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1.
In the last time the number of research works dealing with preservation of vegetables increased again [1]. The interest is directed to the production of lactic acid fermented vegetable juices. By lactic-acid fermentation there are yielded extraordinarily delicious and consistent products owing high nutritive-physiological value. At production, there is applied either spontaneous fermentation, or controlled inoculation using selected and proved microorganisms cultures [2, 3]. The producers demand such fermentation cultures which intensify the aroma and enable to reach rapid decrease of juices' pH value. At lactic-acid fermentation the production of lactic acid is regarded as crucial factor for preservation. With regard to accessibility of vegetables and their favourable chemical composition for microorganisms we began fermentation experiments with various kinds of vegetables as carrot, green pea, celeriac, onion, capsicum and cabbage. In this paper, we publish on fermentation of green pea and onion, reporting on production and amount of organic acids in fermented vegetables determined using isotachophoresis.  相似文献   

2.
The objective of this study was to determine the effect of beet pulp (BP) and lactic acid bacteria (LAB) on silage fermentation quality and in vitro ruminal dry matter (DM) digestion of vegetable residues, including white cabbage, Chinese cabbage, red cabbage, and lettuce. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage without additive or with BP (30% fresh matter basis), LAB inoculant Chikuso-1 (Lactobacillus plantarum, 5 mg/kg, fresh matter basis), and BP + LAB. In vitro incubation was performed using rumen fluid mixed with McDougall's artificial saliva (at a ratio of 1:4, vol/vol) at 39°C for 6 h to determine the ruminal fermentability of the vegetable residue silages. These vegetable residues contained high levels of crude protein (20.6-22.8% of DM) and moderate levels of neutral detergent fiber (22.7-33.6% of DM). In all silages, the pH sharply decreased and lactic acid increased, and the growth of bacilli, coliform bacteria, molds, and yeasts was inhibited by the low pH at the early stage of ensiling. The silage treated with BP or LAB had a lower pH and a higher lactic acid content than the control silage. After 6 h of incubation, all silages had relatively high DM digestibility (38.6-44.9%); in particular, the LAB-inoculated silage had the highest DM digestibility and the lowest methane production. The vegetable residues had high nutritional content and high in vitro DM digestibility. Also, both the addition of a LAB inoculant and moisture adjustment with BP improved the fermentation quality of the vegetable residue silages. In addition, LAB increased DM digestibility and decreased ruminal methane production.  相似文献   

3.
《Food microbiology》2002,19(4):363-373
Two Saccharomyces sp. yeasts isolated from spoiled fermented vegetables were identified, and the effects of pH, temperature, initial yeast count and organic acids (lactic, acetic or propionic) on their growth in a vegetable juice medium (VJM) was examined. The VJM was fermented by a mixed lactic acid culture to a pH of 3·74, which represented the fermented VJM (VJM-F). A fraction of the VJM-F was neutralized to pH 6·0 with 5 N NaOH, which constituted the fermented and neutralized VJM (VJM-FN). Both yeast strains grew at 4°C in VJM and VJM-FN, and prefermentation by the lactic acid bacteria (LAB) did not affect their subsequent development. In VJM-F at pH 3·74, there were important drops in viable populations with the S. bayanus Y-43 strain during incubations at 4 and 30°C, but not with S. unisporus Y-42. In a broth containing 0·7% lactic acid and having a pH of 3·74, the addition of acetic acid or propionic acid generally inhibited growth of yeast. With S. bayanus Y-43, complete growth inhibition is observed with 0·4% of acetic acid, and propionic acid seemed twice as effective as acetic acid in inhibiting the growth of the Y-43 strain. The S. unisporus Y-42 strain was more resistant to organic acids than S. bayanus Y-43, and complete inhibition was only observed with a mixture of lactic, acetic and propionic acids of 0·7, 0·3 and 0·2%, respectively. Results suggest that acidification with lactic acid alone to pH 3·74 is insufficient to prevent the growth of spoilage yeast in fermented vegetables, and that the presence of other organic acids is desirable in this aim. Furthermore, the inoculation level of the yeast had a significant effect on the time at which visible gas production is observed.  相似文献   

4.
Natural populations of lactic acid bacteria (LAB) and silage fermentation of vegetable residues were studied. Fifty-two strains of LAB isolated from cabbage, Chinese cabbage, and lettuce residues were identified and characterized. The LAB strains were gram-positive and catalase-negative bacteria, which were divided into 6 groups (A to F) according to morphological and biochemical characteristics. The strains in group A were rods that did not produce gas from glucose and formed the d and l isomers of lactate. Groups B and C were homofermentative cocci that formed l-lactic acid. Groups D, E, and F were heterofermentative cocci that formed d-lactic acid. Based on 16S rDNA gene sequence analysis, group A to F strains were identified as Lactobacillus plantarum, Lactococcus piscium, Lactococcus lactis, Leuconostoc citreum, Weissella soli and Leuconostoc gelidum, respectively. The prevalent LAB, predominantly homofermentative lactobacilli, consisted of Lactobacillus plantarum (34.6%), Weissella soli (19.2%), Leuconostoc gelidum (15.4%), Leuconostoc citreum (13.5%), Lactococcus lactis (9.6%), and Lactococcus piscium (7.7%). Lactobacillus plantarum was the dominant member of the LAB population in 3 types of vegetable residues. These vegetable residues contained a high level of crude protein (20.2 to 28.4% of dry matter). These silages prepared by using a small-scale fermentation system were well preserved, with low pH and a relatively high content of lactate. This study suggests that the vegetable residues contain abundant LAB species and nutrients, and that they could be well preserved by making silage, which is a potentially good vegetable protein source for livestock diets.  相似文献   

5.
Forages are usually inoculated with homofermentative and facultative heterofermentative lactic acid bacteria (LAB) to enhance lactic acid fermentation of forages, but effects of such inoculants on silage quality and the performance of dairy cows are unclear. Therefore, we conducted a meta-analysis to examine the effects of LAB inoculation on silage quality and preservation and the performance of dairy cows. A second objective was to examine the factors affecting the response to silage inoculation with LAB. The studies that met the selection criteria included 130 articles that examined the effects of LAB inoculation on silage quality and 31 articles that investigated dairy cow performance responses. The magnitude of the effect (effect size) was evaluated using raw mean differences (RMD) between inoculated and uninoculated treatments. Heterogeneity was explored by meta-regression and subgroup analysis using forage type, LAB species, LAB application rate, and silo scale (laboratory or farm-scale) as covariates for the silage quality response and forage type, LAB species, diet type [total mixed ration (TMR) or non-TMR], and the level of milk yield of the control cows as covariates for the performance responses. Inoculation with LAB (≥105 cfu/g as fed) markedly increased silage fermentation and dry matter recovery in temperate and tropical grasses, alfalfa, and other legumes. However, inoculation did not improve the fermentation of corn, sorghum, or sugarcane silages. Inoculation with LAB reduced clostridia and mold growth, butyric acid production, and ammonia-nitrogen in all silages, but it had no effect on aerobic stability. Silage inoculation (≥105 cfu/g as fed) increased milk yield and the response had low heterogeneity. However, inoculation had no effect on diet digestibility and feed efficiency. Inoculation with LAB improved the fermentation of grass and legume silages and the performance of dairy cows but did not affect the fermentation of corn, sorghum, and sugar cane silages or the aerobic stability of any silage. Further research is needed to elucidate how silage inoculated with homofermentative and facultative heterofermentative LAB improves the performance of dairy cows.  相似文献   

6.
Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.  相似文献   

7.
BACKGROUND: Artisanal vegetable fermentations are very popular in Eastern European countries. Fresh vegetables undergo a spontaneous fermentation in the presence of salt, which is mainly carried out by lactic acid bacteria (LAB). RESULTS: Culture‐dependent and culture‐independent analyses of end‐samples of various spontaneous vegetable fermentations carried out in houses of the Chiodju region (central Romania) revealed Lactobacillus plantarum and Lactobacillus brevis as the most frequently isolated LAB species. Leuconostoc mesenteroides and Leuconostoc citreum were also found. Furthermore, the community dynamics of spontaneous cauliflower and mixed‐vegetable (green tomatoes, carrots and cauliflower) fermentations revealed three steps: an initial phase characterised by the presence of Enterobacteriaceae and a wide LAB species diversity, encompassing Weissella species; a second phase from day 3 onwards wherein L. citreum and Lb. brevis occurred; and a final phase characterised by the prevalence of Lb. brevis and Lb. plantarum. Metabolite target analysis revealed that glucose and fructose were mostly depleted at the end of fermentation. The main products of carbohydrate metabolism were lactic acid, acetic acid, ethanol and small amounts of mannitol, indicating heterolactate fermentation. CONCLUSION: Given their prevalence at the end of vegetable fermentations, Lb. brevis and Lb. plantarum appear to be good candidate starter cultures for controlled vegetable fermentation processes. © 2012 Society of Chemical Industry  相似文献   

8.

ABSTRACT

Traditionally, lactic fermentation of vegetables is spontaneous and uncontrolled leading to unstable and inconsistent product. The present work used Leuconostoc mesenteroides and Lactobacillus plantarum in a two‐step controlled fermentation to ensure shelf stable, fermented cabbage with 0.5% added salt concentration. The pH, titratable acidity, lactic bacterial counts, sugar utilization and amino acid profile of the final product were periodically monitored. The pH in controlled cabbage fermentation dropped to less than 4.5, within 60 h of fermentation and glucose was completely utilized in 15 days while about 15–18% of glucose remained in spontaneously fermented cabbage. The spontaneously fermented cabbage samples had a significantly lower content of amino acids such as tyrosine, histidine, threonine, alanine, valine, phenylalanine, isoleucine, leucine, methionine and developed off‐flavors at the end of 90 days of refrigerated storage. In contrast, controlled lactic fermentation stabilized the product in the first 15 days of fermentation and was organoleptically acceptable up to 3 months.

PRACTICAL APPLICATIONS

Use of defined single or mixed starters and precise control of the cabbage fermentation process go a long way in ensuring a consistent product without the need of any chemical preservatives or harsh processing conditions. The present work made use of the benefits of heterofermentative pathway to create a product similar to naturally fermented cabbage in terms of flavor and used the homofermentative pathway to stabilize the product and showed that it is possible to obtain a satisfactory and stable product by the two‐step controlled fermentation as far as commercializing and mechanizing the product is concerned. The amino acid contents are also shown to be more in controlled than spontaneously fermented cabbage.  相似文献   

9.
Viability of dairy-borne Salmonella enterica ssp. enterica serovar Typhimurium PT8 was studied during the fermentation of skim milk by thermophilic lactic acid bacteria (LAB). Longer generation times of Salmonella were found in mixed cultures of skim milk containing Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus or a mixture of them (1:1), as compared with single cultures of the pathogen. Salmonella was less able to survive in mixed cultures with these LAB during prolonged incubation at 41°C and also during cold storage of the fermented milk. L actobacillus ssp. bulgaricus and its mixture with S. thermophilus were more inhibitory to the growth and survival of Salmonella than was S. thermophilus . This was associated with higher ability of L . ssp. bulgaricus and the mixture to develop acidity in milk than S. thermophilus . Examining the antibacterial activity of these LAB towards Salmonella showed that other factors including heat-resistant and heat-labile compounds were involved in inhibiting the pathogen by these cultures. The viability of the same Salmonella strain during the preparation and cold storage of buffalo's yogurt was also examined. Salmonella was found to survive longer in yogurt made with starter containing probiotic bacteria than in that prepared with the traditional starter. This was ascribed to the development of lower pH by the traditional starter.  相似文献   

10.
为了研究一种利用植物乳杆菌发酵的由紫甘蓝、胡萝卜和西红柿混合的饮品。文章确定了由紫甘蓝、胡萝卜和西红柿按照6∶3∶1的比例配制的蔬菜汁,以此为培养基,利用植物乳杆菌发酵产酸。并在单因素实验的基础上,以总酸为指标,利用响应面法对接种量、温度和时间进行发酵优化实验。结果表明,植物乳杆菌在接种量为4.2%,温度为36℃,发酵时间为77 h时达到最佳条件。在该条件下进行验证实验,得到产酸总量为11.238 g/L,与模型预测值11.242 g/L接近,可用于预测植物乳杆菌的发酵条件,为进一步制备饮品提供了依据。  相似文献   

11.
Strains of Leuconostoc mesenteroides, Lactobacillus plantarum, Weissella soli/Weissella koreensis, Enterococcus faecalis, Pediococcus pentosaceus and Lactobacillus fermentum were identified from raw carrots, French beans and marrows by partial 16S rRNA gene sequence. L. plantarum M1, Leuc. mesenteroides C1 and P. pentosaceus F4 were selected based on the rates of growth and acidification in vegetable juice media, and used as the autochthonous mixed starter for the fermentation of carrots, French beans or marrows. An allochthonous starter, consisting of the same species, was also used for fermentation. A two-step fermentation process (1 day at 25 degrees C and 7 days at 15 degrees C) in brine (1% w/v) followed by storage at room temperature in olive oil until 40 days was set up. Unstarted vegetables subjected to the same treatments were used as the controls. Cell numbers of lactic acid bacteria in the started vegetables were ca. 10,000 (autochthonous starter) and 1000 (allochthonous starter) times higher than unstarted samples throughout the process. When fermented with the autochthonous starter, carrots, French beans or marrows were characterized by the rapid decrease of pH (<4.5), marked consumption of fermentable carbohydrates, and inhibition of Enterobacteriaceae and yeasts. Fermentation with the allochthonous starter did not acidify and inhibit bacteria and yeasts so rapidly. After 40 days, carrots, French beans and marrows fermented with the autochthonous starter had significantly (P<0.05) higher total concentration of vitamin C (ascorbate+dehydroascorbate) with respect to those fermented with the allochthonous starter and, especially unstarted vegetables. The same was found for the indexes of color. Firmness of both started vegetables was higher than unstarted vegetables. Sensory analysis differentiated started vegetables. Carrots and French beans fermented with the autochthonous starter were, especially, appreciated for fragrance. Appearance was the sensory attribute that mainly distinguished marrows fermented with the autochthonous starter.  相似文献   

12.
为了探究甘蓝人工接种发酵适宜的发酵剂及发酵条件,采用从四川泡菜老汤中分离的植物乳杆菌(Lactobacillus plantarum)、戊糖乳杆菌(Lactobacillus pentosus)、肠膜明串珠菌(Leuconostoc mesenteroides)3种菌以单一和不同配比混合组合成16组组合发酵剂中选出发酵甘蓝时亚硝酸盐含量低、发酵速度快、风味好的发酵剂。结果表明:肠膜明串珠菌、戊糖乳杆菌,其质量比为1:2(nPb:SPc组合),肠膜明串珠菌、戊糖乳杆菌、植物乳杆菌,其质量比为1:1:1(nPb:bC1:SPc组合),此两种组合为较优化发酵剂。应用响应面分析法优化此两种组合发酵剂接种发酵甘蓝的工艺条件。人工接种发酵甘蓝的条件为食盐质量浓度4g/100mL、接种量0.2%、发酵温度25℃。通过主效应分析说明食盐质量浓度对总酸度影响最大,发酵温度次之,接种量对其影响较小。  相似文献   

13.
硫代葡萄糖苷(简称硫苷)是十字花科蔬菜中一类重要的次生代谢物。在蔬菜发酵过程中,硫苷被代谢为异硫氰酸盐等活性产物,这些代谢产物具有抗氧化、抗癌、调节肠道菌群等多种生理功能。乳酸菌发酵对硫苷的代谢机制包括促进硫苷从蔬菜中释放,以及使其发生降解,且代谢作用既与乳酸菌种属相关,也与发酵体系的盐含量、金属离子、pH值以及蔬菜加热预处理相关。通过总结梳理发酵蔬菜硫苷代谢研究进展,并解析影响因素,为提高发酵蔬菜中活性硫苷代谢产物含量,提升发酵蔬菜的健康效应提供理论指引。  相似文献   

14.
Traditional fermented vegetables have inconsistent quality and high nitrite content, whereas a commercial starter culture could overcome these problems. A total of 34 lactic acid bacteria strains were screened from 2 homemade naturally fermented Chinese cabbages. Fermented characters of single starter or mixed cultures were examined, including acidification, growth rate, and nitrite depletion ability in the fermented culture. As a result, the combined starter culture (Lactobacillus delbrueckii IWQ and Lactobacillus paracasei J21) was selected. The fermented Chinese cabbage resulted from this mixed starter culture had higher sugar content residue (30.5 mg/mL for mixed culture and 22 mg/mL for control). And the titratable acid of the cabbage fermented by the mixed starter was 110°T, which was twice higher than that of control sample. The selected starter culture also had a better texture and sensory qualities than that the starter cultures from a local fermented Chinese cabbage plant, especially for its significantly lower nitrite content (3.00 mg/kg for mixed culture and 4.49 mg/kg for control). The findings of this study form a database for further studies on the development of starter cultures for fermented cabbage production and could replaced the local plant starter culture.  相似文献   

15.
M Jägerstad  J Jastrebova 《LWT》2004,37(6):603-611
The present work aimed to evaluate whether lactic acid fermentation can increase folate concentrations in vegetables making these foods superior to similar foods produced by the more common preservation techniques. The concentrations of folates present in raw vegetables, usually root vegetables, were followed during pre-treatment and fermentation with the purpose to improve the folate retention. Commercial starter cultures aimed for manufacture of fermented dairy products were subjected to mixtures of grated and blanched root vegetables, mainly beetroots and turnips. The results indicate that among 10 different lactic acid bacteria (LAB) cultures, one mixture was superior, resulting in almost a doubling of folate concentration, mainly as 5-methyl-tetrahydrofolic acid (5-CH3-H4folate), a native and bioavailable folate form. Interestingly, one species of propionibacteria produced vitamin B12. The retention of folate during the overall fermentation process varied between 50% and 75% when calculated on wet weight. The concentration of the folate was similar in the surrounding liquid medium as in the solids of the final fermented product. Sauerkraut, a classical fermented vegetable, did not have significantly increased folate content. Some commercial canned samples of sauerkraut contained between 50 and 200 μg/kg, mainly as 5-CH3-H4folate.  相似文献   

16.
Kimchi is a traditional Korean food fermented from a variety of vegetables. We elucidated the microbial community structure of five commercially produced kimchis made from Chinese cabbage by examining culture-independent 16S rRNA gene clone libraries. Most of the clones (347 out of 348) belonged to lactic acid bacteria and included several species of the genera Lactobacillus, Leuconostoc and Weissella. Weissella koreensis was found in all the samples and predominated in three of them (42.6-82%). Leuconostoc gelidum, Leuconostoc gasicomitatum and Lactobacillus sakei were common in the remaining kimchi clone libraries (>34%). The composition of bacterial phylotypes in kimchi varied between samples. Our approach revealed different community structures from those reported in previous culture-dependent studies based on phenotypic identification methods. The culture-independent method used here proved to be efficient and accurate and showed that the bacterial communities in kimchi differ from those in other fermented vegetable foods.  相似文献   

17.
发酵型蔬菜汁饮料作为传统蔬菜汁饮料的技术延伸,理应成为未来蔬菜汁多元化发展的方向之一.以南瓜、胡萝卜和番茄等蔬菜为原料,就果肉型混合发酵蔬菜汁饮料发酵菌种的组成、特性以及发酵条件等进行了系统的研究,研究的结果可为发酵蔬菜汁饮料未来的发展提供必要的技术和生产基础。  相似文献   

18.
对植物乳杆菌(Lactobacillus plantarum)SD2、发酵乳杆菌(Lactobacillus fermentum)SD4在5 L立瓶中分别进行培养,制备尾菜液体青贮菌剂。结果表明,在MRS液体培养基中37 ℃条件下,调控pH值,菌株SD2和SD4最适收获期分别为24 h、20 h,菌株SD2与SD4配比为2∶1时青贮效果最佳,尾菜液体青贮菌剂总活菌数>1×109 CFU/mL。按0.5%接种量,进行废弃白菜叶、青笋叶青贮发酵应用试验,生产的尾菜青贮饲料品质良好,颜色淡黄色或黄绿色,酸香味浓郁,质地较松散,pH值<4.0。研制的尾菜青贮菌剂适用于尾菜青贮。  相似文献   

19.
Malolactic Activity of Lactic Acid Bacteria during Sauerkraut Fermentation   总被引:2,自引:0,他引:2  
ABSTRACT: The frequency of lactic acid bacteria (LAB) involved in sauerkraut fermentation with (MDC+) or without (MDC-) the ability to decarboxylate malic acid was determined. The MDC+ phenotype was found in > 99% of homofermentative LAB isolated from commercial fermentations. In contrast, heterofermentative LAB isolates from 0.25, 3, 7, and 10 d had only 53%, 54%, 15%, and 11% MDC+ phenotype, respectively, indicating that more than 1 strain or species was involved. The malolactic reaction was demonstrated in cabbage juice with known strains of Leuconostoc mesenteroides , raising the question of desirability of such activity in cultures selected for the controlled fermentation of cabbage.  相似文献   

20.
This study aimed at evaluating raw materials as potential lactic acid bacteria (LAB) sources for kimchi fermentation and investigating LAB successions during fermentation. The bacterial abundances and communities of five different sets of raw materials were investigated using plate‐counting and pyrosequencing. LAB were found to be highly abundant in all garlic samples, suggesting that garlic may be a major LAB source for kimchi fermentation. LAB were observed in three and two out of five ginger and leek samples, respectively, indicating that they can also be potential important LAB sources. LAB were identified in only one cabbage sample with low abundance, suggesting that cabbage may not be an important LAB source. Bacterial successions during fermentation in the five kimchi samples were investigated by community analysis using pyrosequencing. LAB communities in initial kimchi were similar to the combined LAB communities of individual raw materials, suggesting that kimchi LAB were derived from their raw materials. LAB community analyses showed that species in the genera Leuconostoc, Lactobacillus, and Weissella were key players in kimchi fermentation, but their successions during fermentation varied with the species, indicating that members of the key genera may have different acid tolerance or growth competitiveness depending on their respective species.  相似文献   

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