Brian C. Bowker

Effects of hydrodynamic pressure processing on the marination and meat quality of turkey breasts

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 min 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 min 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 min 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 marination 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.

Effect of Rapid Thawing on the Meat Quality Attributes of USDA Select Beef Strip Loin Steaks

The objective was to determine the meat quality effects of rapidly thawing beef steaks in a water bath. Frozen beef strip loins (n = 24) were cut into steaks sequentially from the rib end and identified by anatomical location (anterior, middle, posterior) within the loin. Within location, steaks were randomly assigned to conventional (C; 18 to 20 h, 4 °C) or rapid thawing methods. Rapid thawing methods, fast (20 min, 20 °C) or very fast (11 min, 39 °C), were conducted in a circulating water bath. The physical, thawing, cooking, color, and texture characteristics of each steak were recorded. Data were analyzed as a randomized complete block design with a 3 thawing treatments × 3 locations factorial analysis with loin as a block. No location by thawing method interaction was detected (P > 0.05) for the measured variables. Compared to C steaks, rapidly thawed steaks exhibited lower thaw drip loss (P < 0.001) and higher a* values (P < 0.001). Thawing treatment did not influence L*, b*, cook yield, or shear force. Steaks from the posterior end had higher (P < 0.001) surface to volume ratios that may have contributed to the higher thaw loss (P < 0.01), longer cooking time (P < 0.001), lower cooking yield (P < 0.001), and higher shear force (P < 0.02) compared to steaks from the anterior and middle portions of the loins. These data indicate that beef steaks taken from the entire length of the loin can be rapidly thawed in a water bath following food safety guidelines with minimal impact on meat quality. Practical Application:  Freezing rate and frozen storage effects on meat quality have been well documented; however, there is comparatively little information on the meat quality effects of rapid thawing within food safety guidelines. This study demonstrates that beef strip loin steaks can be rapidly thawed in as few as 11 min without affecting texture or cooking yield, while reducing thaw drip loss. Thus, rapid thawing may enhance the apparent juiciness of steaks for consumers and provide an effective method for maintaining consistent control of experimental conditions for researchers.

Measurement of water-holding capacity in raw and freeze-dried broiler breast meat with visible and near-infrared spectroscopy

The feasibility of using visible/near-infrared spectroscopy (vis/NIR) to segregate broiler breast fillets by water-holding capacity (WHC) was determined. Broiler breast fillets (n = 72) were selected from a commercial deboning line based on visual color assessment. Meat color (L*a*b*), pH (2 and 24 h), drip loss, and salt-induced water uptake were measured. Reflectance measurements were recorded from 400 to 2,500 nm in both raw and freeze-dried breast meat samples. Raw and freeze-dried samples had similar spectra in the visible region (400-750 nm), but the freeze-dried samples exhibited numerous bands in the NIR region (750-2,500 nm) corresponding to muscle proteins and lipids that were not observed in the NIR spectra of the raw samples. Linear discriminate analyses were used to classify fillets as high-WHC or low-WHC according to predicted meat quality characteristics. Using the visible spectra (400-750 nm), fillets could be correctly classified into high-WHC and low-WHC groups based on drip loss and salt-induced water uptake with 88 to 92% accuracy in raw samples and 79 to 86% accuracy in freeze-dried samples. Using the NIR spectra (750-2,500 nm), fillets could be correctly classified into high-WHC and low-WHC groups with 74 to 76% accuracy in raw samples and 85 to 86% accuracy in freeze-dried samples. Thus, freeze-drying enhanced the accuracy of WHC classification using the NIR portion of the spectra. Data from this study demonstrate the potential for utilizing vis/NIR spectroscopy as a method for classifying broiler breast meat according to WHC.

Relationship between water-holding capacity and protein denaturation in broiler breast meat1

The objective of this study was to determine the relationship between water-holding capacity (WHC) attributes and protein denaturation in broiler breast meat. Boneless skinless breast fillets (n = 72) were collected from a commercial processing plant at 2 h postmortem and segregated into low-WHC and high-WHC groups based on muscle pH and color (L*a*b*). At 6 and 24 h postmortem, brine uptake (%), cooking loss (%), and protein solubility (sarcoplasmic and myofibrillar) were measured and protein fractions were analyzed using SDS-PAGE. Drip loss accumulation (%) was measured after storage for 2 and 7 days postmortem. High-WHC fillets exhibited lower L*-lightness values and greater pH values at 2 and 24 h postmortem than low-WHC fillets. High-WHC fillets had greater brine uptake and less cooking loss at both 6 and 24 h postmortem compared to low-WHC fillets. Aging from 6 to 24 h postmortem increased brine uptake in high-WHC fillets, but did not affect cooking loss in either low-WHC or high-WHC fillets. Drip loss accumulation was greater in low-WHC fillets at both 2 and 7 days postmortem. Myofibrillar protein solubility decreased with postmortem time but was not different between low-WHC and high-WHC fillets. Sarcoplasmic protein solubility increased with postmortem time and was greater in high-WHC fillets. SDS-PAGE analysis indicated that low-WHC fillets exhibited more glycogen phosphorylase denaturation than high-WHC fillets as evidenced by a more extensive shift of the protein from the sarcoplasmic to the myofibrillar protein fraction. Correlation analysis revealed that overall protein solubility measurements were not related to WHC attributes but that the degree of glycogen phosphorylase denaturation was significantly correlated (|r| = 0.52 to 0.80) to measures of WHC. Data indicated that WHC differences in broiler breast fillets were not due to differences in myofibrillar protein denaturation and suggested that the denaturation of sarcoplasmic proteins onto myofibrils may influence WHC in breast meat.

Impact of white striping on functionality attributes of broiler breast meat1

The influence of white striping (WS) on the water-holding capacity (WHC) and protein functionality attributes of broiler breast meat was investigated. Boneless breast fillets (Pectoralis major) were collected from the deboning line of a commercial processing plant and categorized by WS score (normal, moderate, severe). The physical (weight, pH, CIE-color values), water-holding capacity (salt-induced water uptake, cook loss, final yield), protein functionality (solubility, emulsifying activity), and protein composition (SDS-PAGE) characteristics of the fillets were measured in three experiments. Breast meat with WS exhibited greater fillet weights, higher pH, and similar color values (L*a*b*) to normal fillets. In experiment 1, fillets were frozen-thawed prior to analysis. The WS condition reduced thaw loss, sarcoplasmic protein solubility, and the emulsifying activity of the myofibrillar proteins, but did not significantly affect salt-induced water uptake, cook loss, final yield, or myofibrillar protein solubility. In experiment 2, breast meat was analyzed fresh and after a freeze-thaw cycle. Freezing samples prior to analysis negatively influenced WHC and reduced sarcoplasmic protein solubility in both WS and normal fillets. In fresh and frozen-thawed meat, the WS condition decreased sarcoplasmic protein solubility but did not significantly alter WHC or myofibrillar protein solubility. For experiment 3, fillets were portioned into 3 sections (Location A, cranial end-ventral surface; Location B, cranial end-dorsal surface; Location C, caudal end). The effects of WS on WHC and protein solubility were dependent upon breast fillet sampling location. Fillets with WS exhibited lower salt-induced water uptake, greater cook loss, and lower sarcoplasmic protein solubility than normal fillets when sampled from location A. SDS-PAGE analysis indicated that differences in the composition of sarcoplasmic and myofibrillar protein fractions between WS and normal fillets were influenced by sampling location. These results suggest that WS diminishes the WHC and protein functionality of broiler breast meat, but demonstrate that the WS effects on these traits are not uniform throughout the breast muscle.

Relationship between muscle exudate protein composition and broiler breast meat quality

The objective of this study was to determine 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 water uptake, and higher cook loss than dark fillets. Neither 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 extracts. Gel electrophoresis data from muscle exudates showed that the relative abundance of 4 bands corresponding 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-holding capacity and suggest that muscle exudate could be a potential source of protein markers for fresh meat quality attributes in broiler fillets.

Microstructure alterations in beef intramuscular connective tissue caused by hydrodynamic pressure processing.

Scanning electron microscopy (SEM) was utilized to evaluate microstructural changes in intramuscular connective tissue of beef semimembranosus muscle subjected to hydrodynamic pressure processing (HDP). Samples were HDP treated in a plastic container (HDP-PC) or a steel commercial unit (HDP-CU). Control and HDP samples were obtained immediately post-treatment and after 14days of aging for SEM and Warner-Bratzler shear force (WBSF) analysis. Immediately post-treatment, HDP treated samples exhibited lower (P<0.01) WBSF than did controls. After aging, HDP-PC samples had lower (P<0.01) WBSF than that of aged controls. SEM analysis indicated that HDP-PC treatment disrupted the integrity of the collagen fibril network of the endomysium in both the non-aged and aged samples. Aging effects on the intramuscular connective tissue were observed in the HDP-PC and control samples. Both WBSF and connective tissue changes were greater in the HDP-PC than in the HDP-CU treated samples. Data suggest that shockwave alterations to connective tissue contribute to the meat tenderization of HDP.

Effects of broiler carcass scalding and chilling methods on quality of early-deboned breast fillets

The impact of scalding and chilling methods on quality of broiler breast fillets (pectoralis major) was evaluated. In 4 replications, 6- to 7-wk-old male and female broilers were slaughtered and scalded either at 60°C for 1.5 min (hard scalding) or 52.8°C for 3 min (soft scalding). Following evisceration, the carcasses were either air-chilled (0.5°C, 120 min) or immersion-chilled in water and ice (79 L/carcass, 0.5°C, 40 min, air agitated). Breast fillets were removed from the carcass within 4 h postmortem. Quality attributes including fillet color (both dorsal-bone and ventral-skin sides), pH, total moisture content, water-holding capacity (drip loss and cook loss), and Warner-Bratzler shear force were determined. Significant interactions between replication and scalding were found for pH, ventral side redness (a*) value, and cook loss and between replication and chilling for pH and ventral side a* and yellowness (b*) values. There were no interactions (P > 0.05) between chilling and scalding methods for any of the measurements. Immersion chilling resulted in higher (P < 0.05) ventral side lightness (L*) values, dorsal side b* values, drip loss, cook loss, and shear force compared with air chilling. No significant differences (P > 0.05) between the 2 scalding methods were observed for any of the quality attributes. These results indicate that broiler carcass chilling method has a much greater impact on quality of breast meat than scalding method and that the influence of chilling on breast meat quality is independent of scalding treatment.

Measurement of Muscle Exudate Protein Composition as an Indicator of Beef Tenderness

UNLABELLED The objective of this study was to determine the relationship between the protein composition of muscle exudates and meat tenderness in beef. Frozen, intact beef strip loins (n = 24) were each divided into 3 equal portions (anterior, middle, and posterior). Steaks were removed from each portion, individually vacuum packaged, thawed at 4 °C, and aged for 0, 7, or 14 d. After the designated aging period, exudate was collected from the packaging and 1 steak from each strip loin portion was utilized for shear force measurements. Muscle exudates were analyzed for protein content (biuret assay) and composition (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Shear force decreased (P < 0.0001) with aging from 0 to 14 d. The protein concentrations of the muscle exudates were not influenced by the aging period and were not related to the amount of exudate expressed. Electrophoretic analyses of the muscle exudates indicated that with aging the relative abundance of 4 proteins decreased (P < 0.01) and 10 proteins increased (P < 0.05) within the protein profiles of the exudates. The relative abundance of the 167, 97, and 47 kDa proteins in exudates at day 0 were significantly correlated (|r| = 0.57 to 0.77) to shear force at day 14. These data demonstrate that exudate protein composition changes with postmortem aging and beef tenderness. PRACTICAL APPLICATION This research showed that the protein profiles of exudates that accumulate on the surface and in the packaging of beef change with meat aging and tenderness. These data suggest that muscle exudates may be a good source of protein markers that are useful in the development of rapid, noninvasive methodologies for predicting beef tenderness.

Descriptive texture analyses of cooked patties made of chicken breast with the woody breast condition1

ABSTRACT The woody breast (WB) condition negatively influences the texture characteristics and quality of intact broiler breast fillets (Pectoralis major). But the impact of WB on ground meat is unknown. The objective of this study was to evaluate the effects of WB on the texture and cook loss of ground meat made of broiler breast fillets. Broiler breasts (deboned 3 h postmortem) were collected on 3 separate trial d from the commercial deboning line and classified into normal and severe WB fillet categories. Individual fillets were either ground and formed into patties or left intact prior to being stored for 7 d at −20°C. Samples were then cooked directly from the frozen state to an endpoint temperature of 76 °C for cook loss, instrumental (patties: Allo‐Kramer shear; fillets: Warner‐Bratzler shear), and descriptive sensory analysis of texture. Cook loss was greater (P < 0.05) in intact WB fillets compared to that in intact normal fillets, but there was no difference (P > 0.05) between WB and normal patties. There was no difference (P > 0.05) in shear force between normal and WB samples regardless of meat type. Sensory analysis showed that average scores of springiness and hardness of intact WB fillets were greater than those of normal fillets (P < 0.05). However, there were no significant differences (P > 0.05) in average scores for sensory attributes cohesiveness, hardness, juiciness, fibrous, and rate of breakdown between WB and normal patties. WB patties exhibited lower springiness and chewiness scores (P < 0.05) than normal patties. Data suggest that undesirable differences in sensory texture characteristics between cooked intact WB and normal breast meat can be minimized in a ground product.