Proceedings Volume 2010 (format .pdf) - SimpBTH

MONITORING THE FERMENTATIVE PROCESSES OF THE WINEYEASTS IN GLYCEROL ENRICHED ENVIRONMENTSGASPAR, E. 1 , OPREAN, L. 1 , TITA, O. 1 , TITA, M. 1 , LENGYEL, E. 1 , TUSA, C. 11 University „Lucian Blaga” of Sibiu, Faculty of Agricultural Sciences, Food Industry and EnvironmentalProtection, Sibiu, RomaniaKey words: must malt, glycerol, wine yeasts, mathematical modelABSTRACTThe fermentative processes happen under the influence of the wine yeasts resulting etilicalcohol, carbon dioxide and yeast biomass. Our study has the purpose of increasing the efficiency ofthe selected wine yeast under the influence of the chemical factors, using the enrichment of thegrowing environment with controlled quantities of glycerol. The glycerol added in the growingenvironment leads to increased and activated cellular metabolism during the process of optimalgrowing of the wine yeasts. The glycerol is phosphorilated by the ATP to L- glycerol- 3- phosphate,and the resulted ADP is converted, with the help of pyruvate kinase, into ATP forming the pyruvate.The glycerol contributes to the fermentative activity, a strong correlation exists between them and theprocesses which takes place in the environments with superior osmotic pressure. During this study weobserved that the glycerol is absorbed during the first hours very quickly resulting an equilibrumbetween the intra and extra cellular glycerol. Following the evolution of the samples, we candetermine a mathematical model depending on the cronological set of events.INTRODUCTIONAn important component which influences the preservationof the yeast is the glycerol. The glycerol or glycerine is a tri-alcohol.It is also called 1,2,3-propantryol, having the following chemicalstructure:CH 2CHCH 2OHOHOHGlycerol has the form of a crystalline liquid with t.p. 20 0 C, colorless, syrupy,hygriscopic, sweet, participating in the following biochemical reactions, calalyzedby the enzymes.1. Mild oxidation2CH 2CHCH 2OHOHOH[O]- H 2 OCH=OCH OHCH 2 OH+CH 2OHC OCH 2 OHglycerol aldehidedihydroxiacetone158