Characterization of Carcass Color Differences Between Hen (Small Birds) and Meat-Type (Large Birds) Pheasant Lines Associated with Freezing

ObjectivesThe aim of this study was to determine the cause of why hen carcasses turn red on freezing in contrast to meat-type male pheasants.Materials and MethodsHen pheasant carcasses (n = 5) that were visibly red on the outside and larger meat-type pheasants (n = 5, not red) from the same harvest day at a commercial plant were obtained. The frozen carcasses in their original, sealed plastic bag were brought to the University of Wisconsin Meat Science Laboratory and stored in a –25°C freezer prior to being semi-thawed for about 24 h (4°C). Breast muscles (M. pectoralis major) were collected, cut into similar sections (approx. 2.5 cm × 2.5 cm × 1.5 cm), vacuum-packaged in a Nylon/PE vacuum bag, and stored in the –25°C freezer. The frozen samples were ground (9.5 mm plate). Skins were trimmed of excessive fat prior to pulverization in liquid nitrogen. Instrumental color, pH, proximate composition, myoglobin content (myoglobin-based methodology, Mb), and muscle fiber type determination were conducted. All data were analyzed using the PROC MIXED procedure of the SAS statistical analysis software. Dependent variable means were separated (P < 0.05) by pairwise comparisons using the PDIFF option.ResultsHens exhibited greater redness (CIE a*, 4.87) and were darker (CIE L*, 53.33) than the meat-type pheasants (CIE a*, 4.31 and CIE L*, 55.74) on frozen/semi-thawed breast muscles (P < 0.05), whereas no difference was observed in the yellowness (CIE b*) between the different pheasant types (P > 0.05). The highest pH (6.38) and Mb (1.89 mg/g) values were obtained from the skin of the hen carcasses compared to the skin of the meat-type pheasants (pH 6.21, Mb 1.22 mg/g). In addition, the breast muscle of the hens had a higher pH and Mb content. The hen skin exhibited the highest moisture and protein content as well as a lower fat content than the skin from meat-type pheasants. The intermediate fiber (IIA) type was the only type found in the pectoralis major muscles, regardless of the different pheasant types.ConclusionThe results of the current study reveal that hen carcasses had more red pigmentation and exhibited significantly higher pH values, redness, and Mb level than the meat-type pheasants. In this regard, a higher pH might suggest hens were more stress-susceptible which produced the darker red meat. Also, higher ultimate pH values could protect myoglobin and hemoglobin from denaturation. A major part of the darkening might be related to the lower amount of fat within the skin which may have facilitated transparency to the darker, more red breast muscle. Genetics or production practices differences did not appear to alter muscle fiber types. Our findings suggest that the more intense red appearance may be associated with the presence of hemoglobin rather than myoglobin. Future evaluation of the effects of soaking pheasant skin with various pH solutions and scalding variations on the physicochemical properties of collagen may merit investigation.

Vascular Rinsing and Chilling Carcasses: Effects on Quality Attributes and Metabolic Changes in Beef

ObjectivesRinse & Chill® (RC) is a process applied early postmortem that provides the ability to manipulate muscle metabolism and can have a positive impact on meat quality traits. This study aimed to evaluate the effect of RC on pH decline, shear force, sarcomere length and cooking losses on different cull dairy cow carcass grades. Investigate the ability of different substrates to modulate contractile response as an indirect measure of metabolic activity on beef early postmortem.Materials and MethodsFor each carcass grade (lean, LE; light, LI), ten carcasses were conventionally chilled (CC) and twelve carcasses were chilled using RC technology (MPSC Inc.). The RC process involved infusion of a chilled isotonic solution (98.5% water; balance: glucose, phosphates, and maltose) through the vascular system, beginning in the arterial and exiting the venous side of the vasculature. Shear force and cooking losses were measured on Longissimus dorsi steaks aged (7 d). Sarcomere length (SL) was determined by a laser diffraction method. Animal served as the experimental unit and data were analyzed with a PROC MIXED procedure. For contraction measurements, a muscle-fiber bundle from the Sternomandibularis muscles (n = 14) was collected from cull dairy cows in a commercial packing plant, 15 min after bleeding. The muscle bundle was attached to a force transducer (FT-302, iWorx, Dover, NH). Stimulation electrodes were used to elicit a supramaximal electrical stimulus at a frequency of 50 V, 0.1 Hz (HCS-100 stimulator, iWorx). Muscle weight was standardized, and length was adjusted to obtain maximum twitch-tension output. After 3 min of rest in a test solution, 200 stimuli were given, and the contractile response was recorded. Four solutions were tested (A = RC, B = Fructose, C = Sodium phosphate, D = Dipotassium phosphate; substrates added at 1% except fructose 1.5%). Descriptive means for initial peak twitch force, final peak twitch force, percentage decline and percentage half-time decline were calculated to determine the response associated with each solution.ResultsRC reduced (P < 0.05) shear force by 51.9% (6.79 kgf CC) and 55.8% (8.50 kgf CC) for LI and LE cows, respectively. LI cows were more tender than LE for CC (6.79 vs. 8.50 kgf; P < 0.05). RC compared to CC had longer SLs (LE: 1.80 vs. 1.44µ; P < 0.05) and LI (1.80 vs. 1.40µ; P < 0.05). Purge and cooking losses were not affected by chilling method. The contractile responses of the muscle after the exposure to the solutions were slightly different. The average percentage decline of peak twitch force was higher for solution B, followed by solutions A, D, C (54.8%, 53.5%, 48.0%, 43.4%, respectively). Furthermore, the same pattern was observed for the average percentage decline at half time of the test (82.5%, 80.4%, 78.1% and 74.7%, respectively).ConclusionPacking plants that harvest cull dairy cows have the potential to dramatically improve tenderness and thereby merchandize a greater amount of whole muscle cuts as a result of the application of the Rinse & Chill®. This improvement may be associated with accelerating postmortem glycolysis, thereby limiting cold shortening, although enhanced proteolysis may also be involved. Continuous electrical stimulation of isolated muscle-fiber bundles while being soaked in selected test solutions led to decreased and somewhat varied contractile force responses suggesting the potential to modify muscle metabolism.

Post-Exsanguination Vascular Rinsing of Market Hogs and Cull Dairy Cows on Meat Quality

ObjectivesThe objectives from two separate studies were to determine the meat quality effects of Rinse & Chill® (RC) on market hogs slaughtered under less than ideal harvest conditions (heat stress, warm harvest area, limited cooler air movement) and the impact of RC on commercially harvested cull dairy cows having different body condition scores (BCS).Materials and MethodsImmediately after bleeding, market hogs were conventionally chilled (C, n = 12) or RC processed (RC, n = 13; MPSC Inc.) at the University of Wisconsin harvest facility. RC carcasses were vascularly rinsed (10% of live weight) with an isotonic chilled solution (3°C; 98.5% water; balance: glucose, polyphosphates, maltose). Carcasses were scalded rather than skinned. Carcass temperature (0–24h), carcass cooler shrink, and pH (0.5, 1, 2, 4, 6, 24h) were recorded. At 24 h postmortem (PM), muscles (picnic shoulder, PS;M. Longissimus et lumborum, LL)were further processed (PS: chops, ground pork; LL: chops, ground pork), packaged (polyvinyl chloride, PVC; vacuum, VAC) and displayed continuously (3°C, 1615 lux; 1, 4, 7d PM). Color measurements (CIE L*a*b*, chemical states of myoglobin) along with pH, moisture fat free (MFF), water holding capacity (WHC), oxygen consumption, total pigment, TBARS and hexanal content were determined. Warner-Bratzler shear force on chops aged 4d PM (2°C) were cooked (71°C, endpoint temperature) according to AMSA guidelines.Carcasses from cull dairy cows with two different BCS (Lean, LE; Light, LI) were conventionally chilled (n = 10 each BCS) or RC processed (n = 12 each BCS). Muscles (M. Longissimus et lumborum, LL; M. Triceps brachii, TB) were ground (19mm, 3mm plates), packaged (PVC, VAC) and displayed or stored in the dark. Color, chemical states of myoglobin, pH, temperature, fat content and total pigments were determined. Data were analyzed using PROC MIXED procedures (SAS Institute).ResultsRC resulted in a lower (P < 0.05) pH during the first 4h compared to C.RC ground picnic shoulder was redder (CIE a*), lighter (CIE L*), had greater deoxymyoglobin and less metmyoglobin compared to C (P < 0.05). However, the RC ground loin had less (P < 0.05) oxymyoglobin than C. RC chops (LL) were lighter (CIE L*) and had less deoxymyoglobin compared to C (P < 0.05). RC ground pork had greater (P < 0.05) oxygen consumption. RC pork had lower (P < 0.05) TBARS and hexanal values compared to C. RC did not (P > 0.05) affect cooler shrink, moisture content when assessed on an MFF basis, WHC, purge, cook loss, total pigment and WBS force.RC resulted in a lower (P < 0.05) pH at each time PM than C. C (LE) had a lower pH than C (LI), however pH was not affected by BCS for RC. Generally, RC resulted in lower temperatures during chilling (24h). In LE and LIcows, RC produced greater redness (CIE a*, P < 0.05) associated with blooming and display times. RC LE beef resulted in greater (P < 0.05) oxymyoglobin during all display times, however, RC LI had higher (P < 0.05) deoxymyoglobin on 7d. No differences were found in total pigments.ConclusionFor pork packing facilities that harvest during heat stress times and have less than ideal carcass cooler conditions, RC has the potential to improve color in certain cuts and reduce lipid oxidation. RC on lower quality BCS cull dairy cows has the opportunity to improve color and potentially decrease the incidence of dark cutting beef.

Effects of soy sauce on physicochemical and textural properties of tumbled chicken breast

The objective of this study was to evaluate the effects of soy sauce on the physicochemical and textural properties of tumbled chicken breasts. Chicken breasts marinated with distilled water (Con), 4% NaCl solution, 4% NaCl and lactic acid solution (pH 4.9), and soy sauce solution (4% salt concentration and pH 4.9) were vacuum tumbled at 3°C for 60 min. The chicken breast marinated with soy sauce solution showed lower lightness and higher redness and yellowness due to the color of the soy sauce. The acidic marinades led to a decrease in pH value of tumbled chicken breast. The acidic marinades increased collagen solubility of sample compared with 4% NaCl solution, resulting in decreased shear force. Water-holding capacity, marination and cooking yields, and solubility of myofibrillar proteins were mainly affected by the presence of salt in the marinade, rather than by pH alternation. Our results suggested that soy sauce marination can improve the tenderness of tumbled chicken breast.

Effects of rigor state, thawing temperature, and processing on the physicochemical properties of frozen duck breast muscle

The objectives of this study were to evaluate effects of rigor state, thawing temperature, and processing on the physicochemical properties of intact frozen duck breast muscle and homogenates prepared with the frozen-thawed muscles. Prerigor breast muscle was frozen at -25°C and thawed at 4 and 15°C, and the physicochemical properties of duck breast frozen prerigor compared with those in frozen postrigor and 4°C chilled postrigor muscles. The homogenates prepared with duck breast frozen prerigor showed similar physicochemical properties as the frozen-thawed postrigor muscle homogenate. The thawing temperature did not affect the physicochemical properties of homogenates prepared with duck breast muscle frozen prerigor. Also, no significant differences (P > 0.05) in the ultimate pH value and color parameters were observed among the frozen-thawed treatments despite the differences in rigor state and thawing temperature. However, a higher thawing temperature of the intact frozen prerigor muscle resulted in an increase in thawing loss and shear force due to excessive muscle shortening. In this study, the intact duck breast that has undergone thaw-rigor showed main problems associated with thaw-rigor, such as higher thawing loss and shear force, regardless of thawing temperature. However, the processing (grinding and salting) decreased the difference in physicochemical properties due to rigor state before freezing and thawing temperature. Therefore, the frozen-thawed duck breast muscle used to manufacture ground-type meat product may be frozen before rigor onset.