To prevent weakly flocculating characters of bottom brewing yeast during first fermentation, various technical investigations were carried out using strain of Saccharomyces cerevisiae. It appeared that the propagation at 10℃ promoted the molecular structure and biochemical composition of cell wall in favor of flocculation. The yeast grown at 20℃ by addition of zinc ion also had a stimulating effect on flocculation behavior during first fermentation cycle. The zinc ion did not influence directly on the changes of cell wall in favor of stronger flocculence. The increased fermentation activity of yeast due to addition zinc ion was rather responsible for the intensified flocculation capacity. It was concluded that the weakly flocculating characters of bottom brewing yeast during first fermentation can be solved by using yeast propagated at 10℃ or by means of yeast by addition of zinc ion during propagation.
목차
Abstract Introduction Materials and Methods Strain of yeast Preculture Propagation of yeast Fermentation Viability assay Glycogen assay Hydrophobic interaction chromatography for flocculation (HICF) assay Results and Discussion Influence of propagation step Influence of yeast crop Influence of incubation ratio Influence of temperature Influence of metal ions References