Pale, Soft, Exudative Meat Research Articles

Effects of broiler chilling methods on the occurrence of pale, soft, exudative (PSE) meat and comparison of detection methods for PSE meat using traditional and Nix colorimeters

The aims of this study were to i) estimate the occurrence of pale, soft, and exudative (PSE) meat in modern commercial Ontario broiler flocks, ii) determine the effects of the chilling method (water vs. air) on PSE meat, and iii) investigate a new inexpensive colorimeter (10% of the price of traditional color meters), the Nix Color Sensor, as an objective color measurement of chicken meat. Between June 2019 to March 2020, a total of 17 different broiler flocks were processed. The color of 1,700 boneless skinless Pectoralis major muscles was randomly measured (100/flock), where 255 samples were also measured for pH, water-holding capacity (WHC), cooking loss, and penetration force. In addition, a traditional Minolta colorimeter was used to measure random 95 samples from a single water-chilled flock and subsequently compared the values obtained with the Nix Color Sensor. Strong correlations of L* values (rho=0.75; P < 0.001), a* values (rho=0.72; P < 0.001), and b* values (rho=0.80; P < 0.001) were observed. When an L* value of 43 was used as the cut-off for the Nix, 12.5% of fillets were classified as PSE meat. Statistical differences (P < 0.05) were observed between the air and water-chill methods for L*, pH, and WHC. However, there were no significant differences observed between the 2 methods for cooking loss and penetration force values. The study indicated that PSE meat is still a challenge in Ontario broilers, and that the L*, pH, and WHC of breast meat (all indicate meat quality) are affected by the chilling method. In addition, the Nix was found to be an affordable, objective, and convenient sensor for measuring chicken meat color.

PH post-mortem on poultry carcasses in a slaughter line for industrial identification of PSE (Pale, Soft, Exudative) and normal meat

pH post-mortem on poultry carcasses in a slaughter line for industrial identification of PSE (Pale, Soft, Exudative) and normal meat

PH post-mortem on poultry carcasses in a slaughter line for industrial identification of PSE (Pale, Soft, Exudative) and normal meat [pdf

pH post-mortem on poultry carcasses in a slaughter line for industrial identification of PSE (Pale, Soft, Exudative) and normal meat [pdf

Conditions of southern Ukraine pigs productivity under different methods of breeding in modern

The article presents the results of studies concerning pigs’ productivity for purebred breeding and innovative approaches to crossbreeding schemes in the South of Ukraine. In general, sows of all experimental groups had high productivity both in purebred breeding and because of combining different forms with each other however there was no heterosis effect on the sows’ multiplicity in crossbreeding of Large White breed and the complexity of combining the sows of hybrid origin. Young hybrid animals of experimental groups reached a live weight of 100 kg sooner for 2.6-16.4 days or 1.4-8.9 % and feed costs were lower 0.12-0.34 feed units or 3.4-9.7 % per 1 kg gain during the fattening period.&#x0D; The obtained results show that the proposed production of final hybrids with a conditional proportion of blood landrace Ч large white in terms of live weight is the most successful and adapted to the technology of moderate intensity. The use of purebred and local animals related to the so-called "White breeds" - Large White and Landrace, is characterized by increased intensity of formation and indices of growth stress. The obtained results additionally confirm the complexity of adaptation of non-ferrous breeds (Duroc and especially Pietrain breeds) to the technological conditions of domestic pork farms. Young pigs were obtained in combinations where the parental form was the breed: Large White, Landrace or Duroc had the best exterior features that characterize the development of animals in length. In combinations where the parent form was the Pietrain breed, the latitudinal measurements and the meat index were improved against the background of a decrease in body length.&#x0D; A morphological study of carcasses of young pig stock of different origin has proved that implementation of up-to-date crossbreeding schemes with the use of meat-type breeds as paternal lines results in improved carcass dressing percentage and optimised lean-to-fat ratio. As evident out of the physical and chemical analysis of pork obtained from pigs of different breed-of-origin, all investigated parameters are within the current physiological limits. Most parameters have shown no significant difference, though tended to exhibit some peculiarities associated with the impact of genotype on the manifestation of one or another physical or chemical characteristic. The use of Pietrain breed as a sire line results in decreased intramuscular fat content, and hence the energy value of pork, with the back fat having the highest melting point which is indicative of its enhanced storability, though slightly impaired cooking properties as compared to similar products obtained from the offspring of the Large White and Landrace parents. With respect to its pH level and water-holding capacity, the pork from Pietrain-sired offspring is quite similar to PSE (Pale, Soft, Exudative) meat being slightly less tender and paler in colour and exhibiting greater weight loss during thermal processing. Also, a comprehensive sensory evaluation of boiled pork and pork broth obtained from a group of the Pietrain-sired young stock has got the lowest score, which is consistent with most of the physical and chemical properties of pork from pigs of this genotype; therefore, it is 75% purebred Landrace that should be favoured as a terminal sire line in crossbreeding programmes in order to obtain pork and bacon of improved quality in intensive commercial swine production systems. It is recommended to preliminary combine Pietrain and Duroc lines to produce terminal sires (Pietrain Ч Duroc) which will be further mated with two-breed-cross dams (LW Ч L).

Phosphorylation state of pyruvate dehydrogenase and metabolite levels in turkey skeletal muscle in normal and pale, soft, exudative meats

ABSTRACT 1. Turkey production has increased dramatically as genetic selection has succeeded in increasing body weight and muscle yield to fulfil increasing consumer demand. However, producing fast-growing, heavily muscled birds is linked to increased heat stress susceptibility and can result in pale, soft, exudative (PSE) meat. Previous studies indicated that pyruvate dehydrogenase kinase 4 (PDK4) is significantly reduced in PSE samples, suggesting this as a candidate gene associated with the development of this problem. 2. The objective of this study was to determine whether pre-market thermal challenge results in PSE meat as a result of differential expression of PDK4. Two genetic lines of turkeys were used in this study; the Randombred Control Line 2 (RBC2) and a commercial line. Turkeys were exposed to a pre-market thermal challenge of 12 h at 35°C followed by 12 h at 27°C for 5 d. Birds were slaughtered and processed according to industry standards. Pectoralis major samples were categorised as PSE or normal based on marinade uptake and cook loss indicators. In the first experiment, the relative expression of pyruvate dehydrogenase (PDH) and the phosphorylation state of PDH in normal and PSE turkey meat were analysed by western blotting. In the second experiment, the same samples were used to measure metabolite levels at 5 min post-mortem, comparing the normal to the PSE samples. 3. The results of the first experiment showed that PSE samples had significantly lower total PDH (P = 0.029) compared to normal meat. However, there was no significant difference in the degree of phosphorylation of sites 1, 2 or 3. In the second experiment, there were no significant differences in glycogen, lactate, glycolytic potential or ATP when comparing PSE to control samples. 4. These results suggested that a reduction in PDK4 expression alone does not explain the development of PSE meat.

ASSESSMENT OF THE QUALITY OF MODERN COMMERCIAL PORK PRODUCTS

By a morphological study of carcasses of young pig stock of different origin, it has been proved that up-to-date crossbreeding schemes using meat-type breeds as parents increase the percentage of meat in a carcass and optimise the lean-to-fat ratio. Physicochemical analysis of pork obtained from pigs of different breeds has shown that all the parameters investigated are within the current physiological standards. Most parameters have shown no significant difference, though tend to exhibit some peculiarities associated with the effect of a genotype on how this or that physicochemical characteristic manifests itself. The use of the Piétrain breed as the sire line decreases the intramuscular fat content, and hence the calorific value of pork. The back fat of this breed has the highest melting point, which indicates its high storability, but somewhat lower cooking properties than those of similar products obtained from offspring of Large White and Landrace parents. The pH and water-holding capacity of the pork of Piétrain-sired offspring make it quite similar to PSE (Pale, Soft, Exudative) meat: this pork is slightly less tender and paler in colour and exhibits greater weight loss during thermal processing. Also, the result of a comprehensive sensory evaluation of boiled pork and pork broth obtained from Piétrain-sired young stock was the lowest, which is consistent with most of the physicochemical properties of pork from pigs of this genotype. So, it is the 75% purebred Landrace that should be favoured as a terminal sire line in crossbreeding programmes in order to obtain pork and bacon of improved quality in intensive commercial swine production systems. It is recommended to combine Piétrain and Duroc lines to produce terminal sires, ½ (Piétrain + Duroc), that will be further mated with two-breed-cross dams – ½ (Large White + Landrace).

Further evidence for the existence of broiler chicken PFN (pale, firm, non-exudative) and PSE (pale, soft, exudative) meat in brazilian commercial flocks

Abstract This work aims to investigate the incidence of two color abnormalities in broiler meat: PFN (Pale, Firm, Non-exudative) and PSE (Pale, Soft, Exudative), as well as the physicochemical alterations promoted by those anomalies. The samples of broiler breast meat (n = 700) were classified as Normal (44 5.8), PSE (L*≥53, pH 5.8). The occurrence of Normal, PSE and PFN samples was 69%, 11% and 20%, respectively. PFN samples presented a 4.2% higher water-holding capacity compared to PSE meat. PSE meats displayed a higher MFI (89.4) when compared to PFN and Normal meats. It was also noticed that the levels of lipid oxidation were greater in PSE breasts compared to Normal breasts. The total carbonyl in PFN, Normal and PSE meats was 8.2, 7.4 and 5.7 nmol/mg proteins, respectively. These results confirm the existence of a PFN anomaly in broiler breast meat, which presents functional properties similar to the Normal group. In addition to that, the less firm texture displayed by PSE meats is the result of a greater proteolytic activity, which seems to be related not only to the activation of the calpains, due to the excessive Ca 2+, but also to the lower level of protein oxidation.

Comparison of plasma corticosterone concentration, muscle fibre diameter, and apoptotic markers between normal and pale, soft, exudative (PSE) turkey breast muscles

The increasing production potential of birds is correlated with a lower health and immune potential, resulting in the appearance of numerous meat quality defects. The greatest concern for gallinaceous poultry (chickens and turkeys) is PSE meat, which is characterized by light colour, soft texture and a reduced water-binding capacity. The aim of the study was to compare plasma corticosterone concentration, muscle fibre diameter, and the apoptotic markers between normal and pale, soft, exudative (PSE) turkey breast muscles. The results show, that the PSE group is characterized by a significantly higher plasma corticosterone concentration and a significantly greater muscle fibre diameter at 30 min post mortem compared to the normal group. The time of refrigerated storage (4°C) of meat contributes significantly to reducing muscle fibre diameter in the PSE group at 24 h post mortem compared to 30 min post mortem. Additionally, the results obtain showed that the caspase-3 activity at 30 min post mortem increased significantly in the turkey breast muscles of PSE compared with the normal group. Moreover, the PSE group demonstrated the higher apoptotic potential measured in the breast muscle of turkey compared with the normal group. It is stated from the obtained results that the incidence of PSE meat in turkeys may be associated with their higher susceptibility to stress factors and stressinduced pathological states.

Thermally Induced Changes in Quality of Chicken Breast Meat Protein Fractions

Functional properties of chicken breast meat are affected by heat treatments and the condition of meat, i.e., normal or pale, soft exudative (PSE) meat. The two main fractions of meat proteins, myofibrillar and sarcoplasmic are affected differently by the treatments and the condition of the meat. The aim of this study was to extract myofibrillar and sarcoplasmic proteins from the chicken breast meat and determine differences in protein extractability between normal and PSE meat, and determine temperature transitions in whole muscle and its constituent proteins. The protein concentration of sarcoplasmic protein was less than that of myofibrillar protein in chicken breast muscle. It was also found that the protein solubility differed in normal and PSE muscle. The PSE muscle showed lower protein solubility as compared to the normal muscle which was assumed to be due to the denaturation of some of the protein fractions in PSE muscle. The results of SDS-PAGE did not show much variance in the protein profiles of the PSE and normal samples indicating that the solubilized protein in PSE and normal samples was similar. Thermal denaturation determined using differential Scanning Calorimeter, identified thermal transition peaks which could be of value in the design a scheduled heating sequence for cooking of chicken breast.

Turkey Meat. Seasonal Effect on Meat Quality and on Dead on Arrival Index in a Commercial Plant

ABSTRACT The objective of this study was to determine the incidence of Pale, Soft, Exudative (PSE) meat and to characterize the Dark, Fim, Dry (DFD) meat as well as the Dead on Arrival (DOA) index in a commercial turkey slaughterhouse in southern Brazil during the summer and winter seasons. The journeys (n=64) were over a distance of 36 ± 20 km and took approximately 95 ± 20 min. Color (L*) and pH distribution of turkey breast meat (n=5,352) were evaluated from different farms (n=64) during the 2015-2016 years. The pH, water-holding capacity, color (L*, a*, b*) were used to establish cutoff values for DFD meat (L* 5.90) and presented correlation among them. The L* value was the highest during the summer (P<0.01), indicating the highest incidence of PSE meat (28.35 %), and lowest during winter, observing the highest incidence of DFD meat (10.3 %). Finally, the obtained summer DOA index was 0.23 % higher in relation to winter.

Polyphosphate and myofibrillar protein extract promote transglutaminase-mediated enhancements of rheological and textural properties of PSE pork meat batters

The objective of this study was to improve the rheological (storage modulus G′; phase angle δ) and textural (hardness; breaking force) properties of nitrite-cured sausage batters prepared from pale, soft, exudative (PSE) pork with microbial transglutaminase (TG) using isolated myofibrillar protein (MP) or MP extracted by sodium tripolyphosphate (TPP) as substrates. While TG alone significantly enhanced G′, δ and hardness, its combination with TPP was more pronounced as these product quality parameters were increased to the level equal to that of the counterpart batter made from normal (red, firm, non-exudative, RFN) pork. The addition of MP had negligible such effect on TG functions. Cooking loss of TG-treated RFN and PSE meat with TPP was minimal but the batters were less bright (L*) than other treatments. Redness (a*) was variable between treatments. Therefore, texture-related properties of comminuted PSE meat products can be restored to the RFN level by TG cross-linking of protein that is extracted by TPP.

Quantification of Pyruvate Dehydrogenase in Normal and PSE Turkey Breast Muscles

ObjectivesA major challenge facing the turkey industry continues to be the Pale Soft Exudative (PSE) syndrome. The PSE turkey meat problem is most evident as poor protein extractability and gelation in processed meat products. PSE development is generally thought to result from an unusually high rate of postmortem glycolysis causing a rapid drop of pH while the temperature is still warm, resulting in denaturation of meat proteins. However, the specific mechanism underlying the accelerated postmortem metabolism is still poorly understood. Recent studies from our laboratory have shown that expression of the pyruvate dehydrogenase kinase isozyme 4 (PDK4) gene and the PDK4 protein are dramatically downregulated in PSE turkey. PDK4 serves as a modulator of glycolytic metabolism by regulating pyruvate dehydrogenase (PDH) activity. Phosphorylation of PDH by PDK4 results in inactivation of PDH with a shift to anaerobic metabolism and lactate production. A crucial first step in defining the specific mechanism by which PDK4 expression could affect development of PSE muscle is the quantification of PDH levels in normal and PSE samples. In this study, we test the hypothesis that PDH levels are not different between meat samples characterized as normal or PSE.Materials and MethodsRandombred Control Line 2 turkeys (n = 20), representing the turkey of the 1960s maintained without selection pressure were raised to 22 wk of age, and slaughtered and processed according to industry standards. Muscle samples from pectoralis major were collected at 5 min postmortem, cut into small pieces, snap frozen in liquid nitrogen and stored at –80°C until further use. Breast muscle samples were classified as normal or PSE based on marinade uptake at 24h postmortem, with high uptake for normal and low uptakes for PSE. To quantify PDH levels, frozen muscle samples (6 normal and 6 PSE) were pulverized and extracted with cell lysis buffer supplemented with protease and phosphatase inhibitors. Following centrifugation to remove insoluble material, proteins of the supernatants were separated by SDS-PAGE and analyzed by western blotting using a polyclonal antibody for human E1 component subunit ɑ-PDH, and a monoclonal antibody to chicken β-actin was used as a loading control. Following immunoblotting, the membrane was analyzed using the Odyssey Imaging System (Licor) using fluorescent secondary antibodies.ResultsImaging of the membrane revealed that there was no significant difference (P = 0.24) in PDH abundance between normal and PSE meat samples.ConclusionThese results suggest that variation in PDH abundance does not contribute to the development of PSE meat. Taken together with the previous observation that PDK4 levels are decreased in PSE muscle, the results suggest that the phosphorylation state of PDH may be a determinant of whether a muscle is likely to become PSE.

Prevalence of pale, soft, and exudative (PSE) condition in chicken meat used for commercial meat processing and its effect on roasted chicken breast.

BackgroundStudies on prevalence of pale, soft, exudative (PSE) condition in Sri Lankan poultry industry is minimal. Hence, the objective of present study was to determine the incidence of PSE chicken meat in a commercial meat processing plant and to find out its consequences on meat quality traits of roasted chicken breast.MethodA total of 60 breast fillets were randomly selected, evaluated based on color L* value, and placed into 1 of 2 categories; PSE (L* > 58) or normal meat (L* ≤ 58). A total of 20 breast fillets (10 PSE and 10 normal) were then analyzed for color, pH, and water holding capacity (WHC). After processing those into roasted chicken breast, cooking loss, color, pH, WHC, and texture values were evaluated. A sensory evaluation was conducted using 30 untrained panelists.ResultsThe incidence of PSE meat was 70 % in the present experiment. PSE fillets were significantly lighter and had lower pH values compared with normal fillets. Correlation between the lightness and pH was negative (P < 0.05). Although there was no significant difference in color, texture, and WHC values between the 2 groups after processing into roasted chicken breast (P > 0.05), an approximately 3 % higher cooking loss was observed in PSE group compared to its counterpart (P < 0.05). Moreover, cooking loss and lightness values showed a significant positive correlation. Nevertheless, there were no significant differences in sensory parameters between the 2 products (P > 0.05).ConclusionsThese results indicated that an economical loss can be expected due to the significantly higher cooking loss observed in roasted breast processed from PSE meat.

Improving transport container design to reduce broiler chicken PSE (pale, soft, exudative) meat in Brazil.

Throughout the chicken production chain, transport from farm to the commercial abattoir is one of the most critical sources of stress, particularly heat stress. The aim of this work was to describe the performance of a new prototype truck container designed to improve the microenvironment and reduce the incidence of pale, soft and exudative (PSE) meat and dead on arrival (DOA) occurrences. Experiments were carried out for four different conditions: regular and prototype truck, both with and without wetting loaded cages at the farm (for bird thermal stress relief) just before transporting. While there was no difference in the DOA index (P ≥ 0.05), the prototype truck caused a reduction (P < 0.05) in the occurrence of PSE meat by 66.3% and 49.6% with and without wetting, respectively. The results of this experiment clearly revealed a low-cost solution for transporting chickens that yields better animal welfare conditions and improves meat quality.

Influence of Cooling on the Glycolysis Rate and Development of PSE (Pale, Soft, Exudative) Meat

The aim of this work was to evaluate pH values fall rate in chicken breast meat under commercial refrigeration processing conditions and the development of PSE (pale, soft, exudative) meat. Broiler breast samples from the Cobb breed, both genders, at 47 days of age (n = 100) were taken from refrigerated carcasses (RS) immersed in water and ice in a tank chilled at 0°C (±2). pH and temperature (T) values were recorded at several periods throughout refrigeration in comparison to samples left at room T as control (CS). The ultimate pH (pHu) value of 5.86 for RS carcasses were only reached at 11°C after 8.35 h post mortem (PM) while, for CS samples, pHu value was 5.94 at 22°C after 4.08 h PM. Thus, under commercial refrigeration conditions, the glycolysis rate was retarded by over 4.0 h PM and the breast meat color was affected. At 24.02 h PM, PSE meat incidence was 30% while for CS, meat remained dark and PSE meat was not detected. Results show retardation in the glycolysis rate and PSE meat development was promoted by the refrigeration treatment when compared with samples stored at processing room temperature.

The effect of season of transportation on the welfare of broilers and selected parameters of broiler meat quality

During breeding, especially during transportation from the farm to the slaughterhouse, poultry is exposed to various stressful factors that influence post-mortem muscle metabolism and, consequently, the meat quality. The aim of this study was to investigate the effect of season of transportation on broiler welfare and broiler meat quality parameters: pH, colour and cooking loss t. For the purpose of the experiment, during the summer (July) and winter (November), twelve broilers were tested, reared on the same farm and belonged to the same flock of line hybrid Ross 308. Distance from the farm to the slaughterhouse was 130 km, and transport lasted 3 to 5 hours. Average values of temperature and relative humidity during transport in summer period were 20.60ºC and 65.64%, respectively, and in the winter period 14.42ºC and 69.14%, respectively. It was established that the samples of breast muscle and drumstick muscles of broiler chickens transported in summer had higher average L*(lightness) values. When the L*value of 56L* units, as the limit of PSE (pale, soft, exudative) meat, are applied on the results of the present study, it can be concluded that, in the summer, the share of pale meat in samples of breast and drumsticks was 75%, while in winter it was 33.34% for breasts and 16.67% for drumsticks. After transport, in the summer, pH values of breast and drumstick muscles (5.40 ± 0.20 and 5.71 ± 0.30, respectively) were significantly lower than the pH values measured after transport in winter (5.90 ± 0.18 and 6.46 ± 0.25, respectively). Lower values of cooking loss in the samples of breast muscle and drumstick samples (29.06 ± 2.80 and 29.69 ± 3.47, respectively) were found in broiler chickens transported in November, when exposed to lower temperatures. Between pH and cooking loss, and pH and L*values of samples of breast muscles and drumstick muscles studied after transport in summer and winter periods, negative correlation was determined.

Broiler chicken PSE (Pale, Soft, Exudative) meat and water release during chicken carcass thawing and brazilian legislation

The objective of this work was to investigate the relationship between poultry PSE meat and water loss of frozen chicken carcass in two experiments. The first experiment was carried out in commercial abattoir. Poultry carcass were classified as PSE meat (n=59) (pH 5.8). Water absorption and drip test were performed according to the Brazilian legislation methodologies. The second experiment was carried out with commercial whole five brands frozen carcasses purchased from the local supermarkets (n=30) and analyzed for pH, water holding capacity (WHC) and drip test. PSE poultry meats absorbed 3.59% of water during the processing similar to the control samples; however, released 0.38% more water during thawing of the carcasses. From these five brands evaluated, three presented drip values above 6.0%. The highest drip value was showed by the brand sample that had pH and WHC values characteristics of PSE meat. It could be postulated that PSE meat phenomenon promoted more water release during thawing leading to a misinterpretation in relation to the Brazilian legislation for water carcass liberation during thawing.

Atividades de creatina quinase e lactato desidrogenase na identificação de frangos com estresse e filés PSE (pale, soft, exudative)

Porcine Stress Syndrome (PSS) is a syndrome that occurs in pigs. PSS animals are sensitive to the anesthetic halothane, have higher activities of Creatine Kinase (CK) and Lactate Dehydrogenase (LDH) and are predisposed to the development of PSE (Pale, Soft, Exudative) meat, compromising the meat quality. In chickens, little is known about the relationship between sensitivity to and halothane changes in the activities of these enzymes with the occurrence of PSE meat. The aim of this study was to evaluate the CK and LDH activities in sensitive and non-sensitive halothane chickens and for stress susceptibility identification and PSE meat development. Birds were exposed to halothane at a 3.0 % concentration in pure O2 for 5 min. Afterwords, they were classified into groups: sensitive to halothane (HAL +) (stiffening of the lower limbs) and Non-sensitive (HAL-) (no hardening). After 3 h and 48 h to the test, blood was collected from the wing vein gill, serum extracted and stored at –22 °C until analysis of CK and LDH. No differences were observed (p ? 0.05) in CK activity for HAL+ and HAL- groups. However, differences (p ? 0.05) were observed the LDH activity at 3 h and 48 h, and 44.2 % and 66.1 % higher for the group HAL +, respectively. The determination of lactate dehydrogenase activity indicates to be an alternative to identify animals susceptible to stress thus prone to produce PSE meat.

Vplyv transportu, doby odpočinku a teploty na kvalitu bravčového mäsa z rôznych krajín

The aim of the experiment was to assess the pig meat quality in relation to preslaughter conditions and import country. In the experiment, the meat quality of 1980 pigs was evaluated. The animals were divided into three groups according to country of import (Slovakia, Hungary and Netherlands). The following pre-slaughter indicators were evaluated: duration of transport, duration of housing, temperature during housing and transport. The meat quality was judged on the basis of the pH1 value measured 45 minutes after the slaughter in the musculus longissimus dorsi – pH1 MLD and in the musculus semimembranosus – pH1 MSM. The highest frequency of PSE (pale, soft, exudative) meat in the MLD was in the group of pigs imported from Slovakia (24.13 %). These pigs had also statistically significant (P<0.01) the lowest average pH1 MLD (6.05) in comparison with other imports. The incidence of PSE meat in the MSM was in all evaluated groups above 10 %. Group of pigs from Slovakia had the lowest value of pH1 MSM (6.23) in comparison with other groups of pigs (P<0.01). Even though the average length of housing in a slaughterhouse was from 11.26 to 15.43 hours high incidence of PSE meat was recorded. However group of pigs with the longest rest period (15.43 hours - Netherlands) had significantly higher pH1 MLD and pH1 MSM compared to other imports (P<0.01). From these results can be concluded that the incidence of PSE meat in evaluated groups is relatively high. Prolonging rest period and lower temperatures had positively influence on the incidence of PSE meat and pH value.

Atividades de fosfolipase A2 secretada e glutationa peroxidase em filés PSE (pale, soft, exudative) de frango

The excessive release of calcium from the sarcoplasmic reticulum during the installation of PSE (Pale, Soft, Exudative) meat, leads to increase of phospholipase A2 (PLA2) activity and consequently causes a higher lipid oxidation. In contrast, glutathione peroxidase (GSH-Px) is a selenium-dependent antioxidant enzyme that prevents the oxidative damage. The aim of this work was to investigate the secreted PLA2 (sPLA2) and GSH-PX activities in PSE poultry meat. Breast meat samples (Pectoralis major m.) (n=24) were obtained from commercial slaughterhouse. Samples were classified as PSE and Control Meat based on pH and L* values, fillets with pH1h30? 6.0 and L24h* ?53.0 as PSE and fillets with pH1h30&gt; 6.0 and L24h*&lt;53.0 with Control. sPLA2 was analyzed using enzymatic assay kit and GSH-Px was measured a coupled assay procedure recording the NADPH (nicotinamide adenine dinucleotide phosphate reduced) oxidation. The sPLA2 average was 0.295 Umg-1 of protein for PSE meat and 0.380 Umg-1 of protein for Control meat, did not differ significantly (p &gt;0,05). The GSH-Px activity was approximately 24,4% higher (p?0,05) for Control meat when compared to PSE meat. The sPLA2 activity of PSE fillets did not changed, however PSE fillets present the enzymatic system of antioxidant defense compromised with lower GSH-PX activity.