The impact of serial repitching on dynamics and effects of HG (16%) and VHG (20%) wort fermentations was examined. It was observed that top-fermenting brewing yeasts (S. cerevisiae I-S.c./57) had a better fermentation activity than bottom-fermenting strain (S. carlsbergensis I-S.ca./13). Yeasts maintained good dynamics during serial re-pitching fermentations of 16% worts. Increase of wort concentration up to 20% had a negative influence on dynamics and extract attenuation in serial repitching processes.

The production of food with the highest nutritious guilds and the best organoleptic values induces to undertaking in this range the investigations simultaneously. The suitable level of degradation of proteins and their transformations become key the and necessary condition profitable influence on the consumers' health. The aim of this study was examined influence on transformation of nitrogenous relationships has kind used milk: applied cow's and goat's as well as kind take-off culture. In this work was produced six different kinds of kefirs, three on cow's milk with use of vaccines Wisby, DVS Biolacta also grains and three with the same cultures on goat's milk. Fermented drinks gave up organoleptic assessment, marked active and titration acidity, diacetyl, acetaldehyde also used HPLC (High Performance Liquid Chromatography) and the analysis of texture. The results HPLC of the cow's milk and the goat's they show clearly, that the conducted process of fermentation by kefir cultures milk contributed to saw change in proteolysis in studied drinks. Got results show, that transformation degradation depend in deciding larger degree from kind of used milk than applied vaccine. Goat's milk turned out more susceptible on processes of proteolysis in comparison from cow's milk, and vaccine about the largest abilities degradation were kefirs grains.

The aim of the study was to oligomerise monomers of lysozyme by modifying it in high temperature using RECICLEAN® as an agent facilitating the process. Water solutions of 2% lysozyme were prepared for modification. The prepared samples were treated with 2% solution of an oxidating reagent – RECICLEAN®. The duration of the process was 20 minutes. The obtained products were analysed by electrophoresis, densitometry and by determining hydrolytic activity. As a result of the modification, products containing 73.5–86.8% of oligomers were obtained. As far as this type of modification is concerned, formation of lysozyme tetramers was a new phenomenon. The number of created oligomers depends on the temperature applied in the process. The most favourable conditions in the light of the degree of polymerisation and the amount of active lysozyme, were those with temperature of 95°C. The products of this process contained 82.5% of oligomers, including 31.7% of dimers, and the amount of the active enzyme remained at the level of approximately 87%.