Aroma-producing yeast selection and its impact on aroma components in wine

【Objective】The aroma-producing yeast with excellent fermentation performance and strong aroma was isolated and screened from Zhongtiao Mountain wild Vitis quinquangularis，and its effects on the aroma components and quality of Petit Manseng wine were analyzed，which provided theoretical basis for the development and utilization of wild yeast resources and regional characteristic wine brewing.【Method】The Zhongtiao Mountain wild V. quinquangularis berries were collected and the strains were isolated. Based on olfactory method，Duchenne tube fermentation method and potentiometric titration，a yeast strain with strong aroma，fast fermentation speed，and high ester production was selected，and identified by molecular biology. Petit Manseng wine was fermented by single-strain inoculation（Saccharomyces cerevisiae F15）and mixed-strain inoculation（S.cerevisiae F15 and aroma-producing yeast strain）respectively. The basic physical and chemical indexes of the two wine samples were determined，and the aroma components were analyzed by gas chromatography-mass spectrometry（GC-MS）and sensory evaluation was carried out.【Result】A total of 10 yeast strains were isolated. Among them，the CL1 strain had a fast fermentation speed and an ester yield of 1.76 g/L，with obvious fruity and wine aroma. The CL1 strain was identified as Hanseniaspora uvarum based on the phylogenetic tree constructed by 26S rDNA sequence similarity. The aroma-producing yeast CL1 and S. cerevisiae F15 were inoculated to ferment Petit Manseng wine，and the results showed that the total phenol content was 7.60 mg/L higher than that of single strain inoculation（S. cerevisiae F15）. A total of 36 aroma substances were detected in the wine samples inoculated with mixed strains，which was 12 more than that inoculated with single strain，and the total content of aroma substances increased by 39.83%. Among them，the odor activity values（OAV）of 2,3-butanediol，phenylethyl alcohol，ethylphacetate，ethyl lactate，hexyl acetate and ethyl butyrate in wine sample inoculated with mixed strains were higher，which contributed more to the aroma of Petit Manseng wine，giving it creamy，fruity and rose aroma. The results of sensory evaluation showed that the aroma elegance，aroma persistence and taste intensity of the wine inoculated with mixed strains were greatly higher than those inoculated with single strain.【Conclusion】The aroma-producing yeast strain CL1 has good aroma-enhancing ability，and the mixed inoculation fermentation with S. cerevisiae has obvious effect on the quality improvement of Petit Manseng wine，which has the potential to be applied to brewing regional characteristic wine.