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The relationship between woody breast (WB) and white striping (WS) myopathies were investigated in breast fillets collected from commercial slaughter facilities that process large broilers. For the population of samples collected in this study, 94.2% of all WB fillets also exhibited WS. Of the fillets that did not exhibit WB, 54.0% exhibited WS. Of the fillets that exhibited severe WB, 27.9% had severe WS, 50.9% had moderate WS, and 21.2% had mild or no WS. Approximately 82.8% of all WS fillets also exhibited WB. Of the fillets that did not exhibit WS, 26.0% exhibited WB. Among fillets that exhibited severe WS, 40.7% had severe WB, 46.0% had moderate WB, and 13.3% had mild or no WB. The strength of the relationship between WS and WB scores decreased as average fillet weight increased. In addition to overall WB and WS scores, a subset of fillets was also evaluated for specific attributes of muscle hardness, rigidity, out-bulging shape, and the occurrence of petechial hemorrhages on the skin-side surface of the fillets. Muscle hardness, rigidity, and out-bulging shape were highly correlated to WB scores but their relationships with WS were much weaker. There was a statistically positive, but relatively weak, correlation between the occurrence of petechial hemorrhages and the WB and WS myopathies. With regards to developing WB sorting criteria and methodologies, tactile traits have a greater potential for accurately indicating the presence and severity of the WB myopathy in broiler breast meat than visually-assessed traits such as WS. [ABSTRACT FROM AUTHOR]

The wooden breast (WB) condition in broiler breast meat negatively influences technological meat quality. However, it is unknown if the WB effects are uniform throughout the Pectoralis major. The objective of this study was to determine the effects of WB on the marination and cooking performance of the dorsal and ventral portions of broiler breast fillets. Sixty butterfly breast fillets were collected from the deboning line of a commercial plant and sorted into normal (no WB) and severe WB categories. Each fillet was horizontally portioned into dorsal and ventral halves. Portions from one side of each butterfly were used as non-marinated controls, while portions from the other side were vacuum-tumble marinated (16 rpm, −0.6 atm, 4°C, 20 min) with 20% (wt/wt) marinade to meat ratio. Marinade was formulated to target a final concentration of 0.75% salt and 0.45% sodium tripolyphosphate in the final product. Samples were cooked to 78°C in a combination oven. Marinade uptake and retention were lower (P < 0.001) in both the ventral and dorsal portions of the WB fillets. The dorsal portions had greater (P < 0.001) marinade uptake and retention than the ventral portions in both normal and WB fillets. For non-marinated samples, cook loss was greater (P < 0.05) in both the ventral and dorsal portions of WB fillets. In marinated samples, however, cook loss was similar between the dorsal portions of normal and WB fillets. Final cooked product yield was calculated based on pre-marination and post-cook weights. Non-marinated WB samples exhibited lower (P < 0.001) cooked product yields than normal samples in both portions. For marinated samples, cooked product yields were greater (P < 0.001) in the dorsal portions. Data demonstrated that the dorsal portion of the Pectoralis major more readily absorbs and retains marinade during vacuum tumbling and storage than the ventral portion. Although the WB condition negatively influenced marination and cooking performance in both fillet portions, the effects were less severe in the dorsal portion. [ABSTRACT FROM AUTHOR]

The wooden breast (WB) myopathy influences muscle composition and texture characteristics in broiler breast meat. It is unknown if marination reduces the negative influence of WB on meat sensory quality or if WB effects are uniform throughout the Pectoralis major. The objective of this study was to determine the effects of marination on the sensory attributes and instrumental shear force measurements of the ventral (skin-side) and dorsal (bone-side) portions of normal and severe WB meat. Sixty butterfly fillets (30 normal and 30 severe WB) were selected from the deboning line of a commercial processing plant. Individual fillets were portioned into ventral and dorsal halves. Portions from one side of each butterfly were used as non-marinated controls, and portions from the other side were vacuum-tumble marinated (16 rpm, −0.6 atm, 4°C, 20 min) with 20% (wt/wt) marinade to meat ratio. Marinade was formulated to target a concentration of 0.75% (w/v) salt and 0.45% (w/v) sodium tripolyphosphate in the final product. Descriptive sensory analysis (9 trained panelists) was conducted to evaluate visual, texture, and flavor attributes (0–15 point scale) of breast portions along with Warner-Bratzler shear force. Significant interaction effects between WB and marination were not observed for the sensory attributes. Greater springiness, cohesiveness, hardness, fibrousness, and chewiness scores were observed in WB samples (P < 0.001). Marination decreased cohesiveness, hardness, and chewiness (P < 0.05) and increased juiciness (P = 0.002). The effects of WB on sensory texture attributes were more apparent in the ventral portions of the breast fillets. Flavor attributes (salty and brothy) increased (P < 0.001) with marination. In non-marinated samples, shear force was similar between normal and WB samples. In marinated samples, however, shear force was greater (P < 0.001) in WB samples. Data suggest that the WB effect on meat sensory quality is not uniform throughout the Pectoralis major and that WB-related differences in cooked meat sensory texture attributes are lessened but not eliminated by vacuum-tumbling marination. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of the wooden breast (WB) condition on the texture of cooked broiler breast fillets (Pectoralis major) after fresh and frozen storage. Texture characteristics of normal (NORM) and severe WB fillets were studied by both sensory descriptive analyses and Warner-Bratzler shear force. Broiler breast fillets were collected over 3 separate trial days from a commercial deboning line at 3 h postmortem, classified according to the wooden breast condition, and then stored at either 4°C or –20°C prior to cooking and texture evaluation. Fillets were cooked to an endpoint temperature of 76°C and then evaluated by an 8-member trained sensory panel for springiness, cohesiveness, hardness, juiciness, cohesiveness of mass, bolus size, wetness of mass, fibrous texture, rate of breakdown, and chewiness. The fillets with the WB condition showed higher cook loss than those with NORM condition regardless of storage temperature. The mean value of shear force of WB fillets was lower than NORM fillets when cooked after 4°C storage. Sensory evaluation showed that WB fillets were higher in springiness and cohesiveness than NORM fillets and that the sensory attributes springiness, hardness and fibrousness were perceived differently between ventral and dorsal sections of cooked WB fillets. This work indicates that human perception of cooked WB meat has texture irregularities. The cooked breast meat with the WB condition is perceived with more springiness and cohesiveness than that with no WB condition. [ABSTRACT FROM AUTHOR]

Broilers in the United States are typically electrically stunned using low voltage-high frequency (12-38 V, ≥400 Hz) DC or AC water bath stunners. In the European Union, however, broilers are required to be electrocuted using high voltagelow frequency (50-150 V, 50-350 Hz) AC. Low voltage stunned broilers regain consciousness in the absence of bleeding. In contrast, high voltage stunned broilers die due to induction of cardiac fibrillation. For birds stunned with low voltage systems, concerns have been raised regarding animal welfare during bleeding. This work evaluated the impact of extended DC stunning duration and alternative stunning methods (DC+AC combination) on the recovery of bird consciousness and meat quality. In the absence of bleeding, broilers that were DC stunned for extended times (60, 90, or 120 s), 63, 10, or 0% of broilers, respectively, were able to recover consciousness. Alternative stunning protocols included water bath stunning broilers at 15 or 25 V DC for 10 s followed by plate stunning at 100, 110, or 120 V AC for 5 s. Prior to shackling, live body weight and shank width were measured and during stunning, maximum mA for both DC and AC stuns were recorded. All of the alternative stunning protocols (DC+AC) resulted in non-recoverable stunning. The maximum mA recorded during both DC and AC stunning were moderately/strongly (r = 0.54-0.81) correlated to body weight and poorly/moderately (r = 0.27-0.74) correlated to shank width. No significant differences for carcass or meat quality characteristics (hemorrhages, red wing tips, broken clavicles, pH, cook loss, a* and b* color values, and MORS shear energy) were detected between control (15 or 25 V DC only) and treatment groups (DC+AC combination stunning). The only significant different meat quality parameter was L* values where the lowest voltage group (15 V DC) had the darkest fillets (53.27) and the 15 V DC+100 V AC group had the lightest fillets (55.61) with all other groups intermediate. These data indicate that stunning parameters combining DC and AC stunning may be viable protocols when a stun-to-death is desired. [ABSTRACT FROM AUTHOR]

The white striping (WS) condition in broiler meat results in increased intramuscular fat, connective tissue, and moisture loss during cooking and negatively affects product appearance and consumer acceptance of skinless chicken meat. The effect of WS on the human perception of cooked meat texture is unknown. The objective of this study was to evaluate the effects of WS on sensory texture attributes of cooked chicken breast fillets (Pectoralis major). Over three separate trial days, a total of 105 breast butterfly fillets were collected from the deboning line of a commercial broiler processing plant. Fillets were classified according to the degree of WS (normal, moderate, severe) and stored at -20±C until use. Fourteen representative fillets from each category were cooked directly from the frozen state to an endpoint temperature of 78±C and evaluated by a 7-member trained panel for five texture attributes: cohesiveness, hardness, juiciness, rate of breakdown, and chewiness. There were no differences (P > 0.05) for juiciness or the rate of breakdown between the fillets based on the degree of WS. Among the three WS groups, however, differences (P < 0.05) in cohesiveness, hardness, and chewiness were observed. For these attributes, the mean intensity scores of fillets with severe WS were consistently highest among the groups. There were no differences (P > 0.05) between the normal and moderate WS fillets. These data suggest that the severe WS condition was perceived to be harder, more cohesive, and chewier than either normal or moderate WS fillets by panelists. [ABSTRACT FROM AUTHOR]

Three experiments were conducted to evaluate the effects of postmortem deboning time on cook yield of boneless skinless chicken thighs. In experi-ment 1, chicken thigh meat was deboned at 0.75 (hot-bone), 2, and 24 h postmortem (PM) and trimmed to obtain mainly iliotibialis muscle. Samples were cooked directly from a frozen state. Cook yield of the muscle was significantly influenced by PM deboning time. Hot-boned thighs exhibited a 7% greater cook yield than the samples deboned at 24 li. In experiment 2, boneless skinless chicken thighs were deboned at 0.3, 2, and 24 h PM and cooked directly from a fresh, never-frozen state at 24 h PM. Cook yield of the hot-boned thighs was significantly higher than those of the 2 and 24 h deboned samples, which did not differ from each other. In experiment 3, whole legs (thigh + drumstick) were cut from the carcass backbone at 0.3 (hot-cut), 2, and 24 h PM. Thighs were separated from the legs (drum-sticks) at either the same time the whole legs were re-moved from the carcasses or at 24 h PM. Intact thighs (bone in) were cooked fresh at 24 h PM. Color of fresh thigh muscles, cook yield, and Warner-Bratzler shear force of cooked samples were measured. Cook yield of the thighs cut from the backbone before chilling was significantly higher than those cut from the carcasses at 2 and 24 h PM, which did not differ from each other. The PM time at which intact thighs were separated from the leg (drumstick) did not influence cook yield. These results demonstrate that postmortem deboning time can significantly affect cook yield of boneless skin-less chicken thigh products. Deboning chicken thighs after chilling reduces the cook yield. Differences in the cook yield of thighs may also result from the removal of whole chicken legs from the carcass backbone. [ABSTRACT FROM AUTHOR]

The objective of this study was to deter-mine the relationship between meat quality and the protein content and composition of muscle exudate from broiler breast fillets. Deboned breast fillets (n = 48) were obtained from a commercial processing facility and segregated into 2 groups based on color (light and dark). Meat pH, color, moisture content, 3 measures of water-holding capacity (drip loss, salt-induced water uptake, cook loss), protein solubility, and the protein content of muscle exudates were determined in breast fillets. The protein composition of the muscle exudate was evaluated using SDS-PAGE analysis. Light breast fillets had lower meat pH (4 and 24 h postmortem) and higher L* (lightness) and b* (yellowness) values than dark fillets. Light breast fillets exhibited greater drip loss after 2 and 7 d of storage, lower salt-induced wa-ter uptake, and higher cook loss than dark fillets. Nei-ther sarcoplasmic nor total protein solubility differed between light and dark fillets. Protein concentration of muscle exudates was greater in dark fillets and was negatively correlated to drip loss after 2 d of storage (r = -0.50) and salt-induced water uptake (r = 0.42). Electrophoretic protein banding patterns were similar between muscle exudates and sarcoplasmic protein ex-tracts. Gel electrophoresis data from muscle exudates showed that the relative abundance of 4 bands cor-responding to 225, 165, 90, and 71 kDa was higher in dark breast fillets. The relative abundance of 3 bands corresponding to 47, 43, and 39 kDa was higher in light breast fillets. Muscle pH and measurements of water-holding capacity were significantly correlated to the abundance of several individual protein bands within the protein profile of muscle exudates. Data from this study showed that protein differences in breast muscle exudates are related to meat pH, color, and water-hold-ing capacity and suggest that muscle exudate could be a potential source of protein markers for fresh meat quality attributes in broiler fillets. [ABSTRACT FROM AUTHOR]

The effects of hydrodynamic pressure processing (HDP) on marination and meat quality characteristics of turkey breasts were investigated. Breast muscles from 45 turkey hens were removed from the carcasses within 30 mm postmortem. From each bird, the breast from one side was treated with HDP and the other side served as a nontreated control. Breasts were then marinated in either 15 or 30% brine (water, salt, and phosphate) based on muscle weight with vacuum tumbling for 30 mm or nonmarinated. The control and HDP-treated breasts from each bird received the same marination treatment. Brine uptake, processing yield, and cooking loss were measured as processing characteristics and texture, color, and expressible moisture were measured to document changes in meat quality. Hydrodynamic pressure processing increased (P < 0.001) brine uptake after 10 and 30 mm of marination and increased (P < 0.001) processing yield compared with controls. The HDP-induced improvements in these processing characteristics were augmented at 30% brine levels compared with 15% brine. Cooking loss was lower (P < 0.001) in marinated breasts compared with nonmarinated samples. Hydrodynamic pressure processing decreased (P < 0.0001) Warner-Bratzler shear force and significantly influenced texture profile parameters, resulting in reduced hardness but increased cohesiveness and springiness compared with controls at both marination levels. Hydrodynamic pressure processing did not influence color (L*, a, and b*) or expressible moisture values compared with controls at either mannation level. Marinated samples (15 and 30% brine levels) had lower (P < 0.001) Warner-Bratzler shear force values and lower (P < 0.05) hardness, cohesiveness, and chewiness values compared with nonmarinated samples. Data from this study suggest that HDP enhances brine absorption, increases processing yield, and improves texture characteristics in marinated turkey breasts. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the influence of hydrodynamic pressure processing (HDP) and aging on the overall quality and protein characteristics of pork loins. Boneless pork loins (n = 12) were split into anterior and posterior halves and were assigned to control and HDP treatments. Following treatment on day 0, each half was divided into two portions (0 and 7 days aging). Samples were removed for the determination of Warner–Bratzler shear force (WBSF), centrifugal moisture loss (CML), gravitational drip loss (DL), color, protein solubility and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of whole muscle protein extracts. WBSF decreased with HDP (P < 0.05) and aging treatments (P < 0.0001). CML decreased (P < 0.0001) with aging. Controls exhibited slightly less DL after 1 day than HDP samples, but the increase in DL between 1 and 7 days was similar for control and HDP samples. Treatment effects on L *, a * and b * measurements were minimal. Myofibrillar and total protein solubility were higher (P < 0.01) in HDP samples compared with controls at day 0 but not at day 7. Sarcoplasmic protein solubility decreased (P < 0.05) with aging. SDS-PAGE analysis of muscle proteins demonstrated a strong aging effect and only minor HDP differences. With aging, bands corresponding to 30–33 and 135 kDa increased (P < 0.0001), while bands corresponding to 38 and 95 kDa decreased (P < 0.05) in intensity (relative to the actin band). The 60 kDa band intensity increased (P < 0.05) with both aging and HDP treatments. Thus, data from this study suggest that HDP enhances aging tenderization in pork loins through the physical disruption of the muscle ultrastructure while having little detrimental effect on other parameters of pork quality. PRACTICAL APPLICATIONS This study demonstrates that hydrodynamic pressure processing is an effective postharvest technology for enhancing aging tenderization in pork loins through the physical disruption of the muscle ultrastructure with minimal impacts on other pork quality parameters such as water-holding capacity and color. [ABSTRACT FROM AUTHOR]

Muscle shortening and postmortem proteolysis both influence beef tenderness, but their interacting effects on tenderness are relatively unknown. Inherent myofibril structure and the extent of overlap between myosin and actin filaments are hypothesized to affect the availability of substrates for degradation by calpains. The objective of this study was to determine the influence of sarcomere length on the extent of calpain-induced proteolysis of bovine myofibrils in vitro. Bovine semitendinosus muscles were excised within 20 mm postmortem and dissected into strips, which were stretched and attached to applicator sticks or allowed slack to generate samples with different sarcomere lengths upon rigor completion. Samples were allowed to undergo rigor in a neutral pH buffer containing a protease inhibitor. Myofibrils were isolated and incubated at room temperature with excess exogenous μ-calpain at a ratio of 1:800 (wt/wt; enzyme:myofibrillar protein) at pH 6.8 for 0, 2, 60, 1,440, or 2,880 mm. Purified troponin was subjected to the same digestion conditions. Proteolysis of troponin T (TnT) was monitored using SDS-PAGE and Western blotting. Sarcomere length was greater (P < 0.0001) in stretched versus shortened samples (2.99 μm ± 0.03 vs. 2.12 ± 0.03 pm, respectively, means ± SE). Western blots for both stretched and shortened samples exhibited bands corresponding to intact TnT and TnT fragments. The abundance of intact TnT decreased (P < 0.0001) with incubation time across both treatments. At 1,440 and 2,880 min, less (P < 0.05) intact TnT was detected in samples with long sarcomeres. These data indicate proteolysis of TnT occurs to a greater extent in samples with longer sarcomeres, possibly due to easier access of proteases to their targeted substrates. Degradation patterns of TnT were qualitatively similar between myofibrils and purified troponin after incubation with μ-calpain. Therefore, it is unlikely that the mechanism by which proteolysis is limited in short sarcomeres involves an actomyosin-mediated interference of TnT. [ABSTRACT FROM AUTHOR]

The interaction between sarcomere length and postmortem proteolysis as related to meat tenderness is not clear. The extent of thick and thin filament overlap alters actomyosin binding and may alter substrate availability during aging-induced tenderization. The objective of this study was to determine the influence of sarcomere length on proteolytic degradation in beef. Strips from bovine semitendinosus were either stretched 40% and restrained or allowed to shorten unrestrained in an ice bath. After rigor completion, 0.6-cm cross sections were fabricated and were randomly assigned to 2, 4, 7, or 10 d of aging treatments. Myofibrils were isolated for sarcomere length determination. Samples were collected and frozen for shear force analysis, and muscle proteins were extracted for SDS-PAGE and Western blotting analyses to determine troponin T (TnT) proteolysis. Sarcomere length was greater (P < 0.01) in stretched muscle samples compared with shortened samples (2.57 vs. 1.43 μm, respectively). Correspondingly, shear force values were greater (P < 0.05) in shortened samples than stretched samples. Western blots revealed the presence of 3 major intact TnT bands that diminished with time postmortem and 4 bands (TnT degradation products) that accumulated during postmortem storage. Quantification of intact TnT showed increased (P < 0.05) proteolysis at 4 and 7 d postmortem in samples with long sarcomeres. By 10 d, only traces of the greatest molecular weight intact TnT band were evident in both shortened and stretched samples, suggesting this TnT band may be more susceptible to proteolysis than other intact TnT bands. Degradation products of TnT appeared earlier postmortem in samples with long sarcomeres. The 30- kDa TnT fragment appeared after 7 d of postmortem storage in samples with long sarcomeres but not until 10 d in muscle containing short sarcomeres. Collectively, these data show that postmortem TnT proteolysis is sarcomere length-dependent and suggest that thick and thin filament overlap may influence the postmortem aging process in beef. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of hydrodynamic pressure processing (HDP) and aging on the sarcoplasmic proteins of beef strip loins. Loins (n = 12) were halved at 48 h postmortem and assigned to HDP or control treatments. Following treatment, each half was divided into three portions for aging (0, 5 or 8 d). Samples were removed for Warner-Bratzler shear force (WBSF) determination and sarcoplasmic protein isolation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated that aging significantly influenced the composition of the sarcoplasmic protein fraction and that HDP influenced protein bands corresponding to 143, 65, 44, 36 and 19 kDa. Changes in sarcoplasmic protein composition were significantly correlated to WBSF (r = − 0.58 to 0.45). Sarcoplasmic protein solubility decreased with both HDP (P < 0.05) and aging (P < 0.0001). Changes in solubility were significantly correlated to SDS-PAGE band intensities (r = − 0.53 to 0.60). Data suggest that HDP and aging cause changes to sarcoplasmic proteins that may be indicators of proteolysis and tenderization. PRACTICAL APLICATIONS Results from this study demonstrate that postmortem aging and hydrodynamic pressure processing of beef influences the sarcoplasmic protein profile of the muscle. The relationships between these changes and Warner-Bratzler shear force measurements suggest that sarcoplasmic protein changes may be potentially useful as tenderness indicators. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of hydrodynamic pressure (HDP) processing and aging on the tenderness and myofibrillar proteins of beef strip loins. Loins (n = 12) were halved at 48 h postmortem and assigned to HDP or control treatments. Following treatment, each half was divided into three portions for aging (0, 5 or 8 days). Samples were removed for Warner–Bratzler shear force (WBSF) determination and myofibrillar protein isolation. HDP decreased (P < 0.0001) WBSF values 23% at 0, 5 and 8 days of aging. Myofibrillar fragmentation and myofibrillar protein solubility increased (P < 0.01) with HDP and aging. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting analysis of myofibrillar proteins showed that HDP and aging decreased the intensity of the troponin T (TnT) band and enhanced the accumulation of the 30 kD TnT degradation product. These data suggest that HDP is more effective than aging tenderization, and that HDP tenderization is caused by both protein degradation and physical disruption of the myofibril apparatus. PRACTICAL APPLICATIONS Hydrodynamic pressure (HDP) processing was shown to instantaneously tenderize tough cuts of beef to tenderness levels attained following 8 days of postmortem aging. For the meat industry, these results demonstrate the potential benefits of alternative tenderization techniques, such as high-energy shock waves. Observed changes in protein characteristics due to HDP and aging allow researchers to understand better potential mechanisms of meat tenderization. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of blade tenderization (BT), hydrodynamic pressure processing (HDP) and BT followed by HDP (BT + HDP) on collagen solubility and tenderness-related protein characteristics in top rounds from Brahman cattle. Top rounds (n = 12) were divided in half and randomly assigned to HDP, BT or BT + HDP with each treatment sample having a paired control. HDP and BT + HDP increased (P < 0.0001) collagen solubility, but the correlation between percent soluble collagen and tenderness was low (r = – 0.41). All three treatments increased (P < 0.01) fragmentation of myofibrils 35% compared with controls. HDP and BT + HDP treatments increased (P < 0.05) the content of a 100 to 110-kDa protein observed in myofibrillar protein fractions by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Minimal treatment differences were observed in sarcoplasmic proteins using SDS-PAGE. Results suggest BT physically disrupts the muscle structure to improve tenderness while HDP tenderization potentially results from both physical disruption of the muscle structure and some form of direct alterations to muscle proteins. [ABSTRACT FROM AUTHOR]

The ability of sodium polyphosphate (P) to alter postmortem pH declines and pork quality was investigated. Hams from electrically stimulated carcasses were injected 18 min postmortem with P or sodium bicarbonate (SB). P and SB reduced (P < 0.001) pH decline and improved (P < 0.05) color. P and SB administration improved water-holding capacity as indicated by reductions (P < 0.05) in drip loss, thaw loss, and cooking loss values. P and SB also reduced (P < 0.001) shear values. These data showed delivery of P and SB was effective in altering postmortem pH declines and improving the quality of pork. [ABSTRACT FROM AUTHOR]

1. Early post-mortem pH was used to identify PSE-like turkey meat, characterised by a low waterholding capacity and pale colour. In a commercial turkey processing facility, the pH value of turkey breast muscle was measured at 0, 9, 10, 14, 154, 231, and 246 min post mortem. 2. At 14 min post mortem , the carcases were separated into 3 pH classes: low (<5.70), medium (5.70 to 6.18), and high (>6.18). Low pH carcasses (<5.70) had higher drip loss(1.75%) than medium (0.81%) and high pH carcases (0.75%). Furthermore, high pH carcases (>6.18) had a lower L * value (darker) than low and medium pH carcases. 3. The effects of using CO2 'snow' on turkey breast muscle quality were also investigated. Light CO2 'snow' treatment (57 g snow/kg breast) and heavy CO2 treatment (113 g snow/kg breast) resulted in higher drip losses than the control no CO2 snow) group. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at a symposium held from July 15-19, 2012, on in utero factors that affects postnatal muscle growth, carcass composition, and meat quality is presented. Topics include the impact of maternal obesity on muscle fiber type of offspring in mouse, the impact of intrauterine growth restriction in pig production, mechanisms for the differentiation of progenitor cells. The symposium featured several researchers including C. E. McCurdy, N. Oksbjerg, and M. Du.

The objective of this study was to investigate the effects of tapioca flour (TF) on physicochemical properties and sensory qualities of chicken breast meat patties. The effects were also compared with some other commonly used meat binders. Ground chicken breast meat was either mixed with different concentrations of TF (1%, 2%, or 4% w/w) or mixed with 2% TF, potato flour, garbanzo flour, or egg white. Raw meat pH, color and cook loss and cooked meat expressible moisture, shear force, and sensory flavor and texture profiles were evaluated. The addition of TF reduced pH, cook loss, expressible moisture, and shear force and increased L* values (P < 0.05). Compared to the other binders, the patties with TF did not exhibit any differences (P > 0.05) in pH, L*, and b* values; however, they had lower cook loss, expressible moisture, and shear force (P < 0.05). TF did not change the intensity of flavor but reduced meat cohesiveness, hardness, and chewiness (P < 0.05). There were no differences between TF, potato flour, and garbanzo regardless of sensory attributes; however, TF samples were perceived to be significantly less meaty, cohesive, and hard than an egg white sample. These results suggest that the addition of TF to ground chicken breast meat significantly affects raw product appearance and improves water-holding capacity. TF did not impact flavor but improved the texture of cooked meat. The TF effects on meat texture are either better than or comparable to other commonly used meat binder additives. [ABSTRACT FROM AUTHOR]

The objective was to characterize texture properties of raw and cooked broiler fillets (Pectoralis major) with the wooden breast condition (WBC) using the instrumental texture techniques of Meullenet- Owens Razor Shear (MORS) and Texture Profile Analysis (TPA). Deboned (3 h postmortem) broiler fillets were collected from a commercial plant and categorized as normal, moderate, or severe WBC based on the incidence and severity of diffuse hardened areas throughout fillets and the degree of palpable hardness. The fillets were then either stored at 4°C overnight or in a -20°C freezer. The MORS and TPA of the raw samples were determined at 24 h postmortem for fresh samples and after thawing overnight for frozen samples. The same measurements were also taken after the samples were cooked to 78°C. Regardless of freshness (fresh vs. frozen-thawed), cooking (raw vs. cooked), and degree of WBC, both MORS force and energy of the WBC samples were higher than that of the normal samples (P < 0.05). For TPA adhesiveness and resilience, there were no differences between normal and WBC samples (P > 0.05). However, average TPA hardness and chewiness measurements of the fillets with WBC were higher than the normal fillets (P < 0.05). Regardless of texture measurement, there were no interactions between freshness and the wooden condition or no differences between moderate and severe WBC fillets (P > 0.05). These results demonstrate that there are significant differences in instrumental texture properties between normal fillets and those exhibiting the WBC. The WBC fillets required more force to cut through, harder, and chewier than normal breast muscles. These results suggest that cooked WBC meat would likely be tougher than cooked normal meat. [ABSTRACT FROM AUTHOR]

Foodborne campylobacteriosis has been traced to undercooked chicken liver. We have detected Campylobacter in raw chicken livers from retail and processing plant samples. In the current study, we tested a 1 or 5 min 60(C heat treatment, a 48 h 225(C freeze treatment, and a combination of both as a means to pasteurize raw chicken liver lobes. We cultured treated and untreated liver lobes to determine numbers of Campylobacter and total aerobic bacteria. Overall, the 1 min heat treatment was ineffective. The 5 min heat treatment significantly lowered Campylobacter numbers. Freezing was also moderately effective. The combination of both heating and freezing resulted in nearly 99% decrease in Campylobacter numbers but was accompanied by significant lightening of the liver tissue. A mild heat treatment with or without subsequent freezing will not assure elimination of Campylobacter but may lessen consumer risk because of exposure in kitchen and during meal preparation. [ABSTRACT FROM AUTHOR]

Microbiological safety and quality of fresh chicken meat are important concerns to industry. The objective of this study was to investigate the effects of in-package, non-thermal high voltage dielectric barrier discharge (HVDBD) treatment on microbial quality, safety, and color of fresh chicken breast meat (pectoralis major). Boneless skinless chicken breast meat was collected from a local commercial plant. Non-inoculated meat samples and meat samples inoculated with Campylobacter jejuni and Salmonella Typhimurium were packed in polymeric trays under ambient air conditions. The packaged samples were HVDBD-treated at different voltages (0, 55, 70, or 85 kV) for 180 s, and stored at 4°C for 5 d. Microbial counts (psychrophiles, C. jejuni, S. Typhimurium) and meat color (L*a*b*) were measured before HVDBD treatment and after 5 d of post-treatment storage. Psychrophile growth was inhibited (P < 0.05) and both foodborne pathogens were reduced (P < 0.05) by HVDBD treatments regardless of treatment voltage. No differences in psychrophilic and S. Typhimurium counts were observed between the three treatment voltages; however, increasing treatment voltage beyond 55 kV resulted in additional inactivation of C. jejuni. In terms of meat color, there were no differences (P > 0.05) in a* and b* values between pre-treatment and post-treatment measurements; however, all HVDBD treatments resulted in increased L* value (P < 0.05). Results indicate that in-package HVDBD treatment can be used to reduce both microbial spoilage and foodborne pathogen risks; however, in-package HVDBD treatment may increase pale color in raw chicken breast meat. [ABSTRACT FROM AUTHOR]

Omics techniques, including genomics, transcriptomics, proteomics, metabolomics, and lipidomics, analyze entire sets of biological molecules to seek comprehensive knowledge on a particular phenotype. These approaches have been extensively utilized to identify both biomarkers and biological mechanisms for various physiological conditions in livestock and poultry. The purpose of this symposium was not only to focus on how recent omics technologies can be used to gather, integrate, and interpret data produced by various methodologies in poultry research, but also to highlight how omics and bioinformatics have increased our understanding of poultry meat quality problems and other complex traits. This Poultry Science Association symposium paper includes 5 sections that cover: 1) functional annotation of cis-regulatory elements in the genome informs genetic control of complex traits in poultry, 2) mass spectrometry for proteomics, metabolomics, and lipidomics, 3) proteomic approaches to investigate meat quality, 4) spatial transcriptomics and metabolomics studies of wooden breast disease, and 5) multiomics analyses on chicken meat quality and spaghetti meat. These topics provide insights into the molecular components that contribute to the structure, function, and dynamics of the underlying mechanisms influencing meat quality traits, including chicken breast myopathies. This information will ultimately contribute to improving the quality and composition of poultry products., (Copyright © 2024. Published by Elsevier Inc.)

Balanced ratios of branched-chain amino acids (BCAAs) can enhance chicken growth, immunity, and muscle synthesis. However, these ratios can be affected by changes in crude protein (CP) levels or the substitution of protein sources, leading to BCAA antagonism. This, in turn, can have a negative impact on chicken growth. In Experiment 1, a total of 960 0-d-old male Cobb 500 broilers were divided into 6 treatments with 8 replicates. Three different BCAA ratios were used in High or Low CP diets as follows: 1) Low Leu group (Low level of leucine with increased valine and isoleucine levels), 2) Med Leu group, and 3) High Leu group (High level of leucine with reduced valine and isoleucine levels) for a total of 6 diets. In Experiment 2, a total of 640 0-d-old male Cobb 500 broilers were divided into 4 treatments with 8 replicates. The four diets had either High or Low CP and one of two protein sources with the same medium levels of BCAAs: 1) the soybean meal (SBM) group, which had SBM as the main protein source (protein bound AA), and 2) the wheat middlings with non-bound AAs (WM+AA) group (non-bound AA), which had additional non-bound AAs to replace SBM. The High Leu diet had a negative effect on overall growth performance, carcass weight, breast muscle weight, and body mineral composition compared to the Low Leu and Med Leu groups, particularly in the High CP diet (P < 0.05). The SBM group showed increased growth performance, breast muscle weight, expression levels of genes promoting muscle growth, and improved bone mineral composition compared to the WM+AA group, and the High CP group intensified the negative effect of the WM+AA diet (P < 0.05). In summary, balanced BCAA ratios and SBM-based diets have positive effects on chicken growth and muscle accretion, whereas excessive leucine and non-bound AA levels in the diets may negatively affect growth performance and meat yield in chickens., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Understanding and controlling the dynamic process of aflatoxin B 1 (AFB 1 ) accumulation by Aspergillus flavus (A. flavus) remains challenging. In this study, the A. flavus development and AFB 1 accumulation were investigated using visible/near-infrared (Vis/NIR) hyperspectral imaging (HSI) on culture media, Potato Dextrose Agar (PDA), PDA + l-glutamine (Gln), and PDA + rapamycin (RAPA). In addition, the levels of AFB 1 in various heterogeneous regions of colonies were measured and their microscopic morphology was characterized. In the temporal and spatial domains, fungal colonies exhibited a concentric circular response pattern. A continuous increase in AFB 1 content was observed in the PDA and PDA + Gln groups as culture time increased. The growth of A. flavus and aflatoxin accumulation were promoted by adding Gln to PDA. However, adding RAPA inhibited the development of fungi and the production of AFB 1 . The distribution of AFB 1 across the fungal colony was uneven, and this heterogeneity was associated with the aging and autolysis of the hyphae. Principal component analysis showed that spectral bands of 480, 623, 674, 726 nm were related to the color changes of hyphae and spores during colony growth; however, wavelengths of 840, 882, 867, 972 nm were key bands related to changes in nutritional composition. Multiple preprocessing techniques and modeling methods employed to construct regression models for predicting AFB 1 contents showed that the first-derivative and partial least squares regression (PLSR) provided the best results. A visualization map of AFB 1 levels established using the optimal model showed a spatial pattern similar to the measurement results. This study highlights the application potential of Vis/NIR HSI for monitoring A. flavus growth and AFB 1 content., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Introduction: Spaghetti meat (SM) and wooden breast (WB) are emerging myopathies in the breast meat of fast-growing broiler chickens. The purpose of the study was to investigate the metabolomic differences between normal (N), SM, and WB fillets 24 h postmortem., Materials and Methods: Eight chicken breasts for each experimental group were collected from a commercial processing plant. Supernatant from tissue homogenates were subjected to ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS) analysis., Results and Methods: A total of 3,090 metabolites were identified in the chicken breast meat. The comparison of WB and N showed 850 differential metabolites ( P < 0.05), and the comparison of SM and N displayed 617 differential metabolites. The comparison of WB and SM showed 568 differential metabolites. The principal component analysis (PCA) plots showed a distinct separation between SM and N and between WB and N except for one sample, but SM and WB were not distinctly separated. Compared to N, 15-Hydroxyeicosatetraenoic acid (15-HETE) increased, and D-inositol-4-phosphate decreased in both SM and WB, indicating that cellular homeostasis and lipid metabolism can be affected in SM and WB. The abundance of nicotinamide adenine dinucleotide (NAD) + hydrogen (H) (NADH) was exclusively decreased between SM and N ( P < 0.05). Purine metabolism was upregulated in SM and WB compared to N with a greater degree of upregulation in WB than SM. Folic acid levels decreased in SM and WB compared to N ( P < 0.05). Steroid hormone biosynthesis was downregulated in SM compared to N ( P < 0.05). Carbon metabolism was downregulated in SM and WB compared to N with greater degree of downregulation in WB than SM ( P < 0.05). These data suggest both shared and unique metabolic alterations in SM and WB, indicating commonalities and differences in their underlying etiologies and meat quality traits. Dietary supplementation of deficient nutrients, such as NADH, folic acids, etc. and modulation of altered pathways in SM and WB would be strategies to reduce the incidence and severity of SM and WB., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Choi, Shakeri, Kim, Kong, Bowker and Zhuang.)

Oncomodulins (OCMs), also known as non-α-parvalbumins, are small molecules known for their high-affinity binding of Ca 2+ ions. They play crucial roles as Ca 2+ buffers and participate in signaling pathways within muscle and neuron cells. In chickens, 3 oncomodulin molecules have been identified at the protein level and are named chicken oncomodulin 1 (OCM1), -3 (OCM3), and alpha-parvalbumin (PVALB). OCM4 was newly assigned by genome annotation. A gene cluster containing OCM1, OCM3, and OCM4 is located in chromosome 14, while a single gene of PVALB is on chromosome 1. The Ca 2+ signaling pathway may be a potential contributor to the onset of chicken breast myopathies. However, chicken OCMs have not been extensively studied in muscle tissues. In this study, the genetic specifications, tissue-specific and differential expression of OCM1, OCM3, OCM4, and PVALB in the context of chicken breast myopathies were investigated. OCM1 exhibited moderate expression in the liver, intestine, and kidney. OCM3 was highly expressed in thymus and breast muscle. A long noncoding RNA (lncRNA) transcribed from the antisense strand of the OCM3 gene was found to be expressed in liver, lung, heart, intestine, and kidney tissues. OCM4 was barely expressed in thymus, thigh-, and breast muscle. PVALB exhibited high expression across all tissues examined. Results of quantitative PCR (qPCR) indicated that the expression of OCM3 was significantly increased (4.4 ± 0.7 fold; P-value = 0.03) in woody breast (WB) muscle and even greater (8.5 ± 0.6 fold; P-value = 0.004) in WB/white striping (WS) muscles. The expression of PVALB showed no difference in WB muscle, but it was notably higher (4.6 ± 0.7 fold; P-value = 0.054) in WB/WS muscle, although statistical significance was not reached. These findings suggest that increased expression of OCM3 and PVALB may be linked to chicken breast myopathies with regard to disruption of Ca 2+ buffering., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Published by Elsevier Inc.)

Relationships between texture measurements and meat water properties were investigated in raw intact broiler breast fillets with the wooden breast (WB) condition. Texture measurements included subjective WB scores and blunt Meullenet-Owens Razor Shear (BMORS). Water properties were determined with low-field nuclear magnetic resonance (LF-NMR). Spearman correlation was used to estimate relationships between WB scores and water properties, while Pearson correlation was used for relationships between BMORS force and water properties. LF-NMR measurements exhibited 3 water components: protein-associated or hydration water T 2b , intra-myofibrillar water or immobilized water T 21, and extra-myofibrillar water or free water T 22 in chicken breast meat. Significant and strong Spearman correlations were found between the WB scores and T 21 time constant, the abundance (normalized areas) of T 22 , and the proportion of T 21 and T 22 (r s > 0.60, P < 0.001). Strong Pearson correlations (r = 0.72) were noted only between the T 21 time constant and BMORS force. These results demonstrate that water may contribute to the specific texture characteristics measured with subjective WB scoring (palpable hardness and rigidity) and BMORS (hardness and share force) in raw broiler breast fillets with the WB condition., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)