Meat quality characteristics of springbok (Antidorcas marsupialis). 1: Physical meat attributes as influenced by age, gender and production region

Springbok is the most extensively cropped game species in South Africa. The effects of age (adult, sub-adult, lamb), gender and production region on the physical attributes (pH₂₄, cooking and drip loss, Warner Bratzler shear force and colour) were determined using samples of the M. longissimus dorsi (LD) muscles of 166 springbok. Stressed animals had a higher (P < 0.05) pH₂₄ (6.3 ± 0.07), as observed in the meat originating from the Caledon region. This meat had lower (P < 0.05) cooking loss (27.2 ± 0.62%) and drip loss (1.8 ± 0.08%) values in comparison to meat originating from the other regions. Inverse correlations were noted between pH₂₄ and drip loss (r = −0.26, P < 0.01) and cooking loss (r = −0.42, P < 0.001). Shear force values (kg/1.27 cm diameter) correlated positively (r = 0.25, P < 0.01) with pH₂₄. Age-related effects on tenderness were small in comparison with pH₂₄ effects. CIELab colorimetric values were typical of game meat and venison (L^* < 40, high a^* and low b^* values). It was noted that pH₂₄ correlated negatively (r = −0.51, P < 0.001) and positively (r = 0.33, P < 0.001) with the hue-angle and the chroma value of colour, respectively. Springbok originating from Caledon had a significantly (P < 0.05) higher a^* value, indicating meat to be more red with higher colour saturation.     

Effect of different stunning systems on meat quality of light lamb

The present study was proposed to compare the effect that different types of stunning (TS) had on the quality of refrigerated meat from light lambs of the Spanish Manchega breed at 24 h and 7 days post-mortem. Lambs were electrically stunned (ESL; n = 10), using CO₂ (GSL; n = 10) or slaughtered without previous stunning (USL; n = 10). Measurements on meat quality were carried out by evaluating pH, colour coordinates (L^*, a^*, b^*), water holding capacity (WHC), cooking loss (CL), shear force (SF) and drip loss (DL). At 24 h post-mortem, no significant differences were found in any of the variables studied. However, at 7 days post-mortem, meat quality was affected by the different TS: pH, CL and DL were lower (P < 0.001) in the USL group and GSL obtained the lowest a^* (redness) and b^* (yellowness) values (P < 0.01) than in the other groups. Ageing of meat affected SF in the ESL group (P < 0.01), although there were no significant differences due to treatments at any of the ageing times.     

Chemical, instrumental and sensory characteristics of cooked pork ham

Instrumental, chemical and sensory parameters of cooked pork ham were evaluated. Principal component analysis was carried out on the basis of the instrumental variables related to colour and texture. The four PCs account for almost 94% of the total variance in the data set. The PCA only separated 3 hams with a^* > 10. Hardness was correlated with non-collagen muscle protein (P  0.01), gumminess (P  0.01) and ash (P  0.05). Sensory evaluated tenderness showed positive significant correlation with L^* (P  0.01). The most important colour parameter seems to be a^*, which was negatively correlated with sensory evaluated parameter colour (P  0.01). The PCA performed on all parameters (sensory, chemical and textural) discriminated two groups of hams differing in non-collagen muscle protein content and hardness.     

Addition of tea catechins and vitamin C on sensory evaluation, colour and lipid stability during chilled storage in cooked or raw beef and chicken patties

The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO₂:70% N₂. Fresh raw beef and chicken patties were packaged in 80% O₂:20% CO₂. All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P < 0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P < 0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P < 0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P < 0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.     

The influence of early post-mortem enhancement and accelerated chilling on pork quality

To improve pork quality, the effectiveness of early post-mortem enhancement and accelerated chilling were investigated. The four treatments evaluated were: Enhancement with Accelerated Chilling (ENAC), Accelerated Chilling Only (ACO), Enhancement with Conventional Chilling (ENCC), and Conventional Chilling Only (CCO). ENAC had a higher (P < 0.05) pH than all other treatments. CCO resulted in the highest (lightest; P < 0.05) L^*, while ENAC had the lowest L^* value (darkest; P < 0.05). Subjective color and striping did not differ (P > 0.05) between ENAC and ENCC, although ENAC was numerically higher for both parameters. Sensory analysis for juiciness and tenderness were not different (P > 0.05) between ENAC and ENCC, but both were higher (P < 0.05) than ACO and CCO. Enhancement early post-mortem coupled with accelerated chilling may be used to improve instrumental color and pH over conventional processing methods.     

Influences of dietary conjugated linoleic acid (CLA) and total lysine content on growth, carcass characteristics and meat quality of heavy pigs

To assess the effects of dietary CLA, lysine and sex on performance, blood metabolites, carcass characteristics, meat quality and skeletal development, seventy-two pigs (initially 105.3 ± 6.6 kg live weight) barrows and gilts, were assigned to one of four diets in a 2 × 2 × 2 factorial arrangement. The diets contained 0% or 0.75% CLA, and 0% or 0.16% of l-lysine–HCl. All pigs were slaughtered at an average weight of 153.4 ± 11.0 kg. Neither CLA nor lysine supplementation influenced growth, blood metabolites or carcass characteristics. CLA reduced (P < 0.05) pH₂₄ and increased (P < 0.01) yellowness (b^*) of the Longissimus muscle. Lysine increased (P < 0.01) pH₂₄ and reduced (P < 0.01) muscle ash content. CLA reduced (P < 0.05) collagen synthesis, and lysine increased (P < 0.05) collagen synthesis in Longissimus muscle, but no influence on intramuscular collagen maturity or muscle hydroxylysylpyridinoline crosslink concentration were observed. In addition, metacarpal bone diameter was reduced (P < 0.05) by CLA. Barrows had higher ADG, final weight (P < 0.01), carcass weight, lean percentage (P < 0.05), serum cholesterol (P < 0.05) and triacylglycerol (P < 0.001) than gilts. Metatarsal diameter was larger in gilts than barrows (P < 0.05).     

Meat quality characteristics of springbok (Antidorcas marsupialis). 4: Sensory meat evaluation as influenced by age, gender and production region

The effects of age, gender and production region on the sensory characteristics of springbok M. longissimus dorsi (LD) were investigated in 19 springbok, which originated from two Nature Reserves in the Free State Province of South Africa and were divided into age (adult, sub-adult) and gender categories. The sensory characteristics evaluated were game meat aroma, juiciness, residual tissue, tenderness and game meat flavour. Age, gender and production region had an effect (P < 0.05) on different sensory ratings of the meat. Whereas production region influenced (P < 0.05) the game meat aroma, initial juiciness, sustained juiciness and residual tissue ratings of the meat, gender and age had a significant effect on only the residual tissue rating of the meat. An interaction (P < 0.01) between age, gender and production region was observed for the tenderness attribute where the males from the Gariep Nature Reserve were the only gender that showed a significantly higher tenderness rating in the sub-adult than in the adult category. Sensory ratings were linearly correlated with certain physical and chemical attributes. Warner–Bratzler shear force (kg/1.27 cm diameter) values were inversely correlated with the sensory attributes of tenderness (r = −0.70, P < 0.01), residual tissue (r = −0.68, P < 0.01) and sustained juiciness (r = −0.43; P < 0.05). Age-related effects on perceived tenderness were minor in comparison with pH effects. As the pH₂₄ of the meat increased, tenderness (r = −0.46, P < 0.05) and sustained juiciness (r = −0.54, P < 0.05) decreased significantly. No significant linear correlations were observed between the intramuscular fat (IMF) content and the sustained juiciness ratings of the meat. It can be concluded that production region had some influence on sensory characteristics of springbok meat, whilst the influence of age and gender were negligible.     

Influence of dietary inclusion level of manganese on pork quality during retail display

Boneless pork loins (n = 112) were used to test the influence of dietary manganese (Mn) inclusion level on pork quality traits during retail display. Crossbred barrows and gilts were fed diets formulated with 0, 20, 40, 80, 160, or 320 ppm Mn from Availa^®Mn (AvMn; a Mn–amino acid complex) from 23.8 to 106.8 kg live weight. At approximately 48 h postmortem, boneless pork loins were fabricated into longissimus thoracis et lumborum (LM) chops, which were subsequently placed in open-topped, coffin-chest display cases (2.6 °C) under continuous warm-white, fluorescent lighting (1600 lx) for 7 days. Dietary Mn level had no effect on LM pH (P = 0.47), purge volume (P = 0.60) and loss (P = 0.53), or moisture loss (P = 0.95) during retail display. Chops from pigs fed 80 ppm Mn received higher (P < 0.05) American and Japanese color scores than pigs fed 0 and 40 ppm Mn. Even though the LM from pigs fed 80, 160, and 320 ppm Mn tended to be darker (lower L^* values; P = 0.07) than chops from pigs fed 40 ppm Mn, a^* (redness) and b^* (yellowness) values, as well as hue angle and chroma, were not (P  0.19) affected by dietary Mn. On days 0 and 1, the reflectance ratio of 630 nm/580 nm was similar (P > 0.05) among dietary Mn supplementation levels; yet, by day 4 of retail display, chops from pigs fed 80 ppm Mn had higher (P < 0.05) reflectance ratios than chops from pigs fed 0, 20, 40, and 160 ppm, whereas LM chops from pigs fed 40 ppm Mn had lower (P < 0.05) reflectance ratios than all other dietary treatments on day 7 (Mn supplementation level × display day; P = 0.04). Although TBARS were greater (P < 0.001) on day 7 than 0 of retail display, TBARS values did not (P = 0.43) differ among dietary Mn levels. Results indicate that supplementing swine diets with 80 ppm Mn may improve pork color during retail display without increasing the likelihood of lipid oxidation.     

Effects of transportation at high ambient temperatures on physiological responses, carcass and meat quality characteristics of three breeds of Omani goats

The experiment was designed to determine the effects of short road transportation in an open truck during the hot season on live weight shrink, physiological responses, carcass, and meat quality characteristics in three breeds of Omani goats. Forty-two male goats (12 months of age) representing equally three breeds of Omani goats (Batina, Dhofari, and Jabal Akhdar) were divided into two groups: 2 h transportation stress (TS) or not transported (NT). The NT group remained unstressed in holding pens with feed and water provided ad libitum prior to slaughter, while the TS group was transported on the day of slaughter 100 km in an open truck. The average temperature during transportation was 37 °C. All animals were blood-sampled before loading and prior to slaughter via jugular venipuncture. Animals were weighed just before loading onto a truck and after transport to assess shrinkage. Muscle shear force, sarcomere length, pH, expressed juice, color, and cooking loss were measured on samples from Mm longissimus dorsi (LD), biceps femoris (BF), and semitendinosus (ST) muscles collected at 24 h postmortem at 1–3 °C. Live weight shrinkage losses were between 1.07 and 1.28 kg. The TS goats had higher plasma cortisol (P < 0.01), adrenaline, nor-adrenaline, and dopamine concentrations (P < 0.05) than NS goats. Blood serum from Batina goats had significantly (P < 0.05) higher cortisol, adrenaline and dopamine and nor-adrenaline concentrations than those from Jabal Akdhar goats. Transportation stress had a significant (P < 0.05) effect on meat quality characteristics of the LD, BF, and ST muscles. Meat from TS goats had significantly higher ultimate pH, expressed juice, cooking loss percentage, shear force, but significantly lower sarcomere length, L^*, a^*, and b^* values. LD muscles of Batina goats had significantly higher ultimate pH values and lower L^* values than Dhofari and Jabal Akdhar goats. These results indicated that subjecting goats to the 2-hour road transportation with high ambient temperatures can generate major physiological and muscle metabolism responses.     

Sodium chloride levels in comminuted chicken muscle in relation to processing characteristics and Fresnel reflectance detected with a polarimetric probe

Increasing NaCl from 0 to 2% in comminuted samples of chicken breast meat increased the resistance to compression of cooked samples (r=0.98, p < 0.001), increased water-holding capacity (r=0.95, p < 0.001), decreased cooking losses (r=−0.97, p < 0.001) and decreased paleness (L^*) before and after cooking (r = −0.96 and r=−0.99, respectively, p < 0.001). The decrease in paleness caused by NaCl was associated with an increase in the relative amount of reflected light maintaining its original plane of polarisation, so that NaCl% was correlated with an extinction coefficient for polarised light, r=0.91, p < 0.001. A possible explanation is that myofibrillar proteins may have been dissolved at high levels of NaCl, thus reducing light scattering by myofibrils and allowing more Fresnel reflectance to be detected.     

The impact of lactic acid concentration and sodium chloride on pH, water-holding capacity, and cooked color of injection-enhanced dark-cutting beef

The objectives of this study were to evaluate the effect of enhancement with 0.5%, 1.0%, 1.5%, or 2.0% lactic acid (LA), with or without 0.5% salt (NaCl), on pH, water-holding capacity, and resultant cooked color of dark-cutting (DC) beef. The pH of DC sections treated with LA decreased (P < 0.05), whereas water-holding capacity (WHC) increased (P < 0.05) with increasing concentrations of LA. Sensory panelists noted an increase (P < 0.05) in the degree of doneness (less pink internal color), whereas, a^* and chroma values were lower (P < 0.05), and hue angles were greater (P < 0.05), indicating the internal color of LA-treated DC sections was less red and appeared more well-done. Also, 630:580 nm reflectance ratios were similar (P > 0.05) among DC steaks treated with 0.5% and 1.0% LA and normal pH (NDC) steaks, likely caused by an increase (P < 0.05) in myoglobin denaturation in LA-enhanced DC steaks. These results indicate that the use of LA can reduce postmortem muscle pH and alter the cooked color of DC beef, ultimately resulting in a deletion of the persistent pinking condition.     

Influence of storage period and packaging method on sliced dry cured beef "Cecina de Leon": Effects on microbiological, physicochemical and sensory quality

Quality aspects of sliced dry-cured beef “Cecina de León” preserved in vacuum and gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂) were studied. The evolution of microbiological, physicochemical and sensory parameters were analysed during storage (210 days) at 6 °C. Although microbial counts at 60 days of the gas-packaged samples were lower than the vacuum-packed ones, they were never higher than the spoilage limit (7 log ufc/g). A slight increase (p < 0.05) in pH was observed throughout storage of “Cecina de León” packaged under vacuum and in gas mixtures. However, a decrease (p < 0.05) in a_w was observed during storage of “Cecina de León” packaged under vacuum but a_w did not vary (p > 0.05) during storage in the gas-packaged samples. No changes were observed (p > 0.05) in lightness (L^*), redness (a^*) and yellowness (b^*) in vacuum and gas packaged samples during storage. However, sensorially evaluated colour showed lower values in gas packaged samples during 30 days storage. This difference was decisive in establishing the shelf-life of “Cecina de León” slices preserved in gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂). Therefore, from a microbiological point of view, gas mixtures are more effective in extending the shelf-life of “Cecina de León” slices. It is concluded that vacuum packaging allows longer storage than gas-packaging as it maintains a good visual appearance of “Cecina de León”, the main parameter in consumers’ perception of meat quality.     

Meat quality of lambs of indigenous dairy Greek breeds as influenced by dietary protein and gastrointestinal nematode challenge

The effect of dietary protein and gastrointestinal (GI) parasitism on growth and meat quality of lambs was assessed using 60 animals. The lambs were randomly allocated to one of three treatment groups (n = 20): group A, which served as control, group B that was regularly treated with albendazole and group C, which was given supplementary feeding with dietary protein. The three groups of lambs grazed into a pasture (Lolium perenne), which was contaminated with L₃ larvae of GI nematodes. Lamb growth and condition score were assessed at 21-day intervals. After 126 days grazing all lambs were slaughtered and their carcasses were assessed for conformation and fatness and their ultimate pH was measured. Four carcasses from each group were randomly selected for meat quality measurements including physical analysis as well as colour, moisture, total fat, protein content and fatty acid composition. Parasitic challenge was assessed by means of faecal egg counts of lambs, pasture larvae and numbers of adult nematodes in the GI tract of lambs at slaughter. Growth rate of group B was higher (P < 0.01) than that of group A and resulted in significantly (P < 0.01) heavier carcasses. The produced carcasses had similar fatness, but differed significantly (P < 0.05), in their conformation; carcasses of group C scored higher than either those of group B or group A, respectively. There was a significant difference in the colour attributes (L^*) with group A being significantly lighter (P < 0.05) and in pH (P < 0.01); Group B had the highest values. Carcasses of group C had the highest (P < 0.05) amounts of intermuscular fat compared to those of group B and A, respectively. The proportion of C16:1n-7 and C18:2n-6 was higher (P < 0.05) in subcutaneous fat tissue whereas the proportion of C18:0 was higher (P < 0.05) in muscle tissue. In conclusion, the present results showed that the increased protein content in the diet of growing lambs, grazing on a pasture infected with GI nematode larvae, resulted in the production of acceptable carcasses.     

Irradiation effect on fatty acid composition and conjugated linoleic acid isomers in frozen lamb meat

The effect of gamma radiation processing on the lipid content, fatty acid composition and conjugated linoleic acid (CLA) profile in frozen lamb meat was investigated. Samples of longissimus thoracis muscle from lambs fed lucerne basal diets either unsupplemented or supplemented with polyunsaturated vegetable oils were irradiated (7 kGy) and analysed. CLA contents in lamb meat did not affect (P > 0.05) the levels of lipid oxidation induced by the irradiation. No significant differences (P > 0.05) were observed for fatty acid composition, related nutritional indexes (n − 6/n − 3 and PUFA/SFA), as well as for total lipid and CLA contents, between non-irradiated (control) and irradiated meat samples. In contrast, meat irradiation affected the relative proportions of total trans, trans and cis/trans CLA isomers (P < 0.001), in addition to the percentage of some minor individual CLA isomers (t11, t13 and t9, t11, with P < 0.05 and P < 0.001, respectively). The percentage of total cis/trans CLA isomers slightly decreased in irradiated samples, while the relative proportion of total trans, trans isomers slightly increased. This observation may be explained by the higher susceptibility to autoxidation of the cis double bond relative to the trans configuration.     

Augmented postmortem glycolysis does not occur early postmortem in AMPKγ3-mutated porcine muscle of halothane positive pigs

The objective of this study was to determine the effects of the halothane (HAL) and Rendement Napole (RN) genes on the rate-limiting reactions of glycolysis and their relationship to pork quality development. Samples were collected from the longissimus muscle at 0, 30, 60, and 120 min and 24 h postmortem from homozygous HAL and RN pigs (NN/rn⁺rn⁺, NN/RN⁻RN⁻, nn/rn⁺rn⁺, nn/RN⁻RN⁻). Muscle pH was recorded at 0, 15, and 45 min, and 24 h postmortem. HAL mutants, compared with HAL normal, had lower (P < 0.05) ATP concentrations at 0 and 30 min, lower (P < 0.05) pH at 45 min, and hastened glycogen degradation and lactate accumulation in the first 120 min postmortem (HAL × time, P < 0.0001). RN mutants had greater (P < 0.0001) glycolytic potentials than RN normal, and lower (P < 0.05) 24 h pH compared with the normal genotype, but not the HAL mutant genotype. The HAL mutation negatively affected (P < 0.05) L*, b* and color scores whereas both HAL and RN mutations independently decreased (P < 0.05) firmness, marbling and water holding capacity. RN mutant genotypes had higher (P < 0.0001) phosphocreatine concentrations than other genotypes at 0 min. Compared with HAL normal, HAL mutants had elevated (P < 0.05) muscle glucose concentrations at 30, 60, and 120 min, and 24 h. RN mutants had higher (P < 0.05) glucose levels than RN normal after 60 min. Glucose-6-phosphate (G6P) concentrations decreased (P < 0.05) during the first hour postmortem except in HAL/RN mutants, which had higher (P < 0.01) G6P concentrations than all other genotypes at 30 min. From 60 min to 24 h postmortem, G6P increased (P < 0.05) in HAL normal genotypes. Altogether, these data show that elevated muscle glycogen content does not further aggravate rapid early postmortem metabolism.     

Comparisons of longissimus muscle metabolic enzymes and muscle fiber types in Korean and western pig breeds

We compared differentially expressed genes and muscle fiber types in the longissimus muscles of Korean native pigs (KNP) and the western meat-producing breeds Landrace and Yorkshire. The KNP breed exhibited a higher muscle fat content and more red meat color as determined by the a^* (redness) value (P < 0.01) and b^* (yellowness) value (P < 0.05) compared to the western breeds. Using differential display RT-PCR, we detected two genes that were differentially expressed in skeletal muscle among the pig breeds. These genes were identified as NADH dehydrogenase subunit 1 and ATPase subunit 6 by cloning and sequencing analysis. Both of these genes are involved oxidative phosphorylation and therefore energy metabolism. The genes were more highly expressed in the KNP breed than in the other breeds, indicating that KNPs exhibit more oxidative metabolism than do the western breeds. We also analyzed the mRNA levels of myosin heavy-chain isoforms such as type I (oxidative), type IIb (glycolytic), and types IIa and IIx (intermediate) fibers using real-time RT-PCR. The mRNA levels of oxidative and intermediate fibers were elevated in the KNP breed, whereas the glycolytic fibers were more highly expressed in the Landrace and Yorkshire pigs. These results suggest that the elevated expression of the oxidation-related metabolism genes NADH dehydrogenase and ATPase is related to meat quality as indicated by a higher content of oxidative fibers and muscle fat, as well as redder meat color.     

Chemical, physical and sensory properties of meat from pure and crossbred Podolian bulls at different ageing times

The present study aimed to investigate the effect of crossbreeding with Limousine sires on fatty acid profile, physical and sensory properties of meat produced by Podolian young bulls. Polyunsaturated fatty acid content was influenced by crossbreeding (P < 0.01) with Podolian bulls (P) producing beef characterised by a higher level of unsaturation in comparison with crossbred animals (LP). As a consequence, P/S ratio was significantly higher in meat produced by P animals than LP (P < 0.01). P animals had higher linoleic (P < 0.05), linolenic (P < 0.05), EPA (P < 0.05) and DHA acids (P < 0.001) levels than LP subjects. No breed effect was observed for the ratio n − 6/n − 3 (P > 0.05). WBS force of LD was significantly lower in meat from crossbred subjects (P < 0.05). Both crossbreeding with Limousine and extension of ageing from 2 to 7 days improved LD tenderness as assessed by panel taste (P < 0.001).     

Sensory properties of hot-deboned ostrich (Struthio camelus var. domesticus) Muscularis gastrocnemius, pars interna

Cold-deboning is currently practiced in South African ostrich abattoirs. However, the advantages of hot-deboning include the reduction of costs and time, but there is always the risk of cold-shortening. The effects of hot-deboning of ostrich M. gastrocnemius, pars interna on meat sensory attributes were investigated. The data showed that the hot-deboned muscles’ pH₄₈ (6.57 ± 0.18) was significantly negatively correlated (r = −0.7813; P < 0.038) to the mean Warner–Bratzler shear force values (71.28 ± 18.62 N, 12.7 mm⁻¹ diameter) and positively correlated (r = 0.789; P < 0.035) to the mean scores for taste panel tenderness (66.39 ± 15.45). After storage for 48 h post-mortem, the hot-deboned muscles were found to be less juicy (P < 0.004) and, according to both sensory tenderness scores and Warner–Bratzler shear force values, tougher (P < 0.0001) than the cold-deboned muscles.     

Effects of age on composition and quality of muscle Longissimus thoracis of the Omani Arabian camel (Camelus dromedaries)

The aim of this study was to determine the effects of age on chemical composition and quality characteristics of the Arabian one-humped camel’s meat. Samples of longissimus thoracis (between the 10th and the 13th rib of the left side) were randomly collected from 21 Omani intact male camels of three different age groups: group 1 (1–3 years), group 2 (3–5 years) and group 3 (6–8 years). Samples were chilled (1–3 °C) for 48 h. Moisture, crude protein, fat and ash were determined on freeze dried ground muscle. Mineral contents were determined using an Inductively coupled plasma emission spectrometer (ICP). Meat quality including ultimate muscle pH, Warner–Bratzler shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss percent, and colour L^*, a^*, b^* were measured using standard methods.

The moisture, protein, fat and ash ranged from 64.4% to 76.7%; 18.6% to 25.0%, 1.1% to 10.5% and 1.0% to 1.4% on dry matter basis, respectively. The Ca, Mg, Na, K, P, Cad, Cr, Ni, Pb, Co, Mo, Be and V ranged from, 9.2 to 46.6, 24.7 to 57.3, 104.7 to 257.0, 471.4 to 1053.0, 249.9 to 584.0, 0.005 to 0.024, 0.020 to 0.410, 0.016 to 0.187, 0.010 to 0.299, 0.010 to 0.018, 0.050 to 0.470, 0.005 to 0.030 and 0.013 to 0.141 mg/100 g on dry matter basis, respectively. The percentage of protein decreased and that of fat increased with increasing camel age. The ultimate pH, shear force, sarcomere length, fragmentation index, expressed juice, cooking loss, lightness (L^*), redness (a^*) and yellowness (b^*) ranged from 5.46 to 6.64, 4.25 to 17.82, 0.96 to 2.50, 55.91 to 94.81,19.50 to 33.63, 13.18 to 29.88, 27.86 to 43.21, 10.46 to 22.81, and 4.63 to 10.11, respectively. Muscles of younger camels (group 1) had significantly (P < 0.05) lower shear force value, ultimate pH and higher sarcomere length, fragmentation index, expressed juice, cooking loss, and lightness color (L^*) by 48%, 3.4%, 43%, 25%, 28%, 14%, and 16% than those collected from older camels (group 3), respectively. Values of middle age camels (group 2) camels were in-between. This study confirmed that camel meat is healthy and nutritious as it contains low fat as well as being a good source of minerals. Age is an important factor in determining meat quality and composition.     

Effects of rigor temperature and electrical stimulation on venison quality

The effects of rigor temperature and electrical stimulation on venison quality were assessed using venison longissimus dorsi muscle. In the first trial, effect of rigor temperature (0, 15, 25, 30, 35 and 42 °C) and time post-mortem (at rigor, 3, 7 and 14 days) on drip and cooking losses, % expressible water (water holding capacity, WHC), sarcomere length, protein solubility, meat tenderness and colour were investigated. In the second trial, the effects of rigor temperature (15 and 35 °C), electric stimulation (stimulated or not stimulated) and time (at rigor, 3 and 6 weeks post-mortem) on tenderness and colour were further investigated. Results of the first trial showed no clearly established trends of the effect of rigor temperature and time on the cooking and drip losses and protein solubility except venison muscles that went into rigor at 42 °C tended to have higher drip loss and lower protein solubilities compared to muscles that went into rigor at the other temperatures. Venison water holding capacity (WHC) decreased with the increase in rigor temperature (P < 0.001) and venison became more tender with time post-mortem. Venison colour improved with increasing rigor temperature. During display, samples that went into rigor at 15, 25 and 35 °C had the lowest and those at 0 and 42 °C had the highest rate of change of redness (a^*) value with time. In the second trial, tenderness was improved by stimulation (P = 0.01). Redness (a^*) values were affected by rigor temperature (P < 0.01) and post-mortem time (P < 0.001) but not by electrical stimulation. It is concluded that venison tenderness can be improved via the manipulation of rigor temperature to obtain acceptable level of tenderness early post-mortem with less damaging effect on colour stability.