Pale, Soft, Exudative Research Articles

Effects of sodium tripolyphosphate on the quality and digestion properties of PSE pork

This study aimed to examine the impact of sodium tripolyphosphate (STPP) on the quality and digestive characteristics of PSE pork. The results showed a notable decrease in cooking loss of PSE pork from 29.11% to 25.67% with increasing STPP concentration (P < 0.05). Additionally, the gastric digestibility of PSE pork decreased significantly from 52.01% to 45.81% (P < 0.05). The particle size of digesta decreased significantly after gastrointestinal digestion (P < 0.05). These changes were primarily due to the enhanced cross-linking of proteins through ionic interactions, hydrogen bonds and hydrophobic interactions, and resulted in the embedding of hydrophobic groups and endogenous fluorophores. Furthermore, denser network was formed. These findings give a new insight into considering the impact of STPP on meat nutrition when used to enhance texture and water holding capacity.

The shelf life of pork depends on its quality and microbial and non-microbial meat destructors

This work aimed to establish the maximum shelf life of pork of different quality classes depending on the action of non-microbial and microbial destructors. To achieve this goal, samples were taken from the longest back muscles of domestic and industrial pig carcasses. Depending on the results of organoleptic research, pork was divided into three quality classes: 1) NOR (close to optimal quality indicators), 2) PSE (pale, soft, exudative), and 3) DFD (dark, firm, dry). After that, each of the samples was divided into 1 equal parts and placed for storage in a refrigerator (t = 3 ± 1 °C). Each day, one part of the samples was used for laboratory research. The purpose of laboratory research was to establish the freshness of meat by determining the reaction to peroxidase, amino-ammonia nitrogen, reaction to ammonia with Nessler's reagent, and the content of short-chain fatty acids. In addition, the level of MAFAnM was determined. The results of laboratory studies showed that the fastest signs of spoilage were registered in pork, with signs of PSE obtained after the slaughter of pigs on small farms. The first signs of deterioration appeared already on the sixth day of storage. The second fastest spoilage rate (on the eighth day) was meat samples of the PSE quality class taken from pigs of industrial origin. At the same time, the highest increase in microbial contamination during storage was registered in meat samples of industrial origin with signs of DFD. We found that the microbial contamination of pork depends not only on the initial contamination at the production site but also on the quality class of the meat. On the 12th day of pork storage, only NOR-class meat samples of industrial origin remained fresh. Comparing meat samples of the same quality classes, asserting a shorter shelf life and a higher risk of meat products obtained due to domestic origin and backyard slaughter of pigs is possible. The main reason is a combination of factors, the main of which are the impossibility of observing proper hygienic conditions for animal slaughter, poor bleeding, unbalanced diet, and others.

Heat/Cold Stress and Methods to Mitigate Its Detrimental Impact on Pork and Poultry Meat: A Review.

This paper aims to provide an updated review and current understanding of the impact of extreme temperatures-focusing on heat stress (HS)-on the quality of pork and poultry meat, particularly amidst an unprecedented global rise in environmental temperatures. Acute or chronic HS can lead to the development of pale, soft, and exudative (PSE) meat during short transportation or of dark, firm, and dry (DFD) meat associated with long transportation and seasonal changes in pork and poultry meat. While HS is more likely to result in PSE meat, cold stress (CS) is more commonly linked to the development of DFD meat. Methods aimed at mitigating the effects of HS include showering (water sprinkling/misting) during transport, as well as control and adequate ventilation rates in the truck, which not only improve animal welfare but also reduce mortality and the incidence of PSE meat. To mitigate CS, bedding on trailers and closing the tracks' curtains (insulation) are viable strategies. Ongoing efforts to minimize meat quality deterioration due to HS or CS must prioritize the welfare of the livestock and focus on the scaleup of laboratory testing to commercial applications.

Morphological and biochemical parameters of blood and quality of meat obtained from pigs with different stress resistance

The results of the experiments were used to evaluate the morphological and protein composition of blood, as well as the quality of meat from pigs of different stress resistance. The studies were carried out under the conditions of PJSC ‘Stepovyi’ in Zaporizhzhia Region on Large White (LW) pigs and Large White/Charcoal Landrace (LWCL) crossbreeds. During the study period, the hygienic conditions of keeping, feeding and watering of the animals, their growth and development, clinical condition and morbidity were evaluated. After reaching a live weight of 100 kg, the pork meat quality (pH, moisture content, oxyproline, tryptophan) of slaughtered animals was studied. It was found that the LW genotypes were superior to the local LWCL by the number of leukocytes in passively resistant (PR) animals — by 2.7%, in stress resistant (SR) animals — by 3.15%, and in stress sensitive (SS) animals they were inferior by this indicator by 7.7%. There was no significant difference in erythrocyte content between SR and SS, but erythrocyte content was 8.53% lower in PR. The concentration of hemoglobin was higher in PR animals of the Large White cross. The latter were superior to LW in terms of total protein: PR — by 2.26%, SR — by 1.9%, in terms of albumin — PR had an advantage of 16.6%, SR — by 7.69% (p &lt; 0.05). Gamma globulin content was 6.44% lower in SS animals. They were superior to LW in terms of live weight: PR — by 14% at one month of age; by 4.2% at four months of age, SR — by 6.2%, but the difference between SR and SS was not significant. PR animals of the Large White breed were superior in terms of hemoglobin content. The level of total protein in blood serum was higher in crossbred genotypes: in PR — by 2.26%, in SR — by 1.9%. The concentration of albumin was higher in the crossbred animals than in the LW: PR — by 16.6%, SR — by 7.69%, and the level of gamma globulins was 6.51% lower in the SS. In terms of live weight, crossbred genotypes outperformed LW: passive resistant genotypes — by 14% at one month of age, stress resistant genotypes — by 6.2% and 4.2% at four months of age. The crossbred genotypes reached 100 kg live weight: PR — at 180 days, SR — at 183 days, SS — at 191 days, which is 4, 5, and 12 days earlier than LW, respectively. In crossbred pigs, the positive correlation for thoracic girth was 0.6942 and 0.8310, and for withers height — 0.6643 and 0.6811. In terms of body length, animals of the crossbred genotype were superior to LW: PR by 4.2%, SR by 1.46%, while the difference in chest girth and body length in SS individuals was not significant. Lung weight was 0.84% higher in PR and 3.7% higher in SR, and kidney weight was 9.8% higher in PR, 6.56% higher in SR, and 1.37% lower in SS. LW animals were superior in heart weight. Behavioral responses (fighting, skirmishing) were more pronounced in the crossed genotypes, especially in SR and SS animals. A higher level of tryptophan was found in the meat of SR crossbred animals, oxyproline — in PR and SR, pH of meat — in Large White PR and SR ranged from 5.61 to 5.72 units, in crossbred animals this indicator did not exceed the values of 5.03–5.21 units. Defects in meat with PSE (pale, soft, exudative) signs of LW were found: in PR — 0.4%, SR — 0.63%, SS — 3.7%, and in LWCL respectively — 2.3%, SR — 2.1%, SS — 4.21%, in local — defects in meat with DFD (dark, firm, dry) signs were manifested in 3.1%, 2.15%, and 5.1%

Effect of loading density and weather conditions on animal welfare and meat quality of slaughter pigs.

There are several factors that affect the welfare and meat quality of pigs during pre-slaughter transport. Among various factors, the effects of weather conditions and loading density were studied. A total of 3,726 finishing pigs were allotted to one of nine groups arranged in a 3 × 3 factorial design according to the weather conditions (low temperature [LT], under 10°C; normal temperature [NT], 10°C-24°C; high temperature [HT], upper 24°C), and loading density (low density [LD], upper 0.43 m2/100 kg; normal density [ND], 0.37-0.43 m2/100 kg; high density [HD], under 0.37 m2/100 kg). Each treatment group follow as: LTLD, LTND, LTHD, NTLD, NTND, NTHD, HTLD, HTND, HTHD. In terms of carcass composition, pigs had the highest carcass weight and backfat thickness at LT. Comparing the HD transport to the ND transport, the meat quality indicated a lower pH and more drip loss. The incidence rate of pale, soft, exudative (PSE) pork was high in the order of the HD, LD, and the ND transport (20%, 9%, and 2%, respectively). The HT transport showed the lowest pH and greatest L* value under the given weather conditions. Pigs transported under the HTHD and LTLD conditions had the greatest rates of PSE pork (40% and 20%, respectively). Pigs exposed to HD transport had the shortest laying time and the highest overplap behavior. The LDLT transport pigs had a shorter laying time than the LDNT and LDHT transport pigs. In conclusion, too high or too low density transport is generally not excellent for meat quality or animal welfare, however it is preferable to transport at a slightly low density at high temperature and at a slightly high density at low temperature.

PSV-1 Pasture Does Not Impact Pork Quality of Finishing Hogs

Abstract Sales of certified organic pork continue to increase, and an increasing number of young farmers are looking to rear hogs with organic or other niche labeling claims that require outdoor access. There is limited research available to support pastured pork operations in developing best management practices for rearing pigs in outdoor environments. The goal of this study was to evaluate the impact of housing on swine performance and pork quality and to build best management strategies for raising hogs on pasture. Pigs (n = 50) from the same sire and farrowing cohort were obtained from 10 separate litters. Pigs were grouped into separate treatments according to average body weights (BW) with equal sex rations among both groups: Indoor (n = 25), and Outdoor (n = 25), with 5 hogs per pen within each treatment. The Indoor groups were housed on 7m2 of solid concrete flooring in a ventilation-controlled barn; the Outdoor groups were housed on native grass pasture with pen size being 23m2, and a third shaded with 40% shade cloth. Outdoor pens were rotated to new grass every 14 days to manage soil destruction, while Indoor pigs remained in original pens for the duration of the project. Water access was provided via a nipple drinker system and fed a standard grow-finish ration ad libitum for both groups. All pigs were slaughtered at 26 weeks of age, with the Indoor group averaging BW of 126kg, and the Outdoor group averaging BW of 111kg (P &amp;lt; 0.05). Hot carcass weights were also larger (P &amp;lt; 0.001) of the Indoor group. All pork quality measurements were taken at the 10th rib. Color and marbling scores were not shown to vary between the treatment groups (P ≥ 0.17). Colorimeter values (L*, A*, B*) were similar across treatments as well (P ≥ 0.41). However, loin eye area exhibited a trend with the Outdoor group having a smaller average size (P = 0.07) In addition to this, pH values were also shown to vary at 0h (P = 0.03), 6h (P = 0.01), and 24h (P &amp;lt; 0.01) postmortem, with the Indoor group having the higher ultimate pH. Based on these data, pasture reduced final market size and loin eye area of hogs, but not overall pork quality. Although pH was reduced for the Outdoor group, no values showed a rapid decline in pH that would indicate a PSE pork product. Further, average pH between treatments were within 0.2 at all sampling times. Further research is needed to evaluate efficacy of best management practices to improve efficiency of pig growth rate on pasture and to ensure that pork quality will not be reduced.

On the question of the amino acid composition of pork with quality defects

The article presents the results of determining the amino acid composition of pork with quality defects, such as PSE, DFD, RSE, RFN and PFN. Meat is one of the traditional sources of high-grade protein, the nutritional and biological value of which depends on the ratio of essential and non-essential amino acids that make up these proteins. The nutritional value and amino acid composition of meat proteins are influenced by various factors, such as the type of animal and breed, gender and age, feeding, storage conditions and others. As part of the implementation of the Food Security Doctrine of the Russian Federation, much attention is paid to improving the quality and rational use of meat and other slaughter products, including those with quality defects such as PSE and DFD. In addition to defects PSE (pale, soft, exudative) and DFD (dark, hard, dry) for pork, there are three more categories: PFN — pale, hard, non-exudative (pH 5.58); RSE — red, soft, exudative (pH 5.67); RFN — red, hard, nonexudative (pH 5.71). The purpose of the research was to evaluate the amino acid composition of pork with quality defects. The research was carried out in the conditions of the educational and research center for the examination of food and animal feed of the St. Petersburg State University of Veterinary Medicine in the period 2021-2022. The materials for the study were 66 samples of pork of various quality categories (11 samples of each category). For the tests, point samples were taken from different muscle groups, then a combined sample was made and sample preparation was carried out according to the M method-04-94-2021 "Determination of amino acids in food products". The amino acid composition of the studied samples was determined according to the M method-04-94-2021 "Determination of amino acids in food products" on the device "Kapel-105M" (GC "LUMEX"), with an autosampler and an automatically switched polarity. As a result of the conducted research, it was found that the content of interchangeable and essential amino acids in pork of different quality categories depended on the type of amino acids and the quality category of pork. It should be noted that information about the amino acid composition of pork with quality defects should be taken into account in the production of meat products at processing plants.

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.

Quality improvement and comprehensive utilization of abnormal broiler breast meat: A review

During the past few decades, there has been a notable increase in the demand for poultry meat due to its low cost and good nutritional profile. Rapid growth of chicken breast has become a primary screening criterion in modern broiler industry. However, the rapid growth causes many abnormal meat quality problems. Wooden breast (WB), PSE (pale, soft, exudative)-like broiler meat, and white-striping (WS) meat are the representative features reflecting serious chicken myopathy. The high incidence of these myopathies leads to a range of questions, increasing concerns of producers and retailers. There are many studies involved in the formation mechanism and detection grading of abnormal broiler meat, but there are few reports on the use of abnormal broiler. Several abnormal broiler types and the improvement strategies are reviewed through enhancing its processing properties or alleviating its degenerated functionalities. The improving approaches, include adding non-meat ingredients, marination, vacuum tumbling, high-pressure processing, high-intensity ultrasound, pulsed electric field, pH-shifting and low-speed shearing, glycosylation, isoelectric solubilization/precipitation, blade tenderization, and using them as ingredients in further-processed products. The combined use of various physical and chemical technologies provides the possibility for improvement in utilization of abnormal broiler meat in the future.

Influência de fatores do pré-abate de suínos sobre o pH e temperatura inicial: estudo de caso

ABSTRACT: This study evaluated factors associated with the pre-slaughter handling of pigs in a commercial slaughterhouse located in Minas Gerais and evaluated the influence of these factors on the initial pH and temperature of the carcasses. In all, 4449 carcasses were evaluated. The factors evaluated were transport distance, transport duration, loading density, fasting duration, resting duration, average weight of the animals, average temperature in the resting area, and maximum temperature in the resting area. The effects of these factors on the initial (i.e., at 45 minutes after slaughter) temperature and pH (pH45) were measured. The pH45 values were used to determine the occurrence of PSE; the carcasses were classified as PSE when they presented a pH45 &lt; 5.90. Results showed that animals fasted for more than 24 hours were more likely to result in PSE meat (1.41 times more likely), as did animals that were exposed to an average temperature above 24 °C (1.52 times more likely). Except for the average weight of the animals, which did not affect the initial temperature values, all other pre-slaughter factors have influenced both pH45 and the initial temperature values, and the difference of fasting duration and the temperature in the resting area increase the incidence of PSE 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

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

Changes in Gel Characteristics, Rheological Properties, and Water Migration of PSE Meat Myofibrillar Proteins with Different Amounts of Sodium Bicarbonate.

The changes in the gel and rheological properties and water-holding capacity of PSE meat myofibrillar proteins with different amounts of sodium bicarbonate (SC, 0−0.6/100 g) were studied. Compared to the PSE meat myofibrillar proteins with 0/100 g SC, the texture properties and cooking yield significantly increased (p < 0.05) with increasing SC; meanwhile, adding SC caused the gel color to darken. All samples had similar curves with three phases, and the storage modulus (G’) values significantly increased with the increasing SC. The thermal stability of the PSE meat myofibrillar proteins was enhanced, and the G’ value at 80 °C increased with the increasing SC. Because water was bound more tightly to the protein matrix, the initial relaxation times of T21 and T22 shortened, the peak ratio of P21 significantly increased (p < 0.05), and the P22 significantly decreased (p < 0.05), which implied that the mobility of the water was reduced. Overall, SC could improve the thermal stability of the PSE meat myofibrillar proteins and increase the water-holding capacity and textural properties of the cooked PSE meat myofibrillar protein gels.

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).

Transcriptome-based analysis of early post-mortem formation of pale, soft, and exudative (PSE) pork

Pale, soft, and exudative (PSE) meat can cause consumer dissatisfaction and economic losses. This study determined meat quality, glycolytic enzyme activity, and differential gene expression in the longissimus lumborum (LL) and semimembranosus (SM) of normal and PSE pork carcasses. The SM did not result in PSE meat. Hexokinase, lactate dehydrogenase, and pyruvate kinase activities were lower in the SM of PSE carcasses than in the normal carcasses. Functional enrichment analysis revealed that immune, inflammatory, and muscle fibre genes were significantly enriched in PSE pork. More specifically, PPP1R3G and MSS51 may be key genes regulating pork quality in the SM. Meanwhile, the differential expression of PLVAB, ADIPOQ, LEP, MYH4, MYH7, MYL3, MYL6B, FOS, ATF3, and HSPA6 may induce PSE formation in the LL. These results may provide insights into PSE pork formation mechanisms and reveal candidate genes for improving meat quality after validation.

Prevalence of gross lesions and handling practices in pigs and their association with pork quality, Kiambu, Kenya.

Pre-slaughter handling of pigs has been documented to affect the quality of meat though no studies have investigated this relationship in the Kenyan context. This study aimed to determine the prevalence of gross lesions and practices related to sub-optimal welfare in pigs presented for slaughter while analyzing the relationship between occurrence of these lesions and meat quality. A cross-sectional study was conducted at a medium scale, non-integrated pig abattoir supplying to the Nairobi market, with a capacity to slaughter approximately 40 pigs a day. Data on welfare-associated lesions and handling practices were obtained from 529 pig carcasses and traders respectively. 387 pork samples were collected, and their quality evaluated by measuring their pH, meat color and drip loss. These three parameters were used to classify pork into four recognized categories namely: Red, Firm, Non-exudative (RFN), Pale Soft Exudative (PSE), Dark Firm Dry (DFD) and Red Soft Exudative (RSE). Almost all pigs were inefficiently stunned as evidenced by the presence of consciousness post-stunning. The majority of pigs (82.97%) having one or more welfare-associated gross lesions. Other animal welfare malpractices observed were high loading density and inadequate rest periods between transport and slaughter. A quarter of the pork samples were of sub-optimal quality including: RSE (11.36%), PSE (2.58%) and DFD (2.58%). Multinomial logistic regression revealed that pork originating from pigs transported at a high loading density had increased odds of being classified as DFD (OR 13.41, 95% CI 2.59–69.46). The findings indicate the need to educate stakeholders in the pork value chains on improved pig handling before and during slaughter to enhance pig welfare pre-slaughter and pork quality post-slaughter. Animal welfare legislation enforcement and implementation was observed to be insufficient. There is a need to educate key stakeholders on its importance of being put into practice both from economic and welfare perspectives.

Reactive oxygen species-mediated oxidative stress accelerates glycolysis via activation of the CaMKKβ/AMPK pathway in the yak longissimus dorsi postmortem.

Adenosine monophosphate-activated protein kinase (AMPK) is instrumental in the initiation of early postmortem glycolysis and the advent of pale, soft, and exudative (PSE) meat when cellular energy is altered. However, conflicting studies show that AMPK activation without corresponding energy level changes in PSE meat challenges this long-held notion. Here, we examined the effects of reactive oxygen species (ROS)-mediated oxidative stress on AMPK activation in the context of glycolysis, protein solubility, and water-holding capacity (WHC) in the postmortem yak longissimus dorsi (LD) muscle. Further, we explored the mechanisms underlying these effects. Hydrogen peroxide (H2 O2 ) significantly augmented the degree of oxidative stress, increasing the production of ROS and malondialdehyde excessive production and reducing the activity of the anti-oxidants superoxide dismutase and glutathione peroxidase. In turn, oxidative stress dramatically promoted AMPK activation and glycolysis by increasing glycogen depletion and promoting hexokinase and phosphofructokinase activity. Subsequently, lactic acid accumulation increased, leading to a rapid decline in pH, which aggravated protein solubility degree and centrifugal loss in the early postmortem yak LD muscle. Importantly, these changes caused by oxidative stress were eliminated by the AMPK inhibitor. Mechanistically, oxidative stress elevated calcium ion (Ca2+ ) levels, which mobilized calcium/calmodulin-dependent protein kinase β (CaMKKβ) and AMPK. Rescue experiments confirmed that the increases were attenuated using Ca2+ and CaMKKβ chelators, respectively. These results indicated that oxidative stress caused by ROS hastened early-stage postmortem glycolysis and reduced the WHC of yak meat. These effects were likely mediated by the alternative and energy-independent CaMKKβ/AMPK signaling pathway. © 2022 Society of Chemical Industry.

Study on antemortem stress and seasonal influence to mitigate the incidence of disaggregated fillets in the fish slaughtering industry

The present study aimed to characterize the disaggregated fillets and determine the optimal quality parameters used in the pre-slaughter management of Nile tilapia in the processing industries. The study was carried out in three stages: the first characterized the disaggregated fillet, the second determined the influence of season on the incidence of disaggregated fillets, and the third developed a desirability function to reduce the incidence of disaggregated fillets in the fish slaughter industry. It is believed that the disaggregated fillets are similar to PSE meat, and the influence of the season on their incidence was found in this study; that is, the summer influences the pallor of the tilapia fillet (summer: standard L* = 53.17 ± 0.43 and pH 6.22 ± 0.03; disaggregated L* = 57.54 ± 0.65 and pH = 6.14 ± 0.03 - winter: standard L* = 41.53 ± 0.48 and pH 6.31 ± 0.02; disaggregated L* = 49.07 ± 0.61 and pH = 6.01 ± 0.04), as well as chicken and pork meats, whose values are determined by the L* color parameter and the pH, inversely proportional greatnesses. The incidence of disaggregated fillets is closely related to the management that precedes slaughter, so a desirability function was created to determine optimal values for quality standards of operations immediately before the slaughter of the animal. Novelty impact statement Characterizing Nile tilapia fillets as meats PSE according to the summer and winter seasons. Standardized pH and L* parameter values as determinants for PSE meats in Nile tilapia. Antemortem stress and temperatures influenced the determination of the disaggregated fillets.

Influence of preslaughter stress on poultry meat

In the present article the authors consider the importance of issue of the poultry meat quality. The increasing demand for poultry meat provides for the rapid growth of industrial stock of poultry, which contributes to appearance of meat with various defects in muscle tissue: PSE meat, that features low pH, pale color, soft and watery texture, and DFD meat — it is more dense and drier, of dark saturated color. Till now, the causes and mechanisms of appearance of those anomalies still haven’t been unambiguously formulated, however, a large number of publications prove the influence of the genetic characteristics of modern crosses of broilers and turkeys on disturbances in Ca2+ metabolism process in the sarcoplasm of muscle fibers. The uncontrolled release of calcium along with the high temperature of slaughtered poultry carcasses immediately after slaughter provokes an intense decrease in pH and launches denaturation processes in proteins. The numerous studies have shown deterioration in functional and technological properties of meat in stress-sensitive poultry, such as moisture-binding capacity and high acidity, which increases loss of meat juice during its storage and its weight during heat treatment. Recent publications have been devoted to development of a strategy for use of PSE poultry meat and search for efficient processing of PSE poultry meat, since the scientific community does not provide direct evidence on possibility of genetic adjustment of the poultry in order to exclude the occurrence of PSE quality of meat.

Oxidative changes in cooled and cooked pale, soft, exudative (PSE) chicken meat

The mechanisms involved in the development of oxidative changes in pale, soft, exudative (PSE) chicken meat during storage in the dark at 4 °C for 5 days and after cooking at 80 °C for 30 min, light exposure and reheating were explored in this study. The results indicate that myoglobin, lipid and protein oxidation occurred concomitantly during both treatments in PSE chicken meat during storage, and each process seemed to promote the others. Transition metals and metmyoglobin played pivotal roles in the generation of free radicals that triggered lipid and protein oxidation in cooled and cooked PSE, respectively. In contrast, light played a secondary role as an oxidative inducer of these processes. Different pathways triggered the production of compounds from the interactions between oxidative reactions in cooled and cooked PSE chicken meat. The impact of these reactions on the functionality of PSE chicken meat requires further study.