Pale, Soft And Exudative Research Articles

Effect of ultrasound treatment on the emulsion gelling properties of PSE-like chicken myofibrillar protein

ABSTRACT The effects of ultrasound treatment (20 kHz, 0, 150, 300, 450, 600 W, 6 min) on the gel properties of PSE (pale, soft, and exudative)-like chicken myofibrillar protein (MP) emulsion gels were studied. When the ultrasound power increased from 0 W to 600 W, the water-holding capacity (WHC) and gel strength of PSE-like MP emulsion gel increased by 45.01% and 37.5%, respectively (p < 0.05), the storage modulus (G’) is increased and free water began to move in the direction of immobilized water, changed hydrogen bonds to other types of intermolecular force. Fourier transform infrared spectroscopy (FTIR) showed that ultrasound treatment promoted to the transformation from α-helix to β-sheet. The microstructure showed that the emulsion gel of MP after ultrasound treatment had a dense network structure. Ultrasound treatment effectively improved the gel properties of PSE-like chicken MP emulsion gels, which provides a new idea for improving the gel properties of PSE-like chicken protein.

Effect of vegetable oils on the thermal gel properties of PSE-like chicken breast meat protein isolate-based emulsion gels

To enhance the gel properties of PSE (pale, soft, and exudative)-like chicken meat protein isolate (PPI), the effect of peanut, corn, soybean, and sunflower oils on the gel properties of PPI emulsion gels was investigated. Vegetable oils improved emulsion stability and gel strength and enhanced viscosity and elasticity. The gel strength of the PPI–sunflower oil emulsion gel increased by 163.30 %. The thermal denaturation temperature and enthalpy values were increased. They decreased the particle size of PPI emulsion (P < 0.05) and changed the three-dimensional network structure of PPI emulsion gels from reticular to sheet with a smooth surface and pore-reduced lamellar. They elevated the content of immobile water PPI emulsion gels, decreased the α-helix and β-turn, and increased the β-sheet and random coil. Vegetable oil improved the gel properties of PPI in the following order: sunflower oil > soybean oil > corn oil ≈ peanut oil > control group.

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.

Effect of heat stress on meat quality: A review

One of the stressful situations for livestock and poultry is heat stress (HS), which has a detrimental effect on animal physiology, production, and product quality. Because of their quick development and metabolism, high production, and species-specific characteristics including decreased sweating, the protective layer of skin, and rumen fermentation, some varieties of livestock are more vulnerable to heat stress than others. Muscle that is pale, soft and exudative (PSE) and lacks the ability to retain water can be produced by short-term heat stress that occurs pre-slaughter. This stress increases muscle glycogenolysis. In contrast, animals that experience prolonged heat stress have lower muscle glycogen reserves, which results in meat that is dark, firm, and dry (DFD), has a high final pH and water retention capacity. Moreover, HS causes shortened shelf life, oxidative stress. According to a recent study, HS might plausibly modify the rate and amount of postmortem muscle glycolysis and the resulting pH, which can impact the physiological and metabolic disturbances that occur in live animals as well as the features of carcasses and meat quality. This review reflects the effect of heat stress on meat quality.

Individual effects of l‐arginine and l‐lysine on the physicochemical and textural properties of pale, soft and exudative‐like emulsion sausage

SummaryThis study focused on the individual effects of l‐arginine and l‐lysine on the physicochemical properties of pale, soft and exudative (PSE)‐like chicken batter and sausages. The two amino acids decreased the cooking loss from 7.13 to 1.79 and 2.36%, respectively. They increased the hardness from 24.31 to 47.27 and 41.64 N, cohesiveness from 0.60 to 0.69 and 0.69, and chewiness from 12.15 to 28.30 and 22.80 N of PSE‐like sausage with a dense and uniform microstructure, respectively. Moreover, the two amino acids decreased the total expressible liquid and expressible fat, increased viscosity, and increased the storage and loss modulus of PSE‐like meat batters with smaller oil droplets. Differential scanning calorimetry revealed that the two amino acids increased Tmax1 and Tmax2. In summary, l‐arginine and l‐lysine improved the quality attributes of PSE‐like sausages by improving the emulsifying and gelling properties of PSE‐like meat batters.

A survey of broiler breast meat quality in the retail market of Quebec

In this study, 206 breast fillets were purchased from grocery stores in the province of Quebec and evaluated for the presence of different quality defects. Of these fillets, 48.5% showed breast muscle myopathies (BMM), 19.4% showed pale, soft, and exudative (PSE), and 6.8% showed dark, firm, and dry (DFD) attributes. BMM were equally present ( P &gt; 0.05) in fillets of economical, commercial, and high-quality brands, while PSE-like fillets were more present in economical brands ( P &lt; 0.0001). The combined effect of BMM and DFD induced significantly higher counts of Salmonella ( P = 0.03) and Enterobacteriaceae ( P = 0.03) in myopathic than in unaffected fillets. These quality defects also altered the nutritional quality of breast meat: BMM-affected fillets had greater fat content ( P &lt; 0.0001) and DFD fillets had lower protein content ( P = 0.041) than normal fillets. The technological quality was only slightly impacted by BMM, while PSE-like fillets had higher cooking loss ( P = 0.009) and a tougher texture after cooking ( P &lt; 0.0001) than DFD fillets. For the first time, this study confirmed the presence of multiple quality issues in the Quebec poultry supply chain, and provided valuable data to support future research efforts.

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.

A comparative study of S-nitrosylated myofibrillar proteins between red, firm and non-exudative (RFN) and pale, soft and exudative (PSE) pork by iodoTMT-based proteomics assay

In this paper, the S-nitrosylated myofibrillar protein in pork was comparatively analyzed between pale, soft, and exudative (PSE) and red, firm, and non-exudative (RFN) meat. The S-nitrosothiol and immunoblot of S-nitrosylated protein indicated that the overall protein S-nitrosylation level in PSE pork was higher than that in RFN pork. Proteomics showed that 114 SNO-modified cysteines corresponding to 65 proteins were over-expressed in PSE samples while 74 nitrosylated cysteines of 20 proteins were over-expressed in RFN samples. Differential proteins including myosin, actin, actinin, nebulin, titin, troponin-I, and filamin were distributed in the cytoskeleton and muscle fibers, participating in muscle contraction, cell development, and myofibril assembly by exerting binding activity. The enriched KEGG pathways included tight junction, regulation of actin cytoskeleton, glycolysis/gluconeogenesis, AMPK signaling pathway, and HIF-1 signaling pathway. Our data suggest that S-nitrosylation of myofibrillar protein could be an alternative pathway of NO involved in the regulation of fresh meat quality.

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.

Improvement strategies for quality defects and oxidation of pale, soft and exudative (PSE)-like chicken meat: effects of domestic cooking and core temperature

This study compared the quality, oxidation, and microstructure of high-market-share PSE-like chicken meat (PSE) after domestic cooking with those of normal chicken meat (NOR). Cooking techniques included steaming (ST), boiling (BO), roasting (RO), and microwaving (MV) at 60, 70, and 80 °C. The results indicated that PSE-induced chicken breasts were of poor quality, with significantly higher cooking loss rates (NOR: 22.1% vs. PSE: 26.2%) and shear force (NOR: 50.4 N vs. PSE: 69.2 N) than normal chicken meat. In addition, PSE-like chicken meat showed higher oxidative sensitivity and more severe muscle fiber structure damage. Among the four cooking techniques, RO increased meat toughness (NOR: 78.5 N vs. PSE: 98.3 N) and intensified excessive protein oxidation and aggregation in PSE chicken breast most significantly, manifested by the increased malondialdehyde (NOR: 0.46 vs. PSE: 0.57, mg kg−1 meat) and carbonyl (NOR: 11.2 vs. PSE: 13.4, nmol mg−1 protein), reduced tryptophan and thiols (NOR: 41.3 vs. PSE: 33.7, nmol mg−1 protein), and prominent protein cross-linking such as Schiff bases and disulfide bonds during heat treatment (p < 0.05). BO was the second most destructive technique, while MV caused the least impact (p > 0.05). Principal component analysis indicated a correlation between oxidative damage and meat quality, which was attributed to variations of the PSE and normal samples by BO, RO, and ST treatments. Thus, MV is suggested to be a promising and effective cooking method in reducing the differences in quality and oxidation attributes between PSE and normal chicken meat.

Meat quality, biosecurity, and animal welfare: consequences of an inefficient inspection

In livestock, biosecurity, animal welfare and meat quality have a synergetic effect on the final product. To meet minimal safety and humane production, it is necessary to consider biosecurity risks and procedures to mitigate animal welfare problems. Following guidelines to achieve it, the meat quality improves consequently. Here we tested two parameters regarding the meat quality of beef cattle to understand how the poor inspection affects the quality of the final product. Therefore, 12 samples of the longissimus dorsi muscle were evaluated from different butcheries, using fresh meat recently received by the supplier. There were no sanitary inspection records related to the sampled meat. The results showed a large percentage of PSE (pale, soft, and exudative) and DFD (dark, firm, and dry) meats. Given the pH and color values, it is concluded that the slaughtering was not carried out properly. Hence, technological defects in the meat were observed, making it inappropriate for consumption. We concluded that inefficient pre-slaughter handling is compromising animal welfare, increasing the biosecurity risk, and impairing the quality of the final product. We argue that these problems not only decrease the sustainability of livestock systems, but also compromises human health. Currently, livestock plays an important role in global environmental concerns, such as climate change, land degradation, water pollution and biodiversity loss. Then, it is needed to reduce the waste of such products.

PSIII-2 Infrared technology: A potential tool for improved pork production

Abstract This study investigated infrared technology (IRT) as a non-invasive tool for identifying febrile or stressed pigs before slaughter. A total of 120 market pigs (BW= 105.1 ± 4.9 kg) were transported in five replicate trips (20–25 pigs/replicate) for ~2 hr to an abattoir during summer 2020. Ocular and body temperatures of the pigs were recorded using a consumer grade digital infrared camera (FLIR C3, FLIR Systems) in lairage immediately after transport. Thermographic images were taken from 0.25m and 2m from pigs’ eyes and body (back/flank), respectively. At slaughter, blood samples were collected from each animal for cortisol, glucose and lactate analyses. Carcass pH measures were taken at 1 and 3 h post-mortem and loin samples were collected for meat quality assessment. Linear regression models (SAS 9.4) were used to evaluate whether post-transport temperature was predictive of blood and meat quality responses using ambient temperature and relative humidity as covariates. There were significant relationships between pigs’ ocular and body temperatures and blood measures. The regression coefficient (r2) of ocular temperatures for blood cortisol, glucose and lactate were 0.15, 0.15 and 0.04, respectively (P ≤0.03). There were significant relationships between pig ocular temperatures and pH taken at 1, 3 and 24 h post-mortem (r2=0.32, 0.18 and 0.51 respectively, P &amp;lt; 0.001). Meat yellowness (b*) and drip loss increased with body temperatures [r2=0.12 (P =0.0002) and 0.05 (P = 0.024), respectively]. Results for Warner-Bratzler shear force showed that higher temperatures were associated with tougher meat (ocular temperature: r2=0.51, P &amp;lt; 0.0001). In conclusion, as pig temperature increased, blood stress markers and drip loss increased and pH at 1 and 3 h post-mortem decreased, indicative of pale, soft and exudative (PSE) meat traits. IRT shows potential for identifying diseased/stressed pigs prior to slaughter and could be a valuable tool for improved food safety and meat quality.

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

Trace the difference driven by unfolding-refolding pathway of myofibrillar protein: Emphasizing the changes on structural and emulsion properties

The effective strategy of pH-shifting to improve the emulsifying properties of myofibrillar proteins (MPs) extracted from pale, soft and exudative (PSE)-like chicken was investigated. To determine the mechanism of improvement, changes on structural and physicochemical properties were clarified by tracing the difference driven by unfolding-refolding process. According to the results of tryptophan fluorescence intensity and circular dichroism spectroscopy, it is found that unfolding-refolding process markedly changed MPs secondary and tertiary structure. The atomic force microscopy images showed MPs appeared to have fibrous-like appearance at pH 7.0, however, exhibited as spherical shape after pH-shifting. Both emulsifying activity index and emulsifying stability index increased after pH-shifting. These results systematically illustrated the changes on structural and emulsion properties of MPs during unfolding-refolding process. It proved that the strategy pH 11.0–7.0 could more effectively promote MPs emulsifying properties, whose mechanism was simultaneously the transformation in MPs structure and potentially formation of highly-soluble particle.

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.

Effects of different lipids on the physicochemical properties and microstructure of pale, soft and exudative (PSE)-like chicken meat gel

The objective of this study was to determine effects of lipids on the physicochemical properties and microstructure of pale, soft and exudative (PSE)-like chicken gel. The PSE-like chicken meat gels prepared with lipid possessed higher lightness, whiteness, water-holding capacity but lower hardness, gumminess and chewiness, compared to the gels prepared without lipid. The secondary structure analysis showed that PSE-like meat gels presented increased β-sheet content after adding sunflower oil and peanut oil. Furthermore, the magnetic resonance imaging (MRI) results suggested that lard significantly increased the water holding capacity of PSE-like meat gels (P < 0.05), and the environmental scanning electron microscope (ESEM) results revealed an increase of matrix disorganization and some loss of spongy appearance among the meat gels with the addition of lipids. Sensory evaluation indicated that PSE-like meat gels with lipids had no difference in flavor, springiness and chewiness, but color was more intense and texture was softer compared with meat gels without lipid. Overall, these results suggested that lipid addition improves the functionality of PSE-like chicken meats and increase the economic benefits for the poultry industry.

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).

Prediction of quality traits and grades of intact chicken breast fillets by hyperspectral imaging

ABSTRACT 1. In this study, hyperspectral imaging was evaluated for its usefulness to predict quality traits and grading of intact chicken breast fillets. 2. Lightness of colour (L*) and pH of the fillets were measured as quality traits, and samples were then selected and graded to three different quality categories, i.e., dark, firm and dry (DFD), normal (NORM), and pale, soft and exudative (PSE) based on these two quality traits. Based on the prediction performance of full wavelength partial least square regression (PLSR) models, the spectral range of visible and near-infrared (Vis-NIR) was more suitable for the evaluation of quality traits and grading than the range of near-infrared (NIR). Key wavelengths of each quality trait and grade value were selected by the regression coefficient (RC) method. 3. The new key wavelength PLSR models showed good predictive performances (Rp = 0.85 and RMSEp = 2.18 for L*, Rp = 0.84, and RMSEp = 0.13 for pH, and Rp = 0.80 and RMSEp = 0.44 for quality grading). The classification accuracy for grades was 85.71% (calibration set) and 81.82% (prediction set), respectively. Finally, distribution maps showed that quality traits and grades of samples were able to be visualised. 4. These results suggested that hyperspectral imaging has the potential for quality prediction of fresh chicken meat.