3种酒类酒球菌发酵性能研究及其对樱桃酒品质的影响

在樱桃酒的生产过程中,苹果酸-乳酸发酵(malolactic fermentation,MLF)是降低酒体酸度、改善口感、提升生物稳定性、提高风味复杂性的重要过程,因此,选择合适的乳酸菌株触发MLF对于保障樱桃酒的品质和安全性十分重要。以市售的3种酒类酒球菌(Enoferm ALPHA、VTT.D、Lalvin VP41)为研究对象,比较它们在苹果酸-乳酸发酵过程中的增殖情况,以及它们对樱桃酒基本理化指标、挥发性组分以及生物胺含量的影响,并据此选择适宜的发酵乳酸菌株。研究结果表明,3株酒类酒球菌均可在20天内完成降酸过程,生物胺含量均在可控范围,对酒体成分的影响也不存在显著性差异。Lalvin VP41能够增加樱桃酒多种挥发性物质的合成量,如苯乙醇、丁酸乙酯、乙酸异戊酯和α-松油醇等,从而增强了樱桃酒的果香和花香特征,因此,其更适宜作为樱桃酒发酵的降酸菌株。     

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。     

酿酒酵母和酒类酒球菌原生质体制备与再生的条件优化

应用正交设计，研究酶解时间、酶浓度和酶解温度对酿酒酵母和酒类酒球菌原生质体制备和再生的影响。实验结果表明，酶解浓度对原生质体制备和再生的影响最大。最优组织条件为当蜗牛酶浓度为20g/L，酶解温度为37℃和酶解时间为20min时，酿酒酵母原生质体的制备率为88.4%。再生率为32.5%。当溶菌酶浓度为1mg/mL、酶解温度为37℃和酶解时间为20min时，酒类酒球菌原生质体的制备率为87.5%，再生率为31.2%。     

不同酿酒酵母发酵的干红樱桃酒酒体成分及感官质量分析

为选择适宜樱桃酒酿造的专用酵母,测试和对比了7株市售商业化酿酒酵母对樱桃酒的发酵过程、酒体成分以及感官质量的影响。研究发现,菌株D254发酵效率高,能够高效萃取樱桃果浆中的生物活性物质(如多酚、花色苷等),且赋予樱桃酒较佳的感官品质,使其香气馥郁协调、酒体圆润,因而是适宜樱桃酒酿造的优良酿酒酵母菌株。     

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。     

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。     

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。     

甘肃河西走廊产区本土酒酒球菌对赤霞珠干红葡萄酒香气品质的影响

酒酒球菌(Oenococcus oeni)启动的苹果酸-乳酸发酵(malolactic fermentation,MLF)是酿造高品质葡萄酒的必需工艺,随着L-苹果酸逐渐转化为L-乳酸,葡萄酒的口感及香气均有明显改善和提升。为探究本土酒酒球菌诱导MLF对赤霞珠干红葡萄酒香气品质的影响,以甘肃河西走廊产区分离鉴定出的本土O.oeni为供试菌株,采用GC-MS检测MLF后酒样中的挥发性香气化合物,结合感官分析探讨其对香气品质的影响。结果表明,4株本土O.oeni均具有良好的L-苹果酸降解能力,但相互间却表现出一定的差异; QL-11菌株MLF后的干红葡萄酒中酯类、醇类化合物种类(分别为35、19种)均高于其他菌株发酵酒样,且香气物质总含量(15.16 mg/L)最高,感官分析呈现浓郁的花香、果香味,与商品菌OMEGA发酵酒样的香气特征差异明显,具有酿造代表产区风格葡萄酒的应用潜力。     

Saccharomyces cerevisiae-Oenococcus oeni interactions in wine: current knowledge and perspectives

Winemaking can be summarized as the biotransformation of must into wine, which is performed principally by Saccharomyces cerevisiae strains during the primary or alcoholic fermentation. A secondary fermentation, the so-called malolactic fermentation (MLF) is a biodeacidification that is often encouraged, since it improves wine stability and quality. Malolactic fermentation usually occurs either spontaneously or after inoculation with selected bacteria after alcoholic fermentation. The main organism responsible for MLF, the lactic acid bacterium Oenococcus oeni, develops in physicochemically harsh conditions, which may lead to MLF failure. Furthermore, yeast that ferment must before or together with O. oeni can prevent or stimulate the progress of MLF. These phenomena are part of the interactions observed between yeast and bacteria. The mechanisms that govern yeast bacteria interaction are reviewed and the consequences for winemaking are discussed. In the light of recent advances, future prospects are also presented.     

Co‐inoculation of yeast and lactic acid bacteria to improve cherry wines sensory quality

This study examined the effect of co‐inoculation of yeast and lactic acid bacteria (LAB) on the chemical and sensory characteristics of cherry wines, in comparison with a traditional sequential culture. Three LABs were investigated, including two O. oeni (SG26 and Viniflora) and one L. plantarum (PL18). All co‐inoculations significantly shortened the fermentation time (average 8 days earlier) to reach a stable level of residual sugar (<2 g L^?1) and L‐malic acid (<0.5 g L^?1), and no inhibitory effect on the yeast proliferation was observed. For volatiles determined, co‐culture with SG26 produced the greatest amount of volatile components (138.5 mg L^?1), whereas sequential inoculation with PL18 had the lowest level (119.6 mg L^?1). PCA result revealed that different LABs had diverse influences on the volatile profile of cherry wines, and sensory analysis confirmed that these samples presented distinct sensory profiles, and particularly, a stronger note of fruity was perceived when co‐culture was used.     

Influence of sequential inoculation of Wickerhamomyces anomalus and Saccharomyces cerevisiae in the quality of red wines

The use of mixed inoculation of non-Saccharomyces yeasts and S. cerevisiae in wine fermentations is of increasing interest for quality enhancement and improved complexity of wines. The effect of sequential inoculation of Wickerhamomyces anomalus (formerly Hansenula anomala) with interesting enological properties in terms of secondary metabolite production and a commercial S. cerevisiae strain in fermentation of non-sterilized red musts from Mazuela variety has been examined. The wines elaborated by sequential inoculation presented higher levels of acetates and ethyl esters, compounds that supply a fruity note, higher levels of lineal alcohols, which are responsible for herbaceous notes and lower concentrations of organic acids, that contribute to increase the aromatic quality, than wines produced by a S. cerevisiae monoculture. Both types of wines were comparable in levels of volatile acidity, glycerol, lactic acid and succinic acid produced. Sensory analysis showed that red wines obtained by mixed fermentations were preferred by 71.5 % of the tasters and were particularly appreciated for its floral and/or fruity notes.     

Co-inoculation of different Saccharomyces cerevisiae strains and influence on volatile composition of wines

Wine is the result of the performance of different yeast strains throughout the fermentation in both spontaneous and inoculated processes. 22 Saccharomyces cerevisiae strains were characterized by microsatellite fingerprinting, selecting 6 of them to formulate S. cerevisiae mixed cultures. The aim of this study was to ascertain a potential benefit to use mixed cultures to improve wine quality. For this purpose yeasts behavior was studied during co-inoculated fermentations. Aromatic composition of the wines obtained was analyzed, and despite the fact that only one strain dominated at the end of the process, co-cultures released different concentrations of major volatile compounds than single strains, especially higher alcohols and acetaldehydes. Nevertheless, no significant differences were found in the type and quantity of the amino acids assimilated. This study demonstrates that the final wine composition may be modulated and enhanced by using suitable combinations of yeast strains.