The role of carcass chilling rate in the development of pale, exudative turkey pectoralis

Data-Mining Methodology to Improve the Scientific Production Quality in Turkey Meat and Carcass Characterization Studies

The present research aims to describe how turkey meat and carcass quality traits define the interest of the scientific community through the quality standards of journals in which studies are published. To this end, an analysis of 92 research documents addressing the study of turkey carcass and meat quality over the last 57 years was performed. Meat and carcass quality attributes were dependent variables and included traits related to carcass dressing, muscle fiber, pH, colorimetry, water-holding capacity, texture, and chemical composition. The independent variables comprised publication quality traits, including journal indexation, database, journal impact factor (JIF), quartile, publication area, and JIF percentage. For each dependent variable, a data-mining chi-squared automatic interaction detection (CHAID) decision tree was developed. Carcass or piece yield was the only variable that did not show an impact on the publication quality. Moreover, color and pH measurements taken at 72 h postmortem showed a negative impact on publication interest. On the other hand, variables including water-retaining attributes, colorimetry, pH, chemical composition, and shear force traits stood out among the quality-enhancing variables due to their low inclusion in papers, while high standards improved power.

Effect of chilling methods on the surface color and water retention of yellow-feathered chickens

This study was conducted to investigate the effects of air chilling (AC), water chilling (WC), combined chilling consisting of WC for 20 min and AC (CO₂₀), and combined chilling consisting of WC for 30 min and AC (CO₃₀) on the microbiological status, surface color, processing yield, and moisture content of yellow-feathered chicken carcasses. After chilling, the carcasses treated by AC exhibited the highest total viable counts (TVC) (4.7 cfu/cm²), followed by those treated by CO₂₀ and CO₃₀, whereas the carcasses treated by WC showed the lowest (P < 0.05) mean log TVC (4.2 cfu/cm²). Based on an instrumental color evaluation and photographs of carcass surfaces, the carcasses treated by AC showed a notable yellow color (P < 0.05), whereas no significant difference (P > 0.05) was found among the carcasses treated by CO₂₀, CO₃₀, and WC. The skin samples of carcass parts treated by WC (breast, thighs, drumsticks, back, neck, and wings) exhibited higher moisture contents than the skin samples of the carcasses treated by AC (P < 0.05), providing evidence that weight gain during WC is due to higher water absorption by the skin. The different parts of the broiler carcasses treated by AC had lower cooking losses than those of carcasses treated by combined chilling or WC (P < 0.05), except for the thighs and claws. In breast and drumstick muscles, the moisture contents of the superficial parts from carcasses treated by WC were higher than those of the carcasses treated by AC, whereas the internal parts were not significantly affected by the chilling methods (P > 0.05). The results of this work can be useful for understanding and improving the chilling process for yellow-feathered chickens.

Forced locomotor activity improves walking ability of male turkeys and modifies carcass characteristics

1. This trial investigated the effect of forced locomotor activity (training) on walking ability, leg posture, and growth performance, as well as carcass composition and meat quality in male fattening turkeys.2. A flock of 744 commercial turkeys was divided into three experimental groups, either without any training period (control), training from weeks 2 to 8 (short-term), or training from weeks 2 to 21 (long-term). All birds were slaughtered at an age of 21 weeks. To study the effect of short vs. long time lapse between shackling and stunning (suspension time), each training group was split into two halves that were hooked on the shackle for either 15 s or 3 min prior to stunning.3. Long-term physical training, compared to short-term or no training, resulted in better walking ability and in a lower percentage of leg malposition, as assessed at the end of fattening. No effect on final body weight was detected.4. In a subsample, the composition of 80 carcasses was determined by dissection. Long-term training favoured the percentage of the drumstick over that of the breast cut in comparison to the group without any training.5. Meat quality parameters were determined for breast muscle. The pH values 20 min post-mortem were reduced by long-term training, and the highest value was observed for a combination of no training with short suspension. After 24 h, pH values did not differ between experimental groups. The breast muscles were characterised as fast-glycolysing. Prolonged suspension time resulted in higher electrical conductivity after 24 h, and in higher a* values (redness).6. In conclusion, the study revealed that a long-term training period improved walking ability and leg posture of heavy male turkeys. Thus, training can contribute to the improvement of animal welfare in turkey husbandry. Meat quality variables of breast muscles were partially influenced by locomotor activity and suspension time.

Effect of different short-term high ambient temperature on chicken meat quality and ultra-structure

Objective

This study investigated the effect of different acute heat stress (HS) levels on chicken meat quality and ultra-structure.

Methods

Chickens were randomly divided into 7 groups to receive different HS treatments: i) 36°C for 1 h, ii) 36°C for 2 h, iii) 38°C for 1 h, iv) 38°C for 2 h, v) 40°C for 1 h, vi) 40°C for 2 h, and vii) un-stressed control group (25°C). Blood cortisol level, breasts initial temperature, color, pH, water holding capacity (WHC), protein solubility and ultra-structure were analyzed.

Results

HS temperatures had significant effects on breast meat temperature, lightness (L*), redness (a*), cooking loss and protein solubility (p<0.05). The HS at 36°C increased L*_{24 h} value (p<0.01) and increased the cooking loss (p<0.05), but decreased a*_{24 h} value (p<0.05). However, as the temperature increased to 38°C and 40°C, all the values of L*_{24 h}, cooking loss and protein denaturation level decreased, and the differences disappeared compared to control group (p> 0.05). Only the ultimate pH_{24 h} at 40°C decreased compared to the control group (p<0.01). The pH in 36°C group declined greater than other heat-stressed group in the first hour postmortem, which contributed breast muscle protein degeneration combining with high body temperature, and these variations reflected on poor meat quality parameters. The muscle fiber integrity level in group 40°C was much better than those in 36°C with the denatured position mainly focused on the interval of muscle fibers which probably contributes WHC and light reflection.

Conclusion

HS at higher temperature (above 38°C) before slaughter did not always lead to more pale and lower WHC breast meat. Breast meat quality parameters had a regression trend as HS temperature raised from 36°C. The interval of muscle fibers at 24 h postmortem and greater pH decline rate with high body temperature in early postmortem period could be a reasonable explanation for the variation of meat quality parameters.

The effects of egg albumin incorporation on quality attributes of pale, soft, exudative (PSE-like) turkey rolls

Pale, soft, exudative (PSE-like) poultry phenomenon has been a growing problem in meat industry in terms of quality and economic losses, thus data is required to evaluate PSE raw material in product formulations. The aim of our study was to investigate the effects of egg albumin (EA) utilization on quality characteristics of PSE-like turkey rolls. Turkey Pectoralis major muscles were exposed to either 40 °C to stimulate typical processing causing PSE or 0 °C to reduce PSE and keep the muscles "normal". Turkey rolls were prepared in nine different formulations; using 100% normal (N), 50% normal + 50% PSE (NP) or 100% PSE meat (P). Treatments also included 0, 1 or 2% EA. Addition of EA increased protein content of all samples. L*, a* and b* values were affected by PSE level. Increased levels of PSE caused decreased processing yields, while EA incorporation increased processing yield of the samples. Addition of 1% EA increased water-holding capacity (WHC) of the samples, while higher level of EA (2%) caused decrement in the same. Addition of either 1% or 2% EA was effective in reducing purge loss in P samples. Texture profile analysis showed that EA addition rather had considerable effects on N samples. Sensory scores showed that 1% EA utilization has the potential to increase mostly the mouthfeel of PSE-like products. Results showed that EA could be used as a promising ingredient that improved overall quality of PSE-like turkey rolls.

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

BACKGROUND

Studies 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.

METHOD

A 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.

RESULTS

The 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).

CONCLUSIONS

These results indicated that an economical loss can be expected due to the significantly higher cooking loss observed in roasted breast processed from PSE meat.

Quality Characteristics of PSE-Like Turkey Pectoralis major Muscles Generated by High Post-Mortem Temperature in a Local Turkish Slaughterhouse

The objective of this study was to investigate the effects of high post-mortem temperature application on development of pale, soft, exudative (PSE) turkey meat characteristics in terms of local slaughter conditions. Within this scope, it was targeted to obtain PSE-like muscles benefiting from different post-mortem temperature applications. Immediately after slaughter, turkey Pectoralis major (n=15) muscles were kept at various post-mortem temperatures (0, 10, 20, 30, and 40℃) for 5 h. pH values of 40℃ treatment were lower than four other treatments (p<0.05). L* values, drip loss, cook loss, and thawing loss of 40℃ group were higher than the other groups (p< 0.05). Napole yield of 40℃ treatment indicated that high post-mortem temperature decreases brine uptake. Protein solubility of 40℃ group was lower than 0℃ group (p<0.05). Expressible moisture did not differ between 0 and 40℃ treatments. Hardness, gumminess and chewiness of 40℃ treatment were higher than 0℃ treatment. The results of this research showed that high post-mortem temperature treatment induced development of PSE-like turkey meat, with lower pH, paler color, higher technological and storage losses, and reduced protein solubility and texture.

Effect of different feed supplements on selected quality indicators of chicken meat

The aim of the study was to evaluate the effect of different feed additives (bee pollen extract, propolis extract, and probiotic) on meat quality of broiler chickens. A total of 180 one day-old broiler chicks of mixed sex (Ross 308) were randomly divided into 3 groups. Dietary treatments were as follows: basal diet, free of supplements (control group; C);  basal diet  plus 400 mg bee pollen extract per 1 kg of feed mixtures and 3.3 g probiotic preparation added to drinking water (group E1); basal diet  plus 400 mg propolis extract per 1 kg of feed mixtures and 3.3 g probiotic preparation added to drinking water (group E2). In the experiment, the probiotic preparation based on Lactobacillus fermentum (1.109 CFU.g-1 of bearing medium) was used. Fattening period lasted for 42 days. Feed mixtures were produced without any antibiotic preparations and coccidiostatics. Meat quality was evaluated by following technological properties: cooling, freezing and roasting loss; colour parameters based on CIELab system; and shear force. Both dietary supplementations led to decrease in cooling (p ≤0.05) and freezing (p ≥0.05) losses compared with control. On the contrary, the supplemented diet tended to increase roasting losses (p ≤0.05) and shear force values in thigh muscle (p ≤0.05). Significantly higher L* values (p ≤0.05) in breast and thigh muscles, as well as the b* values in thigh muscle, were found when broiler chickens were fed the supplements, especially bee pollen extract and probiotics. In addition, the supplements improve redness (a*) of meat. The redness of breast muscle appeared to be the most affected (p ≥0.05) by propolis extract plus probiotics supplementation, while thigh muscle had the highest value (p ≤0.05) in bee pollen extract plus probiotics supplemented group. These findings suggested that the supplements have a beneficial effect on quality of chicken meat due to positive changes in most of quality indicators investigated in the study.

Combination of muscle tension and crust-freeze-air-chilling improved efficacy of air chilling and quality of broiler fillets

The objective of this study was to evaluate the effects of water immersion chilling (WIC), air chilling (AC), and crust-freeze-air-chilling (CFAC) on the efficacy of broiler chilling and quality of breast fillets with and without muscle tension (MT), restraining both wings behind the carcass. In each of 3 replications, 66 birds were purchased locally and processed at the Michigan State University meat laboratory. After evisceration, one-half of the birds were subjected to MT and the remaining birds received no MT. Twenty-two birds (11 with and 11 without MT) per chilling were randomly assigned to WIC (ice/water slurry at 0.2°C), AC (air at 1°C/1.5 m/s), or CFAC (air at -12°C/1.5 m/s). After chilling and aging for 3 h postmortem (PM), all breast fillets were deboned, one-half of which were immediately quick-frozen or cooked, whereas the remaining half were further aged on ice for 24 h PM. All left fillets were used for pH, R-value, and sarcomere measurements, whereas all right fillets were used for shear force. During chilling, breast temperature was reduced from 40 to 4°C in an average of 62, 68, and 140 min for WIC, CFAC, and AC, respectively. The birds at 3 h PM had higher pH and shear force than those of birds at 24 h PM except the CFAC with no MT (P < 0.05). Breast fillets with MT showed lower shear force than the fillets without MT at 24 h PM (P < 0.05) in AC and CFAC. Based on these findings, the combination of CFAC and MT appears to improve both air chilling efficacy and breast fillet quality.

Divergent selection for muscle color in broilers

One consumer-related physiological abnormality that is a recent concern for the poultry industry is atypical meat quality. Currently in the processing plant, meat is characterized on appearance such as tears, bruises, discoloration, or missing parts. Unfortunately, this method ignores physical properties such as palatability, texture, tenderness, taste, color, pH, and water-holding capacity (WHC). The growing demand for a convenient, economical, and palatable product has shifted the market toward value-added poultry products. The effect of a meat's physical properties on its marketability and versatility has become apparent to processors attempting to utilize poor quality meat. After 8 generations of divergent selection for muscle color or lightness (L*) in broilers, muscle quality parameters were investigated. The 2 broiler lines divergently selected for high (HMC) and low (LMC) muscle color along with their randombred control line (RBC) were included in the study. Heritability estimates for L* were 0.47 ± 0.05 and 0.51 ± 0.05 in the HMC and LMC lines, respectively. For generation 8, the mean L* for the HMC, RBC, and LMC lines were 53.91, 49.70, and 46.86, respectively. Selection for increased L* was found to result in increased breast fillet yellowness (b*), whereas selection for decreased L* resulted in an increase in breast fillet redness (a*). Selection for increased L* has resulted in increased rate of pH decline over time, whereas selection for decreased L* has resulted in a decreased rate of pH decline. The HMC line exhibited a higher percentage fillet drip loss than both the LMC and RBC lines, which did not differ from each other. Overall selection for L* was effective in modifying breast muscle color as well as correlated responses associated with atypical poultry meat such as drip loss and postmortem muscle pH. These selected lines can serve as resource populations for the study of PSE and DFD-like meat in poultry and demonstrate that L* selection could be applied to primary breeding programs as a way to improve or manage muscle quality in pedigree elite lines.

Cold-batter mincing of hot-boned and crust-freezing air-chilled turkey breast improved meat turnover time and product quality

The purpose of this research was to evaluate the combined effects of turkey hot-boning and cold-batter mincing technology on acceleration of meat turnover and meat quality improvement. For each of 3 replications, 15 turkeys were slaughtered and eviscerated. Three of the eviscerated carcasses were randomly assigned to water-immersion chilling for chill-boning (CB) and the remaining were immediately hot-boned (HB), half of which were used without chilling whereas the remaining were subjected to crust-freezing air chilling (CFAC) in an air-freezing room (1.0 m/s, -12°C) with/without 1/4; sectioning (HB-1/4;CFAC, HB-CFAC). As a result, CB and HB breasts were minced using 1 of 5 treatments: (1) CB and traditional mincing (CB-T), (2) HB and mincing with no chilling (HB-NC), (3) HB and mincing with CO2 (HB-CO2), (4) HB and mincing after CFAC (HB-CFAC), and (5) HB and mincing after quarter sectioning and CFAC (HB-1/4;CFAC). Traditional water-immersion chilling took an average of 5.5 h to reduce the breast temperature to 4°C, whereas HB-CFAC and HB-1/4;CFAC took 1.5 and 1 h, respectively. The breast of HB-CFAC and HB-1/4;CFAC showed significantly higher pH (6.0-6.1), higher fragmentation index (196-198), and lower R-value (1.0-1.1; P < 0.05) than those of the CB controls. No significant differences (P > 0.05) in sarcomere length were seen between CB-T and HB-CFAC filets regardless of quarter sectioning. When muscle was minced, the batter pH (5.9) of CB-T was significantly lower (P < 0.05) than those (6.1-6.3) of HB-NC, HB-CO2, and HB-1/4;CFAC, with the intermediate pH (6.0) seen for the HB-CFAC. When meat batters were cooked, higher cooking yield (90 - 91%; P < 0.05) was found in HB-CFAC, HB-1/4;CFAC, and HB-CO2, followed by HB-NC (90%) and finally CB-T (86%). Stress values (47-51 kPa) of HB-CFAC gels were significantly higher (P < 0.05) than those of CB-T (30 kPa) and HB-NC (36 kPa). A similar trend was found in strain values.

Research developments in pale, soft, and exudative turkey meat in North America

Pale, soft, and exudative (PSE) refers to meat that is pale in color, forms soft gels, and has poor water-holding ability. Most frequently used in reference to pork, this defective meat is being seen with increasing frequency in turkey and broiler processing plants. It has been estimated that this PSE-type meat represents 5 to 40% of meat that is produced in the poultry industry. With the increased production of further-processed products, this PSE problem has become more apparent in the turkey industry. It has been estimated that due to the high incidence, a single turkey processing plant could be losing $2 to 4 million per year, resulting in a loss in excess of $200 million dollars by the turkey industry alone.

The halothane gene, energy metabolism, adenosine monophosphate-activated protein kinase, and glycolysis in postmortem pig longissimus dorsi muscle1

The presence of the halothane gene results in PSE meat. However, the exact mechanisms linking the halothane gene and the incidence of PSE meat remain unclear. We hypothesize that the presence of the halothane gene accelerates energy consumption in postmortem muscle, which activates adenosine monophosphate-activated protein kinase (AMPK), leading to enhanced glycolysis and PSE meat. To test our hypothesis, energy status, AMPK activity, and glycolysis in the postmortem LM of the halothane gene carrier and halothane-negative pigs were compared. The results showed that the presence of the halothane gene accelerated energy depletion in postmortem muscle immediately after exsanguination, leading to rapid and early depletion of ATP, as shown by an increase in the (adenosine monophosphate + inosine monophosphate):ATP ratio in postmortem LM. In addition, an early AMPK activation was observed in LM from halothane carriers. The fructose-2,6-diphosphate concentration in postmortem LM was well correlated with AMPK activation. To be a potent stimulator of phosphofructose kinase, the increase in fructose-2,6-diphosphate is expected to activate phosphofructose kinase, a key enzyme controlling glycolysis, leading to enhanced glycolysis and early accumulation of lactic acid. In summary, this study showed that the presence of the halothane gene induced early energy depletion, which could be a primary reason causing AMPK activation, leading to accelerated glycolysis and an increased incidence of PSE meat. However, AMPK might also be activated by other mechanisms besides energy depletion, which warrants further studies.

Early post-mortem AMP-activated protein kinase (AMPK) activation leads to phosphofructokinase-2 and -1 (PFK-2 and PFK-1) phosphorylation and the development of pale, soft, and exudative (PSE) conditions in porcine longissimus muscle

Pale, soft, and exudative (PSE) meat has been recognized for decades. Fast glycolysis during early post-mortem stage while the muscle temperature is still high is the cause of PSE meat. To elucidate the molecular mechanism underlying this fast glycolysis in muscle to become PSE meat, post-mortem ATP metabolism, fructose-2,6-diphosphate content, and the activities of AMPK, glycogen phosphorylase, and pyruvate kinase were examined in post-mortem muscle. Earlier and faster post-mortem AMPK activation was responsible for the significantly lower pH and higher lactic acid accumulation (p<0.05) seen in PSE muscle, which resulted in the occurrence of PSE meat. In muscle that became PSE meat, AMPK was activated at 0 h post-mortem and reached maximal activation at 0.5 h post-mortem, whereas AMPK reached maximal activation at 1 h post-mortem in the normal pork loin. Higher fructose-2,6-diphosphate content (p<0.05) was detected in PSE muscle compared to normal muscle at early post-mortem stage. However, no difference in the activities of glycogen phosphorylase and pyruvate kinase, rate-controlling enzymes in glycogenolysis and glycolysis, respectively, was detected between PSE and normal pork loins. Because fructose-2,6-diphosphate is a product of phosphofructokinase-2 (PFK-2), these data suggest that AMPK regulates post-mortem glycolysis through its phosphorylation and activation of PFK-2, which then up-regulates the activity of phosphofructokinase-1 (PFK-1), a key rate-controlling enzyme in glycolysis. Early AMPK activation in PSE muscle is associated with early consumption of ATP, because higher AMP and IMP contents and lower ATP content were detected in PSE meat compared to normal meat. Other mechanisms causing early AMPK activation in PSE meat may exist, which warrants further investigation.

Effect of processing on turkey meat quality and proteolysis

Modern processing techniques for turkey involve rapid chilling to slow microbial growth and early deboning of the economically important breast meat. This paper shows that these 2 processes lead to significantly tougher meat with higher cooking losses. The toughening appears to be due to less extensive proteolysis and shortening of the sarcomeres. Calpains I and II and their inhibitor, calpastatin, were quantified in turkey breast. Calpain II was the more common isoform but showed no evidence of activation during aging. In contrast, calpain I and calpastatin activities declined rapidly and were no longer detected 24 h postslaughter. There was no evidence of an association between calpain activity and processing conditions.

Turkey Carcass Chilling and Protein Denaturation in the Development of Pale, Soft, and Exudative Meat

Pale, soft, and exudative (PSE) meat is a growing problem in the turkey industry and has been associated with processing conditions such as slow carcass chilling. The development of PSE meat is caused by protein denaturation resulting from a rapid rate of pH decline early postmortem (PM) while carcass temperatures are still elevated. This research was conducted to determine the relationship of slow chilling to protein denaturation and PSE development. A total of 48 toms were conventionally processed in 2 trials at 22.5 wk of age, and chilled at 0, 10, 20, or 30 degrees C for either 45 or 90 min before deboning (at 60 or 105 min PM). Temperature and pH of the breast muscle was recorded at 15 min PM, at the time of deboning (60 or 90 min PM), and at 24 h PM. Color was determined at deboning and again at 24 h PM. Gel strength, cook loss, expressible moisture, total protein solubility, and bound phosphorylase quantities were determined on the fillets at 24 h PM. There was no difference in carcass temperature at 15 min PM, but by 105 min PM each temperature treatment was significantly different, with the carcasses chilled at 0 and 10 degrees C having the lowest temperature, the 30 degrees C-chilled birds having the highest temperature, and the 20 degrees C-chilled carcasses being intermediate but significantly different from either extreme. The carcass temperature differences at 105 min PM indicated that the carcass experienced differing chilling rates. To varying degrees, slower rates of chilling resulted in lower pH, greater degree of lightness (L* value), greater cook loss, and reduced gel strength. However, chilling rate had no effect on total protein solubility or myofibrillar phosphorylase for any of the treatments. Chilling rate seems to contribute to PSE turkey meat characteristics but by a mechanism independent of total protein solubility or myofibrillar phosphorylase.