Vaquero Cristian, Loira Iris, Bañuelos María Antonia, Heras José María, Cuerda Rafael, Morata Antonio
enotecUPM. Chemistry and Food Technology Department, ETSIAAB, Universidad Politécnica de Madrid, Avenida Puerta de Hierro 2, 28040 Madrid, Spain.
Department Biotecnología-Biología Vegetal, ETSIAAB, Universidad Politécnica de Madrid, Avenida Puerta de Hierro 2, 28040 Madrid, Spain.
Microorganisms. 2020 Jun 1;8(6):830. doi: 10.3390/microorganisms8060830.
In the current scenario of climatic warming, the over-ripening of grapes increases the sugar content, producing flat and alcoholic wines with low acidity, high pH and low freshness. Additionally, a high pH makes wines more chemically and microbiologically unstable, requiring a higher sulphite content for preservation. Some strains of can naturally lower the pH of wine by producing lactic acid from sugars; this pH reduction can reach 0.5 units. The industrial performance of four selected strains has been compared with that of two commercial strains and with that of . The yeasts were assessed under variable oenological conditions, measuring lactic acid production and fermentative performance at two fermentation temperatures (17 and 27 °C), and in the presence or absence of sulphites (25 and 75 mg/L). Lactic acid production depends on yeast populations, with higher concentrations being reached when the microbial population is close to or above 7-log CFU/mL. A temperature effect on acidification can also be observed, being more intense at higher fermentation temperatures for most strains. Ethanol yield ranged from 7-11% vol., depending on the fermentation conditions (temperature and SO) at day 12 of fermentation, compared with 12% for the control in micro-fermentations. The production of fermentative esters was higher at 27 °C compared with 17 °C, which favoured the production of higher alcohols. Volatile acidity was moderate under all fermentation conditions with values below 0.4 g/L.
在当前气候变暖的情况下，葡萄过度成熟会增加糖分含量，从而酿造出酸度低、pH值高、新鲜度低的平淡且带有酒精味的葡萄酒。此外，高pH值会使葡萄酒在化学和微生物方面更不稳定，需要更高的亚硫酸盐含量来保存。某些菌株可以通过将糖转化为乳酸来自然降低葡萄酒的pH值；这种pH值降低可达0.5个单位。已将四种选定菌株的工业性能与两种商业菌株以及[此处原文缺失相关内容]的性能进行了比较。在不同的酿酒条件下对酵母进行评估，测量在两个发酵温度（17和27°C）以及有无亚硫酸盐（25和75mg/L）存在的情况下乳酸的产生和发酵性能。乳酸的产生取决于酵母数量，当微生物数量接近或高于7-log CFU/mL时会达到更高的浓度。还可以观察到温度对酸化有影响，对于大多数菌株而言，在较高发酵温度下影响更为强烈。在发酵第12天，乙醇产量在7-11%（体积）之间，这取决于发酵条件（温度和SO[此处原文缺失相关内容]），而在微型发酵中对照为12%。与17°C相比，在27°C时发酵酯的产量更高，这有利于高级醇的产生。在所有发酵条件下，挥发酸含量适中，值低于0.4g/L。
