Selection and modification of yeasts and lactic acid bacteria for wine fermentation

Historically, the fermentation of grape juice to wine has been carried out by indigenous yeasts found on the berry. However, in newer wine regions, e.g. the USA, inoculation with selected wine yeast strains is employed. Grape juice is high in nutritional factors and difficulties in fermentation usually arise from the inhibitory effects of the high concentration of sugar initially present and the ethanol produced. A secondary fermentation, brought about by indigenous or added lactic acid bacteria, converts malic acid to lactic acid and carbon dioxide and often occurs. This ‘malolactic’ fermentation is usually slow. For both yeast and bacterial fermentations strain selection is based more on fermentation performance than on sensory characteristics of the wine, with increased tolerance of the yeast to ethanol and of the bacteria to low pH being emphasized. Attempts to increase the malolactic fermentation rate have been made by cloning and transferring the malolactic gene from Lactobacillus to wine yeast. In early attempts to produce wines with enhanced or novel sensory characteristics a leucine-less mutant of a homothallic wine yeast has been obtained which does not produce isoamyl alcohol.     

Ethyl carbamate production by selected yeasts and lactic acid bacteria in red wine

This study was designed to investigate the formation of ethyl carbamate during the fermentation of musts of Vitis vinifera L. cv. Tempranillo and Cabernet Sauvignon by selected yeasts in different conditions of temperature and pH. Secondary malolactic fermentation was then induced by selected lactic acid bacteria. The results indicate an increased concentration of ethyl carbamate after malolactic fermentation, irrespective of the bacteria used or the prevailing physicochemical conditions.     

Effects of different types of salts on the growth of lactic acid bacteria and yeasts during kimchi fermentation

Food Science and Biotechnology - Kimchi was prepared with different types of salts: purified salt (PS), solar salt aged for 1 year (SS1), aged for 3 years (SS3), and bamboo salt...     

具有共生关系的乳酸菌和酵母菌的筛选

对分离自酸马奶酒中的9株乳酸菌和8株酵母菌存在共生作用的菌株进行筛选。分别于各自培养基中加入相应的代谢产物,以等量的生理盐水作为对照,测定其稳定期的浊度值和干重值。结果表明:乳酸菌的代谢产物促进的酵母菌生长有12个组合,而接近一半的酵母菌代谢产物对乳酸菌有促进作用。有7个组合的乳酸菌和酵母菌存在共生作用。结论是7个共生组合分别是:LAB2YST4、LAB4YST2、LAB5YST2、LAB7YST2、LAB7YST4、LAB8YST2、LAB9YST2。7个组合中酵母菌YST2和除LAB2外其余的乳酸菌均存在不同程度的共生,共生原因还待进一步研究。     

Metabolites produced during fermentation of wine by mixed cultures of yeasts and lactic acid bacteria

Certain aspects of the interrelationship between associations of yeasts and lactic acid bacteria during the fermentation of grape must were studied. Action bySaccharomyces pastorianus gave rise to increased formation of keto acids and residual metabolites. Addition ofLactobacillus plantarum to the fermentation process may inhibit alcoholic fermentation and considerably increased the production of acetaldehyde andl(+) andd(–)lactic acids.

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Entstehung von Metaboliten bei der Fermentation von Wein durch Mischkulturen von Hefen und Milchsäurebakterien

Zusammenfassung Es wurden Wechselbeziehungen zwischen Hefen und Milchsäurebakterien während der Fermentation von Traubensaft untersucht.Saccharomyces pastorianus bewirkte ein Ansteigen der Ketosäurenproduktion und der Bildung von Rest-Metaboliten. Das Hinzufügen vonLactobacillus plantarum beim Gärungsprozess kann die alkoholische Gärung unterdrücken und hat die Produktion von Acetaldehyd sowie vonl(+)- undd(–)-Milchsäuren beträchtlich gesteigert.

     

不同商用酵母对葡萄酒外观品质影响机理研究

用不同种类酵母发酵的红葡萄酒,其颜色会有一定差异.本文测定了4种商业酵母对红葡萄酒中5个与葡萄酒外观品质相关的颜色指标(色度、色调、葡萄酒总颜色、色素总颜色、聚合色素颜色)的影响,初步研究了酵母对葡萄酒外观品质的影响机理.结果表明,酵母对葡萄酒中的色素有吸附作用,添加酵母降低了葡萄酒颜色指标,不同酵母对葡萄酒外观品质有一定影响.     

浅谈乳酸菌在黄酒生产中的作用

为了全面地了解乳酸茵兼在黄酒生产全过程中的作用,介绍了黄酒米浆水中乳酸茵的应用、黄酒深层酿造兼氧浸米中乳酸菌的作用和乳酸菌在黄酒发酵过程中的作用,同时也介绍了乳酸茵代谢产物乳酸和乳酸乙酯在黄酒中的含量和作用。     

Putrescine production from different amino acid precursors by lactic acid bacteria from wine and cider

The aim of this work was to study the production of biogenic amines and particularly putrescine in lactic acid bacteria (LAB) related to wine and cider. We applied an analytical protocol that involves the use of PCR and TLC techniques to determine the production of putrescine from different precursors. Moreover, we also studied the ability of the Lactobacillus and Pediococcus tested to produce histamine and tyramine. The results showed that the majority of the Lactobacillus brevis analyzed harbour both AgDI and tdc genes and are tyramine and putrescine producers. Conversely, among the other LAB tested, only one Lactobacillus hilgardii and one Pediococcus pentosaceus produced putrescine. The AgDI gene was also detected in two other LAB (Lactobacillus mali and Pediococcus parvulus), but no putrescine production was observed. Finally, hdc gene and histamine production were found in strains (L. hilgardii 5211, isolated from wine, and Lactobacillus casei 18, isolated from cider) that were not putrescine producers.     

酸马奶酒中乳酸菌和酵母菌互作关系的研究

选取来自酸马奶酒中的2株乳酸菌(坚强肠球菌W1和粪肠球菌W2)和2株酵母菌(厚壁酵母属J1和娄德酵母属J2)进行互作关系的研究,采用固体平板涂布法的定性研究法和液体培养测定OD值、pH、滴定酸度的定量研究法。结果表明:2株乳酸菌发酵液都对酵母菌菌落生长有促进作用,发酵液经110℃、7min灭菌后,并不影响其促进作用;2株酵母菌发酵液对坚强肠球菌W1培养过程中的OD值、pH和滴定酸度无明显影响,而对粪肠球菌W2的生长及其产酸能力具有明显地促进作用;随着发酵液的添加量增加,促进作用更为明显。     

Comparative study of the inhibitory effects of wine polyphenols on the growth of enological lactic acid bacteria

This paper reports a comparative study of the inhibitory potential of 18 phenolic compounds, including hydroxybenzoic acids and their derivatives, hydroxycinnamic acids, phenolic alcohols and other related compounds, stilbenes, flavan-3-ols and flavonols, on different lactic acid bacteria (LAB) strains of the species Oenococcus oeni, Lactobacillus hilgardii and Pediococcus pentosaceus isolated from wine. In general, flavonols and stilbenes showed the greatest inhibitory effects (lowest IC?? values) on the growth of the strains tested (0.160-0.854 for flavonols and 0.307-0.855 g/L for stilbenes). Hydroxycinnamic acids (IC?? > 0.470 g/L) and hydroxybenzoic acids and esters (IC?? >1 g/L) exhibited medium inhibitory effect, and phenolic alcohols (IC?? > 2 g/L) and flavanol-3-ols (negligible effect) showed the lowest effect on the growth of the LAB strains studied. In comparison to the antimicrobial additives used in winemaking, IC?? values of most phenolic compounds were higher than those of potassium metabisulphite for O. oeni strains (e.g., around 4-fold higher for quercetin than for potassium metabisulphite), but lower for L. hilgardii and P. pentosaceus strains (e.g., around 2-fold lower for quercetin). Lysozyme IC?? values were negligible for L. hilgardii and P. pentosaceus, and were higher than those corresponding to most of the phenolic compounds tested for O. oeni strains, indicating that lysozyme was less toxic for LAB than the phenolic compounds in wine. Scanning electron microscopy confirmed damage of the cell membrane integrity as a consequence of the incubation with antimicrobial agents. These results contribute to the understanding of the inhibitory action of wine phenolics on the progress of malolactic fermentation, and also to the development of new alternatives to the use of sulphites in enology.     

蜂蜜对酸奶生产中乳酸菌生长和产酸能力的影响

在脱脂乳粉制成的全乳固体含量为12%(w/v) 的复原乳中,分别添加5%(w/v)的蔗糖、果糖或蜂蜜,并以不添加甜味剂的复原乳作为对照,经过70℃、15min灭菌,冷却至室温,分别接种唾液链球菌嗜热亚种、德氏乳杆菌保加利亚亚种和嗜酸乳杆菌,接种量5%(v/v),培养温度37℃,分别在培养初始和经过24h培养时取样,测定其乳酸菌活性、pH值和乳酸含量。结果表明,添加量为5%(w/v)的蜂蜜对于3种乳酸菌均没有抑制作用,是酸奶生产的合适甜味剂。     

乳酸菌的培养方法及在葡萄酒中的应用

采用109#培养基,使用不同方式对乳酸菌进行培养研究。结果表明:平板培养条件要求高,在目前条件下,几乎培养不出;斜面培养比较容易,但只能定性;液体培养能估测出最大活菌数;以上培养方式在葡萄酒中的乳酸菌检测方面都处于摸索阶段。     

Occurrence of biogenic amine-forming lactic acid bacteria in wine and cider

A collection of 810 lactic acid bacteria (LAB) strains isolated from wine and cider was screened for potential biogenic amine (BA) producers by combining molecular and phenotypic approaches. A newly developed multiplex PCR method allowed for the simultaneous detection of four genes involved in the production of histamine (histidine decarboxylase, hdc), tyramine (tyrosine decarboxylase, tyrdc) and putrescine (via either ornithine decarboxylase, odc, or agmatine deiminase, agdi) while TLC and HPLC analysis allowed for BA-production determination. One hundred and fifty-eight LAB strains were monitored by the molecular/phenotypic double approach and revealed a good correlation between genotypic and phenotypic data. Eighteen per cent of the tested strains were positive for at least one BA target gene with up to three detected simultaneously, in particular amongst Lactobacillus brevis and Lactobacillus hilgardii isolates for the tyrdc and agdi genes. The most frequent gene corresponded to the agdi gene detected in 112 strains (14% of all LAB strains) of 10 different LAB species. The tyrdc gene was detected in 67 strains represented by 7 different LAB species (8% overall), especially those isolated from wine. Lower levels of hdc⁺ (2% of strains) and especially odc⁺ (0.5% of strains) strains were observed. Interestingly, species that have never been described to carry BA-producing pathway genes were identified in this study. Furthermore, only one cadaverine-producer was detected and corresponded to Lactobacillus 30a, a collection strain not found in fermented beverages, although cadaverine is commonly detected in wines.     

乳酸菌产生挥发性酚的初步研究

对7株分离于葡萄酒中的乳酸菌产生挥发性酚的能力进行了研究。利用气相色谱对p-香豆酸和阿魏酸的代谢产物4-乙烯基酚和4-乙基酚的含量进行了测定。结果显示,有2株菌能够利用p-香豆酸产生较多量的挥发性酚;乳酸菌利用阿魏酸产生挥发性酚的能力低于利用p-香豆酸产生挥发性酚的能力。     

Compartmentalization of lactic acid bacteria and yeasts in the fermentation of brined cucumbers

Lactic acid bacteria were distributed between the brine and cucumbers in brine-fermented cucumbers. The percentage of bacterial cells located within the cucumbers, of the total cells produced, varied from c. 8–51%, depending upon: (1) gas exchange treatment of the cucumbers before brining and (2) time of inoculation with Lactobacillus plantarum after brining. Oxygen exchange of the cucumbers before brining, and early inoculation of the brine, resulted in higher percentages of cells within the fermented cucumbers. Nitrogen exchange of the cucumbers before brining, and delay in inoculation of the brine for 2 days after brining resulted in lower percentages of cells within the cucumbers. No evidence was found to indicate that yeast cells were present within fermented cucumbers, even when the brines were inoculated with Saccharomyces cerevisiae and the cucumbers had been O₂-exchanged prior to brining. Yeasts, because of their greater size than bacteria, appear to be excluded from the cucumber interior.     

A new chemically defined medium for wine lactic acid bacteria

Growth and activity of lactic acid bacteria is crucial for the production and quality of grape wines but studying their metabolism is difficult in wines or complex laboratory media because of the undefined substrate pools. This work presents a new chemically defined medium that meets the fastidious nutritional requirements of wine lactic acid bacteria and yields rapid and strong growth. The new medium is composed of 44 constituents and a precise protocol is provided for its preparation. Maximum specific growth rates and growth yields of the wine strains studied were comparable to those obtained in common laboratory media, and the new medium allows for various modifications, such as changing the medium pH to the wine range, addition of L-malic acid or utilization of different carbon sources while maintaining growth of wine lactic acid bacteria. The medium was successfully tested with 22 wine strains of the genera Oenococcus, Lactobacillus and Pediococcus. It is suggested that this chemically defined medium be considered for the investigation of the nutritional requirements and metabolism of wine lactic acid bacteria.     

培养时间对乳酸菌自溶影响及菌体形态学变化

乳酸菌自溶对干酪的成熟有着及其重要的意义，但对生产发酵剂却有较大的负面影响。研究了培养时间对乳酸杆菌LB-3自瘩行为的影响．研究结果表明，在迟滞期向对数生长期的过渡时期乳酸杆菌LB-3的自溶度最大，有73％的菌体发生自溶。同时利用透射电镜对乳酸杆菌LB-3在自溶期间菌体细胞所发生的形态学变化进行了观察，在自溶过程中乳酸杆菌LB-3菌体细胞变得透明，细胞质浓缩．而且部分细胞壁被自溶酶水解掉。     

Factors influencing the production of volatile phenols by wine lactic acid bacteria

This work aimed to evaluate the effect of certain factors on the production of volatile phenols from the metabolism of p-coumaric acid by lactic acid bacteria (LAB) (Lactobacillus plantarum, L. collinoides and Pediococcus pentosaceus). The studied factors were: pH, L-malic acid concentration, glucose and fructose concentrations and aerobic/anaerobic conditions. It was found that, in the pH range of 3.5 to 4.5, the higher the pH the greater the production of volatile phenols. This behaviour is correlated with the effect of pH on bacterial growth. Increasing levels of L-malic acid in the medium diminished the production of 4-vinylphenol (4VP) and stimulated the production of 4-ethylphenol (4EP) by L. plantarum NCFB 1752 and L. collinoides ESB 99. The conversion of 4VP into 4EP by the activity of the vinylphenol reductase may be advantageous to the cells in the presence of L-malic acid, presumably due to the generation of NAD+, a cofactor required by the malolactic enzyme. Relatively high levels of glucose (20 g/L) led to an almost exclusive production of 4VP by L. plantarum NCFB 1752, while at low concentrations (≤ 5 g/L), 4EP is mainly or solely produced. Part of the glucose may be diverted to the production of mannitol as an alternative pathway to regenerate NAD+. This is corroborated by the experiments done with fructose, a compound that can be used as an electron acceptor by some bacteria becoming reduced to mannitol. In anaerobiosis, the reduction of 4VP into 4EP is clearly favoured, which is consistent with the need to increase the availability of NAD+ in these conditions. This study shows that the amount and the ratio 4VP/4EP produced by LAB are greatly affected by certain environmental and medium composition factors. The behaviour of the bacteria seems to be driven by the intracellular NAD+/NADH balance.     

低醇半干白葡萄酒中乳酸菌耐受性试验

本文研究了低醇半干白葡萄酒中乳酸菌对山梨酸钾和游离二氧化硫的耐受性。结果表明,7.5%(v/v)半干白葡萄酒中山梨酸钾浓度为150mg/L,游离二氧化硫浓度为30～35mg/L,乳酸菌的安全耐受浓度为乳酸菌数<300个/100mL。     

In vitro removal of ochratoxin A by wine lactic acid bacteria

A study was carried out to determine the in vitro interaction between ochratoxin A (OTA) and wine lactic acid bacteria (LAB). Fifteen strains belonging to five relevant oenological LAB species were grown in liquid synthetic culture medium containing OTA. The portion of OTA removed during the bacterial growth was 8 to 28%. The OTA removed from the supernatants was partially recovered (31 to 57%) from the bacterial pellet. Cell-free extracts of three representative strains were produced by disrupting cells in a French pressure cell. The ability of crude cell-free extracts to degrade OTA was studied. OTA was not degraded by cell-free extracts of wine LAB strains, and no degradation products of OTA were detected in the high-performance liquid chromatograms of the methanol extract of the bacterial pellet. On the basis of these results, we conclude that OTA removal by wine LAB is a cell-binding phenomenon. The chemistry and the molecular basis of OTA binding to wine LAB remains unknown.