Pale, Soft And Exudative Meat Research Articles

Number of denatured rigor cross-bridges determines the intracellular volume shrinkage in porcine muscle fibre under PSE-inducing condition

Earlier onset of rigor mortis is a critical physiological progress occurring in the development of pale soft and exudative (PSE) meat. However, how rigor cross-bridges denature under different physiological conditions and their impacts on water-holding capacity remains unclear. To address this scientific question, we firstly established a method to quantify the extent of rigor cross-bridge denaturation using skinned fibres prepared from porcine longissimus thoracis et lumborum muscle. Effects of pH and temperature on the kinetics of rigor cross-bridge denaturation, actomyosin denaturation and shrinkage of muscle fibre were studied. We then manipulated the number of rigor cross-bridges before the denaturation condition was initiated (pH 5.5, 38 °C). Results suggested that the loss of water-holding capacity in PSE meat is determined by the number of denatured rigor cross-bridges. Physiochemical analysis on myofibrils demonstrated that increase in protein oxidation, surface hydrophobicity and loss of electrostatic repulsive force between myofibrils may be involved in the mechanism.

The red, firm, non-exudative and pale, soft, exudative pork have different in vitro digestive properties of protein

Pale, soft and exudative (PSE) meat has worse edible quality than red, firm and non-exudative (RFN) meat, but their difference in nutritional values is still unclear. In this study, the differences in digestive properties between PSE and RFN pork were explored, and the potential mechanisms were analyzed in terms of protein conformation. The PSE pork showed significantly higher digestibility and smaller particle size compared with RFN pork (P < 0.05) after gastrointestinal digestion. Mechanistically, the lower viscosity was seen in the PSE pork digestion system. The protein structure of PSE pork was disordered with weaker hydrogen bond and ionic bond before and after heating. In addition, the protein (mainly salt-soluble protein) of PSE pork was highly oxidized. The results suggested that higher level of oxidation in PSE pork leads to the destruction of the molecular forces, resulting in the impaired protein conformation and disordered protein structure. The serial changes caused the meat proteins more accessible to digestive enzymes, thus improving the digestibility. The findings provide new insights into the evaluating the quality of PSE meat.

Evaluation of visible spectroscopy and low-field nuclear magnetic resonance techniques for screening the presence of defects in broiler breast fillets

The potential of using simple visible spectroscopy (VIS) and low-field nuclear magnetic resonance (LF-NMR) was evaluated for differentiating three muscle conditions, normal (NORM), pale, soft and exudative (PSE), and woody breast (WB), in broiler pectoralis major. A total of 162 of pectoralis major, 54 for each condition, were collected from a commercial plant. Meat VIS spectra and transverse relaxation curve were collected using a spectrophotometer and LF-NMR, respectively. Principal component analyses (PCA) showed the better separation of PSE from NORM by VIS spectra. LF-NMR distinguished WB from NORM and PSE meat. However, the combination of VIS spectra and NMR relaxation curve differentiated the three conditions. PCA linear discriminant analysis and support vector machine discriminant analysis models further demonstrated that PCA analyses of combined VIS and LF-NMR data can correctly identify the presence of the defects in broiler breast meat.

Exploring the role of protein DJ-1 in quality of pale, soft and exudative (PSE) and red, firm and non-exudative (RFN) pork during post-mortem aging

The purpose of this study was to investigate the changes of oxidative attributes, protein DJ-1 expression, oxidized form (oxDJ-1), and cellular localization in RFN and PSE pork meat during the post-mortem aging. The longissimus thoracis of RFN and PSE groups were collected and classified by determination of pH, color and purge loss and then aged for 1, 3 and 7 d at 4 °C postmortem. Results showed that the content of DJ-1 and oxDJ-1 was continuously increased during 7 d of postmortem aging. A relatively higher protein DJ-1, oxDJ-1, oxygen reactive species and disulfide bond contents were found in PSE meat in comparison to RFN meat. Immunostaining showed that protein DJ-1 was located in cytoplasm, membrane and some nucleus of muscle cells. DJ-1 was shown to correlate with meat quality and oxidative attributes, suggesting a regulatory role in resisting oxidative stress and meat quality formation during post-mortem aging.

Effect of sodium bicarbonate on solubility, conformation and emulsion properties of pale, soft and exudative meat myofibrillar proteins

To investigate the effects of sodium bicarbonate on aggregation and emulsion properties of pale, soft and exudative (PSE) meat myofibrillar proteins, the changes in pH, turbidity, particle size, free sulfhydryl, surface hydrophobicity, emulsifying ability, and emulsion stability were studied. The pH, solubility, proportion of free sulfhydryl groups, surface hydrophobicity, emulsifying ability, and emulsion stability significantly increased (P < 0.05) with an increase in sodium bicarbonate concentration from 0 g/kg to 6 g/kg. In contrast, zeta potential, turbidity, and particle size significantly decreased (P < 0.05). In summary, the addition of sodium bicarbonate increased the pH of PSE meat myofibrillar proteins and enhanced the electrostatic repulsion between the proteins, causing the absolute value of zeta potential to increase, leading to greater exposure of sulfhydryl and hydrophobic groups and formation of smaller aggregations, enhancing its solubility, emulsifying ability and emulsion stability. Thus, sodium bicarbonate could improve the processing performance of PSE meat.

Meat quality of commercial turkey strains with slower growth rate

Introduction Pale, soft and exudative (PSE) meat was identified first as a quality defect of pig meat and became a serious problem during the 1980 s and 1990 s (Warriss and Brown, 1987; Grashorn, 2010). At this time, the occurrence of PSE meat was

Comparative Study on Pale, Soft and Exudative (PSE) and Red, Firm and Non-Exudative (RFN) Pork: Protein Changes during Aging and the Differential Protein Expression of the Myofibrillar Fraction at 1 h Postmortem.

In this paper, the protein changes during aging and the differences in the myofibrillar protein fraction at 1 h postmortem of pale, soft and exudative (PSE), and red, firm and non-exudative (RFN) pork longissimus thoracis (LT) were comparatively studied. The PSE and RFN groups were screened out based on the differences in their pH and lightness (L*) at 1 h, and their purge loss at 24 h postmortem. Based on the measured MFI, desmin degradation, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, PSE meat presented more significant changes in the myofibrillar protein fraction compared to RFN meat during postmortem aging. Through liquid chromatograph-mass spectrometer/mass spectrometer (LC-MS/MS) analysis, a total of 172 differential proteins were identified, among which 151 were up-regulated and 21 were down-regulated in the PSE group. The differential proteins were muscle contraction, motor proteins, microfilaments, microtubules, glycolysis, glycogen metabolism, energy metabolism, molecular chaperones, transport, and enzyme proteins. The AMP activated protein kinase (AMPK) signaling pathway, HIF-1 signaling pathway, calcium signaling pathway, and PI3K-Akt signaling pathway were identified as the significant pathways related to meat quality. This study suggested that the different changes of the myofibrillar protein fraction were involved in the biochemical metabolism in postmortem muscle, which may contribute to the molecular understanding of PSE meat formation.

Evaluation of pH in swine carcasses regarding on the trasport distance of the animals: a case study

The PSE (Pale, Soft and Exudative) swine meat is an anomaly that produces great economic losses in the swine industry and products because proteins lose their functionality, affecting the ability of water retention, binding, and emulsification of meat. Due to the importance of quality control of carcasses, the determination of the pH parameter is necessary to perform the classification of the product in: normal; PSE; and DFD (Dark, Firm, and Dry). In this sense, the purpose of the work was to perform the evaluation of pH values after 45 minutes of bleeding (pH45) and function of the distance from farms to a slaughterhouse and calculate the indicator of Meat PSE in swine carcasses. The experiment was carried out in a large plant, under the supervision of the Federal Inspection Service (SIF). A total of 725 carcasses were used, separated into lots and the transport distance from the farms to the slaughterhouse ranged from 25 to 427 km. For the evaluation of the incidence of PSE, pH45 was measured by a direct method, and the management of pre-slaughter animals was standardized for all lots, except for rest time. The animals transported for shorter distances (25 and 65 km) presented 11% indicative of PSE meat, a fact that shows that the stress response is higher when the animals are subjected to short transport distances compared to longer distances (320, 340, and 427 km).

Incidence of pale, soft and exudative (PSE) pork meat in reason of extrinsic stress factors.

The incidence of PSE (pale, soft and exudative) pork meat is directly influenced by pre-slaughter handling of animals, compromising meat quality and resulting in economic losses for industry. Considering management, the main extrinsic stress factors are: the pre-slaughter rest time in lairage, the total fasting time and at farm and the transport time. To evaluate the effects of these factors on PSE meat incidence, pH of 1038 carcasses was measured at 45 minutes post mortem (pH45) in a pig slaughterhouse in Paraná, Brazil. Carcasses with pH45≤5.8 were classified as PSE, and those with pH45>5.8 as normal. In order to verify if the factors influence PSE meat appearance, it was divided into categories according to it duration, and according to the number of animals evaluated in each category, the PSE meat frequency was estimated, and which time intervals obtained the lower incidence of the change. The total incidence of PSE carcasses was 19.17%. The periods of rest in lairage, total fasting, fasting at farm and transport that minimized the occurrence of PSE meat were from 04h01 to seven hours, from 14h01 to 17h00, from 03h01 to five hours, and from 02h01 to three hours, respectively.

A splicing mutation in PHKG1 decreased its expression in skeletal muscle and caused PSE meat in Duroc × Luchuan crossbred pigs.

In recent years, Luchuan pigs in southern China have been used to produce high-quality meat by crossbreeding them with Duroc boars; however, PSE (pale, soft and exudative) meat was frequently reported in the crossbred pigs, and the underlying reason remains unknown. We excluded the possibility of the well-known causative mutations in RYR1 and PRKAG3 but identified the existence of an unfavorable allele of a splicing mutation (g.8283C>A) in PHKG1 in two Duroc boars and three Duroc×Luchuan crossbred pigs with PSE meat. An association analysis with 425 Duroc×Luchuan crossbred pigs revealed that the polymorphism of the splicing site of PHKG1 has significant association with the ultimate meat pH value (P=0.035) and color score (P=0.004). In addition, a strong cis-eQTL (expression QTL) signal for the expression of PHKG1 was identified in 189 Duroc×Luchuan crossbred pigs, and the splicing mutation was proven to be significantly associated with the expression of PHKG1 (P=4.01e-11). Furthermore, RNA-sequencing data analysis confirmed that 131 CC homozygotes had only one transcript (T1), with FPKM (fragments per kilobase of transcript per million) of 35.40±7.28, and 58 CA heterozygotes had two types of transcripts (T1 and T2), with FPKM of 19.63±5.11 and 9.20±2.39 respectively. Based on the association and eQTL analysis results, we concluded that PSE meat in Duroc×Luchuan crossbred pigs is caused by the splicing mutation in PHKG1. Our findings further support the effect of the causative mutation in PHKG1 on meat quality. The GEO accession number for the data is GSE124315.

Evaluation of factors in development of Vis/NIR spectroscopy models for discriminating PSE, DFD and normal broiler breast meat

ABSTRACT1. To evaluate the performance of visible and near-infrared (Vis/NIR) spectroscopic models for discriminating true pale, soft and exudative (PSE), normal and dark, firm and dry (DFD) broiler breast meat in different conditions of preprocessing methods, spectral ranges, characteristic wavelength selection and water-holding capacity (WHC) indexes were assessed.2. Quality attributes of 214 intact chicken fillets (pectoralis major), such as lightness (L*), pH and WHC indicators including drip loss (DL), water gain and expressible fluid were measured. Fillets were grouped into PSE, normal and DFD categories based on combination of L*, pH and WHC threshold criteria. Classification models were developed using support vector machine based methods on characteristic wavelengths selected from the unprocessed or 2nd-derivative spectra, respectively, in three spectral subsets of 400–2500, 400–1100 and 1100–2500 nm.3. Better classification of three meat groups was obtained based on unprocessed spectra (72–94%) than 2nd-derivative spectra (55–72%). The classification based on 400–2500 nm (91% average) and 400–1100 nm (89% average) performed better than that on 1100–2500 nm (78% average). In terms of the three different WHC indicators, the combination of L*, pH and DL produced better results than the other two groups, with recognition accuracy of 94.4% using 400–2500-nm range.4. These analytical results suggest that for a better classification of true PSE, normal and DFD broiler breast meat with Vis/NIR spectra, unprocessed spectra wavelengths should be used, ranges of 400–1000 nm should be included in the data collection, and DL as an indicator of WHC might provide a better prediction model.

The Effect of PSE and Non-PSE Adductor and Semimembranosus Pig Muscles on the Occurrence of Destructured Zones in Cooked Hams

The aim of this study was to analyse pig muscles used in the production of cooked hams with a view to the occurrence of PSE-type defects and their potential effect on the frequency of destructured zones in finished products. One hundred and six samples of m. adductor (AD) and m. semimembranosus (SM) pig muscles were studied. The two kinds of muscle differed from each other in terms of their pH values and colour (L⁎: lightness, a⁎: redness, and b⁎: yellowness); these differences between the two categories were statistically significant (P&lt;0.001). The AD muscles were divided into meat with PSE (pale, soft, and exudative) defects and non-PSE meat by sensory examination. A total of 44.3% of AD muscles showed PSE defects. Lightness L⁎ fell within a range of 50.68–55.23 in non-PSE meat (AD) and was statistically significantly lower (P&lt;0.001) than in PSE meat (56.25–58.78). Drip loss (AD) was higher (P&lt;0.001) in PSE meat (4.83–6.27%) than in non-PSE meat (3.53–5.0%). Cooked hams prepared from pig muscles showed evident destructured zones when sliced, the number and overall area of which were not affected by the occurrence of PSE defects in the raw meat used.

Effects of various pre-slaughter conditions on pig carcasses and meat quality in a low-input slaughter facility

The aim of this study was to determine the effects of gender, slaughter weight, stocking density, lairage time and season on carcass and meat quality parameters in a low-input production system. The study was conducted on 400 slaughter pigs (200 barrows and 200 gilts) with live weight of 115.0 ± 4.70 kg. Barrows had higher slaughter and carcass weights, fat thickness and lower meatiness. Heavier pigs had higher hot and cold carcass weights, fat thickness, lower meatiness, and higher incidences of pale, soft and exudative (PSE) and dark, firm and dry (DFD) meat. Low stocking density during transportation increased skin lesion score, pH45 value and the incidence of DFD meat; while high stocking density decreased pH45 value and increased T45 value and the incidence of PSE meat. Long lairaging reduced slaughter weight, carcass weight, dressing percentage and backfat thickness and increased skin lesion score. After overnight lairaging, pH45 value and the incidence of DFD meat became higher. After short lairaging, the pH45 value was lower, while the incidence of PSE meat increased. Pigs slaughtered in winter had the highest slaughter weight, backfat thickness, pH45 value and incidence of DFD, and the lowest meatiness. Pigs slaughtered in summer had the lowest slaughter and carcass weights and pH45 value, and the highest incidence of PSE meat. In conclusion, gender influenced carcass quality, slaughter weight and lairage time, and season affected carcass and meat quality, while stocking density had an impact on meat quality.Keywords: DFD meat, gender, lairage time, low-input slaughter system, PSE meat, season, slaughter weight, stocking density

Effect of lairage time, behaviour and gender on stress and meat quality parameters in pigs.

The objective of this study was to determine the effects of lairage time (short vs. long), behavior (aggressive vs. non-aggressive) and gender (gilts, barrows and boars) on stress and meat quality parameters in pigs (n = 100). In the group with short lairage, aggressive behavior of gilts and boars was observed. At exsanguination, blood samples were collected and levels of blood lactate and plasma cortisol were determined. Post mortem pH value, temperature, drip loss, sensory and instrumental color and meat quality class were determined on the muscle Longissimus dorsi. Higher blood lactate concentration (P < 0.05) and skin blemish score (P <0.001), lower temperature (P < 0.05) and drip loss (P < 0.01), as well as darker, less red and yellow meat color (P < 0.001) were found after long lairage compared to short lairage. Gilts had higher plasma cortisol concentrations than barrows (P < 0.05), while barrows had lower skin blemish scores (P < 0.05) than gilts and boars after long lairage. The highest incidence of PSE (pale, soft and exudative) meat was observed in barrows (100.00%) and boars (91.67%) after short lairage, while the lowest incidence of PSE meat was found in barrows (28.89%) after long lairage. Aggressiveness affected meat temperature, as aggressive pigs had higher meat temperature (P < 0.05) than non-aggressive pigs.

The Influence of Pre-Mortem Conditions on Pale, Soft and Exudative (PSE) and Dark, Firm and Dry (DFD) Pork Meat

Abstract The aim of this study was to determine the effect of gender, stocking density in the transport vehicle, lairage time and season on the incidence of skin lesions on pig carcasses and PSE and DFD meat. Skin lesions on carcasses (480, in total) were assessed according to the Welfare Quality® protocol (2009). The pH and temperature measurements were performed 45 minutes after slaughter. The group of carcasses with skin lesions score 2 had significantly higher incidence of PSE and DFD meat compared to the groups of carcasses with skin lesions score 0 and 1. With regard to gender, there were no differences in meat quality parameters, as well as for the incidence of skin lesions and PSE and DFD meat. The results showed that a space allowance lower than 0.3 m2/100 kg and higher than 0.5 m2/100 kg pig had a detrimental effect to animal welfare and meat quality. Lairage time affected meat quality parameters, incidence of skin lesions score and PSE and DFD meat, where after long lairaging (&gt; 17 h) mean pH45 and t45 values became significantly higher, as well as the incidence of skin lesions and DFD meat. After short lairaging (&lt; 1 h) mean pH45 value became significantly lower, while mean t45 value and the incidence of PSE meat became significantly higher. A significantly higher number of skin lesions on the carcass were observed in winter compared to all other seasons. High temperatures during summer and low temperatures during winter had a negative influence on meat quality parameters and incidence of PSE and DFD meat.

Disorder of endoplasmic reticulum calcium channel components is associated with the increased apoptotic potential in pale, soft, exudative pork

Eight pale, soft and exudative (PSE) and eight reddish-pink, firm and non-exudative (RFN) porcine longissimus muscle samples were selected based on pH and L* at 1h postmortem (PM), and drip loss at 24h PM, and used to evaluate the cellular calcium and apoptosis status. We found that SERCA1 was decreased, while IP3R was decreased in PSE meat (P<0.05), indicative of the overloaded sarcoplasmic calcium status. In PSE meat, the pro-apoptotic factor BAX was increased while the anti-apoptotic factor Bcl-2 was decreased (P<0.05). The significantly increased activity of caspase 3 and the expression of its cleavage fragment suggested higher apoptotic potential in PSE meat compared with RFN meat (P<0.05). Moreover, the significantly higher expression level of cytochrome C (P<0.05) suggests the important role of mitochondria during apoptosis appearance in PSE meat. Taken together, our data inferred that the calcium channel disorder present in PSE meat was associated with the increased apoptotic potential.

Application of near infrared reflectance (NIR) spectroscopy to identify potential PSE meat.

Pale, soft and exudative (PSE) meat is a quality problem that causes a large economic loss to the pork industry. In the present work, near infrared (NIR) quantification and identification methods were used to investigate the feasibility of differentiating potential PSE meat from normal meat. NIR quantification models were developed to estimate meat pH and colour attributes (L*, a*, b*). Promising results were reported for prediction of muscle pH (R(2) CV = 70.10%, RPDCV = 1.83) and L* (R(2) CV = 77.18%, RPDCV = 1.91), but it is still hard to promote to practical application at this level. The Factorisation Method applied to NIR spectra could differentiate potential PSE meat from normal meat at 3 h post-mortem. Correlation analysis showed significant relationship between NIR data and LF-NMR T2 components that were indicative of water distribution and mobility in muscle. PSE meat had unconventionally faster energy metabolism than normal meat, which caused greater water mobility. NIR spectra coupled with the Factorisation Method could be a promising technology to identify potential PSE meat. The difference in the intensity of H2 O absorbance peaks between PSE and normal meat might be the basis of this identification method. © 2015 Society of Chemical Industry.

Frequency of the malignant hyperthermia gene in the South African pig industry

Porcine stress syndrome (PSS) is a genetic disorder caused by a recessive mutation in the halothane (HAL) gene and results in sudden death of pigs when placed under stress during transport and pre-slaughtering conditions. Animals that are affected by this mutation tend to develop pale, soft and exudative (PSE) meat, which results in an economic loss. In South Africa, the frequency of the number of carriers (Nn) and recessive (nn) pigs has increased by 21% to 30% from 2000 to 2003. This study aims to determine the prevalence of the malignant hyperthermia (MH) gene in breeding boars at nucleus or seed-stock level, and the prevalence at commercial abattoirs across the South African pig industry. Results indicate a low number of carriers (Nn = 17) and recessive (nn = 1) pigs at seed-stock level. For commercial abattoirs, 96.4% of the pigs tested did not carry the mutation. The low incidence of the MH mutation from breeding stock should eliminate a contributory factor to PSE meat in South Africa. Transport over long distances to abattoirs may ultimately have an effect on pork obtained even from non-carriers of the MH mutation. Keywords : MH gene, halothane gene, PSE meat, ryanodine receptor, seed stock herds

Operação de transporte e tempo de descanso na incidência de carne PSE em suínos

Este estudo foi conduzido com o objetivo de investigar a incidência de carne PSE (pale, soft and exudative) em suínos abatidos em um abatedouro comercial, localizado em Mato Grosso do Sul, no período de maio de 2009 a julho de 2010. A partir do banco de dados (n = 854 carcaças), aplicou-se a regressão logística múltipla com a finalidade de desenvolver um modelo para constatar a influência das variáveis selecionadas na probabilidade de risco de incidência de carne PSE. Desta forma, a variável dependente foi construída pela identificação de carne PSE em carcaças de suínos com valores de pH45 inferior ou igual a 5,8. Para obtenção do modelo com maior capacidade de predição foram aplicados o método de máxima verossimilhança para estimação de parâmetros e a técnica stepwise para seleção de variáveis explicativas. As variáveis selecionadas com maior poder de predição foram: temperatura de carcaça, tempo de embarque, velocidade média durante o transporte e o tempo de descanso médio dos animais nas baias. O modelo obtido apresentou capacidade de predição de 91,8%.

Integrated multivariate analysis to evaluate effects of pre-slaughter handling on pork quality

The aim of this study was to investigate the effect of pre-slaughter handling on the occurrence of PSE (Pale, Soft, and Exudative) meat in swine slaughtered at a commercial slaughterhouse located in the metropolitan region of Dourados, Mato Grosso do Sul, Brazil. Based on the database (n=1,832 carcasses), it was possible to apply the integrated multivariate analysis for the purpose of identifying, among the selected variables, those of greatest relevance to this study. Results of the Principal Component Analysis showed that the first five components explained 89.28% of total variance. In the Factor Analysis, the first factor represented the thermal stress and fatiguing conditions for swine during pre-slaughter handling. In general, this study indicated the importance of the pre-slaughter handling stages, evidencing those of greatest stress and threat to animal welfare and pork quality, which are transport time, resting period, lairage time before unloading, unloading time, and ambience.