Smoked sprats are delicious and nutritionally valuable product. Besides protein, it contains high amount of unsaturated fatty acids and fat soluble vitamins. Nowadays, human interest for fish product consumption is increasing. It leads to the demand for increased shelf life of the smoked sprats. One way to prolong the shelf life is to use some pre-treatment prior to smoking. The aim of study was to analyse the effect of pre-treatment on smoked Baltic sprat quality and microbiological parameters. Various compositions of brine using salts (NaCl, CaCl₂) and acetic acid in different proportions were used for fresh sprat pre-treatment. Pre-treatment had the influence on physical parameters; pre-treated samples had higher salt and lower moisture content, and lower pH, which allowed prolonging the shelf life of smoked sprats. The highest pH was in the control sample 6.6, and it allowed growth of yeasts, moulds, Pseudomonas spp., and mesophilic and facultative anaerobic microorganisms. The results demonstrated that after two-week storage of the smoked sprats the growth of moulds (1×10² CFU g⁻¹) was observed only for smoked sprats without pre-treatment (control sample), indicating the positive effect of pre-treatment. Salmonella spp., Clostridium perfingens, Listeria monocytogenes, and Escherichia coli were not detected in any of the analysed samples. After pre-treatment in brine, containing combination of NaCl and CaCl₂, smoked fish had darker colour compared to control sample or sample with sodium chloride only. Any of applied pre-treatments, except brine containing NaCl, made firmer texture of the smoked fish.

Potato proteins contains essential amino acids in considerably high concentration, therefore potatoes are considered to be one of the most valuable plant origin food for human consumption. Patatin forms one of the largest group of potato proteins with high potential to be used in food industry as a novel food. This study has been performed to approbate patatin determination method for evaluation of protein quality of potato genotypes, as well as evaluate patatin relative abundance (PRA) for breeding programmes to create in the future potato cultivars with higher value and potential to develop new products. The evaluation of patatin was performed in following steps– extraction proteins from potato, determination of patatin concentration and calculation of its relative abundance in proteins. Separation of patatin from potato tubers was made using extraction by SDS extraction buffer and determination of patatin in organically and conventionally (with differnt N suply) grown samples of 20 potato genotypes. The results of one-year study showed that patatin relative abundance of different cultivars varied from 1.65% to 50.2% and it was significantly different among genotypes. The nitrogen content of soil and maturity type of potato did not affect PRA significantly. Results provide impetus for further research.