Estación de Viticultura e Enoloxía de Galicia (EVEGA-AGACAL), Ponte San Clodio s/n, 32428 Leiro, Ourense, Spain.
Front Biosci (Elite Ed). 2024 Mar 14;16(1):10. doi: 10.31083/j.fbe1601010.
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.
and non- yeasts were identified using Wallerstein Laboratory (WL) Nutrient Agar and lysine plating, followed by polymerase chain reaction (PCR) amplification, enzymatic digestion, and sequencing. 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.
A wide diversity of autochthonous yeasts was found, which were predominantly species of oenological relevance, such as , , , , , spp., and from the must and paste stages of Tostado wine. In addition, 19 different 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.
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.
托斯塔多酒（Tostado）是来自西班牙西北部加利西亚（Galicia）里贝罗（Ribeiro）和瓦尔德奥拉斯（Valdeorras）产区的传统甜酒。收获的葡萄经过风干并压榨，以提高糖、酸和风味化合物的浓度。因此，了解在这些条件下发酵所涉及的酵母对于保证优质、独特且昂贵的托斯塔多葡萄酒的品质和独特性至关重要。
使用 Wallerstein 实验室（WL）营养琼脂和赖氨酸平板对酵母和非酵母进行鉴定，然后进行聚合酶链反应（PCR）扩增、酶切和测序。分离株进一步通过线粒体 DNA（mtDNA）限制性片段长度多态性（RFLP）在菌株水平上进行特征描述。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）、邻接聚类、简约系统发育树和网络图。此外，还分析了托斯塔多葡萄酒的总酸度、挥发酸、还原糖和酒精度。
发现了广泛的本土酵母多样性，其中主要是具有酿酒相关性的物种，如、、、、、、和从托斯塔多葡萄酒的醪液和发酵泥阶段。此外，还鉴定出 19 种不同的菌株。这种从发酵早期开始变化的高酵母多样性可能有助于托斯塔多葡萄酒的独特特征。
早在发酵前阶段就发现了具有特征和区分性的化学和微生物特征，这为这些很少被研究的特殊葡萄酒增加了价值。
