-expression of the tpi A gene affected the acid production and growth of the strain.
作者
李晨
张国文
赵云
卢海强
田洪涛
罗云波
Li Chen;Zhang Guowen;Zhao Yun;Lu Haiqiang;Tian Hongtao;Luo Yunbo(Food Science and Technology College,Agricultural University of Hebei,Baoding 071001,Hebei;College of Food Science and Nutritional Engineering,China Agricultural University,Beijing 100083)
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2018年第7期256-262,共7页
Journal of Chinese Institute Of Food Science and Technology
基金
国家自然科学基金项目(31301520)
河北省高等学校科学技术研究项目(QN2014065)
河北省自然科学基金项目(C2017204094)
