瑞士乳杆菌AJT在酸奶中的应用研究

发布时间：2018-03-19 03:04

  本文选题：瑞士乳杆菌　切入点：广谱　出处：《内蒙古农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着生活质量的提高,我国乳制品生产消费发展迅速,尤其是各种酸奶的消费更是突飞猛进。但有一个制约酸奶行业发展的问题,就是酸奶的货架期太短,由于冷链运输是控制酸奶质量的一个重要环节,但是中国大多数的生产厂家仍然无法保证冷链物流,因此为了提高酸奶的质量,开发长保质期的酸奶,就成为值得研究的课题。本试验选用瑞士乳杆菌AJT和嗜热链球菌ST962作为混合发酵菌种,研究瑞士乳杆菌AJT在脱脂乳培养基中的发酵特性、混合菌种最优发酵工艺条件及酸奶的保质期进行了系统的研究。1.瑞士乳杆菌AJT以2.0%(v/v)的接种量在脱脂乳培养基中培养至12h凝乳,凝乳时活菌数可达1.6×109 CFU/mL,pH值为4.08,酸度值是84°T;嗜热链球菌ST962以2.0%(v/v)的接种量在脱脂乳中培养至6h凝乳,凝乳时活菌数可达到1.3×109 CFU/mL,pH 值为 3.42,酸度 61.86°T。2.以菌种配比、接种量、发酵温度、蔗糖添加量等因素作为因变量对酸奶最佳发酵工艺进行研究,得出最优发酵工艺为:菌株AJT和ST962配比为1:3、接种量为4.0%(v/v)、发酵温度为42℃、蔗糖添加量为6.0%(g/v)。3.保质期试验中,酸奶在4℃条件下保质期可以延长至42天,常温条件下能够保存21 d。因此,菌株AJT酸奶相较于传统酸奶可以抑制大肠菌群的生长,并且具有抑制酸奶后酸化作用。4.通过室温暴露试验得知,菌株AJT酸奶比较传统酸奶未被霉菌污染的时间延长了 3 d,说明菌株AJT在酸奶中的应用具有一定的抑制霉菌的效果。
[Abstract]:With the improvement of quality of life, dairy production and consumption is developing rapidly in our country, especially the consumption of all kinds of yoghurt is advancing by leaps and bounds. However, there is a problem that restricts the development of yoghurt industry, that is, the shelf life of yogurt is too short. Since cold chain transportation is an important link in controlling the quality of yogurt, but most manufacturers in China still cannot guarantee the cold chain logistics, in order to improve the quality of yogurt, we develop yogurt with a long shelf life. In this experiment, Lactobacillus helicus AJT and Streptococcus thermophilus ST962 were selected as mixed fermentation strains to study the fermentation characteristics of Lactobacillus Switzerland AJT in defatted milk medium. The optimum fermentation conditions of mixed strains and the shelf life of yoghurt were studied systematically. 1. Lactobacillus helittidis AJT was cultured in skim milk medium for 12 hours to curd milk at the inoculation amount of 2.0% v / v. The number of live bacteria reached 1.6 脳 10 ~ 9 CFU 路mL ~ (-1), pH value was 4.08, acidity value was 84 掳T, inoculation amount of Streptococcus thermophilus ST962 was 2.0 v / v) in skim milk for 6 h, the number of live bacteria reached 1.3 脳 10 ~ 9 CFU / mL pH value was 3.42, acidity was 61.86 掳T. 2. The optimum fermentation technology of yoghurt was studied by using sucrose addition as dependent variable. The optimum fermentation technology was obtained as follows: the ratio of strain AJT and ST962 was 1: 3, the inoculation amount was 4.0 v / v / v, the fermentation temperature was 42 鈩，

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