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ABSTRACT: The objective of the present study was to characterize possible variations in the quality of wooden chicken breast meat during freezing for 12 mo, in order to prove whether the shelf life recommended by the industry allows the storage of that type of meat without compromising its consumption. Three hundred samples of male Cobb 500 broilers slaughtered at 42 d of age were used. Part of the samples (n = 20 normal—control group; n = 20 moderate degree; n = 20 severe degree) were analyzed on the day of collection (beginning), previously kept under refrigeration (4°C). The other samples were stored (−18°C) for up to 12 mo. At the end of each proposed freezing period (3, 6, 9, and 12 mo), physical and chemical analyses were performed (per period: n = 20 normal—control group; n = 20 moderate degree; n = 20 severe degree). Color (L*, a*, and b*), pH, water-holding capacity, cooking losses, tenderness, lipid oxidation, chemical composition, cholesterol concentration, mineral profile, and collagen concentration were evaluated. The physicochemical quality of wooden chicken breast meat is significantly altered during frozen storage for 12 mo, being of inferior quality when compared to normal chicken breast meat, which can negatively affect consumer acceptance. However, it should be noted that even after 12 mo of freezing, the meats did not show oxidative rancidity.

ABSTRACT: In recent times, meat quality has become a key aspect of poultry production. In the current study, 2,400 sex separate broilers from 4 commercial strains were placed in 6 replications to evaluate various meat quality characteristics when grown to 2 market weights. Broilers were fed 1 of 2 diets with varying degrees of amino acid inclusion to evaluate meat quality of broiler raised on varying planes of nutrition. Birds were processed to meet 2 specified target weights (2.5 and 3.8 kg) representing small bird and big bird debone markets in the United States, respectively. Birds were processed using commercial methods, deboned at 3-h postmortem, and meat quality was assessed. Myopathies (woody breast, white striping, spaghetti meat, along with tenderloin quality), fillet dimensions, color, water-holding capacity (e.g., drip loss, cook loss), and Meullenet Owens Razor Shear was determined. Data were analyzed using the Mixed Model platform of JMP Pro 15.2 (SAS Institute, Cary, NC). Diet had no effect (P > 0.05) on the key quality responses; data were then pooled resulting in main effects of sex, strain, and target weight (noted as carcass size). On the day of processing, high yielding (HY) strains produced higher breast and tender yields (P < 0.05) when compared to standard yielding (SY) strains. In addition, and as expected, females exhibited higher breast and tender yields (P < 0.05) than males. However, males had significantly thicker (P < 0.05) and longer (P < 0.05) fillets, higher incidences (P < 0.05) of white striping, and higher (P < 0.05) cook loss when compared to females. Differences were also observed in tenderness as SY strain A produced the lowest shear values, whereas SY strain B produced the highest shear values across parameters (P < 0.05). SY strains in the small bird (SB) market performed better than SY strains in the big bird (BB) market as indicated by lower incidences of breast and tender myopathies white striping, woody breast, spaghetti meat, woody-like tender, and tender feathering and improved quality attributes (P < 0.05). Similar trends were observed (P < 0.05) in HY strains as SB carcasses produced a better overall product than BB. Differences in carcass size directly impacted quality (P < 0.05) as SB markets showed improvements in most parameters assessed, but broilers representing BB markets had greater breast yield. Although strain had minimal impacts on quality measures, carcass size, and sex had a greater impact on muscle myopathies, water-holding capacity, and shear properties.

ABSTRACT: The main objective of this study was to explore the effects of dietary selenium yeast and jujube powder on mitochondrial oxidative damage and cell apoptosis of broilers during postmortem aging, chicken breasts of broilers fed diets supplemented with different concentrations of selenium yeast and jujube powder were used as research subjects. With the prolongation of postmortem aging time, the levels of reactive oxygen species (ROS), carbonyl content, mitochondrial permeability transition pore (MPTP) openness, and mitochondrial membrane permeability increased significantly (P < 0.05). The contents of the sulfhydryl, mitochondrial membrane potential, shear force, and cytochrome C (Cyt-c) reduction level decreased significantly (P < 0.05). The activity of Caspase-3 and Caspase-9 increased from 0 to 24 h postmortem but fell from 24 to 72 h postmortem. Compared with the control group, dietary selenium yeast and jujube powder significantly reduced mitochondrial oxidative damage. They greatly increased the shear force, mitochondrial membrane potential, and Cyt-c reduction levels (P < 0.05). Among them, the combination group of high-dose selenium yeast and jujube powder had more significant effects on ROS scavenging, reducing cell membrane permeability, protecting cell membrane integrity, and increasing Cyt-c reduction level (P < 0.05). In conclusion, cell apoptosis intensifies during the chicken breast's aging time, and muscle tenderness continues. Still, different doses of dietary selenium yeast and jujube powder can inhibit mitochondrial oxidation to various degrees. The combined group of selenium yeast and jujube powder with 0.6 mg·kg−1 has the best effect. This study is of great significance for applying natural antioxidant ingredients such as selenium yeast and jujube powder in the development and utilization of poultry feed.

The objective of the present study was to characterize possible variations in the quality of wooden chicken breast meat during freezing for 12 mo, in order to prove whether the shelf life recommended by the industry allows the storage of that type of meat without compromising its consumption. Three hundred samples of male Cobb 500 broilers slaughtered at 42 d of age were used. Part of the samples (n = 20 normal—control group; n = 20 moderate degree; n = 20 severe degree) were analyzed on the day of collection (beginning), previously kept under refrigeration (4°C). The other samples were stored (−18°C) for up to 12 mo. At the end of each proposed freezing period (3, 6, 9, and 12 mo), physical and chemical analyses were performed (per period: n = 20 normal—control group; n = 20 moderate degree; n = 20 severe degree). Color (L*, a*, and b*), pH, water-holding capacity, cooking losses, tenderness, lipid oxidation, chemical composition, cholesterol concentration, mineral profile, and collagen concentration were evaluated. The physicochemical quality of wooden chicken breast meat is significantly altered during frozen storage for 12 mo, being of inferior quality when compared to normal chicken breast meat, which can negatively affect consumer acceptance. However, it should be noted that even after 12 mo of freezing, the meats did not show oxidative rancidity. [ABSTRACT FROM AUTHOR]

In recent times, meat quality has become a key aspect of poultry production. In the current study, 2,400 sex separate broilers from 4 commercial strains were placed in 6 replications to evaluate various meat quality characteristics when grown to 2 market weights. Broilers were fed 1 of 2 diets with varying degrees of amino acid inclusion to evaluate meat quality of broiler raised on varying planes of nutrition. Birds were processed to meet 2 specified target weights (2.5 and 3.8 kg) representing small bird and big bird debone markets in the United States, respectively. Birds were processed using commercial methods, deboned at 3-h postmortem, and meat quality was assessed. Myopathies (woody breast, white striping, spaghetti meat, along with tenderloin quality), fillet dimensions, color, water-holding capacity (e.g., drip loss, cook loss), and Meullenet Owens Razor Shear was determined. Data were analyzed using the Mixed Model platform of JMP Pro 15.2 (SAS Institute, Cary, NC). Diet had no effect (P > 0.05) on the key quality responses; data were then pooled resulting in main effects of sex, strain, and target weight (noted as carcass size). On the day of processing, high yielding (HY) strains produced higher breast and tender yields (P < 0.05) when compared to standard yielding (SY) strains. In addition, and as expected, females exhibited higher breast and tender yields (P < 0.05) than males. However, males had significantly thicker (P < 0.05) and longer (P < 0.05) fillets, higher incidences (P < 0.05) of white striping, and higher (P < 0.05) cook loss when compared to females. Differences were also observed in tenderness as SY strain A produced the lowest shear values, whereas SY strain B produced the highest shear values across parameters (P < 0.05). SY strains in the small bird (SB) market performed better than SY strains in the big bird (BB) market as indicated by lower incidences of breast and tender myopathies white striping, woody breast, spaghetti meat, woody-like tender, and tender feathering and improved quality attributes (P < 0.05). Similar trends were observed (P < 0.05) in HY strains as SB carcasses produced a better overall product than BB. Differences in carcass size directly impacted quality (P < 0.05) as SB markets showed improvements in most parameters assessed, but broilers representing BB markets had greater breast yield. Although strain had minimal impacts on quality measures, carcass size, and sex had a greater impact on muscle myopathies, water-holding capacity, and shear properties. [ABSTRACT FROM AUTHOR]

Marination is an effective method that can be used to improve the tenderness of early deboned breast fillets. The present study was designed to evaluate the effect of pre- and post-marination aging of 2 h postmortem (PM) deboned chicken fillets to get optimum meat quality. In this study, a total of 300 broilers (43 to 46 d of age) were processed using an in-line system and deboned at 2 h PM. Fillets were marinated, at either 2.5, 4, 6, 8 or 24 h PM, using vacuum tumbling (20 min) with a 15% marinade (final concentration of 0.5% salt and 0.45% phosphate). A non-marinated control (CON) was included. The left (HOLD) fillets were aged (held at 4°C for 24 h) prior to freezing post-marination while the right (NO HOLD) fillets were frozen immediately after marination to simulate various commercial practices. Marination pickup (MPU), total marinade retained after thawing (TMR), total purge loss after thawing (TPL), cook loss (CL), and Meullenet-Owens Razor Shear energy (MORSE) values were measured. Both in HOLD and NO HOLD fillets, there was an increase (P < 0.05) in MPU and TMR as the time of marination increased from 2.5 to 24 h PM. Furthermore, the HOLD fillets had a higher (P < 0.05) TPL when compared to the NO HOLD group. There was a higher (P < 0.05) CL for the CON fillets when compared to all marinated fillets suggesting that marination resulted in better water holding capacity. However, both in HOLD and NO HOLD groups, the MORSE values for the marinated fillets decreased (P < 0.05) from 4 h PM onwards, with 8 and 24 h PM having lower (P < 0.05) values than all other treatments. The results of this study suggest that pre-marination aging (aging after deboning prior to marination) of early (2 h PM) deboned fillets to 8 h PM can provide better tumble marination pickup and retention as well as tenderness (or lower shear values). [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of fast pH decline during the early postmortem period on calpain activity and the degradation of cytoskeletal proteins in broilers. Eighty broilers were randomly categorized into two groups: physical restraint (PR) and free struggle (FS). M. pectoralis major (PM) was used for determination of calpain activity, shear value, ultrastructure of myofibrils, and the degradation of desmin, titin, nebulin, and troponin-T. The pH (6.05) of FS group is significantly low than PR group (6.38) at 0.3 h postmortem. Fast pH decline during the early postmortem period led to a decrease of Ψ/m-calpain activities at 0.3 and 3 h postmortem (P < 0.05), but did not affect the ultimate Ψ/m-calpain activity. An initial fast decrease in pH increased the degradation of desmin, titin, nebulin, and increased the 30 kDa degradation fragments of troponin-T. Therefore, the fast pH decline during the early postmortem period decreased the Ψ/m-calpain activity and increased the degradation of cytoskeletal proteins in broiler muscle. It is possible that the fast pH decline experienced an earlier activation of calpains that resulted in earlier protein degradation and ultimately lower shear force. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of skin on the textural properties of semi-dried jerky produced with different acid treatments. Jerky was prepared with no skin (control) or with 1, 3, or 5% chicken skin. After hand mixing (for 3 min) and tumbling (for 30 min) to distribute the curing ingredients, the cured meats were dried for 180 min at 55°C, for 180 min at 65°C, and finally for 60 min at 75°C. The presence of skin was shown to result in a higher fat content, TBA value, and metmyoglobin due to the high fat content of the skin. In contrast, acid treatment decreased the TBA value and metmyoglobin in jerky relative to samples that were not subjected to acid treatment. The presence of skin also improved the moisture contents, processing yields, and mechanical tenderness. [ABSTRACT FROM AUTHOR]

The relationship between meat tenderness and the protein composition of muscle exudates collected from broiler breast fillets deboned at different postmortem times was investigated. A total of 85 broilers were processed and breast fillets from each carcass were deboned at either 2 h (early-deboned, EB) or 24 h (control) postmortem. One fillet per carcass was used for 1 d postmortem meat tenderness measurements and the other fillet was stored at 4?C until 6 d postmortem for the collection of exudate prior to tenderness evaluation. Protein content and composition of muscle exudates were determined by a biuret assay and SDSPAGE. Fillet pH, color, drip loss, and cook loss were also measured. Early-deboned fillets exhibited greater (P < 0.05) Warner-Bratzler shear force (WBSF) than controls at 1 d (7.4 vs. 3.1 kg) and 6 d (4.1 vs. 2.5 kg). Deboning time did not influence pH or color values (L*a*b*). Control fillets exhibited less drip loss after 6 d of storage (P = 0.005) and less cook loss at 1 and 6 d (P < 0.001). Exudate protein concentration was not influenced by deboning time. From the SDS-PAGE profiles of the exudates, the relative abundances of seventeen protein bands were quantified. Electrophoresis analysis revealed that, in general, the protein profiles of exudates from control and EB fillets were not distinct from each other. However, the band corresponding to 225 kDa was more abundant in controls (P = 0.021). Although the protein concentrations and SDS-PAGE profiles of muscle exudates varied widely between breast fillets, variations in exudate protein characteristics were not strongly associated with changes in the tenderness of broiler breast meat due to the combined effects of postmortem deboning time and post-deboning aging. [ABSTRACT FROM AUTHOR]

The main objective of this study was to explore the effects of dietary selenium yeast and jujube powder on mitochondrial oxidative damage and cell apoptosis of broilers during postmortem aging, chicken breasts of broilers fed diets supplemented with different concentrations of selenium yeast and jujube powder were used as research subjects. With the prolongation of postmortem aging time, the levels of reactive oxygen species (ROS), carbonyl content, mitochondrial permeability transition pore (MPTP) openness, and mitochondrial membrane permeability increased significantly (P < 0.05). The contents of the sulfhydryl, mitochondrial membrane potential, shear force, and cytochrome C (Cyt-c) reduction level decreased significantly (P < 0.05). The activity of Caspase-3 and Caspase-9 increased from 0 to 24 h postmortem but fell from 24 to 72 h postmortem. Compared with the control group, dietary selenium yeast and jujube powder significantly reduced mitochondrial oxidative damage. They greatly increased the shear force, mitochondrial membrane potential, and Cyt-c reduction levels (P < 0.05). Among them, the combination group of high-dose selenium yeast and jujube powder had more significant effects on ROS scavenging, reducing cell membrane permeability, protecting cell membrane integrity, and increasing Cyt-c reduction level (P < 0.05). In conclusion, cell apoptosis intensifies during the chicken breast's aging time, and muscle tenderness continues. Still, different doses of dietary selenium yeast and jujube powder can inhibit mitochondrial oxidation to various degrees. The combined group of selenium yeast and jujube powder with 0.6 mg·kg−1 has the best effect. This study is of great significance for applying natural antioxidant ingredients such as selenium yeast and jujube powder in the development and utilization of poultry feed. [ABSTRACT FROM AUTHOR]

In this study, 20 broilers were used to examine the effect of high-voltage electrical stimulation (HVES) on meat quality and the microstructure of the pectoralis muscle. After slaughter, carcasses were randomly distributed into 2 treatment groups (n = 10). In the first group, carcasses were electrically stimulated (500 V, 100 Hz) for 60 s. Carcasses in the second group (nonelectrical stimulation) were used as a control. Meat quality was evaluated by the rate of pH, water-holding capacity, cooking loss, color (L*, a*, b*), shear force, and sarcomere length. As a result, HVES increased the rate of muscle pH decline (P < 0.001). High-voltage electrical stimulation had no effect on water-holding capacity and cooking loss values. Only L* (lightness) values were improved during the storage time (P < 0.01). Tenderness (P < 0.001) and sarcomere length (P < 0.05) values were significantly increased at 2 and 5 d postmortem. In addition, microstructure examination demonstrated that the stimulated muscles had longer sarcomeres; however, the A-, I-, and Z-bands and the mitochondrial membrane structure were intact in HVES and nonelectricaily stimulated carcasses. The resuits showed that HVES is a useful method for improving the tenderness of broiler breast meat. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the role of myofiber characteristics and the thickness of 2 major muscle membranes, perimysium and endomysium, in determining the breast meat tenderness of chickens. Birds from 2 breeds (White Leghorn and a line of broiler) were chosen. Chicks were sexed and wing-banded at hatch and were grown in separate cages in a single house. Sixty broilers and 60 White Leghorns were harvested at 6 wk of age, respectively, whereas another 60 White Leghorns were slaughtered at 18 wk of age. An equal number of males and females was maintained for each group. Body weight, breast muscle weight, pH, drip loss, cooking loss, WarnerBratzler shear force value (SFV), total energy of shear force, fiber diameter, sarcomere length, myofiber density, and the thickness of endomysium and perimysium of the breast were determined for each bird. At 6 wk of age, histological examination indicated that the size of myofiber and thickness of endomysium and perimysium of broilers were larger than that those of White Leghorns (P < 0.01), whereas the SFV, drip loss, and cooking loss of broilers were smaller (P < 0.01). A comparison between the White Leghorns at 18 wk and the broilers at 6 wk, which were at similar BW but different ages, showed that the breast muscle weight of broilers was larger (P < 0.01) than that of White Leghorns. For breast muscle, the endomysium of broilers at 6 wk was thicker than that of White Leghorns at 18 wk (P < 0.01), whereas the perirnysium was thinner (P < 0.01). The SFV, drip loss, and the cooking loss of broilers were smaller than those of White Leghorns at similar BW (P < 0.01). Meat tenderness was negatively correlated with myofiber density (-0.27) and the thickness of endomysium (-0.29) and positively correlated with the thickness of perimysium (0.20). It is suggested that muscle membrane should be considered in evaluating meat tenderness of the chicken. [ABSTRACT FROM AUTHOR]

Prerigor deboning and marination of broiler breast fillets are growing trends in the poultry industry. Marination can often enhance product attributes such as flavor, juiciness, and texture. The purpose of this study was to evaluate consumer acceptance of marinated broiler breast fillets deboned pre- (<4 h postmortem) and postrigor (⩾4 h postmortem). A total of 400 broiler carcasses were processed using an inline system and dehoned at various times: 0.25, 1.25, 2, 2.5, 3, 3.5, 4, 6, arid 24 h postmortem. A 2-stage chilling system was used for all treatments with the exception of the 0.25 h treatment, which was deboned before chilling. After chilling, carcasses or fillets, or both, were aged on ice. Breast fillets were marinated with a 1% salt and 0.45% phosphate final concentration. Consumer sensory evaluations for moistness, tenderness, saltiness, flavor, and overall impression were obtained on all treatments using hedonic and just-about-right (JAR) scales. Although there were slight differences in hedonic ratings for overall impression, texture, and flavor of marinated breast fillets, all treatments could be categorized as "like slightly" to "like moderately." Using a JAR scale, only a small percentage of consumers (<18%) considered any of the treatments as "too tough." The scores for overall flavor or moistness were not affected by the deboning times because the majority of the people considered them to be JAR. Most the consumers reported the potential for purchase of the product as "probably would buy" to "may or may not buy." The results of this study indicate that marination of prerigor deboned meat (with 1% salt) is effective in producing product similar to marinated postrigor deboned meat, suggesting its effectiveness in improving meat quality attributes of early deboned meat. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the influence of aging on the levels of bioactive amines, microbial flora, physico-chemical characteristics, and tenderness of broiler breast. Forty-five 1-d-old Cobb broilers were aged at temperatures from 1.0 to 5.7°C for 8 h. Nonaged broiler breast contained spermine, spermidine, and low levels of putrescine. There was prevalence of aerobic mesophiles followed by Pseudomonas. Mean pH, nonprotein N, weight loss after roasting, and shear force were 5.92, 0.46 g of N/100 g, 19.4%, and 5.57 kg, respectively. During aging, there was a significant increase in Pseudomonas and on the levels of amines. Two different amines were detected tyramine and histamine. Aging resulted in a significant increase in tenderness without affecting pH, nonprotein N, and weight loss after roasting. There was significant correlation between aging temperature and total bioactive amine levels. Aging above 4.9°C induced the formation of histamine; therefore, aging should be performed at temperatures ⩽4.9°C to prevent the formation of this amine, which has been associated with human health hazards. During storage of aged broiler breast at -18 ± 1°C for 89 d, there was no significant difference on pH, nonprotein N, and weight loss after roasting; however, there was a significant decrease on spermine, spermidine, putrescine, and tyramine levels. On the 89th day of storage, histamine was detected, and the shear force was significantly lower when compared with the samples immediately after aging. Therefore, the storage time of aged breast should not exceed 64 d to prevent histamine formation and to avoid excessive softening of the meat. Histamine in aged broiler breast could be used as an index of aging temperatures above 4.9°C and also of frozen storage for more than 64 d. [ABSTRACT FROM AUTHOR]

The potential application of a new laser air puff system to assess poultry meat tenderness was investigated. Ninety broilers were deboned at either 1.25, 4, or 24 h postmortem. The raw breast fillets were scanned on a conveyor belt longitudinally by a laser distance sensor to obtain overall shape profiles and scanned again with a pressurized source of air (206.8 kPa). The 2 resulting profiles were superimposed to quantify the amount of deformation caused by the application of pressurized air. Five parameters including a height and length of each fillet were calculated and used to establish a model to predict tenderness. Tenderness of cooked fillets was determined instrumentally with the Meullenet-Owens razor shear, Blunt-Meullenet-Owens razor shear, and with sensory analysis. Hardness, Meullenet-Owens razor shear energy, and Blunt-Meullenet-Owens razor shear energy were modeled with the parameters extracted from the air puff system. Predicted values obtained from the models and observed values of individual fillets were subjected to logistic regression to classify fillets into tenderness levels. Tender fillets in the air puff predicted tender group represented 82, 81, and 88% based on hardness, Meullenet-Owens razor shear energy, and Blunt-Meullenet-Owens razor shear energy, respectively. The use of this tool resulted in more than a 20% improvement in the number of tender fillets after classification. The results suggested that this new system could potentially be implemented as an online tool for sorting poultry breast fillets by tenderness levels. [ABSTRACT FROM AUTHOR]

Marinated broiler breast fillets were evaluated using both air- and immersion-chilling treatments. Ninety fillets from air-chilled broiler carcasses and 90 fillets from immersion-chilled broiler carcasses were obtained from a processor to determine differences in meat quality, sensory, and shelf life. At 24 h postmortem, the fillets were vacuum-tumbled (25 in Hg, 30 min, 14 rpm, 4°C) in 2 replications per treatment with a 20% solution (wt/wt) yielding 0.70% NaCl and 0.45% sodium tripoly-phosphate in the final product. One-third of the fillets in each replication were packaged in a tray covered with plastic wrap and stored in retail cases to simulate retail shelf-life conditions. The remaining fillets were stored at 4°C for 24 h until analysis for marinade retention, cook loss, consumer evaluation, and objective tenderness. The immersion-chilled fillets had a significantly lower pH (5.56) and were lighter (L* 54.73) when compared with the air-chilled fillets (5.64, L* 50.13, respectively). The air-chilled fillets had a significantly higher marinade pick-up (15.51%) than the immersion-chilled (14.07%) fillets. However, there were no significant differences in cook loss percentage in either treatment (approximately 20.03). Shear value was significantly higher in the immersion-chilled fillets (4.14 N), indicating less tender meat than the air-chilled fillets (3.62 N). In the consumer analyses, the air-chilled fillets were significantly different. Of the respondents that noted differences, 19% indicated differences in texture, and 9.67% indicated taste differences. The air-chilled treatment had significantly lower aerobic plate count in postpackaging d 0, 3, and 9. Also, coliforms were significantly lower in the air-chilled treatment through d 6. Therefore, air chilling carcasses may improve color, marination yield, tenderness, and increase the shelf life of retail-packaged broiler breast fillets. [ABSTRACT FROM AUTHOR]

In the United States a large percentage of raw poultry meat is marinated prior to cooking. Many products are marinated by vacuum tumbling meat with a mixture of water, salt, and phosphates to increase cook yield and perceived tenderness. This study was designed to determine the effect of 3 pressure treatments (ambient, vacuum, or positive) and phosphate on yield, tenderness, and color on broiler breast meat. In each of 3 replicate trials, 60 broiler breast fillets were randomly assigned to a tumble marination treatment of 1) ambient tumble pressure (101 kPa); 2) vacuum tumble pressure (50 kPa); or 3) positive tumble pressure (204 kPa). Each pressure treatment was conducted with and without phosphate in the marination solution. Marination tumblers were operated at 15 rpm for 20 mm at a temperature of 3°C. Broiler breast fillets were weighed (raw, immediately after marination, 1 h postmarination, and after cooking), sheared after cooking with a Warner-Bratzler device, and evaluated for color (CIE L∗, a∗, and b∗) before marination and after cooking. Pressure and phosphate treatment combinations did not significantly (P < 0.05) affect marinated or drip weights, Warner-Bratzler shear values, cooked b∗, or percent drip loss. There was no effect of pressure treatment except for marinade uptake, where ambient tumble uptake was 12.7%, which was significantly higher than positive tumble (11.4%); vacuum tumble uptake (12.0%) was not different from either. Phosphate significantly increased cook weight (from 94.9 to 106.1 g) and cook yield (from 76.6 to 86.1%); L∗ and a∗ values were slightly but significantly decreased. Type of pressure during tumble marination had no effect except on marinade uptake, but the effect disappeared with 1 h holding time and cooking. Phosphate improved cook weight and yield. These data show that vacuum pressure during tumbling is not necessary, but phosphate is important to cook yields. [ABSTRACT FROM AUTHOR]

A total of 1,040 birds from 5 common commercial genetic broiler strains were raised and processed to analyze the effect of strain and deboning time on meat quality. The birds were processed at either 6 or 7 wk of age in 4 replications each. Carcasses were deboned at either 2 or 4 h postmortem (PM; n = 52 birds per treatment). Carcass and breast weights were measured on each bird to calculate breast yield. Muscle pH was measured at time of deboning. Fillets deboned at 4 h PM were measured for length, width, and height to evaluate footprint analysis. At 24 h PM, fillets were weighed to calculate drip loss, and color (L*) was also measured. The fillets were then cooked to 76°C, and cook loss was calculated. Fillets were then subjected to shear analysis using the Meullenet-Owens razor shear method where shear energy (N·mm) was calculated to evaluate tenderness. The strains in this study were chosen for differences in yield; therefore, as expected, breast yield was significantly different among strains. Variation in meat quality attributes existed among strains deboned at 2 h PM, but there was no consistent relationship between meat quality and breast yield. However, at 4 h PM, fewer differences among strains existed in meat quality characteristics (tenderness, water holding capacity, and pH). As expected, deboning at 2 h PM resulted in higher shear energy, higher muscle pH, and lower L* value compared with deboning at 4 h PM in all but one strain. However, water-holding capacity was not affected by deboning time at either age interval. Footprint analysis showed that most differences among strains were in heights measured at the fillet midpoint and caudal end. These results suggest that early deboning may affect meat quality of broiler strains differently, resulting in greater variation within the industry. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Broiler carcasses are often trimmed during evisceration to remove damaged areas of the carcass. Because deboning before rigor mortis development can toughen meat, trimming during evisceration may toughen the meat. This study evaluated the effects of trimming on the tenderness of broiler breast meat. To evaluate the effect of wing removal on tenderness, breast halves from 2 flocks were collected after chilling at a commercial plant. One-third were untrimmed controls, one-third had small amounts of breast meat removed with wing (WMin), and one-third had large amounts of breast meat removed with wing (Wmax). Salvage fillets from the 2 flocks were also collected from the salvage table of the plant. Carcasses were also processed to evaluate the effect of breast blister trimming that removed a superficial amount of muscle tissue, half of which had breast blister trims, and half did not. All front halves or carcasses were aged until 24 h post-mortem and deboned. Salvage fillets were held refrigerated until 24 h postmortem. Fillets were cooked and then sheared in 2 locations on the fillet, upper and lower, to determine if tenderness was more affected at areas close to the trim. Carcasses with wing trims had significantly higher shear values compared with the control, and shear values from the upper portion of the fillets from the WMax and WMin (nearer the trim) were significantly greater than for the lower portion. Location, however, did not affect shear values in the control carcasses. This finding indicated that tenderness of the areas nearest the trim might be affected more by the trim process. Salvage table deboning significantly increased shear values throughout the fillet. There was no significant difference in shear value due to breast blister trimming. The results of this study suggest that trimming carcasses by wing or breast fillet removal results in decreased meat tenderness. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of aging prior to deboning and deepfreezing on the tenderness of cooked broiler breast fillets. Broilers (Ross-208) that were 37 and 38 d old were slaughtered in a licensed poultry meat plant. After spray chilling, carcasses with BW between 1,080 and 1,300 g were selected for the study and transported to a chilling room (2 to 4°C). The whole carcasses were aged for up to 24 h. During the aging process, continuous measurements were made of pH values, electric conductivity, and firmness of the raw fillets. After the aging process, the carcasses were deboned, and the breast fillets were immediately frozen to an internal temperature of -20°C. Tenderness was measured both mechanically with a Warner-Bratzler shear force device and by sensory testing. The ultimate pH values in the fillets were reached during the first 5 h of aging. Electric conductivity increased during the whole aging period. During the first hours of aging, firmness increased significantly, corresponding with the onset of rigor mortis. After between 8 and 9 h of aging, firmness decreased significantly. Shear force values of aged fillets also changed significantly; the highest values were found at the beginning of aging, which then decreased from the sixth hour. The results of the instrumental tenderness measurements were confirmed by the sensory evaluations. Implementation of in-plant measurements of firmness, thus, seemed to be useful in predicting the sensory quality of poultry meat. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study on meat quality and protein alterations of fast glycolyzing (FG) and normal glycolyzing (NG) turkey breast muscles. In a commercial processing plant, 34 breast muscles were sampled at 20 mm postmortem from a large flock: 17 samples showing the lowest PH20min (6.04 ± 0.09; FG) and 17 showing average pH20min (6.47 ± 0.01; NG). Over a 9-d storage period at 4°C, L&ast; values did not differ between the 2 groups. The FG group showed higher drip, thawing, and cook loss values, and lower processing yield than the NG group. Warner­Bratzler shear force values of cooked meat were higher in the FG group than in the NG group. The FG meat presented a lower protein extractability with low ionic strength buffer than the NG meat. No differences in SDS-PAGE banding patterns were detectable for the different protein extracts between the 2 groups. On the contrary, when SDS-PAGE gels were performed on basic proteins, they showed differences in banding intensity for 2 proteins: glyceraldehyde-3-phosphate dehydrogenase and aldolase A. [ABSTRACT FROM AUTHOR]

In each of 2 trials, 75 female and 75 male broilers of different sizes (large and small) were obtained from a commercial grower and were commercially processed. Breast fillets were deboned at 0.25, 1.5, 3, 6, and 24 h postmortem (total n = 15 per treatment per time point). Muscle pH and L&ast; value were determined for each deboning time. Breast fillets were subjected to texture analysis using Allo­Kramer (10-blade), needle puncture (2 mm diameter), or razor blade shear (8.9 mm wide) methods. Allo­Kramer tests were performed on a strip (40 × 20 × 7 mm); needle puncture and razor blade shear were performed on intact muscles. Body size and sex had no effect on rigor development or color as indicated by no significant difference in breast muscle pH, R-value, or L&ast; value. Allo­Kramer and razor blade tests exhibited significant shear value differences among samples deboned early (<1.5 h) and late (>6 h) PM. Allo­Kramer shear and razor blade tests performed similarly for differentiating breast meat of different toughness though Allo­Kramer shear force and razor blade energy were only moderately correlated (r = 0.72). Although both instrumental tests were performed in the same approximate area on each breast, it is possible that variation within the breast would have caused this marginal correlation. Although further studies would be necessary to compare the performance of both tests for assessing poultry meat toughness, the proposed razor blade test has the advantage of requiring no sample preparation (i.e., cutting a strip of constant dimensions) other than cooking. [ABSTRACT FROM AUTHOR]

Presents abstracts of several studies on the nutrition of sheep species. "Effect of Substitution of Alfalfa Hay With Sun Dried Pig Excreta on Performance of Sheep Feed Growing Diets," by A. Estrada-Angulo et al; "Comparative Effect of Tallow and Dark Poultry Fat on Apparent Digestibility of Diets for Sheep," by J. C. Robles and colleagues; "Digestibility of Fermented Bagasse Fed to Suffolk Ewes," by R. Pradhan, E. Shirakabe, T. Nishioka and K. Batajoo.

Presents abstracts of several articles on meat science and muscle biology. "Effect of Feeding Program and Sex on Productive Performance and Carcass Quality of Iberian Crossbred Pigs," by D. G. Valencia, R. Lázaro, M. Nieto and G. G. Mateos; "Early Postmortem pH Influences Proteolysis of Cytoskeletal Proteins During Aging in Porcine Longissimus Muscle," by S. M. Lonergan and E. Huff-Lonergan; "The Use of Creatine as a Means of Improving the Belly/Bacon Quality of Market Barrows Fed 4.5 g/ton Paylean," by C. A. Stahl, M. S. Carlson, T. B. Schmidt, G. Rentfrow, E. K. Burger and E. P. Berg; "Effects of Sedated-Harvest on Channel Catfish Fillet Color, pH, and Drip-Loss," by B. G. Bosworth and D. J. Gregory.

Presents abstracts of several studies on forages and pastures. "Nutritive Quality of Poa Pratensis in Model Grassland Communities Exposed to Ground-Level Ozone," by D. Dodson, J,. Bender, J. Lin and R. Muntifering; "Effect of Increased Cutting Height of Corn Silage on Nutritive Value, Milk Yield and Milk Composition," by D. Domiguez-Diaz and L. D. Satter; "Forage Production and Quality of Triticale Cultivars in the Tennessee Valley," by M. Lema and E. Cebert; "Kura Clover Spreading Ability With Grass Competition," by B. Kim and K. Albrecht.

Presents abstracts of several studies on animal breeding and genetics. "The Impact of Herd Opportunity and Milk Recording Periods in Estimating Lifetime Net Income," by E. Yook, R. E. Pearson and B. G. Cassell; "Joint Genetic Evaluation of Male and Female Fertility Using Longitudinal Binary Responses," by R. Rekaya and T. Averil; "Contribution of Inbreeding and Recessive Defects to Early Embryo Loss," by P. M. VanRaden and R. H. Miller; "Effects of Climate and Photoperiod on Feed Intake of Beef Bulls During Feedlot Performance Tests," by G. T. Tabler Jr., A. H. Brown Jr., Z. B. Johnson, E. E. Gbur Jr., I. L. Berry, D. W. Kellogg and K. C. Thompson.

The feasibility of predicting pH, color, shear force, and sensory characteristics of chicken breasts deboned at 2, 4, 6, and 24 h postmortem by visible/near infrared reflectance spectroscopy (NIRS) in the 400 to 1850 nm region was determined. Prediction of physical attributes of Commission Internationale de l'Eclairage (CIE) color values (L&ast;, a&ast;, and b&ast;), pH, and shear force had better accuracies than those of individual sensory attributes. Calibration and validation statistics for shear force and sensory traits indicated that visible/near infrared models were not significantly improved for cooked muscles compared with predictions based on raw muscle characteristics. On the basis of predicted shear values from the partial least squares (PLS) model, breast samples were classified into “tender” and “tough” classes with a correct classification of 74.0% if the boundary was set at 7.5 kg. The model developed from measured shears using soft independent modeling of class analogy/principal components analysis (SIMCA/PCA) showed nearly the same classification success. [ABSTRACT FROM AUTHOR]