The aim of study was to assess the effect of fishing season on value in use, intrinsic properties, chemical composition, and the fatty acid profile of the muscle tissue of free-living perch Perca fluviatilis L. caught in the Bystrzyca River. The research material comprised forty specimens of both sexes aged over 4 years. The fish were caught during two seasons in 2011, i.e. 20 specimens in spring (March/April), and 20 specimens in fall (October/November). No significant differences in the weight, length and condition, or in the value in use of the fish from the spring and fall seasons were noted. Fishing season had no significant effect on pH or the electrical conductivity value of perch muscle tissue. However, the color of the muscle tissue of fish from the spring season was redder and more intense. Significantly higher levels of fat and ash were noted in the muscle tissue of perch from the fall season, and this contributed to its higher nutritional value in comparison to fish caught in the spring. Furthermore, the muscle tissue of fish caught in the fall season was of greater preventive health value for consumers because of the significantly lower share of saturated fatty acids and higher concentration of long-chain n-3 polyunsaturated fatty acids, especially eicosapentaenoic, docosapentaenoic and docosahexaenoic.
The aim of the research was to evaluate the influence of calf age on proximate composition, fatty acid composition and mineral contents, as well as postmortem ageing under vacuum on the inherent properties of musculus longissimus lumborum of Limousin suckler beef aged to 6, 7 or 8 months. The moisture, protein, fat, and ash content, fatty acid composition, mineral concentrations and intrinsic properties (pH, electrical conductivity, drip and cooking loss, shear force, and CIE colour parameters) were determined. The calf age significantly (P≤0.05) correlated with an increased protein content and energy value of meat and decreased water:protein proportion. Moreover, increased age correlated with higher concentrations of Mg (P≤0.01), Zn and Fe (P≤0.05) and reduced concentrations of Cu (P≤0.05). The fatty acid composition was similar irrespective of calf age, with the exception of CLA content, which was significantly (P≤0.01) reduced in older animals. Muscles of calves aged 6 months were significantly lighter, less red, and showed the most significant drip loss compared to the muscles of older animals. There was no significant (P>0.05) interaction between calf age and postmortem ageing for the intrinsic properties analysed. Postmortem ageing under vacuum resulted in a significant decrease (P≤0.05) in the shear force of meat (irrespective of the age of the calves). The lack of significant differences, especially with regard to the meat pH, shear force, fatty acid composition, and with the significantly higher content of protein and major elements (Fe, Mg and Zn) in relation to the slaughter age, indicates the validity of increasing the duration of fattening of the Limousin calves reared with their mothers on the pasture until the age of 8 months, which is a maximum in this category.
The objective of the present research was to assess the instrumental and sensory textural attributes of lamb meat depending on the cold storage ageing under vacuum. The research material included two skeletal muscles, i.e. semimembranosus (SM) and rectus femoris (RF) from carcasses of Uhruska lambs. The age of animals ranged from 120 to 135 days. The ageing and muscle influenced significantly shear force and shear energy. However, significantly lower shear force and higher score of tenderness were observed on 7 vs. 2 days of ageing only for SM. The evaluated factors (ageing and muscle) affected slightly and not significantly the parameters of texture profile analysis. The muscle samples after the 7-day ageing showed higher hardness and chewiness. Significant correlation of sensory tenderness with instrumental shear and energy force and springiness was confirmed. The obtained results indicated that vacuum-packed lamb meat during cold storage for 7 days following slaughter develops the sensory attributes, especially tenderness.
An evaluation was conducted of the suitability for fattening in a semi-intensive system (mainly with fodders from permanent grassland) and the slaughter value of 15 young bulls of the Polish Red (PR) breed and 10 each of the White-Backed (WB) and Polish Black-and-White (BW) breeds. The reference group consisted of young bulls of the Black-and-White variety of the Polish Holstein- Friesian (HF) breed and the Simmental (SIM) breed, fattened on the same farms. Control fattening was carried out until the age of 18 months. Mean daily weight gain in the bulls of the native breeds during the control fattening period (which lasted 314-358 days) was 0.9 kg, similarly to HF, but significantly lower (P≤0.05) than in the Simmentals (986 g). During the entire fattening period, i.e. from birth to the age of 18 months, daily weight gain was 832 g in PR and 889-919 g in WB and BW. Dressing percentage was lowest in PR bulls (51.69%), and higher in WB (53.1%) and BW (53.49%), with values similar to the reference group, i.e. young bulls of the Simmental (52.97%) and HF (53.29%) breeds. The difference between PR and BW (1.8%) and HF (1.6%) was statistically significant (P≤0.05). In the EUROP classification system, the carcasses of the young bulls of the native breeds were most often placed in classes R- and O+ (conformation) and 2+ and 3- (fat cover), as in the case of young HF bulls. Carcasses of young Simmental bulls were assigned to much higher classes. The young bulls of the three Polish native breeds evaluated are good material for fattening in a semi-intensive system (mainly with fodder from permanent grasslands), while the young PR bulls were the least suitable
The material for the study consisted of 80 samples taken from the longissimus lumborum (LL) and semitendinosus (ST) muscles of young bulls of five breeds (8 samples of each muscle per breed), including three native breeds included in the genetic resources conservation programme, i.e. Polish Red, White-Backed and Polish Black-and-White, which together with the Simmental and Polish Holstein-Friesian breeds. The content of the elements (K, Na, Mg, Ca, Zn, Fe, Mn, and Cu) analysed in the meat of the young bulls (fattened in a semi-intensive system on fodder from permanent grassland) was found to depend (in varying degrees) on the breed of cattle. The greatest differences (P<0.01 and P<0.05) were noted between the Polish Holstein-Friesians (PHF) and the remaining breeds, mainly in the content of Mg, Ca, Zn and Mn. The results obtained in the four other breeds for most of the macro- and microelements were more uniform, with the highest content noted in the muscles of the young bulls of the native breeds.