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为改善青贮饲料发酵品质筛选提供乳酸菌资源,实验采用实验室纯培养方法结合生理生化分析,对新疆传统发面面肥样品中乳酸菌的种类、形态学及生理生化特性进行研究,对分离的菌株运用16S r DNA基因序列和系统发育研究进行种属鉴定。结果表明,分离得到三株乳酸菌,其中F5和F28两株被鉴定为Bacillus sp.,F3被鉴定为Paenibacillus sp.。3株菌在p H4~7能生长,在3%和6.5%Na Cl条件下生长状况良好,在10~45℃温度范围能生长。两株芽孢杆菌中F5菌株产酸能力较强,F28菌株生长速率较快,并且这两株菌均能利用多种碳源。所以,实验中筛选出的三株乳酸菌均可选作青贮饲料制作过程中的添加剂。 相似文献
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The metabolic pathways of lactic acid bacteria that influence bread quality are coupled to the central carbon flux by the availability of cofactors influencing the cellular and environmental redox potential. Homo- and heterofermentative metabolism differ fundamentally with respect to the requirement for regeneration of reduced cofactors, NADH or NADPH. The utilization of co-substrates such as oxygen or fructose as electron acceptors by obligate heterofermentative lactobacilli is coupled to an increased production of acetate in dough. Recently, several oxidoreductases involved in cofactor regeneration were characterized and glutathione and short-chain aldehydes derived from lipid oxidation were identified as substrates for cofactor regeneration by Lactobacillus sanfranciscensis. Based on the different metabolic requirements for cofactor regeneration, homo- and heterofermentative lactobacilli exert divergent effects on redox-reactions in sourdough that influence bread quality beyond the formation of acetate. Proteolysis, followed by peptide or amino acid metabolism by LAB is one of the key routes of flavour formation in bread flavour, and enables the strain-specific formation of antifungal metabolites. Peptide metabolism as well as the metabolism of cysteine, arginine, and phenylalanine in Lactobacillus plantarum, L. sanfranciscensis, and Lactobacillus pontis is increasingly understood and these insights provide new opportunities for the directed application of sourdough LAB for improved bread quality. 相似文献
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Herv Robert Valrie Gabriel Catherine Fontagn-Faucher 《International journal of food microbiology》2009,135(1):53-59
The lactic acid microflora of nine traditional wheat sourdoughs from the Midi-Pyrénées area (South western France) was previously isolated and preliminary characterized using conventional morphological and biochemical analysis. However, such phenotypic methods alone are not always reliable and have a low taxonomic resolution for identification of lactic acid bacteria species. In the present study, a total of 290 LAB isolates were identified by PCR amplification using different sets of specific primers in order to provide a thorough characterization of the lactic flora from these traditional French sourdoughs. Overall, the LAB isolates belonged to 6 genera: Lactobacillus (39%, 8 species), Pediococcus (38%, 1 species), Leuconostoc (17%, 2 species), Weissella (4%, 2 species), Lactococcus (1%, 1 species) and Enterococcus (< 1%, 1 species) and 15 different species were detected: L. plantarum, L. curvatus, L. paracasei, L. sanfranciscensis, L. pentosus, L. paraplantarum, L. sakei, L. brevis, P. pentosaceus, L. mesenteroides, L. citreum, W. cibaria, W. confusa, L. lactis and E. hirae. Facultative heterofermentative LAB represent more than 76% of the total isolates, the main species isolated herein correspond to L. plantarum and P. pentosaceus. Obligate heterofermentative lactobacilli (L. sanfranciscencis, L. brevis) represent less than 3% of the total isolates whereas Leuconostoc and Weissella species represent 21% of the total isolates and have been detected in eight of the nine samples. Detection of some LAB species was preferentially observed depending on the isolation culture medium. The number of different species within a sourdough varies from 3 to 7 and original associations of hetero- and homofermentative LAB species have been revealed. Results from this study clearly confirm the diversity encountered in the microbial community of traditional sourdough and highlight the importance of LAB cocci in the sourdough ecosystem, along with lactobacilli. 相似文献
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目的:筛选出产胞外多糖能力强的乳酸菌菌株。方法:从实验室分离保藏的乳酸菌中挑选40株乳酸菌,以商业菌株鼠李糖乳杆菌(L.rhamnosus GG,LGG)为阳性对照菌株,采用菌落拉丝法和苯酚—硫酸法筛选出胞外多糖产量高的菌株,对其进行体外抗逆性、安全性和抗生素敏感性试验,并对最终得到的菌株进行表型特征分析和种属鉴定。结果:对40株乳酸菌进行初筛和复筛,得到了10株胞外多糖产量较多的乳酸菌;最终分离鉴定出4株高产EPS乳酸菌,产量均在600 mg/L以上,分别为2株副干酪乳杆菌(LZ9089、LZ9Y10)、1株干酪乳杆菌(LZ9183)和1株短乳杆菌(LZ9285)。结论:4株高产胞外多糖的菌株具有良好的益生特性,具有潜在的开发利用价值。 相似文献
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乳酸菌的分类鉴定及在食品工业中的应用 总被引:1,自引:0,他引:1
乳酸菌是一类革兰氏阳性杆菌或球菌、可収酵乳糖或葡萄糖产生大量乳酸的细菌的通称,将乳酸菌应用到食品中具有提高其营养价值,改善食品风味,抑制食品中腐败菌的生长,延长食品保质期等作用。因其独特的生理特性,近年来国内外学者对乳酸菌的研究逐渐增多。本文主要论述了乳酸菌的分类和鉴定技术,介绍了传统鉴定斱法和分子生物学鉴定斱法的优缺点以及乳酸菌在食品工业(乳制品、肉制品、果蔬制品、食品保鲜)中的应用,为提高乳酸菌的鉴定效率以及乳酸菌在食品工业、饲料生产和临床医疗上的迚一步应用提供参考。 相似文献
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自然发酵辣椒酱中乳酸菌的分离与鉴定 总被引:2,自引:0,他引:2
从自然发酵的辣椒酱中分离出产酸量高、生长良好的菌株,经过形态学鉴定、生理生化特性及发酵性能试验,最终选定Lact.1和Lact.2两株适用于发酵辣椒试验的乳酸菌。鉴定结果表明Lact.1为植物乳酸杆菌(Lactobacillusplanetarium),Lact.2为肠膜明串珠菌(Leuconostocmesenteroides)。试验结果表明两株乳酸菌产酸速度快,最适生长温度在30℃到40℃之间,最适生长pH 6.0,当食盐浓度在7%以下能生长。 相似文献
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利用益生菌提高人类健康水平是当前营养健康领域最具前景的方向之一。乳酸菌是食品中常用的益生菌,迄今为止,联合国粮食及农业组织(FAO)和世界卫生组织(WHO)推荐仅从人的胃肠道分离的乳酸菌可在食品中使用。而越来越多的研究从食品来源中分离出具有益生功能的菌株以扩大益生菌的选择范围。随着分子生物学和检测分析等技术的发展,基质辅助激光解吸电离-飞行时间质谱(MALDI-TOF MS)、全基因组测序、实时荧光定量聚合酶链式反应(RT-FQ-PCR)等技术可以鉴定到亚种及菌株水平上的益生菌。鉴于分离鉴定技术是益生菌安全规范应用的先决条件,该文综述了近年来针对潜在益生乳酸菌有效分离和鉴定技术的研究进展,以期为我国益生乳酸菌自主开发利用提供借鉴。 相似文献
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Flavour of type II sourdoughs is influenced by the ingredients, processing conditions, and starter culture composition. It is, however, not fully clear to what extent different sourdough lactic acid bacteria (LAB) contribute to flavour. Therefore, two types of flour (rye and wheat) and different LAB starter culture strains were used to prepare sourdoughs, thereby leaving the yeast microbiota uncontrolled. All LAB starter culture strains tested were shown to be prevalent and to acidify the flour/water mixture to pH values between 3.1 and 3.9 after 24 h of fermentation. Multiple aldehydes, alcohols, ketones, and carboxylic acids were produced by the sourdough-associated microbiota throughout the fermentation period. Based on the organoleptic evaluation of breads produced with these sourdoughs, five LAB strains were selected to perform prolonged wheat and rye fermentations as to their capacity to result in an acidic (Lactobacillus fermentum IMDO 130101, Lactobacillus plantarum IMDO 130201, and Lactobacillus crustorum LMG 23699), buttermilk-like (Lactobacillus amylovorus DCE 471), or fruity flavour (Lactobacillus sakei CG1). Upon prolonged fermentation, higher metabolite concentrations were produced. For instance, L. sakei CG1 produced the highest amounts of 3-methyl-1-butanol, which was further converted into 3-methylbutyl acetate. The latter compound resulted in a fruity banana flavour after 48 h of fermentation, probably due to yeast interference. Rye fermentations resulted in sourdoughs richer in volatiles than wheat, including 3-methyl-1-butanol, 2-phenylethanol, and ethyl acetate. 相似文献
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为筛选亚硝酸盐降解能力强、产酸快、发酵风味好的乳酸菌,以新疆传统酸马乳为筛选源,经亚硝酸盐降解试验初筛、接种辣 椒酱复筛,筛选出一株亚硝酸盐降解率达88.91%、发酵辣椒酱风味佳的乳酸菌C27。 总酸复筛试验显示,菌株C27可以明显缩短发酵 周期,发酵辣椒酱第8天,总酸含量达2.15 g/100 g。 菌株C27经形态观察、生理生化试验及16S rRNA序列分析鉴定为肠膜明串珠菌(Leuconostoc mesenteroides)。 耐酸及耐胆盐试验显示,菌株C27在pH 3.0及0.30%胆盐环境中能够生长,满足益生菌在肠胃定植的首要条件。因此菌株C27可以作为发酵辣椒酱专用发酵剂进行生产应用。 相似文献
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为了研究传统鱼露发酵过程中乳酸菌的种类及性质,以发酵周期为两年的传统鱼露发酵液为研究对象,利用乳酸菌分离培养基对中后期发酵液中的优势乳酸菌进行筛选,并考察其生理生化性质。研究结果表明:从发酵液中共分离获得28种乳酸菌,其中至少有5种优势乳酸菌贯穿整个鱼露发酵的中后期,经生理生化鉴定初步确定R1为发酵乳杆菌(Lactobacillus fermentum)、R2为德氏乳杆菌乳亚种(L.delbrueckii subsp.lactis)、R4为短乳杆菌(L.brevis)、R5为乳酸乳球菌乳亚种(L.lactis subsp.lactis),而R3未能鉴别出种属。其中R1、R4的耐盐性比较强,而R3、R5的产酸能力则相对较强。这5株乳酸菌均不具有对蛋白质和脂肪的降解能力。这为下一步多菌种的添加应用奠定基础。 相似文献