河南省自然发酵酸菜中优良乳酸菌的分离鉴定及应用

【作者】 胡书芳；

【导师】 王雁萍；

【作者基本信息】 郑州大学 ， 生物物理， 2009， 硕士

【摘要】 泡菜是一种独特而具有悠久历史的大众化乳酸发酵制品,它具有清淡爽口、开胃理气的特点。泡菜是各种蔬菜经过乳酸菌发酵而成。乳酸菌是正常人畜肠道中极为重要的生理菌群,担负着人畜机体多种重要的生理功能,具有维持人体中微生态平衡的作用,与机体健康息息相关。本研究通过对河南栾川自然发酵酸菜中乳酸菌的分离鉴定,经一系列实验研究,筛选出19株乳酸菌,经生理生化实验研究,从中筛选出4株性状优良的乳酸菌L1、L3、L8和L9,分别鉴定为:Lactobacilllus plantarum I、Lactobacillus brevis I、Lactobacillus collinoides和Lactobacilus curvatus。菌株L1的发酵性能优良,产酸快,产酸量多,30℃发酵24小时内pH即可达到3.7左右。同时菌株L1耐酸性较好,pH4左右仍能较好地生长。菌株L8、L9延滞期、指数期较短,繁殖较快,6个小时基本达到稳定期。菌株L9的耐盐性最好,在8%左右盐浓度条件下仍能生长。菌株L3、L8耐盐性次之。利用分离出的乳酸菌接种发酵白菜,泡菜品质的鉴定比较结果表明应用L1和L8菌株(1:1),接种量为5%,添加食盐量为3%,25℃条件下发酵,泡菜品质最好,其中样品中亚硝酸盐含量较低,浓度为10.712mg/Kg,乳酸(0.693)以及游离氨基酸总量较高(6.66g/Kg)。用此法发酵的泡菜色泽、气味、口味、口感等方面良好,评定分值也是最高的。对泡菜汁的抑菌实验表明,泡菜汁可以抑制指示菌大肠杆菌(Escherichiacoli)、金黄色葡萄球菌(Staphylococcusaureus)、藤黄微球菌(Micrococcusluteus)、铜绿假单胞杆菌(Pseu-domonasaeruginosa)、枯草芽孢杆菌(Bacil-lussubtilis)及沙门氏菌(Salmonella Lignieres)的生长;较低的pH(3以下)的酸能够抑制细菌的生长,当把酸中和到pH6以上时,酸对指示菌生长抑制作用消失。在排除泡菜汁中的酸和过氧化氢作用后,泡菜汁仍对指示菌有抑制作用。表明泡菜中确有抑菌物质的存在。对传统自然发酵的酸菜中的乳酸菌进行分离鉴定并利用优良的菌株进行发酵泡菜,取得了良好效果。为泡菜的接种发酵和工业化生产提供了理论依据。更多还原

【Abstract】 Pickle is a very popular fermented food with a long history,which has the characteristic of very subtle and refreshing taste and appetizing.vegetables become pickles by fermenting of lactic acid bacteria.Lactic acid bacteria is an extremely important physiological flora in human and animal intestinal tract,which is closely related to human health.Lactic acid bacteria plays an important physiological functions in human and animal,and it could maintain micro-ecological balance of body.We got 19 strains from the natrul sauerkraut made in luanchuan city henan province,and we screening out four strains of lactic acid bacteria with the fine fermentation throug researching on physiological and biochemical character.After a series of identity tests,indicating these 4 strains are Lactobacilllus plantarumI,Lactobacillus brevis I、Lactobacillus collinoides and Lactobacilus curvatus.The strain L1 has very good performance,such as acid-forming fast, acid-output large.Within 24 hours fermentation liquor’s pH could reach 3.7 in 30℃.At the same time,acid fastness of the strain L1 is best among the 4 strains,which could grow very well under the condition of pH4.The lag phase and the exponential phase of the strains L8 and L9 are comparatively short,which reproducting rapidly,six hours could reach stationary phase.Salt tolerance of strain L9 is best among these four,and it can survive in 8%salinity.Salt tolerance of strain L3 and L8 is weaker relative to strain L9.These four strains were used for fermenting cabbage,then we compared to the quality of these pickles.The results indicated that the pickle is best which is fermented under those conditions:inculturing:L1 and L8(mixed 1:1),inoculum concentration:5%, salt concentration:3%,fermentation temperature:25℃.Thenitrite of the pickle is lower, its concentration below 10.712mg/Kg.As well as the total volue of free amino acid and lactic acid is higher in the pickle.The co-lout,the smell and the taste,and so on are better,and the score is highest.Bacteriostatic test of pickle juice shows that:pickle juice could inhibit the indicator(Escherichiacoli,S taphylococcusaureus,Micrococcusluteus, Pseu-domonasaeruginosa,Bacil-lussubtilis and Salmonella Lignieres) growth.Lower pH(under 3) of acid can inhibit the growth of bacteria,but if the pH of the acid over 6, the growth inhibition disappeared.After the exclusion of acid and hydrogen peroxide in pickle juice,pickle juice still has inhibition action.Which indicates that there do exist the inhibitory substances.Fine lactic acid bacteria are Isolated and Identifyed from natural fermentation sauerkraut.These strains were used to fermentating chinese cabbage,and we got well-pleasing result.We Accumulate experience for vegetable fermentation and industrialization of pickle.更多还原