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制备冷冻干燥乳酸菌的相关影响因素的研究进展 总被引:1,自引:0,他引:1
从技术和经济角度出发,让乳酸菌在干燥及其后续的贮藏过程中,尽可能多的存活是非常重要的。这篇文章主要综述与冷冻干燥乳酸菌制备的几个相关因素。 相似文献
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乳酸菌冻干特性的研究 总被引:7,自引:1,他引:7
对乳酸菌冻干存活率的影响因素及质粒稳定性进行研究。结果表明,乳酸菌冷冻干燥过程中,残余水分质量分数在2%~3%,菌体的相对存活率较高;悬浮液中菌体密度降低,存活率降低;在冷冻干燥过程中,存在两个最大冰晶生成带,即:0~-3.7℃和-30~37.4℃。快速通过最大冰晶生成带可以减小菌体的冷冻损伤。复水介质中营养组分对菌株的存活性影响不显著(P>0.05)。LDB菌株在冻干前后质粒保持了很好的稳定性。液态发酵剂、冻干发酵剂、冻藏发酵剂的生长迟滞期分别为0.61,1.26,0.84h;对数生长末期每小时pH值分别为0.5992,0.3968,0.5159。冻藏发酵剂比冻干发酵剂更利于保持菌体活力。 相似文献
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《International Dairy Journal》2007,17(3):183-189
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Survival of lactic acid bacteria in the human stomach and adhesion to intestinal cells 总被引:21,自引:0,他引:21
The survival of four strains of lactic acid bacteria in human gastric juice, in vivo and in vitro, and in buffered saline, pH 1 to 5, has been investigated. The strains studied include two Lactobacillus acidophilus strains, Lactobacillus bulgaricus, and Streptococcus thermophilus. In addition, the adhesion of these strains to freshly collected human and pig small intestinal cells and to pig large intestinal cells has been studied and the effect of milk on both survival and adhesion tested. As a result of these investigations, an in vitro test system for screening potential cultures for use as human dietary adjuncts can be developed. The ability to survive in gastric juice and to adhere varied significantly for the strains tested; L. acidophilus ADH survived and adhered better than the others while S. thermophilus survived and adhered poorly. For all strains, both survival and adhesion was enhanced by milk. As all strains adhered to some extent to both human and pig intestinal cells, the adhesion mechanism is probably a nonspecific attachment as opposed to other reported specific Lactobacillus adhesion to gastric tissue. From the survival and adhesion data it seems feasible to obtain elevated levels of viable Lactobacillus sp. in human intestine by careful selection of the bacterial strains ingested. Furthermore, the in vitro methods used here should be valuable to screen potential strains. The data presented here can then be correlated with human in vivo studies monitoring the beneficial effect of ingestion of these Lactobacillus. 相似文献
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The proteolytic activity of 12 lactic acid bacteria (LAB) strains, assayed on soy protein extract at a temperature of 37 °C for 6 h, was evaluated by SDS–PAGE, reverse-phase HPLC and free-amino acid analyses. The results indicated that α- and α′-subunits of β-conglycinin were the preferred substrates for the majority of the LAB. Only a few strains exerted some action against the basic polypeptides of glycinin, this fraction was the least degraded of all soy protein fractions. Whole-cell suspensions of LAB used in this study generated hydrophilic and hydrophobic peptides from mainly soy protein fractions. RP-HPLC analyses indicated differences in the profiles of the hydrolysates, with several peaks decreasing in size and new peaks being formed. Three of the selected strains assayed increased the level of total free amino acids in the soy protein extract (SPE) and hydrolyzed principally essential amino acids and flavour precursor amino acids. 相似文献
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吴丹 《中外食品工业信息》2011,(9):34-34
乳品是消费者每天都需要摄入的东西,但因消费者自身原因会在摄入后产生不适的状况.加之最近频繁爆出乳品安全问题,让消费者对乳品的选择有了一些担忧.所以纯奶制品的销售额一直不太稳定,这给纯奶企业与经销商的投资带来了不利因素。但如果不是纯奶制品的乳品.例如果奶、花生奶等,却一直没有在销售业绩上出现下滑征兆。 相似文献
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为快速、准确地计数活性乳酸菌制品中的乳酸菌,用CO2烛缸法代替现行国家标准GB/T16347-1996活性乳酸菌饮料中乳酸菌微生物检验方法中的有氧培养法,CO2烛缸法操作简便,计算准确可靠,在菌种对比实验中,CO2烛缸法的乳酸菌计数结果是国家标准方法的8倍,在试样的对比实验中,CO2烛缸法的乳酸菌计数结果是国家标准方法的20倍,CO2烛缸法较目前国家标准方法更能真实施反映活性乳酸菌制品中乳酸菌的数量。 相似文献
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The study reported here deals with the survival of ropy slime-producing lactic acid bacteria in two different heat processes used in the Finnish meat industry. In both processes tested, ropiness was prevented in products inoculated with the bacteria before cooking. The bacterial count in the sausages decreased during processing over 4–5 log units/g. The bacteria were evidently unable to survive the processes, and the contamination of the products apparently takes place after cooking. Heat treatment given to vacuum-packed grill sausages after packing could delay the formation of ropy slime. 相似文献
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对四川腊肉中乳酸菌进行筛选,研究其产酸特性及氨基酸产物。利用可培养方法,对四川腊肉中乳酸菌进行分离筛选,利用16SrDNA的序列测定技术对其鉴定,并对分离菌株在不同温度、pH、NaCl浓度、亚硝酸浓度条件下的生长代谢、产酸能力进行研究及发酵产物中氨基酸成分进行测定分析。结果显示:分离菌株为植物乳杆菌(Lactobacillus paraplantarum),分离菌株对数生长期为6~18h;最适产酸作用温度范围为30~40℃;最适产酸作用pH范围为5.5~6.0;对NaCl及NaNO2耐受能力分别达6.0%和150mg/L;分离菌株释放游离氨基酸11种,其中必需氨基酸占总氨基酸含量的45.76%,可为后续该植物乳杆菌在发酵肉类中的应用提供基础研究数据。 相似文献
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Horvath P Coûté-Monvoisin AC Romero DA Boyaval P Fremaux C Barrangou R 《International journal of food microbiology》2009,131(1):62-70
Clustered regularly interspaced short palindromic repeats (CRISPR) are hypervariable loci widely distributed in bacteria and archaea, that provide acquired immunity against foreign genetic elements. Here, we investigate the occurrence of CRISPR loci in the genomes of lactic acid bacteria (LAB), including members of the Firmicutes and Actinobacteria phyla. A total of 102 complete and draft genomes across 11 genera were studied and 66 CRISPR loci were identified in 26 species. We provide a comparative analysis of the CRISPR/cas content and diversity across LAB genera and species for 37 sets of CRISPR loci. We analyzed CRISPR repeats, CRISPR spacers, leader sequences, and cas gene content, sequences and architecture. Interestingly, multiple CRISPR families were identified within Bifidobacterium, Lactobacillus and Streptococcus, and similar CRISPR loci were found in distant organisms. Overall, eight distinct CRISPR families were identified consistently across CRISPR repeats, cas gene content and architecture, and sequences of the universal cas1 gene. Since the clustering of the CRISPR families does not correlate with the classical phylogenetic tree, we hypothesize that CRISPR loci have been subjected to horizontal gene transfer and further evolved independently in select lineages, in part due to selective pressure resulting from phage predation. Globally, we provide additional insights into the origin and evolution of CRISPR loci and discuss their contribution to microbial adaptation. 相似文献
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Elisa Sgarbi Benedetta Bottari Monica Gatti Erasmo Neviani 《International Journal of Dairy Technology》2014,67(3):342-347
A new device named a cell sonicated substrate membrane system (CSSMS), consisting of a tissue culture insert that supplies nutrients, in the form of starter lactic acid bacteria (SLAB) lysate extract, through a polycarbonate membrane which isolates it from the nonstarter lactic acid bacteria (NSLAB) inoculum and serves as a support for bacterial growth, was developed. The CSSMS was used to demonstrate that the Lactobacillus helveticus SLAB lysate provides sufficient nutrients to allow the growth of L. casei and L. rhamnosus NSLAB in vitro. The results support the hypothesis that NSLAB could grow in aged cheese using only SLAB cell lysate as nutrients. 相似文献
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Development of a microbial time-temperature integrator system using lactic acid bacteria 总被引:1,自引:0,他引:1
Seong Hwan Lim Woo Yeong Choe Byung Hyun Son KwangWon Hong 《Food science and biotechnology》2014,23(2):483-487
A microbial time-temperature integrator (TTI) system was developed using lactic acid bacteria (Weissella koreensis) obtained from baechukimchi. Activation energy (Ea), which represents the temperature dependence of the TTI response, was calculated using the Arrhenius equation. Ea values for the color change (ΔE value), maximum specific growth rate (μmax), and pH change of the TTI measured under different isothermal conditions (5, 10, 15 and 20°C) were 99.88, 95.91, and 93.38 kJ/mol, respectively. According to the time taken to reach the TTI endpoint by the initial inoculum level of W. koreensis (6.2, 5.5, 4.5, and 3.4 log CFU/mL), a negative correlation was observed in 63.5, 101.8, 115.1 and 166.6 h. In addition, initial bacterial counts decreased significantly up to almost 4% at 20°C in 3 months when W. koreensis viability was measured at the freezing point of the microbial TTI system (20 and ?80°C) for 1 week, 1 month, 2 months, and 3 months. However, viability was about 95% at 80°C. This microbial TTI system would be useful to monitor the quality of food with similar Ea values during storage or distribution. 相似文献