The paper presents the results of a study on the relationship between acidification (pH) and standard quality characteristics of the meat of Polish Large White × Polish Landrace pig crossbreds. The meat for the study was obtained from 184 F1 Polish Large White × Polish Landrace fatteners from a herd free of the stress-sensitivity gene. The obtained results were analysed in groups formed according to the meat’s measured pH45 values (≤ 6.3; 6.3–6.7; > 6.7) and pHu values (≤ 5.3; 5.3–5.6; > 5.6). Increasing measured pH45 values were paralleled by greater water-holding capacity and plasticity, lower drip loss, darker colour L* as assessed visually and with equipment, and greater content of muscle pigments (P < 0.01) of the evaluated meat. Higher pHu values had a more pronounced impact on WHC, free drip loss, tenderness, water content, and colour parameters: a*, b*, chroma C* (P < 0.01), and hue angle ho (P < 0.05). The obtained simple correlations between pH45 and pHu acidity and meat-quality characteristics indicate that the measured pH45 value was correlated more closely than ultimate acidification (P < 0.01) with visually assessed colour intensity, tactilely assessed meat hardness, colour lightness L* (P < 0.01), hue angle ho (P < 0.05), and muscle pigment content. On the other hand, pHu was more strongly correlated with water-holding capacity, drip loss, meat tenderness as well as water and protein content (P < 0.01).

Carcass, meat quality and muscle fibre traits of m. longissimus lumborum were studied in 61 Z³otnicka Spotted (ZS) pigs and 35 commercial crossbred (Polish Large White × Polish Landrace) pigs. The animals received organic feed ad libitum and were slaughtered at 210 days of age. The current findings indicate that both slaughter weight and cold carcass weight were significantly lower, and backfat thickness higher for ZS pigs compared to commercial pigs, while the commercial pigs exhibited longer carcasses and greater area, height and width of the loin eye. No significant differences were found in IMF content between the analysed groups. Moreover, the percentage of type I fibres was higher and their diameter was larger in m. longissimus lumborum of ZS compared to commercial pigs, whereas the opposite occurred for type IIB fibre percentage and diameter, and that concurred with markedly higher pigment content and higher pH K , redness (a*), plasticity values, and significantly lower drip loss, WHC-loose water, and colour lightness (L*) values in ZS pigs than those found in commercial pigs. Also, sensory assessment of raw meat confirmed that m. longissimus lumborum of ZS pigs was characterized by more favourable colour and less exudative meat.

Streszczenie. W pracy przedstawiono wyniki badań dotyczących zależności między obiektywną oceną barwy i jej zmianami (∆) po 48 h przechowywania a standardowymi wyróżnikami jakości mięsa wieprzowego. Mięso do badań pozyskano od 30 tuczników F1 (wbp × pbz) pochodzących ze skupu na terenie woj. kujawsko-pomorskiego. Na próbach pobranych z mięśnia longissimus lumborum, 48 h po uboju, zmierzono zakwaszenie (pH), oznaczono intensywność barwy, zawartość barwników mięśniowych oraz określono właściwości technologiczne mięsa, tj.: wodochłonność, swobodny wyciek soku, wyciek termiczny. Barwę mięsa mierzono 48 i 96 h po uboju w systemie CIE L*a*b*, wyliczono nasycenie barwy C* i ton barwy h°. Wykazano istotne zmiany barwy mięsa w czasie 48 h jego przechowywania w wartościach parametrów barwy a*, b* i h° (p ≤ 0,01). Największe zmiany stwierdzono w udziale barwy żółtej (∆b*) i tonie barwy (∆h°). Uzyskano znaczące zależności pomiędzy parametrami barwy mięsa L*, a*, b* i tonu barwy h° w czasie 48 i 96 h po uboju a kwasowością mięsa (pH48), intensywnością barwy, barwnikami mięśniowymi oraz swobodnym wyciekiem soku (p ≤ 0,01; p ≤ 0,05). Uzyskane wartości korelacji prostej między parametrami barwy a cechami jakości mięsa mierzonymi 48 h po uboju wskazują na istotną rolę cech jakości mięsa w kształtowaniu parametrów jego barwy. Słowa kluczowe: mięso wieprzowe, cechy fizyczne, jakość mięsa Wstęp Jednym z ważniejszych wyróżników jakości technologicznej i konsumpcyjnej mięsa wieprzowego jest jego barwa (Karamucki, 2008). Obiektywna ocena barwy w skali CIE L*a*b* i CIE L*C*h° pozwala na niezależne określenie parametru L*, tj. jasności barwy, zawierającej się między bielą (100%) i idealną czernią (0%), parametru a*, będącego miarą czerwoności, parametru b*, będącego miarą żółtości, oraz nasycenia C* i tonu barwy h° (Karamucki, 2008).

The aim of this study was to compare the characteristics of the productive lifetime (plT) of sows kept on two farms, from the aspect of reasons for culling. The study was based on data from animals from two breeding farms in hungary, using the data of 3493 crossbred dutch large white and dutch landrace sows (dlw × DL) between their first farrowing until the time of culling (2006 and 2012). For six years, the annual culling rate for both farms averaged 45%. The most frequent reasons for removal on both farms were reproductive problems (40%, 51%), leg problems (29%, 23%) and mortality (19%, 15%). There was a significant difference between the distributions of reasons for culling on the two farms (χ 2 =41.7, P≤0.001). The distributions of reasons for culling differed in three periods of sow breeding (Farm A: χ 2 =264.7, P≤0.001; Farm B: χ 2 =511.1, P≤0.001). The percentage of main removal reasons decreased, whereas the frequency of culling due to age increased. Using survival analysis (Kaplan-Meier method and Cox proportional hazard model), significant differences were identified between the PLT of sows culled due to reproductive problems (P≤0.001), leg problems (P≤0.001) and old age (P≤0.001). Reproductive problems (HR: 1.34, P≤0.001) and leg problems (HR: 1.39, P≤0.001) were higher and culling due to old age (HR: 0.44, P≤0.001) was lower on Farm A compared to Farm B. There were no significant differences between the two farms in terms of mortality (HR: 0.99, P=0.923). Overall, the results can be useful for breeders of crossbred (dlw × DL) sow populations in more accurately defining their culling systems.