Fermentation Character Compare Of Two Different Volume Yeasts And Development Of Nostoc Flagelliforme Beer

By the mensuration of the parameters during the fermentation, the changing of paremeters of two different volume brewing yeasts were investigated. The yeast of less volume comparing with the bigger one, the rate of sugar consumption is bigger, the times of diacetyl production and deoxidization are latter, the rate of surface tension reducing is less. The rate of alcohol production is bigger and the rate of ester production is less.Built a metabolic network of S. cerevisiae, and made the metabolic flux analysis with the ability of fermentation of different yeasts and effect on pressed yeast during fermentation. The result indicated that the yeast of less volume comparing with the bigger one,it's metabolic flux of cell synthesis and ethanol production are bigger, the flux of diacetyl production is less. In the pressed situation, the inhibition of the PPP and the TCA are bigger and the inhibition of ethanol production is less.The brewing process of Nostoc flagelliforme polysaccharide beer was studied tentatively. The optimal process is to add-in after the end of the fermentation. The best additive rate of Nostoc flagelliforme polysaccharide to fermented liquor was 0.3mg/L. On the condition that the traditional flavor and nutrition of beer were saved, the beer has the function of antivirus.The physical parameters of different beers under storing conditions were determined. The results showed that with the advance of storing time, the foam property of beers decreased, while the specific gravity, surface tension and chroma increased. The difference of effect between accelerated staling(aging) and true storing is small, but the effect of accelerated staling to low surface tension matter reducing is less.