酿酒酵母-酒类酒球菌接种方式对樱桃酒品质的影响

对比分析了酿酒酵母(F10)-酒类酒球菌(VP41)顺序接种和同时接种2种模式对樱桃酒的发酵过程、酒体成分、生物胺含量以及感官质量的影响。结果显示,同时接种模式能够缩短发酵时间,更高效地萃取樱桃果浆中的多酚和花色苷,降低色胺、苯乙胺、亚精胺和组胺的生成量,赋予樱桃酒更浓郁的果香。因此,酿酒酵母-酒类酒球菌同时接种模式具有在樱桃酒生产中推广应用的潜力。     

酒类酒球菌分离培养基研究

研究了9种乳酸菌培养基对酒类酒球菌的分离培养效果。结果表明，ATB，改良MRS培养基对酒类球菌的相对鉴别力（ROF值）最高；在以上2种培养基中添加50mg/L放线菌酮能有效地报制酵母菌的生长，可以用于酒类酒球菌分离。     

酒类酒球菌的分离及发酵适应性研究

对我国葡萄酒主产区的酒类酒球菌进行了分离和筛选。通过考查分离菌株苹果酸—乳酸发酵性能后,对鉴定为酒类酒球菌的127株菌株进行了pH、SO2和酒精单因素耐受性试验,然后再选择抗性较好的初选菌株(8株)进行复合因子(pH×酒精×SO2)梯度筛选实验。结果表明,有4株酒类酒球菌分离株具有较强的苹果酸—乳酸发酵适应性,其中分离菌株O.oeniSD-2a对胁迫条件的适应性显著高于对照商业菌株O.oeni31DH。     

酒类酒球菌新菌株苹果酸-乳酸发酵条件的研究

酒类酒球菌(Oenococcus oeni)普遍应用于葡萄酒生产中,它可以触发苹果酸-乳酸发酵,促进葡萄酒中的苹果酸转化为乳酸,降低总滴定酸,提高酒体生物稳定性,改善酒体口感。本文针对3株自主筛选的酒类酒球菌,研究了酒精度、pH、SO2浓度、发酵温度、接种量等因素对葡萄酒苹-乳发酵过程的影响。     

不同酒类酒球菌苹果酸—乳酸发酵对葡萄酒中氨基酸的影响

不同酒类酒球菌茵株完成MLF后,葡萄酒中氨基酸均发生显著变化:种类增多,诸多氨基酸含量提高。SD-2a发酵酒样中的丙氨酸和谷氨酸、SD-1b发酵酒样中甘氨酸、丝氨酸和脯氨酸、SD-2h酒样中谷氨酸、甘氨酸、丝氨酸、脯氨酸含量明显增加;含量呈极显著增加的氨基酸为:在SD-2h发酵酒样中的丙氨酸、在SD-1b发酵酒样中的丙氨酸、缬氨酸和谷氨酸;对照菌株31DH发酵酒样中各种氨基酸的增减没有达到显著水平。葡萄酒学院分离筛选的3个菌株发酵酒样中的精氨酸含量增加,而对照菌株31DH则有所降低。因此,3个菌株代谢特性良好,在葡萄酒中不会导致致癌物质——氨基甲酸乙酯的前体物脲、瓜氨酸等的过多合成。鉴于各种氨基酸独特的生化和生理特性,3株酒类酒球菌菌株完成MLF后,氨基酸种类、含量的增加可以提高葡萄酒的营养价值和保健功能。     

酒类酒球菌对葡萄酒中相关物质代谢的影响

酒类酒球菌是触发葡萄酒苹果酸-乳酸发酵(malolactic fermentation,MLF)的主要乳酸菌,其代谢产物如乳酸、乙酸、双乙酰、乙偶姻、生物胺等对葡萄酒的感官品质有重要作用。本文对酒类酒球菌在葡萄酒MLF过程的代谢情况进行总结,阐述糖、有机酸、含氮物质和酚类化合物的代谢情况,以及在不同影响因素下酒类酒球菌生长和代谢途径的改变状况,已经证明pH值、SO2、乙醇体积分数、葡萄糖/果糖比等都是影响代谢的因素。随着研究的不断深入,酚类化合物在代谢中的作用也受到越来越多的关注。酚类化合物一方面通过刺激或者抑制酒类酒球菌的生长而间接影响MLF的进行;另一方面,不同的酚类物质也会影响细菌对其他酚类的代谢,从而影响葡萄酒的口感和质量。通过全面综合了解酒类酒球菌在葡萄酒中的代谢情况有助于更好地调控MLF过程。     

分子生物学技术在酒类酒球菌分类鉴定方面的应用

酒类酒球菌(Oenococcus oeni)是葡萄酒进行苹果酸乳酸发酵(malolactic fermentation,MLF)的主要菌群,对其进行快速、高效的分离鉴定非常重要,该文针对不同分子生物学技术在筛选优良酒球菌的原理及应用进行了分析,同时对其前景进行了展望。     

樱桃品种对樱桃酒品质及生物胺含量的影响

樱桃品种是决定樱桃酒品质和风味特性的关键因素。为选择适宜的酿造品种,以山东烟台地区的5种甜樱桃(美早、萨米脱、大紫、拉宾斯和红灯)为原料酿造樱桃酒,测试和对比这些樱桃酒的发酵进程、理化指标、生物活性物质、感官品质以及生物胺含量方面的差异。研究发现,拉宾斯酿造的樱桃酒富含多酚、花色苷等活性物质,具有上乘的口感和风味,且生物胺含量较低,因而是适宜酿造樱桃酒的优良品种来源。     

酒类酒球菌SD-2a高密度培养的研究

对酒类酒球菌SD-2a液体培养条件和半连续高密度培养进行了研究,研究结果表明,酒类酒球菌SD-2a的适宜培养条件为:培养温度25℃,接种量5%,pH值4.8.在培养过程中,每4 h添加一次CaCO3溶液,调整pH值至最适值.并结合优化培养条件,对酒类酒球菌SD-2a进行半连续法高密度培养,使其菌体密度达到了6.5×1010 cfu/mL,比二次培养前提高了近10倍.     

酿酒酵母对樱桃酒挥发性组分及感官品质的影响

鉴于酿酒酵母（Saccharomyces cerevisiae）对樱桃酒挥发性香气及感官品质的重要贡献,测定了5种商业化酿酒酵母的产香性能,以期从中挑选适用于樱桃酒酿造的优质发酵剂。结果表明,5种酵母发酵的樱桃酒基本理化指标无差异（P＞0.05）,但是挥发性组分含量却存在显著差异（P＜0.05）。Lalvin 2323与Lalvin 71B能够增加丁酸乙酯、己酸乙酯、苯甲醛、β-大马酮等多种挥发性物质的合成量,赋予樱桃酒更浓郁的果香和花香特征,且Lalvin2323的整体香气比Lalvin 71B更浓郁;Laffort B0123可以提高里那醇、异戊醇、乙酸异戊酯的含量,感官品质也较好;Laffort X16酿造的樱桃酒果香味寡淡,生青气味浓郁,评分较低;Laffort Cervisiae（AC）酿造的樱桃酒整体香气略显不足,评分最低。总体来看,酵母Lalvin2323发酵樱桃酒的感官品质优于其他酵母。     

Phenotypic and genotypic characterization of Oenococcus oeni strains isolated from Italian wines

A phenotypic and genotypic characterization of 84 Oenococcus oeni isolates from Italian wines of different oenological areas was carried out. Numerical analysis of fatty acid profiles grouped the isolates into two clusters at low level of similarity (63%), the minor cluster containing seven isolates besides the type and the reference strains. Forthy-eight O. oeni isolates, representative of the two clusters, showed no differences in their metabolic properties (heterolactic fermentation pattern, citrate degradation capability and formation of some secondary metabolites). Moreover, the analysis of species-specific randomly amplified polymorphic DNA and 16S-23S rDNA intergenic spacer region polymorphism as well as the sequence-specific separation of V3 region from 16S rDNA by denaturing gradient gel electrophoresis demonstrated a substantial homogeneity among the isolates. On the basis of ApaI Pulsed Field Gel Electrophoresis (PFGE) restriction patterns, the 84 isolates were grouped into five different clusters at 70% similarity, but no correlation with the phenotypic groups could be demonstrated. However, by combining phenotypic and genotypic data, the 84 O. oeni isolates grouped into eight phenotypic-genotypic combined profiles and a relationship between the origin of the isolates and their combined profile became evident, so that a sort of strain specificity can be envisaged for each wine-producing area.     

Characterization and amino acid metabolism performances of indigenous Oenococcus oeni isolated from Chinese wines

Oenococcus oeni is a multiple physical stress-tolerant lactic acid bacterium that plays an important role in wine making. It is often added as a starter culture to carry out malolactic fermentation (MLF). In this study, a total of 22 out of 127 lactic acid bacteria, isolated from Chinese wines undergoing MLF, were identified as O. oeni by species-specific PCR and 16S rRNA sequencing. Single-enzyme amplified fragment length polymorphism (SE-AFLP) analysis showed that all strains could be typed under these conditions, and three main groups were determined by cluster analysis, which showed intraspecific homology higher than 69 %. Eight strains, representative of SE-AFLP clusters, were tested for malolactic activity. Significant differences were observed among strains with regard to the amount of malic acid consumed. Seventeen amino acids in different wines that were inoculated by 4 O. oeni strains, respectively, were analyzed before and after MLF. The results indicated that the amino acid metabolism of the 4 strains was significantly different between each strain.     

Inducing malolactic fermentation in Chardonnay musts and wines using different strains of Oenococcus oeni

Malolactic fermentations (MLF) were induced in a commercially prepared Washington State Chardonnay must to evaluate the influence of timing of inoculation and pre-culture conditions of Oenococcus oeni strains MCW, EQ-54, and WS-8. The must (pH 3.62, 21.5°Brix) was divided into lots and inoculated with Saccharomyces cerevisiae strain CY3079. Strains of O. oeni were pre-cultured by growing in diluted juice or by re-hydration of freeze-dried strains. Bacteria were inoculated into the musts before (Day 0) or after completion of the alcoholic fermentation (Day 22). Yeast populations exceeded 10⁷cfu/mL in all fermentations that proceeded to dryness. However, the viability of most strains of O. oeni quickly declined after inoculation regardless of the timing of inoculation or the strain used. MLF was induced in the wines inoculated with strains EQ-54 and WS-8 but not with MCW, and the rate depended on the time of inoculation. The method used to prepare bacterial starter cultures had no apparent influence on the completion of MLF. Values for volatile acidity were slightly higher (P< 0.05) in wines inoculated with O. oeni before alcoholic fermentation compared with those inoculated after alcoholic fermentation.     

Assessment of the genetic polymorphism and biogenic amine production of indigenous Oenococcus oeni strains isolated from Greek red wines

In the warm climate country of Greece malolactic fermentation (MLF) has received limited attention. Molecular techniques and High Performance Liquid Chromatography (HPLC) were used to study the genetic polymorphism of autochthonous lactic acid bacteria developing towards the end of spontaneous MLF of Greek red wines and for the assessment of their potential to produce harmful biogenic amines. This research revealed that native Oenococcus oeni isolates are very much adapted to specific winery conditions since the majority of spontaneous MLF were driven mostly or exclusively by a single strain of O. oeni. Native O. oeni strains showed only limited dispersion since cluster analysis uncovered only few common genotypes among indigenous isolates from different wineries. The genotype of a frequently used malolactic starter was more than often detected among autochthonous isolates without nevertheless compromising the biodiversity of natural microflora residing in wineries but rather becoming a part of it. For the majority of the wine samples studied, MLF implementation and storage in bottles resulted in negligible changes on the levels of the BA histamine, tyramine, phenylethylamine, cadaverine as well as of ethylamine, methylamine, isobutylamine. We provide evidence that autochthonous O. oeni isolates can only contribute to putrescine accumulation in Greek wines but still the specific trait behaves as strain-specific with a limited dispersion.     

RNA fingerprinting analysis of Oenococcus oeni strains under wine conditions

Oenococcus oeni is a lactic acid bacterium of economic interest used in winemaking. This bacterium is the preferred species for malolactic fermentation (MLF) due its adaptability to the chemically harsh wine environment. MLF enhances the organoleptic properties and ensures deacidification of wines.     

Genotyping by Amplified Fragment Length Polymorphism and malate metabolism performances of indigenous Oenococcus oeni strains isolated from Primitivo wine

The Amplified Fragment Length Polymorphism (AFLP) technique was applied for the first time to investigate the genotyping of Oenococcus oeni, the most important species involved in malolactic fermentation (MLF) in wine. A total of 87 out of 220 lactic acid bacteria, isolates from "Primitivo" wine (Apulia, Italy) undergoing MLF, identified as O. oeni by species-specific PCR and 16S rRNA sequence analysis, were studied by AFLP analysis. Four main clusters were distinguished and three of them showed intraspecific homology higher than 60%. A total of 28 strains, representative of AFLP clusters, were tested for malate metabolism in order to gain information on their malolactic performances. Significant differences were observed among strains for malic acid consumed, biomass produced and specific malic acid consumption rate. These findings indicated that AFLP technique is reliable for typing O. oeni strains and that, together with metabolism studies it may be used to individuate possible candidates as industrial malolactic starters.     

A survey of glycosidase activities of commercial wine strains of Oenococcus oeni

Lactic acid bacteria play an important role in wine-making by undertaking the malolactic fermentation, yet little information is available on other aspects of their physiology, such as their profile of external enzymatic activities. In this study we sought evidence for the existence and action of glycosidase enzymes in wine isolates of Oenococcus oeni. This group of enzymes is of interest because of their potential for liberation of grape-derived aroma compounds from their natural glycosylated state. This comprehensive study reveals that these bacteria produce glycosidases that might be important in wine-making. Strains did not necessarily hydrolyse all substrates tested, but rather were grouped according to substrate specificity. Thus a subset comprising strains 2, 5 and 16 possessed high cumulative activities against beta-d- and alpha-d-glucopyranoside substrates, while a group comprising strains 4, 21 and 22 was noted for superior hydrolysis of beta-d-xylopyranoside, alpha-l-rhamnopyranoside and alpha-l-arabinofuranoside substrates. Key physico-chemical inhibitors of analogous systems from other microorganisms were seen to produce variable responses across the strains investigated here. Accordingly, several strains retained significant hydrolytic activity at typical wine pH values ( approximately 3.0-4.0), residual glucose and fructose contents (up to 20 g/L), and ethanol contents (up to 12%). These findings highlight the potential of O. oeni as a useful alternative source of glycosidase enzymes for use in wine-making.     

酒酒球菌计数方法研究

以酒酒球菌为试验材料,分别用平板计数法、浊度计法、分光光度计法进行计数,所得的细胞数分别与对应的NTU值、OD值建立回归方程,方程分别为y=(0.0913 3.0075x)×107;y=(73.561x-4.8994)×107.结果显示,两个方程均有极显著的直线回归关系(P＜0.01),但前者的回归系数大于后者.因此,在酒酒球菌计数时最好用浊度计法代替平板计数法.