背景:Tostado是一种传统的甜葡萄酒,来自加利西亚(西班牙西北部)的Ribeiro和Valdeorras的原产地名称(DOs)。收获的葡萄被风干并压榨以增加糖的浓度,酸,和风味化合物。因此,在这些条件下参与发酵的酵母的知识对于保证有价值的酵母的质量和独特性至关重要,独特的,和昂贵的Tostado葡萄酒。
方法:使用Wallerstein实验室(WL)营养琼脂和赖氨酸平板鉴定酵母和非酵母属酵母,然后进行聚合酶链反应(PCR)扩增,酶消化,和测序。使用线粒体DNA(mtDNA)限制性片段长度多态性(RFLP)在菌株水平上进一步表征酿酒酵母分离株。还进行了统计分析,包括不同的多样性指数,相似性百分比(SIMPER)分析,主成分分析(PCA),邻居加入聚类,简约-phylogram,和网络情节。此外,总酸度,挥发性酸度,减少糖,并分析了Tostado葡萄酒按体积计算的酒精强度。
结果:发现了各种各样的自生酵母,主要是酿酒相关的物种,如Lachanceathermotolerans,星型杆菌,Hanseniassporauvarum,汉森德巴酵母,Torulasporadelbrueckii,Pichiaspp.,和酿酒酵母来自Tostado葡萄酒的必加和糊状阶段。此外,鉴定了19种不同的酿酒酵母菌株。这种高度的酵母多样性,从发酵的早期阶段开始改变,可能有助于在Tostado葡萄酒中观察到的独特特征。
结论:早在发酵前阶段就发现了特征和差异的化学和微生物学特征,这增加了这些很少被研究的特殊葡萄酒的价值。
BACKGROUND: Tostado is a traditional sweet wine from the Designations of Origins (DOs) of Ribeiro and Valdeorras in Galicia (NW Spain). The harvested grapes are air-dried and pressed to increase the concentrations of sugars, acids, and flavour compounds. Therefore, knowledge of the yeasts involved in fermentation under these conditions is essential to guarantee the quality and uniqueness of the valuable, distinctive, and expensive Tostado wines.
METHODS: Saccharomyces and non-Saccharomyces yeasts were identified using Wallerstein Laboratory (WL) Nutrient Agar and lysine plating, followed by polymerase chain reaction (PCR) amplification, enzymatic digestion, and sequencing. Saccharomyces cerevisiae isolates were further characterised at the strain level using mitochondrial DNA (mtDNA) restriction fragment length polymorphism (RFLP). Statistical analyses were also performed, including different diversity indices, Similarity Percentage (SIMPER) analysis, principal component analysis (PCA), neighbor-joining clustering, parsimony-phylogram, and network plot. In addition, the total acidity, volatile acidity, reducing sugars, and alcoholic strength by volume of the Tostado wines were analysed.
RESULTS: A wide diversity of autochthonous yeasts was found, which were predominantly species of oenological relevance, such as Lachancea thermotolerans, Starmerella bacillaris, Hanseniaspora uvarum, Debaryomyces hansenii, Torulaspora delbrueckii, Pichia spp., and Saccharomyces cerevisiae from the must and paste stages of Tostado wine. In addition, 19 different S. cerevisiae strains were identified. This high yeast diversity, which changed from the early stages of fermentation, could contribute to the distinctive characteristics observed in Tostado wine.
CONCLUSIONS: Characteristic and differentiating chemical and microbiological profiles were found as early as the pre-fermentation stages, which adds value to these special wines that have rarely been studied.