The aim of the study was to monitor changes in selected physical (a _w water activity, pH values) and chemical (TVBN total volatile basic nitrogen, TMA-N trimethylamine nitrogen, FFA free fatty acids, PV peroxide values, TBA thiobarbituric acid value) properties in the shelf life of rainbow trout ( Oncorhynchus mykiss ) muscle. A total of 192 trout were examined. Control samples (96 samples) were simply packaged in contact with atmospheric oxygen, while experimental samples (96 samples) were packaged in a commercial vacuum (98%). All the samples were stored at 2 ± 2° C for 11 days. Analyses were performed on storage days 1, 2, 4, 7, 9, and 11. During the experiment, a _w values increased in both types of packaging (in air: 0.982; vacuum-packaged: 0.989). At the end of storage, TVBN and TMA concentrations were at 28.88 ± 4.42 and 19.28 ± 3.00 g mg·100 ^-1 , respectively, in the muscle of vacuum-packaged trout; and at 30.52 ± 2.91 and 19.94 ± 2.05 mg·100 g ^-1 , respectively, in fish in simple packaging. The FFA content in vacuum-packaged fish initially declined before increasing to 3.67 ± 2.37% of total fat as oleic acid later in the experiment. The pattern of PV changes was inconclusive, and significant changes ( P < 0.01) were observed in both types of packaging. On monitoring day 11, TBA values had ​​increased to 7.34 ± 3.10 mg·kg ^-1 in vacuum-packaged fish and to 26.03 ± 8.00 mg·kg ^-1 in fish in simple packaging. Free fatty acids are not a good indicator of spoilage because they are converted to hydroperoxides. Vacuum packaging effectively slowed down oxidative changes in rainbow trout muscle. The peroxide content is not a suitable indicator of shelf life as peroxides are decomposed to secondary products. Total volatile basic nitrogen and thiobarbituric acid value can be recommended as suitable indicators of freshness and shelf life.

Efforts to reduce sodium chloride levels in meat products within the European Union are closely aligned with the World Health Organization’s recommendation to limit daily sodium intake to a maximum of 5 g per person. The nutritional significance of excessive salt intake is well-established, and the role of sodium chloride in meat products is not only crucial for sensory quality but also for hygienic safety. The aim of this study was to evaluate the impact of varying salt concentrations (1.4%, 1.6%, 1.8%, and 2.0%) on selected quality parameters of two common processed meat products: grilling sausages (Špekáčky) and frankfurters (Wiener Würstel). Sensory analysis was conducted with a relatively high number of trained evaluators (n = 73 for Wiener Würstel; n = 63 for Špekáčky). The results indicated that moderate salt reduction had no statistically significant effect (p > 0.05) on either the sensory attributes or the hygienic quality of the products. The method of salt content determination was shown to be critical for accurate assessment. These findings suggest that both types of reformulated products with reduced sodium content can be effectively used in production without compromising quality. Therefore, such formulations may serve as viable strategies for the food industry to contribute to public health objectives by reducing dietary sodium intake.

The aim of the present study was to evaluate the influence of castration (surgical and immunological) and sex on lipid hydrolysis, oxidation and antioxidant capacity in selected muscles/cuts of pigs. Nine muscles/cuts from four groups of pigs (surgically castrated, entire males, immunocastrated and sow) were analysed. Free fatty acids (FFA) were analysed using standard methods according to CSN EN ISO 660. Thiobarbituric reactive substances (TBARS) were determined as malondialdehyde (MDA) equivalents and antioxidant capacity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method . The highest content of FFA was observed in sows, detected to be significantly ( P < 0.001) higher than in entire males. The highest content of TBARS was found in entire males; the content was significantly ( P < 0.05) higher than in sows. Generally, the highest values of DPPH inhibition were detected in samples of surgically castrated pigs whereas the lowest values were observed in samples of entire males. Antioxidant capacity in musculus longissimus dorsi and backfat of surgically castrated pigs was significantly ( P < 0.05) higher than in other evaluated groups of pigs. The study confirmed the differences in FFA and TBARS formation between analysed groups of pigs, probably due to differences in the fatty acid composition. The results of our study indicate that methods of castration have an effect on the antioxidant capacity of pork. These findings are of value to the meat industry.

Meat aging is an important process that affects the quality of meat and is traditionally used mainly for beef. However, in recent years, there has been an increasing demand for pork products subjected to dry aging. The aim of this study was to compare selected parameters (microbiological quality, instrumental analyses of texture and color of meat, weight loss) of pork neck and loin with bone and skin together subjected to dry aging for 14 days. The microbiological profile (total viable psychrotrophic count, Enterobacteriaceae, psychrotrophic lactic acid bacteria, Pseudomonas spp.) on the surface of the meat with the skin and the lateral cutting surfaces without skin was compared on the first day after slaughter and after 14 days of dry aging. The results of this study demonstrated that dry aging did not significantly deteriorate the microbiological profile. Statistically significant weight losses were observed after 14 days of aging. The dry aging of pork had no significant effect on lightness (L*), redness (a*), and shear force. Significant differences were observed for yellowness (b*) and meat hardness (p < 0.05).