本土酵母NX11424对赤霞珠葡萄酒发酵中酵母菌多样性及香气成分的影响

Effects of indigenous yeast NX11424 inoculation on the yeast diversity and aroma compounds during Cabernet Sauvignon wine fermentation

摘要:

【背景】NX11424酵母是一株具有良好发酵特性且能赋予赤霞珠葡萄酒浓郁果香的宁夏本土酿酒酵母。【目的】解析NX11424酵母发酵的赤霞珠葡萄酒中的水果香气特征。【方法】以赤霞珠为材料，设置3个发酵处理：自然发酵、灭菌接种NX11424的发酵和直接接种NX11424的发酵，利用26S rDNA D1/D2区测序分析法鉴定发酵过程中酵母菌的种类，并通过顶空固相微萃取和气相色谱-质谱联用技术定量测定不同发酵处理下赤霞珠葡萄酒的香气成分及含量。【结果】三个发酵处理下赤霞珠葡萄酒各理化指标无显著性差异。所分离到的酵母菌鉴定为2属3种：萄葡汁有孢汉逊酵母(Hanseniaspora uvarum)、酿酒酵母(Saccharomyces cerevisiae)和布拉迪酵母(Saccharomyces boulardii，S. boulardii)；这2属3种均存在于自然发酵中，接种发酵中仅存在H. uvarum和S. cerevisiae两种酵母。三个发酵处理下的赤霞珠葡萄酒中香气物质种类无差异，均为69种；其中，酯类28种，醇类25种，有机酸5种，萜烯类2种和其他类化合物9种；但各发酵处理下香气物质的含量存在显著差异。聚类分析表明，69种香气成分被聚为3类。第1类香气物质包括香茅醇、丙醇等9种成分，其中7种香气物质的含量在灭菌接种发酵中较高；第2类香气物质包括己酸乙酯、棕榈酸乙酯等31种成分，其含量均在直接接种发酵中较高；第3类香气物质包括丁酸乙酯、乳酸乙酯等29种成分，其中27种香气物质的含量在自然发酵中较高。虽然直接接种发酵处理中酵母菌的多样性低于自然发酵处理，但是该处理的赤霞珠葡萄酒中酯类香气物质含量较多，水果香气浓郁，对赤霞珠葡萄酒香气的改善更明显。【结论】NX11424与发酵中的其他本土酵母间的相互作用可以改善葡萄酒的质量，为宁夏本土酵母NX11424在赤霞珠葡萄酒酿造过程中改善葡萄酒质量奠定了坚实的基础。

Abstract:

[Background] The indigenous Saccharomyces cerevisiae NX11424 in Ningxia enjoys a reputation in fermentation, as it endows the Cabernet Sauvignon wine with strong fruit aroma. [Objective] To investigate the fruit aroma characteristics of Cabernet Sauvignon wine fermented with NX11424. [Methods] Cabernet Sauvignon was used for wine fermentation. Three fermentation conditions were designed:spontaneous fermentation, inoculation with NX11424 after grape sterilization, direct inoculation with NX11424. 26S rDNA D1/D2 sequencing was used to analyze and identify the yeast species during wine fermentation. The aroma components of Cabernet Sauvignon wine fermented under different conditions were determined by head space-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). [Results] The physicochemical indexes of wine fermented under the three conditions showed no significant difference. The isolated yeasts belong to 3 species in 2 genera:Hanseniaspora uvarum, S. cerevisiae, and S. boulardii. All the 3 species were detected in spontaneous fermentation and only H. uvarum and S. cerevisiae in fermentation with NX11424. A total of 69 kinds of aroma components were identified respectively in the wine fermented under the three conditions:28 esters, 25 alcohols, 5 organic acids, 2 terpenes, and 9 others. There were no significant differences in species of these aroma components among different treatments but significant differences in the content of them. Cluster analysis showed that these 69 kinds of aroma components were clustered into 3 clades. Clade Ⅰ contained 9 components such as citronellol and propanol, among which 7 had high content in the wine fermented by inoculation with NX11424 after grape sterilization. The 31 components in clade Ⅱ such as ethyl hexanoate and ethyl palmitate had high content in the wine fermented by in direct inoculation with NX11424. Clade Ⅲ had 29 components such as ethyl butanoate and ethyl lactate, among which 27 had high content in the wine under spontaneous fermentation. Although the yeast diversity under direct inoculation fermentation was lower than that under spontaneous fermentation, the wine fermented by direct inoculation showed high content of esters and strong fruit aroma. [Conclusion] The interaction between NX11424 and other indigenous yeast during wine fermentation could improve wine quality. This study lays a solid foundation for using S. cerevisiae NX11424 to improve wine quality of Cabernet Sauvignon wine.