【作者】 卢士玲；

【导师】 李开雄；

【作者基本信息】 石河子大学 ， 农产品加工与贮藏工程， 2006， 硕士

【摘要】 本实验从发酵肉制品中分离、筛选适用于生产发酵香肠的乳酸菌、葡萄球菌和微球菌，通过对所筛选菌株的性能测定，优选4株菌进行了初步鉴定。利用所选菌株作为发酵剂生产发酵香肠，并对其作用机理进行了探讨。主要内容包括： 1．从发酵香肠、腊肠、金华火腿中，用MRS培养基分离到67株革兰氏阳性菌，用MSA培养基分离到58株革兰氏阳性球菌；根据乳酸菌、葡萄球菌和微球菌的筛选标准，筛选得到RFx1、RH33、RF261、RL32四株乳酸菌和AFx5、AHx1、AF5b、ALx3四株革兰氏阳性球菌。其中RFx1、RH33、RF261、RL32具有耐盐、耐亚硝酸盐、发酵葡萄糖不产气、精氨酸水解不产氨气、不具有氨基酸脱羧酶活性，不产H₂O₂，不产粘性，产酸速度和产酸能力较好，能够抑制大肠杆菌等特点；AFx5、AHx1、AF5b、ALx3除了有一些上述特征外，还具有硝酸盐还原酶活性、过氧化氢酶活性、蛋白酶活性和脂肪酶活性。 2．通过测定所选菌株在不同温度条件下生长能力，乳酸菌的产酸能力等，RFx1和RF261在低温条件下的产酸能力和生长能力要比RH33、RL32强。AFx5、ALx3在低温条件下生长能力要比AHx1、AF5b强。通过混合培养，RFx1、RF261分别对AFx5、ALx3均有微弱的抑制作用，RFx1在发酵前期抑制作用要强于RF261，但总体上看，AFx5和ALx3均能大量生长。所以选取RFx1、RF261、AFx5、ALx3进行鉴定。 3．根据表型特征和生理生化特征，初步鉴定RFx1和RF261都为德氏乳杆菌；初步鉴定AFx5为变异微球菌，ALx3为肉糖葡萄球菌。 4．通过经口急性毒理实验，确定AFx5、ALx3无毒。 5．利用筛选的菌种制作发酵香肠，并在成熟期间检测菌相变化、生化变化、理化变化和感官变化，对微生物的作用机理进行了探讨。在没有加入乳酸菌发酵剂的发酵香肠中乳酸菌也是优势菌，在成熟的第8天达到最大(10^8-gcfu／g)，pH值达到5.0以下。微生物的发酵作用可以加速发酵香肠水分活度的降低、提高香肠的硬度、弹性、胶粘性，改善风味，并且对加速亚硝酸钠的降解起到微弱的作用；乳酸菌能加速肠杆菌的死亡；变异微球菌和肉糖葡萄球菌产生的过氧化氢酶具有明显的防止脂肪氧化的作用，并且变异微球菌和肉糖葡萄球菌生长繁殖可以明显的改善香肠的色泽；在本研究中微生物酶在促进蛋白质和脂肪水解方面起微弱的作用，内源酶起主要作用。更多还原

【Abstract】 In this research strains such as lactic acid bacteria, Micrococcus, StapHylococcus were isolated and screened from fermented meat product. After capacity of acid and growth were tested, 4 strains with excellent characteristics were selected and preliminary identified. As starter the strains were applied to fermented sausage and their mechanism of action were discussed. The report including several parts as follows:1.67 stains of Gram-positive and 58 stains of Gram-positive cocci were isolated from fermented sausage, Chinese sausage and ham with MRS agar and MSA agar. Based on the standards of screening lactic acid bacteria, Micrococcus and StapHylococcus for fermented meat product, four stains of lactic acid bacteria including RFx1,RH33,RF261 and RL32 and four stains of Gram-positive cocci such as AFx5,AHx1,AF5b and ALx3 were screened. The four stains of lactic acid bacteria did not produce CO₂ from glucose,H₂S,NH₃ from arginine,H₂O₂ and slime. They also had no decarboxylase activity and they can resist nitrite and Nacl.Acidificaction rate and acidifying capacity of them were better than others.E.coli and S.aureus were inhibited by them. AFx5, AHx1, AF5b and ALx3 displayed nitrate reduction, catalase-positive, proteinase and lipase activity beyond some characteristic of RFx1, RH33,RF261 and RL32.2.After growth capacity of all strains and acidifying capacity of lactic acid bacteria were tested at different temperature, I knowed that the growth and acidifying capacity of RFx1 and RF261 were better than RH33 and RL32 at low temperature （10℃）. The growth capacity of AFx5 and ALx3 were better than AHxl and AF5b at the same temperature.The growth of RFx1 and RF261 had inhibition to AFx5 and ALx3 to a degree in mixed cultivation and the inhibition of RFx1 was stronger than RF261 during ferment propHase, but AFx5 and ALx3 could breed a lot in general. RFxl, RF261, AFx5 and ALx3 were selected to identify.3.Based on pHenotype and pHysiological biochemical characteristic RFx1 and RF261 were preliminary identified as L.delbruecki, AFx5 and ALx3 were preliminary identified as M.varians and S.carnosus.4. According to acute toxicity test, AFx5 and ALx3 are safety.5.Fermented sausage was produced with the selected strains and their mechanism of action was disscussed after changes of microbial succession, pHysico-chemical properties, biochemistry properties and sensory quality were studied. The lactic acid bacteria was also dominant flora in without addition group, its maximum bacterial number was 10^8-9cfu/g and pH was lower than 5.0 at the eighth day. Aw was accecelerated decrease and sensory quality such as hardess, gumminess, springiness and flavor were improved with fermented action of microorganism. On the other hand, decompound of nitrite was promoted faintly with the fermented action of microorganism. The growth of lactic acid bacteria can expedite death of enterobacteriaceae .The catalase that M.varians and S.carnosus produced can prevent the oxidation of lipid significantly and the multiplication of M.varians and S.carnosus can improve colour significantly. Relatively speaking, entogenous enzyme is more important to更多还原