中条山野生葡萄产香酵母的筛选及其混菌发酵对葡萄酒香气成分的影响

Mixed fermentation with an aroma-producing yeast strain screened from the wild grape on Zhongtiao Mountain affects aromatic components of the wine

摘要:

【背景】产香酵母可赋予葡萄酒独特的香气，因此，分离筛选优良产香酵母对酿造具有地域风味的特色葡萄酒具有重要意义。【目的】从中条山野生葡萄中筛选产香酵母，进行种群鉴定和生理生化特性研究，并将其应用于葡萄酒发酵过程，研究其对葡萄酒香气成分的影响。【方法】采用稀释涂布平板法从中条山野葡萄中分离筛选酵母菌，对其进行分子生物学鉴定。优选其中具有显著香气的产香酵母，与酿酒酵母F15进行混合发酵，采用气相色谱质谱联用(gas chromatograph-mass spectrometer,GC-MS)对香气成分进行分析，采用半定量法测定香气成分含量。【结果】共分离获得各种菌株13株，26S rRNA基因D1/D2区序列分析表明它们分布于Issatchenkia、Torulaspora、Pichia、Saccharomyces和Rhodotorula等5个不同属内。优选其中一株香气较为浓郁的酵母菌株Issatchenkia orientalis strain XS-6开展研究，结果发现该菌株最高耐受乙醇浓度为8%，最高耐受NaCl浓度为6%，最适生长温度为38℃。与酿酒酵母F15混菌发酵的葡萄酒中共检测出31种香气成分。香气物质总含量较单菌发酵增加19.8%，其中11种香气成分含量增加明显，尤其是具有玫瑰香气的苯乙醇。醇类与酯类物质含量较单菌发酵增加19.6%，并发现了香草酸乙酯(ethyl vanillate)、邻苯二甲酸二丁酯(dibutyl phthalate)等7种新的酯类物质。【结论】产香酵母XS-6对乙醇、NaCl、温度等具有良好的耐受性，而且与酿酒酵母F15混菌发酵对西拉葡萄酒香气成分具有明显的影响，可能在改善葡萄酒风味方面具有潜在的应用价值。

Abstract:

[Background] Aroma-producing yeast can endow wine with unique aroma. Therefore, the isolation and screening of excellent aroma-producing yeast strains is of great significance for brewing the wine with regional characteristic flavor. [Objective] Aroma-producing yeast strains were screened from the wild grape growing on Zhongtiao Mountain, identified, and characterized for the physiological and biochemical properties. Further, we applied the strain with the strongest aroma to wine fermentation and studied its effect on aromatic components of the wine. [Methods] The aroma-producing yeast strains were isolated with plate-streaking method and then identified based on the molecular evidence. The strain with the strongest aroma was used for mixed fermentation with Saccharomyces cerevisiae F15. The aroma components of the wine were analyzed by gas chromatograph-mass spectrometer (GC-MS). The content of aroma components was determined with semi-quantitative method. [Results] A total of 13 strains was isolated. The D1/D2 region sequence of the 26S rRNA gene indicated that these strains belonged to five genera of Issatchenkia, Torulaspora, Pichia, Saccharomyces, and Rhodotorula. The strain Issatchenkia orientalis XS-6 with the strongest aroma was selected for further study. It could tolerate the highest ethanol concentration of 8% and NaCl concentration of 6% and showcased the most vigorous growth at 38 ℃. A total of 31 aroma components were detected in wine fermented with I. orientalis XS-6 and S. cerevisiae F15. The total content of aroma substances in the wine produced by mixed fermentation increased by 19.8% compared with that by single strain fermentation. The total content of aroma compounds increased by 19.8%, and the content of 11 aroma components, especially phenylethanol with rose aroma, increased significantly. The content of alcohols and esters increased by 19.6%, and seven new esters such as ethyl vanillate and dibutyl phthalate were detected. [Conclusion] The aroma-producing yeast stain XS-6 has good tolerance to ethanol, NaCl, and temperature. Mixed fermentation of XS-6 with S. cerevisiae F15 significantly affects the aromatic components of Syrah wine, which suggests that XS-6 may have a potential application value in improving wine flavor.