Screening Of Starmerella Baillaris And Application In The Vidal Icewine Brewing

In this study,the Starmerella bacillaris was selected from the spontaneous fermentation of Vidal icewine by WL（Wallerstein Laboratory）nutrient agar medium and molecular sequencing（ITS1-5.8S-ITS2region or the 26S r DNA D1/D2 domain）.These Starmerella bacillaris strains with high performance were screened by analyzing their tolerance and aroma-related enzymes activity.The screened strains were mixed with commercial Saccharomyces cerevisiae at a ratio of 10:1,with pure commercial Saccharomyces cerevisiae fermentation as a control.The dynamic changes of yeast population were monitored during fermentation.The main chemical components and volatile aroma compounds in icewines were determined by high performance liquid phase（HPLC）and headspace solid phase microextraction with gas chromatography-mass spectrometry（HS-SPME-GC-MS）.It provides a theoretical basis for screening indigenous Starmerella bacillaris and applying it to the production of icewine in China.（1）In this study,a total of 10 Starmerella bacillaris strains were selected during the spontaneous fermentation of Vidal icewine and were respectively named as HA01,HB07,SFA1,SFA3,SFC2,SFC5,SFD1,SFD2,SFE1 and SFG2.（2）The results of tolerance analysis showed that all the 10 Starmerella bacillaris strains could tolerate500 g/L glucose,4%ethanol,20 g/L tartaric acid and 350 mg/L SO₂.（3）The results of enzymes activities analysis showed that,except for SFA1,SFD1 and SFE1,the other7 Starmerella bacillaris strains hadβ-glucosidase,β-xylosidase and pectinase activity,among them HA01and SFA3 had better enzymes activity,which could be used in mixed fermentation of icewine in the future.（4）Compared with the pure Saccharomyces cerevisiae fermentation,the inoculation of Starmerella bacillaris strains has a negative effect on the growth of Saccharomyces cerevisiae but significantly increased the production of glycerol and alcohol,and decreased the production of L-malic acid.In addition,compared with the icewine of pure Saccharomyces cerevisiae fermentation,the icewines of mixed fermentation were significantly higher the expression of terpenes such asβ-damascenone,β-citronellol and linalool,especially the one of mixed with HA01 has strong floral and fruity aroma and effectively improves the sensory quality of icewine.