發(fā)布時(shí)間：2018-03-19 03:04

  本文選題：瑞士乳桿菌　切入點(diǎn)：廣譜　出處：《內(nèi)蒙古農(nóng)業(yè)大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：隨著生活質(zhì)量的提高,我國(guó)乳制品生產(chǎn)消費(fèi)發(fā)展迅速,尤其是各種酸奶的消費(fèi)更是突飛猛進(jìn)。但有一個(gè)制約酸奶行業(yè)發(fā)展的問(wèn)題,就是酸奶的貨架期太短,由于冷鏈運(yùn)輸是控制酸奶質(zhì)量的一個(gè)重要環(huán)節(jié),但是中國(guó)大多數(shù)的生產(chǎn)廠(chǎng)家仍然無(wú)法保證冷鏈物流,因此為了提高酸奶的質(zhì)量,開(kāi)發(fā)長(zhǎng)保質(zhì)期的酸奶,就成為值得研究的課題。本試驗(yàn)選用瑞士乳桿菌AJT和嗜熱鏈球菌ST962作為混合發(fā)酵菌種,研究瑞士乳桿菌AJT在脫脂乳培養(yǎng)基中的發(fā)酵特性、混合菌種最優(yōu)發(fā)酵工藝條件及酸奶的保質(zhì)期進(jìn)行了系統(tǒng)的研究。1.瑞士乳桿菌AJT以2.0%(v/v)的接種量在脫脂乳培養(yǎng)基中培養(yǎng)至12h凝乳,凝乳時(shí)活菌數(shù)可達(dá)1.6×109 CFU/mL,pH值為4.08,酸度值是84°T;嗜熱鏈球菌ST962以2.0%(v/v)的接種量在脫脂乳中培養(yǎng)至6h凝乳,凝乳時(shí)活菌數(shù)可達(dá)到1.3×109 CFU/mL,pH 值為 3.42,酸度 61.86°T。2.以菌種配比、接種量、發(fā)酵溫度、蔗糖添加量等因素作為因變量對(duì)酸奶最佳發(fā)酵工藝進(jìn)行研究,得出最優(yōu)發(fā)酵工藝為:菌株AJT和ST962配比為1:3、接種量為4.0%(v/v)、發(fā)酵溫度為42℃、蔗糖添加量為6.0%(g/v)。3.保質(zhì)期試驗(yàn)中,酸奶在4℃條件下保質(zhì)期可以延長(zhǎng)至42天,常溫條件下能夠保存21 d。因此,菌株AJT酸奶相較于傳統(tǒng)酸奶可以抑制大腸菌群的生長(zhǎng),并且具有抑制酸奶后酸化作用。4.通過(guò)室溫暴露試驗(yàn)得知,菌株AJT酸奶比較傳統(tǒng)酸奶未被霉菌污染的時(shí)間延長(zhǎng)了 3 d,說(shuō)明菌株AJT在酸奶中的應(yīng)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 擄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 擄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，

本文編號(hào)：1632517