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1.
提高嗜酸乳杆菌酸乳菌活力的研究   总被引:2,自引:1,他引:1  
以嗜酸乳杆菌为主发酵剂,嗜热链球菌和保加利亚乳杆菌为辅助发酵剂制作嗜酸乳杆菌酸乳,采用正交实验,并分析发酵过程中pH、乳酸菌数以及感官品质的变化,确定混合菌种的最佳比例。结果表明,嗜酸乳杆菌1.8%、嗜热链球菌1.4%、保加利亚乳杆菌0.6%混合发酵,可以提高乳中嗜酸乳杆菌的菌活力并改善其风味。经验证,混合菌种发酵制作的酸奶在风味和保健功能等方面明显优于单一菌种发酵制作的酸乳。  相似文献   

2.
酸奶的连续发酵   总被引:2,自引:0,他引:2  
金世琳 《中国乳品工业》1997,25(1):18-21,37
叙述了酸奶发酵剂中嗜热链球菌和德氏乳杆菌保加利亚亚种事菌种在连续培养中的原始合作情况和相互作用,协同生长中共生关系和互补作用。对两种菌的刺激作用和连续发酵工艺予以介绍。  相似文献   

3.
以保加利亚乳杆菌和嗜热链球菌作为酸豆乳的发酵菌种,对发酵型酸豆乳菌种的驯化、增殖条件,以及对酸豆乳直投式液态发酵剂的浓缩条件进行了研究,制得了发酵性能良好的直投式液态发酵剂。  相似文献   

4.
罗地亚9001直投型发酵剂发酵特性研究   总被引:3,自引:1,他引:2  
利用罗地亚90001直投型发酵剂来发酵酸奶,探讨了利用直投型发酵剂发酵的酸奶不能作为后续发酵剂进行酸奶生产的原因。在实验中首先利用直投型发酵剂发酵牛乳,然后依次利用各代次产物作为后续发酵剂生产酸奶,直至第6代牛乳不能再正常发酵为止。同时,对每代酸奶中嗜热链球菌和保加利亚乳杆菌进行计数,并观察嗜热链球菌和保加利亚乳杆菌比例上的变化。最后将第6代不能正常发酵酸奶中的嗜热链球菌和保加利亚乳杆菌分离并进行鉴定。将二者按1:1(数量比)的比例接种牛乳,发现牛乳能够正常发酵。结果表明。利用酸奶作为后续发酵剂的第6代牛乳不能正常发酵的原因是嗜热链球菌和保加利亚乳杆菌的数量比发生变化。而导致此情况发生的原因可能是由于低温下二者的生长速率不同。  相似文献   

5.
通过对保加利亚乳杆菌、嗜热链球菌、嗜酸乳杆菌单一菌种,以及保加利亚乳杆菌和嗜热链球菌复合菌种发酵酸奶中多肽物质的测定、分析与比较,找出不同菌种所产多肽的特异性,研究多肽在乳酸细菌鉴定中的应用.  相似文献   

6.
目前,生产酸奶时所使用的乳酸菌一般都需经多次活化和多次扩大培养制成生产发酵剂后才能被利用。在实际生产中,嗜热链球菌和保加利亚乳杆菌的获得过程都很费时费工,极不方便。为了提高制作酸奶的方便性与时效性,本文采用包埋法对乳酸菌进行固定化,就是将菌种均匀地包埋在水不溶性载体中,使菌种细胞中的酶处于原始状态,菌种活力强而耐久。本文采用海藻酸钠作包埋剂,把嗜热链球菌及保加利亚乳杆菌分别固定在其中,制成凝胶珠。  相似文献   

7.
为了研究9种益生菌之间的相互作用及协同共生机理,采用牛津杯扩散法,对德氏乳杆菌保加利亚亚种、植物乳杆菌、嗜热链球菌、鼠李糖乳杆菌、嗜酸乳杆菌、乳双歧杆菌、两歧双歧杆菌、干酪乳杆菌、副干酪乳杆菌9种益生菌进行拮抗试验,再将菌种之间无拮抗作用的实验组,按1%接种量以1∶1的比例两两混合发酵,测其OD600nm值。约1/3的益生菌之间都存在拮抗作用,但嗜热链球菌与德氏乳杆菌保加利亚亚种、嗜酸乳杆菌、干酪乳杆菌,以及干酪乳杆菌与嗜酸乳杆菌存在协同共生作用,由于乳杆菌有较强分解蛋白质的能力,能产生多种氨基酸可刺激嗜热链球菌生长,嗜热链球菌因产酸速率快,可以快速代谢产生乳酸、甲酸、CO2等,从而促进乳杆菌的生长。该研究分析了9种常用益生菌之间的相互作用,为益生菌混合发酵、微生物制剂的开发提供理论依据。  相似文献   

8.
新型酸奶发酵剂的研究   总被引:12,自引:3,他引:9  
研究了具有不同粘度,风味和保健功能的新型酸奶发酵剂,首先通过对专用酸奶菌种嗜热链球菌和保加利亚乳杆菌不同菌株的组合筛选,优选出具有不同粘度和风味的3种组合;其次,酸奶的疗效保健作用来源于嗜酸乳杆菌,通过研究缓冲盐,生长促进物质对该菌生长的影响,确定了适宜的培养基成分和发酵剂中菌种的配比。  相似文献   

9.
杜磊  袁超  杜杨 《食品工业科技》2011,(10):259-260
保加利亚乳杆菌和嗜热链球菌是酸奶生产过程的主要发酵菌种,在酸奶制作过程中起着极其重要的作用。但是由于菌种在其保藏过程中极易出现活性退化的现象,使得保藏后的菌种活性大大降低,影响了菌种的使用特性。分别对单独的保加利亚乳杆菌、嗜热链球菌及这两种菌的混合菌种进行菌种在保藏期间的传代实验,通过对实验数据的分析比较可得出,在没有特殊要求的情况下,乳酸菌菌种的保藏最好是使用保加刺亚乳杆菌和嗜热链球菌的混合菌种.这样可以大大降低乳酸菌菌种在保藏期内的特性变化。  相似文献   

10.
酸奶生产液体发酵剂的研究   总被引:11,自引:4,他引:7  
房兴利  晋津 《中国乳品工业》1994,22(5):207-208,228
保加利亚乳杆菌和嗜热链球菌培养液收集的菌体,分散在pH4.2的乳酸缓冲液中制成酸奶液体发酵剂,具有菌体存活率较高,活性较强和保藏时间长的优点,属即时菌种,不需复活,用于酸奶生产有较冻干发酵剂发酵周期短的特点。  相似文献   

11.
Interactions among lactic acid starter and probiotic bacteria were investigated to establish adequate combinations of strains to manufacture probiotic dairy products. For this aim, a total of 48 strains of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium spp. (eight of each) were used. The detection of bacterial interactions was carried out using the well-diffusion agar assay, and the interactions found were further characterized by growth kinetics. A variety of interactions was demonstrated. Lb. delbrueckii subsp. bulgaricus was found to be able to inhibit S. thermophilus strains. Among probiotic cultures, Lb. acidophilus was the sole species that was inhibited by the others (Lb. casei and Bifidobacterium). In general, probiotic bacteria proved to be more inhibitory towards lactic acid bacteria than vice versa since the latter did not exert any effect on the growth of the former, with some exceptions. The study of interactions by growth kinetics allowed the setting of four different kinds of behaviors between species of lactic acid starter and probiotic bacteria (stimulation, delay, complete inhibition of growth, and no effects among them). The possible interactions among the strains selected to manufacture a probiotic fermented dairy product should be taken into account when choosing the best combination/s to optimize their performance in the process and their survival in the products during cold storage.  相似文献   

12.
被污染的鸡蛋与人类肠炎沙门菌病感染之间存在明显的联系,鸡蛋和鸡蛋产品是肠炎沙门菌暴发最主要的食品源头。本文主要阐述肠炎沙门菌病原与蛋鸡及鸡蛋之间的相互作用,揭示肠炎沙门菌菌株比其他血清型菌株更易污染鸡蛋的原因。  相似文献   

13.
The cell surface physicochemical properties of 50 Lactococcus lactis strains of different subspecies and isolated from different origins (dairy, vegetal and animal) were examined. Cell surface hydrophobicity and Lewis acid-base properties were evaluated by affinity measurements to solvents in a partitioning test, while the global electrical charge of the cells was assessed by micro-electrophoresis using a laser zeta-meter. A global multivariate analysis of the results revealed a high natural diversity of L. lactis cell surface properties. While 52% of the strains present a hydrophilic and electronegative cell wall surface, a group of strikingly hydrophobic strains (12% of the strains) and a group of strains with unusual low charged surface (18%) were identified. Adhesion on polystyrene microtitre plates was evaluated for twelve strains selected from the multivariate analysis as representatives of the various observed cell wall surface physicochemical patterns. A significant correlation between adhesion, hydrophobicity and low electronegativity was observed when adhesion was performed in a low ionic strength suspending medium. The most adhesive strains were hydrophobic or low charged. The presence of repulsive electrostatic interactions led to a decrease in adhesion of the most negatively charged hydrophilic strains. The present study highlights the diversity of L. lactis cell surface physicochemical properties, diversity that could not be connected to the origin or to the subspecies of the strains.  相似文献   

14.
The objective of this study was to establish suitable combinations of selected probiotics and nutraceuticals. Interactions among 24 probiotic strains were investigated, and the effect of a blend of isoflavones and phytosterols on viability of single and mixed probiotic strains under incubation and refrigeration storage in milk was assessed. Upon incubation, counts of single strains increased by 7–15 times, while mixed strains showed slight insignificant decrease. Both single and mixed probiotic strains retained high counts (>log 8) throughout refrigeration storage. Eight probiotic strains showed nil or very weak interactions. Results revealed the possibility of developing novel multibenefits synbiotic products using combinations of these probiotic strains and nutraceuticals.  相似文献   

15.
The effect of coaggregation of the two bacterial strains Propioniferax-like PG-02 and Comamonassp. PG-08 on phenol degradation and aerobic granulation was investigated. While PG-02 was characterized as a phenol-degrader with a low half-saturation kinetics constant, PG-08 possessed strong aggregation ability with poor phenol degradation ability. The two strains coaggregated through involvement of lectin-saccharide interactions with the adhesin protein on strain PG-02 and the complementary sugar receptor on strain PG-08. Using the V. harveyi reporter strain BB170, it was found that both strains could produce autoinducer-2-like signals. If incubated together, the two strains showed cooperation for phenol degradation. In batch, the coculture degraded phenol at an initial concentration of 250 mg L(-1), faster than each strain separately. Bioaugmentation with simultaneously the two strains in sequencing batch reactors significantly improved phenol removal and aerobic granulation as compared to monoculture bioaugmentation. Bacterial coaggregation might be an integral component of the aerobic granulation process. Investigation of in situ occurrence of coggregation in aerobic granulation would help unveil its molecular mechanism. Then the granulation process could be improved through selection of specific microbial groups.  相似文献   

16.
Some strains of the food borne pathogen Listeria monocytogenes persist in food processing environments. The exact reason behind this phenomenon is not known, but strain differences in the ability to adhere to solid surfaces could offer an explanation. In the present work, initial adhesion of nine strains of L. monocytogenes was investigated under liquid flow at two levels of shear stress on six different surfaces using a flow chamber set-up with microscopy measurements. The surfaces tested were glass and PVC, and glass coated with beef extract, casein, and homogenised and unhomogenised milk. In addition, the effect of prior environmental stress (5% NaCl, low nutrient availability) on initial adhesion was investigated. The hydrophobicity of the investigated surfaces was determined by contact angle measurements and the surface properties of the investigated L. monocytogenes strains were determined using Microbial Adhesion To Solvents (MATS). All surfaces with the exception of PVC were found to be hydrophilic. Strain differences were found to significantly influence the initial adhesion rate (IAR) of all nine strains to all the surfaces (p < 0.05) at both low and high shear stress. Furthermore, there was a significant effect of the surfaces tested (p < 0.05) in the adhesion ability of almost all strains. The IAR was affected by flow rate (shear stress) as seen by a decrease in adhesion at high shear stress for most strains. A significant effect of interactions between strain-surface and strain-shear stress (p < 0.001) was observed but not of interactions between surface-shear stress. No correlation between surface hydrophobicity and IAR was observed. Addition of 5% NaCl during propagation resulted in a decrease in IAR whilst propagation in low nutrient media caused an increase indicating a general change in surface characteristics under these conditions. Known persisting strains did not display general better adherence.  相似文献   

17.
The cell surface charge and microstructure of four commercial strains of brewing yeast were examined using electrokinetic and scanning electron microscopic (SEM) techniques. Flocculent and non-flocculent ale and larger strains were observed to possess non-normally distributed surface charges while suspended in buffers of various pH values with and without 1.0 mM calcium, 5% ethanol and 0.5 M KCl. Non-normal charge distributions were also observed when the strains were suspended in commercial ale and lager beers. During SEM examination, a number of distinct structures appeared to be involved in cell-to-cell interactions. Observed differences in cell wall microstructure and the finding of non-normally distributed surface charges indicate that these pure brewing strains possessed substantial phenotypical variation.  相似文献   

18.
19.
The isolation of Listeria monocytogenes from food is carried out using a double enrichment. It is believed that the double enrichment can allow the overgrowth of Listeria innocua in samples where both species are present. In this study, we have evaluated the impact of overgrowth between Listeria species and strains during each step of the enrichment process. The effect of factors minimizing interactions between strains or phage inhibitory effects has also been estimated. In an artificially contaminated food undergoing enrichment, overgrowth could result from competitive interactions between Listeria spp. resulting from the production of bacteriocins and bacteriophage at high initial contamination levels (>10(4) cfu/g), but not at lower levels (50-100 cfu/g) as generally found in contaminated foods. At high levels of inoculation, the competitive effect could be reduced by solidification of the selective broths, to limit the diffusion of the inhibitors. Overgrowth resulting from differences in growth rate occurred independent of the initial contamination level. However, in naturally contaminated foods undergoing enrichment, there were no absolute correlations between growth rates or inhibitory profiles in terms of strain evolution during enrichment. In fact, Listeria strains which were predominant in the original sample in most cases remained the dominant strains at the end of the enrichment, although the relative proportion of any given strain could change significantly over the enrichment process. Additional factors which have yet to be identified impact on the evolution of Listeria in the two-step enrichment process. Analysis of strain evolution in eight naturally contaminated foods has indicated that the second enrichment step in Fraser broth can be reduced from 48 to 24 h without impacting on the recovery of L. monocytogenes. Our limited survey of naturally contaminated foods also demonstrated that maximum recovery of L. monocytogenes and other Listeria strains was found following 24 h incubation in 1/2 Fraser Broth. This finding suggests that it may be possible to shorten the current two-step isolation method further without reducing method sensitivity.  相似文献   

20.
In hard cooked cheeses, any interactions between the thermophilic starters as they grow during the cheese-making are critical, since they modify bacterial growth kinetics and acidification kinetics, so affecting the ripening process and the final characteristics of the cheese. Twenty-four experimental hard cooked cheeses were made under controlled conditions, the milk being inoculated with various combinations of thermophilic strains of Streptococcus thermophilus, Lactobacillus helveticus and Lactobacillus delbrueckii. Over the first day of manufacturing we recorded a wide range of different growth kinetics for each starter species used, and a wide range of pH kinetics, depending on the starter combination. Most of the bacterial variability could be statistically explained by the nature, quantity, and/or presence or absence of the different strains inoculated. Four main interactions between the three species were evidenced during cheese-making. There was antagonism between L. helveticus and L. delbrueckii. The lactobacilli had a positive effect on S. thermophilus, which was reciprocal for L. helveticus. L. helveticus had a negative effect on S. thermophilus cultivability. And the combination of S. thermophilus inoculated in large quantities and L. helveticus strain H2 had a negative effect on the growth of the L. delbrueckii strain D2. While the positive effect of L. delbrueckii on S. thermophilus probably corresponds to interactions in milk that have already been described and published, the other interactions were hitherto unknown. These interactions are of major importance for the growth kinetics of streptococci and thermophilic lactobacilli during cheese-making.  相似文献   

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