Study Of Yeast-containing Beer

The famous beer in the world has its typical taste characteristic. The main type of beer in our country is Lager beer. In yeast-containing beer, there are rich nutritions, and the active yeast in beer can suppress flavor aging in extent. The proper adding yeast and the proper adding concentration of yeast were studied with the performance of yeast strain and the turbidity changes of beer after adding yeast. The feasibility of yeast-containing beer was confirmed by studying on flavor of beer with adding yeast.The physiological and biochemical indexes and the fermentation performance of four strains were studied. According to the characteristics of yeast-containing beer, extinction temperature, flocculability, activity and flavor of four kinds of yeast strains, strain T was chosen to be adding yeast because of its high extinction temperature, low flocculability, high activity and low flavor contents. Strain GT was chosen to be standby adding yeast because of its little higher flocculability and little lower activity than strain T.Turbidity changes of beer which contained different concentration yeasts and turbidity changes during beer aging were studied. 104 cell/mL was chosen to be the suitable concentration of strain adding concentration. The yeast-containing beer in 104 cell/mL concentration was clarifying and transparent even during beer aging.The routine technology of beer brewing was used. After fermentation the yeast strain T was added to beer with 104 cell/mL concentration.The change of trans-2-nonenal, DPPH(1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl -1-(2,4,6-trinitrophenyl)hydrazyl), reducing power, total polyphenol and biacetyl content in yeast-containing beer on different yeast concentration were studied comparing with beer which did not contain yeast. Trans-2-nonenal content in yeast-containing beer was lower than beer without adding yeast. There are little effects of adding yeast on DPPH, reducing power, total polyphenol and biacetyl content in beer.Yeast strain T and 104 cell/mL concentration were determined to be the suitable strain and concentration for producing yeast-containing beer.