Vigentini Ileana, Barrera Cardenas Shirley, Valdetara Federica, Faccincani Monica, Panont Carlo A, Picozzi Claudia, Foschino Roberto
Department of Food, Environmental and Nutritional Sciences, Università degli Studi di MilanoMilan, Italy.
Consorzio per la Tutela del FranciacortaErbusco, Italy.
Front Microbiol. 2017 Jun 30;8:1225. doi: 10.3389/fmicb.2017.01225. eCollection 2017.
The in-bottle fermentation of sparkling wines is currently triggered by few commercialized strains. This lack of diversity in yeast cultures leads to a prevalent uniformity in sensory profiles of the end products. The aim of this study has been to exploit the natural multiplicity of yeast populations in order to introduce variability in sparkling wines throughout the re-fermentation step. A collection of 133 strains were screened on the basis of technological criteria (fermenting power and vigor, SO tolerance, alcohol tolerance, flocculence) and qualitative features (acetic acid, glycerol and HS productions). These activities allowed the selection of yeasts capable of dominating the in-bottle fermentation in actual cellar conditions: in particular, the performances of FX and FY strains (isolated in Franciacorta area), and OX and OY strains (isolated in Oltrepò Pavese area), were compared to those of habitually used starter cultures (IOC18-2007, EC1118, Lalvin DV10), by involving nine wineries belonging to the two Consortia of Appellation of Origin. The microbiological analyses of samples have revealed that the indigenous strains showed an increased latency period and a higher cultivability along the aging time than the commercial starter cultures do. Results of chemical analyses and sensory evaluation of the samples after 18 months have shown that significant differences ( < 0.05) were present among the strains for alcoholic strength, carbon dioxide overpressure and pleasantness, whereas they were not observed for residual sugars content, titratable acidity or volatile acidity. Indigenous exhibited comparable values respect to the commercial starter cultures. The ANOVA has also proven that the base wine formulation is a key factor, by significantly affecting ( < 0.01) some oenological parameters of wine, like alcoholic strength, volatile acidity, carbon dioxide overpressure, titratable acidity and dry extract. The use of native yeast strains for the re-fermentation step can be considered a convenient way for introducing differentiation to the final product without modifying the traditional technology. In a perspective of "precision enology," where the wine is designed on specific vine cultivars and microorganisms, this work underlines that exploring yeast biodiversity is a strategic activity to improve the production.
目前，起泡酒的瓶内发酵由少数商业化菌株引发。酵母培养物缺乏这种多样性导致最终产品的感官特征普遍单一。本研究的目的是利用酵母种群的自然多样性，以便在二次发酵阶段为起泡酒引入变异性。基于技术标准（发酵能力和活力、耐二氧化硫性、耐酒精性、絮凝性）和定性特征（乙酸、甘油和硫化氢生成量）对133株菌株进行了筛选。这些筛选活动使得能够选出在实际酒窖条件下能够主导瓶内发酵的酵母：特别是，将FX和FY菌株（从弗朗齐亚柯达地区分离得到）以及OX和OY菌株（从奥尔特雷波帕韦斯地区分离得到）的性能与常用的起始培养物（IOC18 - 2007、EC1118、Lalvin DV10）进行了比较，涉及两个原产地名称保护联盟的九个酒庄。对样品的微生物分析表明，与商业化起始培养物相比，本土菌株在陈酿过程中显示出更长的延迟期和更高的可培养性。18个月后对样品进行化学分析和感官评价的结果表明，各菌株在酒精度、二氧化碳超压和愉悦度方面存在显著差异（P < 0.05），而在残糖含量、可滴定酸度或挥发酸度方面未观察到差异。本土菌株与商业化起始培养物表现出相当的数值。方差分析还证明，基础葡萄酒配方是一个关键因素，因为它会显著影响（P < 0.01）葡萄酒的一些酿酒参数，如酒精度、挥发酸度、二氧化碳超压、可滴定酸度和干浸出物。在二次发酵阶段使用本土酵母菌株可被视为一种在不改变传统工艺的情况下为最终产品引入差异化的便捷方法。从“精准酿酒学”的角度来看，即根据特定的葡萄品种和微生物来设计葡萄酒，这项工作强调探索酵母生物多样性是提高葡萄酒产量的一项战略活动。
