The Study Of Yeast Flocculation's Influence Factors

Yeast flocculation at the end of main fermentation is very important for green beer during the production.The thesis is researched from the three following aspects: the evaluation of quantitative method of flocculation, malt or barley on the effect of premature yeast flocculation (PYF), laser and chloridize lithium mutated and selected yeast with appropriate flocculation.The study of quantitative method of yeast flocculation is indispensable proportion. At first, Burns method, Citrate method, modification of ASBC method, modification of Helm method, and modification of light density method were studied systemically. Among the methods, it is proved that modification of light density method is fine.Among the study of PYF from the view of malt or barley, a method determining the activity of PYF is established. There are convenient, steady and accurate advantages. It can effectively estimate activity of PYF factor. Therefore precondition was provided for the sake of researching the relation of malt and yeast flocculation. Yeast flocculation has something of internal and exterior factors. PYF factor is a kind of z type protein, an inhibitor of protease A.Yeast was processed by laser and chloridize lithium in order to select a strain with appropriate flocculation. An approach is supplied to solve the problem of flocculation.Along with lucubrating of yeast flocculation, it will show tremendous value and bring more economic benefit.