The aim of this study was to compare the diagnostic values of two methods in pork meat quality evaluation, that is, Method I: pH 1 and pH 24 and Method II: electrical conductivity (EC 2 ) and pH 24 , which included pH 24 , and their modifications, that is, Method III: pH 1 and pH 48 and Method IV: EC 2 and pH 48 , which included pH 48 measurement. Five meat quality classes, namely reddish-pink, firm and non-exudative (RFN), high quality (HQ), pale, soft and exudative (PSE), dark, firm and dry (DFD) and acid meat (AM) were assessed in four even-numbered genetic groups of 40 fatteners each, namely (L×Y)×D-A, (L×Y)×D-B, (L×Y)×H and (L×Y)×(D×P). The change of diagnostic method and therefore pH time measurement from 24 hours to 48 hours post mortem caused a major increase in the percentage of acid meat (AM) that was diagnosed. Most differences were observed in (L×Y)×H fatteners, namely 77.5% between Methods I and III and 75% between Methods II and IV. This increase in AM frequency indicates that as a result of significant changes in the post-mortem metabolism that occur in the meat ageing process pH 48 should be regarded as ultimate pH (pH u ). ______________________________________________________________________________________
the objective of this study was to investigate the effect of the range of pH decline from 45 min to 48 h after the slaughter on the quality of meat in (landrace × yorkshire) × Hampshire fattening pigs. the mean value and standard deviation for the range of pH fall from 45 min to 48 h postmortem served to create the following experimental groups: group i with pH decline less or equal to 0.88 units pH; group ii with pH decline higher than 0.88 but lower than 1.26 pH units; and group iii where pH decline was equal to 1.26 units or higher. this investigation showed that glycolytic resources in meat (glycogen and lactate) were connected with the range of pH decline from 45 min to 48 h postmortem. the different ultimate pH in meat with the same lactate concentration was noted (group i vs. ii). although the range and the rate of pH decline from 3 h postmortem was higher and significantly faster (P≤0.05 and 0.01) in both groups with a higher pH fall (groups II and III), there was no statistically confirmed influence of the investigated range of pH fall on drip loss and on colour. the average values for drip loss and colour obtained in this experiment were related to ultimate pH of meat of (L × Y) × H fatteners, being characteristic for acid meat. Key words: pork meat quality, pH changesOne significant postmortem change in muscle due to anaerobic metabolism is the lowering in the pH of the muscle. The acidification of meat (pH) is an easy to measure parameter, and pH changes are widely used to monitor quality differences in fresh pork. The typical pattern of meat acidification does not have a linear character with the time postmortem (Przybylski et al., 1994; Warris, 2010). Normally, pH declines gradually from approximately 7.0-7.2 in living muscle to 5.3-5.7 at 24-48 h postmortem. In extreme cases, the pH falls from 7.0 to a value between *Work financed from statutory activity. Unauthenticated Download Date | 5/12/18 7:39 PM
ABSTRACT:The objective of the paper was to classify 50 SNPs (from 17 chromosomes) according to their contribution to the meatness of 293 boars of two breeds (Polish Landrace and Polish Large White) using entropy analysis and standard association analysis. The collected data were classified into two groups (according to the official EUROP procedure) and used for entropy analysis. Associations of single genotypes versus their groups (located at single chromosomes) with the trait studied were estimated by the use of the Generalized Linear Model
Celem przeprowadzonych badań było określenie przydatności takich parametrów, jak: zawartość kwasu mlekowego i glikogenu, pH 45 oraz przewodność elektryczna (EC 2 ) w mięśniu Longissimus lumborum (LL) do oceny jakości wieprzowiny. Wymienione parametry oznaczano 45 min post mortem, a dodatkowo przewodność elektryczną mierzono po 2, 3 i 24 h po uboju. Wykazano większą przydatność oznaczania zawartości kwasu mlekowego i EC 2 w mięśniu LL do oceny jakości wieprzowiny. Potwierdzeniem są statystycznie istotne zależności tych parametrów od większości cech fizykochemicznych mięśnia LL. Statystycznie istotna (p ≤ 0,01) ujemna zależność pomiędzy zawartością kwasu mlekowego oznaczonego 45 min post mortem a pH 45 mięśnia LL (r = -0,72**) wskazuje na przydatność wykorzystania tych pomiarów do oceny jakości wieprzowiny. Wzrost zawartości kwasu mlekowego (45 min post mortem) o 10 µmol/g tkanki mięśniowej przyczynia się do obniżenia pH 45 mięśnia LL aż o 0,1 jednostki.
Background The purpose of the study was to determine the level of physical activity of young mothers living in rural and urban areas and their free time budget. The article also aims to indicate motivating factors and barriers encountered during physical activity. Methods A diagnostic survey method, including two survey IPAQ questionnaires – the long version and author’s questionnaire, has been applied in the study. A representative sample consisted of 1064 young mothers who gave birth in 2017. Student T test and discriminate function analysis have been used in statistical analysis. Results No significant difference appeared between young mothers from rural areas and urban areas in the level of physical activity. At the same time, the authors of the study identified several smaller differences when analyzing particular aspects of physical activity. Young mothers from rural areas more often declared their participation in physical activity to improve their physical condition and reduce pain complaints. On the other hand, young mothers from urban areas emphasized that physical activity helps them to strengthen self-confidence and improve their position in the family. In case of the main barriers to physical activity, both group of respondents pointed to the lack of money and interest in occasional events. Conclusions The main conclusion is that more efforts are needed is to strengthen family support and material status of young families. It is also important to eliminate infrastructure barriers, mostly in rural areas and raise awareness on the importance of health education.
The aim of the study was to evaluate the frequencies of meat quality classes in pigs from the mass population. The study was carried out in the spring/summer season on 220 fatteners. The rearing and pre-slaughter handling conditions were the same for all animals. Slaughter and carcass handling were carried out according to the procedures used at the meat plant. The research material was similar in terms of hot carcass weight (85.27 ±3.06 kg) and lean meat content (58.02 ±2.76%). The results have shown that significant issues for the pork meat industry are acid meat (AM, with low suitability for processing) and exudative meat. The percentage of AM meat was as high as 25%, while 68% was exudative meat within the category of meat assessed as RFN (red, firm, normal). For accurate and detailed conclusions, studies must be conducted in fatteners of known origin (genotype).
The objective of this study was to determine phenotypic relations between glycolytic potential (GP) measured 45 min postmortem and meat quality traits of stress-resistant fatteners, with consideration of carcass chilling system. The investigations involved 35 Duroc fattening pigs whose left halfcarcasses were chilled conventionally (4ºC for 24 h) and right half-carcasses were rapidly chilled in a three-phase chilling tunnel (-10ºC for 15 min, -15ºC for 25 min and -5ºC for 40 min with air velocity of 3 m/s). In this study we showed that rapid chilling significantly slows the rate of pH fall from 2 to 96 h after slaughter. The negative relationship between glycolytic potential and pH (especially 24 h postmortem) was stronger for conventionally chilled carcasses but the regression coefficient (b) does not suggest increased rate of pH fall in meat of conventionally chilled carcasses (especially compared to rapid chilling) at the later stages of conversion of muscle to meat (from 24 to 144 h after slaughter). In this investigation GP was positively correlated to drip loss at 48 h postmortem, and a stronger correlation was noted for rapidly chilled carcasses. Moreover, the regression coefficient indicates that rapid chilling to 48 h postmortem can cause a slightly higher drip loss from meat than when the carcasses are chilled conventionally (0.55 vs. 0.46 percentage points per 10 μmol/g GP). At the later stages of conversion of muscle to meat (96 and 144 h postmortem) the correlation and regression coefficients were the same regardless of the chilling system.
This study compared the diagnostic value of pork quality evaluation methods using different pH threshold values and time-points with muscle metabolites concentration threshold values measured 45 min. post mortem in assessment of meat with lowered drip loss. Samples of 100 longissimus dorsi (LD) (Landrace × Yorkshire) × Duroc fatteners were examined after slaughter for following parameters: muscle acidity in 35 min, 2 h, 3 h, 24 h and 48 h (pH1, pH2, pH3, pH24 and pH48), colour lightness (L*, a*, b*), meat yield after curing and thermal processing in 72 °C (technological yield), water-holding capacity (WHC) and drip loss in 48, 96 and 144 h (DL48, DL96, DL144). To verify the accuracy of analysed methods two groups were distinguished according to DL48, e.g. Low DL (DL48≤4%) and High DL (DL48>4%). In High DL pH1 to pH48 were statistically lower while L*, WHC, DL48, DL96, DL144 were statistically higher (P≤0.05). On the basis of pH-dependent methods classification to RFN (red, firm, normal), PSE (pale, soft, exudative), DFD (dark, firm, dry) and AM (acid meat) was performed and then the percentage share of Low DL and High DL among meat classified as RFN was evaluated. Despite most samples were classified as RFN Low DL share among them did not exceed 50%. If meat sample shows metabolites concentration below threshold value and was assigned to Low DL (or was assigned to High DL above threshold value) it was regarded as correctly classified. The most promising cut-off point (correct classification of 73%) was 45 µmol both for glycogen and lactate.
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