The Metabolic Characteristics Of Yeast Strain During Yellow Rice Wine Fermentation And The Preparation Of Haploid

This thesis studies to choose and establish the method for the determination of higher alcohols in yellow rice wine. In research of the metabolic characteristics of four major strain, it shows that the fermentation capability is very different. I select out the yeast with decent perforance for haploid preparation, and will compare the fermentation property between the haploid and the parents, then preserve the strains of haploid for the laboratory to do deep study.Testing by gas chromatography, under the condition, HP-INNOWAX (30m*0.32mm*0.5μm) column,2.0mL/min the carrier gas flow rate,1μL sample size;1:10shunt ratio, temperature programmed work is from45℃, maintaining1min, speeding up to120℃at the rate of15℃/min, holding5min, and then speeding up to220℃at the rate of15℃/min, keeping5min, using external tap standard method to fix quantity and calculating the peak area to determine the content of higher alcohols in yellow rice wine, the result indicates that the relative standard deviation of the method is1.496%-3.331%, and the mark recovery rate of72.20%-115.02%.Analysis on the fermentation performance of the four kinds of yeast in the liquification and the traditional method of fermentation shows that the pH of Yeast B changes steadily from3.8to4.1, the content of total sugar is less than20g/L. the total acid is lower than6g/L, the content of amino acid nitrogen in liquid fermentation is0.24g/L, higher than that in traditional fermentation, the alcohol content is both above12%vol and the content of higher alcohols is low. Thus, Yeast B is the decent strain for haploid separation.The optimization of yeast sporulation conditions demonstrates the spore production rate of Yeast B can reach68.90%under the condition of controlling temperature of the sporulation medium at28℃, using McClary medium culturing for7days. The ctritical factors which influence spore release are the concentration of snail enzyme and the enzymatic hydrolysis time. The optimal condition is the enzyme concentration for3%, the enzymatic hydrolysis time for40min.The comparision of the fermentation capbility within Yeast B, Haploid bb1and Haploid bb2indicates that haploid has inherited the good characters from Yeast B, the growth rate and fermentation performance is almost consistent with Yeast B. The alcoholic strength of Haploid bb1and Haploid bb2is11.8%vol and10.9%vol respectively. The content of higher alcohol is164.9mg/L and214.96mg/L separately.