| Abstract [eng] |
The aim of this thesis is to investigate genotypes of peas (Pisum savitum) cultivated in local conditions by selecting the most protein-rich raw materials and by analysing ultrasound impact on protein substances in peas, their functional properties and nutrition value under LAB solid state fermentation conditions. It was found out that fractioning of pea products on the basis of their geometrical characteristics is an effective way to obtain the fraction with the highest protein content: in the V fraction (Ø < 0,5 mm) pea products protein content was higher by 3,44 % if compared to the I fraction (Ø ≥ 2 mm). The experiment results show a significant ultrasound impact on the reduction of microbiologic pollution in pea products: after ultrasound treatment for 60 minutes (37 kHz), the total count of microorganisms reduced five times. The amount of total protein in the ultrasound treated LAB solid state fermentation pea products was found to decrease on average by 3 % and the amount of soluble protein to increase by 2 % comparing to the LAB solid state fermentation samples that received no ultrasound treatment. Evaluation the anti-nutritional factors of the pea products helped determine that in comparison to the control group LAB solid state fermentation has increased digestibility of the pea proteins in vitro by 13 % and reduced the activity of protease inhibitors by 5 %, whereas the ultrasound treatment had no significant effect on the analyzed criteria. It was noticed that the ultrasound treatment unter the LAB solid state conditions has decreased the protease activity by half, as opposed to the LAB solid state fermentation samples with no ultrasonic exposure, where the protease activity has been increasing at the same pace. It has also been determined that both LAB solid state fermentation and the ultrasound treatment had positive effects on the emulsification and foam formation potentials of the pea products. However, formation of gels from ultrasonic treated raw materials required a lower protein concentration (10 %) if compared to LAB solid state fermentation pea samples without ultrasonic treatment (12 %). The average gel viscosity of the ultrasound treated LAB solid state fermentation pea products has been determined to be on average 3 % higher than the viscosity of the LAB solid state fermentation samples with no ultrasonic exposure. In this way, the studies suggest that ultrasonic treatment is an important measure in reducing microbiological contamination of fermented raw materials of vegetable origin and functional characteristics of proteins. |
