摘要
为解析干酪乳杆菌的表面物质在冻干过程中的作用,首先优化菌株表面物质的剥离条件,并测定菌株在被剥离表面物质后添加不同保护剂的冻干存活率及表面物质总量与成分,最后测定菌株分别在不同碳氮比、不同碳源条件下培养产生的表面物质含量,探究其与菌体冻干存活的关系。结果表明:干酪乳杆菌17005、173011CQQJ3与PS5-4的菌体表面物质分别在90 W/6 min、90 W/12 min、90 W/12 min条件下被有效剥离,且表面物质中蛋白含量约是多糖的3倍;以海藻糖或水苏糖为保护剂,被剥离表面物质后菌体的冻干存活率提高,菊粉反之;菌株以阿拉伯糖为碳源,较葡萄糖产生更少的表面物质;低碳氮比发酵下也可有效降低菌体表面物质,低含量的表面物质可提高对数期菌体在水苏糖或海藻糖作为保护剂时的冻干存活率。该研究为提高干酪乳杆菌的冻干存活率和单位质量菌粉的活菌数提供了指导。
In order to analyze the role of Lactobacillus casei cell surface substances during the freeze-drying process,the surface substances stripped conditions were optimized.The freeze-drying survival rate of the strains with different protective agents,and the total amount and composition of the surface substances were then determined after the surface substances were stripped off.The surface substances content of L.casei cultured in medium with different carbon-nitrogen ratios and different carbon sources were determined,and the relationship between the amount of surface substances and the freeze-drying survival rate was investigated.The results showed that the surface substances of L.casei 17005,173011CQQJ3 and PS5-4 were effectively stripped off in the conditions of 90 W/6 min,90 W/12 min and 90 W/12 min,respectively.The protein content in the surface substances was about 3 times as much as polysaccharides.With trehalose or stachyose as cryoprotective agents,the lyophilization survival rate of cells without surface substance was improved,and inulin was on the contrary.With arabinose as carbon source,L.casei produced fewer surface substances than glucose.Under the condition of low carbon-nitrogen ratio,the amount of surface substances was also effectively reduced.The smaller amount of surface substance was beneficial to improve the lyophilized survival rate of bacterial cells collected during the phase time when using trehalose or stachyose as cryoprotectants.The conclusions provided guidance for the improvement of the survival rate of lyophilized L.casei and the number of viable cells per unit mass of lyophilized bacterial powder.
作者
吴晟
崔树茂
毛丙永
唐鑫
赵建新
张灏
陈卫
WU Sheng;CUI Shumao;MAO Bingyong;TANG Xin;ZHAO Jianxin;ZHANG Hao;CHEN Wei(School of Food Science and Technology,Jiangnan University,Wuxi 214122,China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2020年第17期73-79,共7页
Food and Fermentation Industries
基金
国家食品科学与工程一流学科建设项目(JUFSTR20180102)
国家青年科学基金项目(31801530)。
关键词
干酪乳杆菌
表面物质
剥离
冻干存活率
Lactobacillus casei
surface substance
stripped off
freeze-drying survival rate
