Abstract
Currently, many breweries experience difficulties in storing brewer's production yeast until the next fermentation cycle begins, since it is not always possible to maintain the appropriate parameters, which leads to a decrease in the microbiological characteristics of the strains. Therefore, microbiologists use many methods to create optimal conditions for improving these indicators. This work explores the possibility of using natural zeolite-containing tuffs from deposits in East Kazakhstan and the Almaty region in order to prevent negative changes in the physiological and biochemical properties of seed yeast at the stage of storage in yeast. The object of study is bottom-fermenting production yeast of races 11 and 44. The yeast was cultivated in wash water, young beer or 11% beer wort (1:1), zeolite was added in an amount of 1-4% of the suspension volume and stored for 3 days at a temperature of 3-4°C. It has been established that the addition of minerals to the yeast cultivation medium increases the content in the biomass relative to the initial value of budding cells by 1,2-2,5 times, cells with glycogen – from 9 to 85%, and reduces the ability to flocculate. The effect of minerals is more effective on yeast of the sixth and eighth generations than on the young population (fourth generation). The effectiveness of the influence depends on the composition of the cultivation medium, the duration of biomass storage, and the dose of zeolite. More significant changes in the studied parameters are observed when using the Taizhuzgen and Shankanai minerals, apparently this is due to the peculiarities of the chemical composition and structure of the minerals. The results obtained indicate the advisability of using natural zeolites at the storage stage before the fermentation process of seed crops as a preventive measure of negative changes in the physiological and biological activity of yeast.