Study On The Semi-solid Brewing Process Of Defined Fungal For Rice Wine

Rice wine is a famous folk product in China. In traditional fermentation, thesubstrate is fermented by mass kinds of wild microbes, and the quality of the ricewine is not stable due to the empirical practice in local winery, therefore, it has been aproblem urgent to be solved. In this study, three single strains were employed toenhance and control the quality of wine, as well as keeping the original flavor of thetraditional rice wine. Based on the characteristics of different strains etc. yeast has thestrong ability to produce ethanol while the mould presents a better ability of starchhydrolysis instead, so the co-fermentation was carried out in the thesis. The majorresults were as follows.1.27yeasts were isolated from the local wineries and one strain with strongcapacity of producing alcohol, named5-1Y, was screened. The isolate was identifiedas Saccharomyces cerevisiae by morphology, biochemical tests and16S rDNAanalysis. The glucose concentration and the mortality of the isolate were detectedcontinuously in YEPD medium, which contain various concentrations of glucose (50g/L-320g/L)and alcohol(0%-9%), to analyze the fermentation characterization of thisyeast. The results revealed that high concentration of initial sugar could affect thefermentation and the suitable glucose concentration for5-1Y was230g/L.When theinitial ethanol concentration reached9%, the ethanol would strongly affect thefermentation.Single or mixed3-1Y and5-1Y were chosen at the fermentation stage. Thecombination of3-1Y and5-1Y had significant effects on fermentation. The goodtechnical parameters were listed below: the proportion of each strains of3-1Y:5-1Y=5:5, the total inoculation amount was10%, fermentation time was15days，and the fermentation temperature was30℃。2. One Phizopus With high saccharification power was chosen, while theoptimum working conditions found for saccharification were: water content of the ricemeal was60%, saccharifying strain add1×106spores/100g rice meal, saccharifyingtemperature was30℃, saccharifying time was48hours.3. The scale-up test was carried out based on the lab-scale (small-scale)experiments under the same operating conditions.4. Gas Chromatography (GC) Determination of the10kinds of volatile flavorsubstances in the rice wine showed no significant differences between traditional solid starter and mixed-pure-culture starter.