【作者】 王永霞；

【导师】 牛天贵；

【作者基本信息】 中国农业大学 ， 食品科学， 2004， 硕士

【摘要】 我国传统发酵食品中存在着广泛的菌种资源，可以作为筛选发酵肉制品优良菌种的来源。本实验对自然发酵食品（主要是发酵肉制品）中的发酵微生物进行了分离、纯化、筛选和应用研究，主要内容包括如下几个部分： 1．从发酵食品中分离、纯化乳酸菌132株，研究了其主要发酵特性。不同菌株耐盐和耐亚硝能力差异较大；大部分的菌株发酵葡萄糖不产CO₂（74％），不生成H₂S（72％）；很少菌株产粘液（6％）；大部分能使牛奶酸凝；一部分生长过程中不产H₂O₂（33％），不会发生氨基酸脱羧反应（48％）；77％的菌株水解精氨酸不产氨；少数菌株V-P反应阳性（9％）；大约一半菌株对大肠杆菌和金黄色葡萄球菌有抑制作用。这些乳酸菌在不同培养基上的产酸速度和产酸能力有较大差异。 2．以生产干发酵香肠为目标，选出四株乳酸菌优选菌株R17、P20、P30和J33，四株菌生长速度有显著差异，温度对其生长速度有显著的影响。初步鉴定R17为戊糖乳杆菌，P20和P30为戊糖片球菌，J33为米酒乳杆菌。R17和P20之间没有拮抗关系，可以作为混合发酵剂。 3．以MSA培养基从发酵肉制品中分离、纯化过氧化氢酶阳性球菌158株，采用半定量硝酸盐还原酶平板的方法快速筛选出活性较大的菌株50株，进行发酵基本试验，得到两株优选菌株S15和S113。两株菌均具有蛋白酶和脂肪酶活性，生长速度没有显著差异。初步鉴定为肉糖葡萄球菌。 4．通过乳酸菌和葡萄球菌在模拟肉汤混合培养相互关系的研究，确定出混合发酵剂P20+S15。对S15进行了急性经口毒性试验，证明属无毒型。 5．优选出的菌株作为发酵剂生产发酵香肠，研究了主要微生物、理化和感官指标的变化。添加发酵剂各组发酵和成熟期间乳酸菌始终处于支配地位；P20+S15组葡萄球菌数显著高于其他各组；添加发酵剂各组肠杆菌均显著下降，加工14天和28天后即未检出。添加发酵剂各组pH值显著低于对照，发酵三天达到最低值，以后稍有回升；加工7天，发酵剂各组Aw值开始显著低于对照。添加发酵剂的各组质地指标之间没有显著差异；色泽差异显著，其中P20+S15组红度值显著高于其他各组。结合感官评价，认为四组均可作为发酵剂用于发酵香肠的生产。更多还原

【Abstract】 There are a lot of bacterium resources in natural fermented foods, and can be used to select starter cultures with excellent characteristic for fermented meat products. Isolation, purified, screening and application of fermentative microbiology from naturely fermented food ( most meat products ) had been carried out in this study. The report including several parts as follows:1.132 strains of lactic acid bacteria were isolated and purified from fermented food, their important fermentation characteristics were studied. Salt and nitrite tolerance for different strains had significant difference. Most isolates produced no gas(CO2) from glucose(74%),H2S (72%)and NH3 from arginine(77%) . Few strains were responsible for slime production. Some were no H2O2 producers (33%) and had no decarboxylase activity (48%) . About half of LAB inhibited E.coli and S.aureus. Acidification rate and acidifying capacity varied significantly for these lactic acid bacteria in different broth.2. 4 strains with excellent characteristics were selected on the basis of fermented dry sausage. The growth of 4 strains had significant difference, the effect of temperature on the growth of 4 strains were significant. Four strains were preliminary identified, R17 was Lactobacillus pentosus, P20 and P30 were Pediococcus pentosaceus, J33 was Lactobacillus sake. R17 and P20 were selected as mixed culture following compatibility tests between strains.3. 158 catalase-positive cocci were isolated and purified from traditional fermented meat products with MSA agar. 50 strains showing very high nitrate reduction according to a fast semiquantitative plate assay were selected, then according to fermentation adaptation, two cocci S15 和 S113. were selected , two strains displaying proteinase and lipase activity were preliminary identified as staphylococcus carnosus S15 和 S113.4. lactic acid bacteria with two staphylococci were mixed cultured on simulative broth medium, their relationship were studied and mixed starter cultures P20+S15 was initial selected. According to acute toxicity test , S15 are safety.5. Fermented sausage were produced with selected strains, microbial and pHysico-chemical changes were studied. Lactic acid bacteria of 4 batchs with starter culture rapidly dominateds the total microflora. P20+S15 showed significantly more staphylococci counts than other batch.. The growth of enterobacteriaceae was inhibited and they were reduced to undectectable levels after 14 and 28 day. The lowest value were reached at 3th day, then the pH values increased slightly. Aw values significantly decreased. No significant difference was found in texture between 4bacths with starters. There were significant difference in colou between different batchs, The a value of P20+S15 showed siginificantly higher than other batchs. Combined with sensory evaluation, 4 batch could be used as meat starter cultures in fermented sausage.更多还原