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 aim of this study was to determine the diagnostic value of glycolityc and energetical quantities on selected meat quality characteristics of Duroc fatteners. A total of 40 Duroc porkers were investigated. Among two analysed sets of determinants (R1 with glycogen and R1 with lactate) measured in 45 min after slaughter, the best diagnostic value for meat quality characteristics exhibit a set involving R1 and glycogen that composed determination coefficient (RC 2 ) was 0.66 for pH measured in 45 min up to 144 h post mortem. Also, with currently used meat diagnostic methods the most useful one that explains the glycolytic and energetic quantities in the highest degree is method that exploits 5 determinants, i.e. pH1, pH24, EC2, EC24 and L * 24. Higher composed determination coefficient and canonical correlation (CR) for this method was obtained for set involving R1 and lactate -0.41 and 0.64 ** respectively. Keywords: canonical analysis, fatteners, meat quality, pigs Streszczenie Celem niniejszej pracy było określenie stopnia oddziaływania zasobów energetycznych i glikolitycznych na wybrane cechy jakościowe mięsa tuczników rasy Duroc. Badaniem objętych zostało 40 tuczników wyżej wymienionej rasy. Z dwóch badanych zbiorów determinant (R1 i glikogenu oraz R1 i kwasu mlekowego) mierzonych w 45 min. post mortem wyższą wartością diagnostyczną cechowały się poziom R1 oraz glikogenu, które w 66 % determinowały stopień zakwaszenia tkanki mięśniowej od 45 min. do 144 godz. po śmierci zwierzęcia. Stwierdzono również, że z wykorzystywanych obecnie metod diagnostycznych jakości mięsa najbardziej przydatną i w największym stopniu objaśniającą stan zasobów glikolitycznoenergetycznych jest metoda uwzględniająca 5 parametrów, tj. pH1, pH24, EC2, EC24, i L * 24. Dla materiału badawczego uwzględnionego w niniejszej pracy większe 177Journal 1560 wartości współczynnika korelacji kanonicznej (CR) oraz złożonego współczynnika determinacji (RC 2 ), wynoszące odpowiednio 0,64 ** i 0,41 odnotowano dla zbioru obejmującego R1 i kwas mlekowy. of Central European Agriculture, 2015, 16(1), p.177-187 177 Journal of Central European Agriculture, 2015, 16(1), p.177-187 177 Journal of Central European Agriculture, 2015, 16(1), p.177-187 DOI: 10.5513/JCEA01/16.1.1560 177 Journal of Central European Agriculture, 2015, 16(1), p.177-187 DOI: 10.5513/JCEA01/16.1.

The objective of this study was to examine the effect of accelerated chilling on ultimate pH (pH u ), drip loss, color (L*a*b*), and Warner-Bratzler shear force (WBSF) of fresh pork using a meta-analytical approach. Additionally, two subgroups differentiated by stunning method (electrical vs. CO 2 ) were included. The meta-analysis shown that accelerated chilling has an ability to improve quality of fresh pork, however, not all benefits were obviously evident. The overall effects with no overlapping zero CI provide that accelerated chilling can increase ultimate pH and prevent negative alterations in drip loss and color of pork with the evidence of heterogeneity (except pHu). Moreover, CO 2 stunning favors fast chilling in development of fresh pork but undesired changes in lightness, redness, and yellowness may occur as well as relatively low shear force increase (probably not detectable by average consumer). Also, fast chilling followed by CO 2 stunning has no effect on drip loss. Practical applicationsThe study demonstrated, that accelerated chilling regime has an ability to improve quality of fresh pork, due to increase in ultimate pH and prevention of negative changes in drip loss and color. Additionally, it has been stated, that use of CO 2 stunning favors accelerated chilling, however, undesired changes in lightness, redness, yellowness, and shear force may occur. The abovementioned results could provide possibility of chilling processes optimization, which should benefits development of high quality fresh pork in meat industry.

The purpose of this study was to examine the high pressure processing (HPP) on four pork meat quality traits, for example, pHu, DL, WBSF, and L* with meta‐analytical approach. Three different sub‐groups were included, for example, moderate (100–250 MPa) and high pressure (>250 MPa), low to ambient (0–20°C) and medium to high (33–80°C) temperature, and unaged (pre‐rigor) and aged (post‐rigor) meat. Meta‐analysis demonstrated, that HPP treatment results in significant increase in pHu by 0.18 units, regardless of applied pressure. No effect of HPP on drip loss was observed. The greatest effect on tenderness was obtained when muscles were pressurized at moderate to high temperatures (1.04 kg in WBSF reduction). Significant increase in longissimus dorsi lightness (17.55 units) was observed—pressurization of pork loins at medium to high temperatures resulted in an increase in lightness by 2.04 units, whereas at low to ambient temperatures the overall effect achieved was 22.59. Practical applications The study shown, that high pressure processing (HPP) has an ability to prevent pH declines without a negative effect on drip loss and improves tenderness of fresh pork meat with a minimum negative effect on the color. The best results were achieved when fresh pork loins were pressurized at medium pressures (100–250 MPa). Due to raising demands of consumers toward meat quality, HPP has a potential to become a remarkable technology in pork meat industry. Its application could notably improve the efficiency of production and the resources use, which could eventually translate to lower financial losses.

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.

The aim of the study was to determine the usefulness of criteria (pH, R1 and EC) used to determine pork quality classes (RFN, PSE, DFD and AM) in assessing culinary value characteristics of pork. The study was carried out on 320 fatteners from the mass population in the spring-autumn season. Rearing conditions, pre-slaughter handling and carcass handling were the same for all animals. The fatteners were similar in terms of hot carcass weight (87.09 ±4.05 kg) and lean meat content (56.68 ±3.01%). The statistically significant correlations found confirmed that basic pork quality criteria are suitable for assessment of selected parameters of culinary value that are important to the consumer. To obtain more precise conclusions regarding the suitability of basic pork quality criteria (pH1, pH24, pH48, R1, EC2 and EC24) for estimation of characteristics of culinary value, canonical analysis should be used to determine the relationships between two sets of variables: independent (basic criteria of pork quality classes) and dependent (basic culinary values of pork).

Muscle metabolites greatly determine pork quality. However, precise threshold values which indicate its deterioration or improvement are not fully known. This study aimed to determine the influences of pork Longissimus lumborum (LL) glycogen and lactate concentrations measured at 45 min post mortem on pH, colour (L*a*b*) and drip loss (DL) measured during 144 hours post mortem in order to prescribe appropriate threshold values. The investigation used 30 gilts and 30 barrows being fattened for slaughter. After slaughter, the carcasses were assigned to groups based on the observed levels of glycogen and lactate: low GlyL with glycogen ≤35 μmol/g, GlyM with glycogen between 35 and 55 μmol/g, GlyH with glycogen >55 μmol/g; LacL with lactate ≤40 μmol/g and LacH with lactate >40 μmol/g. Lower muscle pH was noted up to 24 h post mortem in the LacH group compared to LacL (P ≤0.01). 24 h post mortem higher pH was found in GlyL than in GlyM and GlyH (P ≤0.01), which were similar. Similarly no statistical differences were noted between The GlyM and GlyH groups were also similar in L*, DL96 and DL144, with lower values found for GlyL (P ≤0.01). Compared to LacH, LacL had lower L*, DL48, DL96 and DL144 (P ≤0.01) and higher a* and b* values. Muscle pH, drip loss, L* and a* values were more affected by lactate concentration if the glycogen concentration ≥35 μmol/g muscle tissue. Thus, metabolite concentration may be a useful and valuable indicator of pork quality. Keywords: drip loss, glycolytic resources, pork colour, post-mortem muscle metabolism

The objective of this study was the comparative analysis of selected attributes of nutritional and technological quality of pork from Naïma and DanBred gilts mated with P-76 boars. The research was carried on 50 pigs (25 in each group) reared under the same environmental conditions and slaughtered at about 115±5.0 kg. Both analyzed crossbreds populations were characterized by overall good nutritional and technological quality. However the loins from DanBred×P-76 compared with those from Naïma×P-76 had significantly greater glycogen and less lactate concentration in early post mortem period, higher pH at all measurement points (besides no statistical differences in pH measured 2 hours post mortem), lower thermal drip and drip loss measured 96 and 144 hours post mortem and lower lightness (except no differences measured 48 hours post mortem). Additionally loins from DanBred×P-76 contained more protein and less water. No statistical differences in IMF content between both analysed groups were noted (their average values were below 2%). Aforementioned may suggest that crossing both Naïma and DanBred hybrids with P-76 boars may not improve IMF content or increase marbling scores to the levels preferred for culinary purposes.