The influence of RN genotype, including the new V199I allele, on the eating quality of pork loin

The eating quality of M. longissimus dorsi (LD) from RN⁻ homozygotes, RN⁻ heterozygotes and RN⁻ non-carriers was investigated in a Swedish Hampshire×Finnish Landrace pig population. The recently identified new allele (V199I, here denoted rn*) at the RN locus was also detected among the pigs selected and included in the sensory evaluation. The number of animals varied from 10 to 15 in the five genotype groups; RN⁻/RN⁻, RN⁻/rn+, RN⁻/rn*, rn+/rn+ and rn+/rn* (in total 59 pigs). In addition, one pig was determined to be rn*/rn* but was excluded from the analysis. The three genotypes in which the RN⁻ allele was represented (RN⁻/RN⁻, RN⁻/rn+ and RN⁻/rn*) had higher glycogen and lower protein contents as well as lower ultimate pH (measured 48 h post-mortem) in LD than the non-carriers (rn+/rn+ and rn+rn*). Of the sensory parameters evaluated (tenderness, chewing time, chewing residual, juiciness, meat flavour and acidity), the five RN genotypes only affected acidity significantly; the RN⁻ allele contributing to a more acid taste in LD. The influence of the rn* allele resembled that of rn+ on the sensory parameters. When the material was divided into three groups (homozygous, heterozygous and non-carriers of the RN⁻ allele) the juiciness was found to be significantly influenced by RN genotype, and LD from animals that were homozygous and heterozygous with respect to the RN⁻ allele exhibited a higher juiciness than LD from non-carriers. The RN⁻ allele also tended to contribute to greater tenderness, which was significantly higher in LD from heterozygous carriers than from non-carriers of the RN⁻ allele. A more rapid decline in pH (measured as pH at 45 min and 3 h post-mortem) contributed to a greater tenderness in LD (according to a trained panel and Warner-Bratzler shear force). In addition to the RN genotype, the decline in pH was influenced by carcass weight, which varied between 71 and 97 kg, and by stunning procedure, which changed during the course of the study from individual to group stunning with CO₂. The individual stunning procedure contributed to a lower pH in the initial post-mortem phase (pH₄₅), whereas a higher carcass weight and the RN⁻ allele lowered the pH in the mid-post-mortem region (pH_3h and pH_24h), significantly (P0.05). The pH continued to decline after 24 h post-mortem and the ultimate pH was not reached until 48 h post-mortem. The cooking loss, juiciness and acidity were related to the specific characteristics of the RN⁻ carriers, such as higher glycogen content, lower protein content and lower ultimate pH (pH_48h).     

Effect of tumbling and RN genotype on sensory perception of cured-smoked pork loin

Effects of tumbling and RN genotype on sensory perception of cured-smoked loins were studied on loins from 32 crossbred female pigs containing Hampshire blood. Right-side loins were intermittently tumbled during 4 h, whereas left-side loins were left non-tumbled. Tumbled loins were more tender and uniform in cured colour as well as less acidulous in taste compared with non-tumbled loins. Further, the formation of undesirable pores was lower in tumbled loins. Final juiciness tended to be higher and meat taste intensity lower in tumbled loins, whereas initial juiciness did not differ. There were no significant interactions between tumbling and RN genotype for sensory attributes. RN⁻ carriers (RN⁻/rn⁺) were more acidulous in taste, had more pronounced meat taste and were saltier than non-carriers (rn⁺ /rn⁺). Moreover, they tended to have higher initial juiciness and more undesirable pores, and be less homogeneous in cured pink colour. No differences in consumer preference between the four treatments were detected in the ranking test, but most persons ranked non-tumbled loins highest regarding overall liking. Instrumental tenderness measurements agreed well with sensory tenderness scores.     

Pore formation in cured-smoked pork determined with image analysis-effects of tumbling and RN(-) gene

The objective of the present study was to investigate the effects of RN genotype (rn⁺/rn⁺ or RN⁻/rn⁺) and tumbling condition (tumbled or non-tumbled) on the number of undesirable pore formation in cured–smoked loins using image analysis. Even when not significant, RN⁻/rn⁺ loins contained more pores than rn⁺/rn⁺ loins. Tumbling clearly decreased the total number of pores, but increased the mean area per pore. Tumbled rn⁺/rn⁺ loins contained half the number of pores compared with tumbled RN⁻/rn⁺ loins. Even if RN genotype and tumbling influenced the number of pores they did not explain the development of pores in processed meat. The high correlations found when comparing the image analysis results with data from a trained sensory panel and visually scored images indicate that image analysis is a good tool in this type of investigations.     

Significance of storage time on degree of blooming and colour stability of pork loin from different crossbreeds

The objective was to investigate the effect of ageing time (1 day vs. 8 days postmortem) and sire breed used in the crossbreed (Duroc sired vs. Landrace sired pigs) on blooming ability and colour stability of pork M. longissimus dorsi (LD). The colour was measured during blooming (0, 10, 30, 60, 90 min and 24 h after cutting) and during subsequent display (1, 2, 3 and 6 days) at 3 °C. The contents of deoxymyoglobin (Mb), oxymyoglobin (MbO₂) and metmyoglobin (MetMb) were calculated. Ageing improved the blooming of LD from both crossbreeds with increased content of MbO₂ and decreased content of Mb, resulting in increased lightness, redness and yellowness. Ageing had smaller effect on colour stability with slightly lower MetMb in aged meat. Crossbreed affected both blooming and colour stability. LD from Landrace-sired pigs bloomed more than LD from Duroc-sired pigs, but more MetMb was formed during subsequent storage, although at a low level in both crossbreeds. The present data show superior colour characteristics of fresh pork aged for 8 days.     

Diverse lamb genotypes-2. Meat pH, colour and tenderness

The effect of genotype on meat ultimate pH, colour and tenderness was studied in 3 experiments involving 436 lambs. The lambs were sired by a selection of Texel (T), Poll Dorset (PD), Border Leicester (BL) and Merino (M) rams, crossed with Border Leicester × Merino (BLM) and Merino (M) ewes giving 6 genotypes (T × BLM, PD × BLM, T × M, PD × M, BLM and M × M). In experiment 1, pH data were obtained for 4 muscles (M. Semimembranosus (SM), M. Biceps femoris M. Semitendinosus and M. Longissimius thoracis et lumborum (LL)) from 198 carcasses representing two sexes (104 cryptorchid males, 94 ewes). There were significant differences for pH between genotypes in both sex groups. BL × M and M × M lambs tended to have higher pH values than the other genotypes.

In experiment 2, meat pH, colour using a chromameter, and tenderness data were obtained for 186 lambs representing two sexes (101 cryptorchid males, 85 ewes). There were few significant differences between genotypes for the various meat quality traits amongst the ewes. The PD × BLM ewes had a significantly lower (p < 0.05) pH than the BL × M ewes for the LL and SM muscles.

The BL × M crypt orchids had a higher LL muscle pH (p < 0.05) than the PD × BLM cryptorchids with other genotypes being intermediate. There were no significant differences between the genotypes for muscle shear force values. Within experiment 2, LL samples were taken from an additional 52 cryptorchid carcasses these being from 3 specific Poll Dorset sires (experiment 3). One of these sires (sire 3) was suspected of carrying a gene for increased muscling. Sire had a significant effect (p < 0.05) on shear force values, cooking loss and L^* colour values, but not a^* or b^* colour values or pH. Sire 3 progeny had significantly (p < 0.001) tougher LL muscles than those from the other 2 sires. Sire 3 also had the lowest L^* values, but was intermediate for cooking loss. There was no significant sire effect on LL area at the same carcass weight, but boneless loins from the progeny of Sire 3 were significantly (p < 0.05) heavier.

In a fourth experiment, meat colour was measured at three sites (LL, diaphragm and M. Obliquus externus abdominis) on 86 cryptorchid carcasses 24 hr post-mortem. There was little association between L^*, a^* and b^* values measured at the different sites.     

Significance of early postmortem temperature and pH decline on colour characteristics of pork loin from different crossbreeds

The significance of early postmortem (pm) temperature and pH decline and the level of the muscle metabolites creatine phosphate (CP) and adenosine triphosphate (ATP) on the colour of porcine M. longissimus dorsi was studied in a factorially designed experiment. Two stress levels peri mortem (minimal stress vs treadmill exercise and electrical stunning of the pigs) and four genotypes (Duroc boars crossed with Landrace–Yorkshire sows vs. Hampshire–Duroc boars crossed with Landrace–Yorkshire sows, including carriers and non-carriers of the halothane and RN⁻ genes, respectively) were included. Early pm muscle temperature and the accompanying pH decline had a significant influence on the pork colour independent of genotype. The combination of high temperature and low pH early pm increased lightness and yellowness, which is ascribed to inactivation of oxygen-consuming enzymes and protein denaturation. The effect of early pm temperature and pH on pork redness was more complex. It appears to be closely related to the extent of heat generation, CP and ATP levels and pH immediately pm in the muscle, which influence the activity of oxygen-consuming enzymes.     

Effect of Duroc content, sex and ageing period on meat and eating quality attributes of pork loin

This study was conducted to determine the effect of percentage Duroc content of entire male and female pigs and ageing period on meat and eating quality attributes of pork loin (M. longissimus thoracis et lumborum). A total of 84 pigs [entire males (n=42) and female (n=42)] of 0% Duroc (100% Large White), 50% Duroc (Duroc×Large White) or 100% Duroc (n=14 pigs per sex×genotype combination) were slaughtered at a liveweight of 100 kg. Steaks from the M. longissimus lumborum of female pigs were aged for either 2 or 7 days post-slaughter and evaluated using a consumer taste panel. Eating quality attributes of tenderness, flavour and overall liking of pork loin steaks from female pigs were not (P>0.05) influenced by Duroc content. Pork from 100% Duroc pigs was juicier (P=0.05) and had a higher (1.84%, P=0.05) intramuscular fat content than pork from 0 and 50% Duroc pigs (1.40 and 1.25%, respectively). Pork from entire male pigs had a lower (P<0.001) intramuscular fat content, was darker (P<0.01) in colour and recorded higher (P<0.01) Warner Bratzler shear force values compared with pork from female carcasses. Ageing pork loin steaks in vacuum bags for 7 days improved tenderness (P<0.01), flavour (P<0.05) and overall liking (P<0.05) compared with steaks aged for 2 days post-slaughter. Ageing of pork steaks for 7 days post-slaughter improved eating quality attributes far more effectively than increasing percentage Duroc content of pigs, which only influenced consumer scores for juiciness.     

Effect of high power ultrasound and ageing on the physical properties of bovine Semitendinosus and Longissimus muscles

Tenderness is an important meat quality parameters and the use of high power ultrasound to disrupt muscle structure may prove effective for reducing both myofibrillar and collagenous toughness. The experiment was carried out with Longissimus lumborum et thoracis and Semitendinosus muscles from 3 to 4 year old steers. Uncooked beef samples (60 × 40 × 20 mm) were treated with high power ultrasound (24 kHz, 12 W/cm²) for up to 240 s, and aged for up to 8.5 days before evaluation of pH, drip loss, cook losses Warner–Bratzler shear (WBS), compression hardness, and colour. Ultrasound treatment significantly reduced WBS force and hardness, but significantly increased pH. Ageing significantly reduced hardness and WBS force, but there was no significant interaction between ultrasound treatment and ageing time. Ultrasound treatment did not affect any of the colour parameters (L^*a^*b^*, chroma and hue) but the ageing time significantly increased the lightness, chroma and hue. There was no significant effect of ultrasound treatment on drip loss, but it did significantly reduce the cook and total loss. During ageing, cook loss and total losses significantly increased. The results suggest that high power ultrasound is capable of reducing objective texture measurements of beef without compromising the other quality parameters investigated.     

Possible mechanism for the effect of the RN(-) allele on pork tenderness

The effect of the dominant RN⁻ allele on rigor development, ageing and tenderness was studied in M. longissimus dorsi (LD) from 11 heterozygous carriers and five non-carriers of the RN⁻ allele. Rigor development was followed by measurements of muscle shortening, isometric tension, pH and FOP. During ageing the myofibrillar length and Warner–Bratzler shear force were measured in the meat. Sensory analysis was performed at 4 days post-mortem using a trained expert panel. It was found that the decrease in pH was faster for RN⁻ carriers than non-carriers during the first 5 h post-mortem, after which the pH-time slope was similar for the two groups. This resulted in a significantly lower mean ultimate pH in LD from RN⁻ carriers than non-carriers. During rigor development the isometric tension was lower in RN⁻ carriers than in non-carriers, while contraction (shortening and sarcomere length) did not differ significantly between the two genotypes. The myofibrillar length, which is an indirect measure of the proteolytic activity that has occurred in the meat, was shorter for the RN⁻ carriers than for the non-carriers. The difference in myofibrillar lengths between the genotypes was significant at 1 and 4 days post-mortem but not at 7 days post-mortem, which indicates that the RN⁻ carriers have a higher proteolytic activity earlier post-mortem. The results from the Warner–Bratzler shear force measurements showed that the meat from the RN⁻ carriers was significantly more tender, 1 and 4 days post-mortem, than the meat from the non-carriers. The meat from non-carriers needed 7 days to reach the tenderness attained by that from the RN⁻ carriers 4 days post-mortem. The greater tenderness in LD from RN⁻ carriers than that from non-carriers was also confirmed by a sensory panel at 4 days post-mortem. In conclusion, differences observed in the course of rigor and ageing in muscle from carriers and non-carriers of the RN⁻ allele suggest that proteolytic action, as initiated by a more rapid fall in pH, is the most important factor governing the variation in tenderness of the two genotypes.     

Effect of low voltage electrical stimulation of pig carcasses and ageing on sensory attributes of fresh pork

The effect of electrically stimulating pig carcasses and ageing on sensory attributes of pork was evaluated in this study. A total of 48 female pigs [Duroc×Large White/Landrace (A; n=24) and Large White/Landrace (B; n=24)] were randomly allocated immediately prior to slaughter to one of two low voltage stimulation treatments; no stimulation or 150 mA applied for 30 s at 2 min post-exsanguination. Each side of the carcass was then randomly allocated to an ageing treatment of either 2 or 7 days post-slaughter. Muscle pH of the M. longissimus lumborum was lower (P<0.001) in electrically stimulated carcasses when measured from 40 min to 8 h post-slaughter compared with non-stimulated carcasses. Percentage drip loss, muscle lightness and PSE incidence were not influenced (P>0.05) by electrical stimulation. Electrical stimulation of pig carcasses and ageing pork for 7 days post-slaughter both improved (P<0.001) consumer scores for tenderness, juiciness, overall liking and quality category, however the interaction term of electrical stimulation and ageing was not significant for any of the sensory attributes. Pork from non-stimulated carcasses that was aged for 2 day post-slaughter was less tender (P<0.01) compared with pork in all other treatments. These results indicate that electrical stimulation (150 mA applied for 30 sec at 2 min post-exsanguination) was effective in improving eating quality attributes of pork, particularly when pork was aged for only 2 days post-slaughter, without detrimentally affecting colour or drip loss.     

The significance of pre-slaughter stress and diet on colour and colour stability of pork

The influence of pre-slaughter stress and a diet known to affect post mortem muscle metabolism or a standard diet (control pigs) on colour and colour stability of m. longissimus dorsi, m. biceps femoris and m. semimembranosus from 112 female pigs, free of the Halothane gene, was investigated. Pre-slaughter stress increased the early post mortem temperature in the three muscles, as well as the pH decline in control pigs, but not in pigs fed the experimental diet. Colour was measured on sliced samples after 0, 2 and 5 days retail display (1, 3 and 6 days post mortem, respectively) from the three muscles aged 1 day before cutting as well as on sliced m. longissimus dorsi samples aged 8 days before cutting (8, 10 and 13 days post mortem, respectively). Early post mortem pH was not a main determinant of the colour and colour stability, while the degree of pre-slaughter stress and especially its influence on temperature early post mortem was crucial in relation to colour development and colour stability. The discoloration rate was enhanced in m. longissimus dorsi aged for 8 days prior to retail display compared with samples aged for 1 day. However, the extent of the discoloration after 5 days of retail display was not inferior in muscle samples aged for 8 days due to a higher degree of blooming. Finally, present data indicate that 3-4 days ageing of pork prior to retail display results in the optimal colour stability.     

The effects of spray and blast-chilling on carcass shrinkage and pork muscle quality

Combinations of blast- and spray-chilling of pork carcasses were compared to spray-chilling at conventional chilling temperatures with regard to carcass shrinkage during chilling and pork muscle quality. In experiment 1, pork sides were spray-chilled at 1°C for the first 10 h (40 spray cycles of 60-s duration every 15 min) of cooling or blast-chilled at −20°C for 1, 2 or 3 h followed by spray-chilling for 9, 8 or 7 h duration, respectively. All pork sides were then chilled to 24 h post mortem at 1°C. Experiment 2 followed the same procedures as experiment 1, except that −40°C was used as the blast-chill temperature.

Carcass shrinkage was similar for all treatments in experiment 1 at 24 h ranging from 0·5–0·7 g 100 g⁻¹. Blast/spray-chilling increased the rate of chilling and reduced the rate of post-mortem pH decline in two muscles (longissimus thoracis, LT and semimembranosus, SM) compared to the combined conventional/spray-chill treatment. Carcasses that were blast-chilled for 3 h had LT muscles that were darker with a higher protein solubility, less drip loss, shorter lengths and higher shear values compared to those from carcasses in the conventional/spray-chill treatment. In experiment 2, carcasses blast-chilled for 3 h at −40°C recorded a weight gain at 24 h of 0·4 g 100 g⁻¹, compared to a weight loss in all other treatments (0·2–0·4 g 100 g⁻¹). Muscle colour was darker in both the LT and SM of carcasses blast-chilled for 3 h at −40°C compared to carcasses from the conventional/spray-chill treatment, but most other measurements of muscle quality showed an inconsistent response to chilling treatment.     

Identification of halothane genotypes by calcium accumulation and their meat quality using live pigs

The three halothane genotypes (NN, Nn, and nm) were identified by measuring the capacity for Ca²⁺ accumulation by sarcoplasmic reticulum in whole muscle homogenate preparations of M. longissimus dorsi with a Ca²⁺ specific electrode at 35°C. Significant differences (P < 0·001) in deterioration (%) of Ca²⁺ accumulation, 12% for NN, 35% for Nn, and 81% for nn pigs, were observed after ageing the whole muscle homogenate preparations for 24 h in ice.

Predictions of meat quality in live pigs (n = 34) based on the values for water-holding capacity, assessed as fluid (g/0·5 g wet wt LD), and pH (fluid) by using small biopsy LD samples (Cheah et al. 1993) were performed on all the halothane genotypes. The halothane genotype NN (n = 11) showed a fluid value of 0·37 ± 0·01 and a pH (fluid) value of 6·62 ± 0·03 as compared with 0·61 ± 0·02 and 5·84 ± 0·04, respectively, for the halothane genotype nn (n = 13). The Nn pigs (n = 10) showed fluid (0·49 ± 0·03) and pH (fluid) (6·19 ± 0·11) values between those values observed for the two homozygotes (NN and nn). Predictions of meat quality in live pigs from biopsy LD muscles were confirmed from assessments on post-mortem LD muscles based on pH₁ and fibre optic probe (FOP) measurements.

The extent of deterioration (%) in Ca²⁺ accumulation showed high correlations with fluid (r = −0·861) and pH (fluid) (r = −0·831) in the biopsy LD samples, and with pH₁ (r = 0·663), FOP (r = −0·812), and drip (%) loss (r = −0·777) in the post-mortem LD samples.     

Effect of transport time and ageing on aspects of beef quality

Forty-eight bulls were transported by road in groups of eight for approximately 30 min, 3 or 6 h in two replicates. After slaughter, steaks from the longissimus dorsi thoracis of all transported animals were analysed in terms of pH, water-holding capacity, myoglobin concentration, texture at 7 and 14 days of ageing (compression and Warner-Bratzler analyses) and colour of the same surface of meat cut at 24 h post-mortem and allowed to bloom for 24 h and 7 d (L^*a^*b^*, chroma and hue). The myofibrillar resistance of the meat from animals transported 30 min was significantly greater at 20% compression (P<0.05). The maximum load and a^*b^* and chroma were all lower for meat aged 14 days.     

The effect of a muscle-glycogen-reducing finishing diet on porcine meat and fat colour

The objective of the present study was to elucidate the significance of a muscle-glycogen-reducing finishing diet containing a high ratio of rapeseed and grass meal on fat colour and pork colour compared with a control diet. Pork colour was determined as the extent of blooming of M. longissimus dorsi (LD) and M. semimembranosus (SM) after 1, 2, 4, 8 and 15 days of aging, while fat colour was measured on back fat and stripped bacon the day after slaughter. The muscle-glycogen-reducing diet significantly decreased the glycogen content measured 1min after slaughter in LD. This was reflected as decrease in early post-mortem temperature, as well as a tendency to higher initial pH in both muscles. Moreover ultimate pH was significantly higher in LD from strategically fed pigs compared to the control group and the same tendency was found in SM. Independent of muscle and time of aging, the colour of bloomed pork from pigs fed the control diet had higher chroma and L(?), a(?) and b(?) values compared with pork from the pigs fed the muscle-glycogen-reducing diet with the effect being most pronounced in LD. This can be explained by the slightly higher pH(45min) in the muscles from the pigs fed the muscle-glycogen-reducing finishing diet, which sustain the metmyoglobin reductase activity and the oxygen consumption potential in the muscle and hereby minimise the degree of blooming. The more pronounced influence of the experimental diet on the degree of blooming in LD compared to SM may be explained by the lower T(45min) in LD, which minimise denaturation of the enzymatic processes. This clearly shows that the diet composition can be used to control the extent of blooming in pork. Finally, despite the high content of grass meal in the muscle-glycogen-reducing finishing diet, this diet had negligible influence on the colour of the back fat and stripped bacon fat.     

Thermal inactivation of lectins (PHA) isolated from Phaseolus vulgaris

The influence of the thermal process on the loss of ability to bind a carbohydrate target was studied on lectins (PHA) purified from Phaseolus vulgaris seeds. Thermal inactivation of aqueous solutions of pure PHA occurred according to a biphasic first-order mechanism, the thermodynamic parameters, at pH 7·3, being as follows: ΔH*₁ = ΔH*₂ = 86·2 kcal mole⁻¹, ΔS*₁ = − 54·04 cal deg⁻¹ and ΔS*₂ = − 56·71 cal deg⁻¹. The first-order rate constants appeared to be dependent on pH (minimal around 7) and divalent cations. All different subunits constituting the whole PHA were inactivated at the same rate. The biphasic nature of this process is independent of the presence of 10 m Ca⁺⁺ or Mg⁺⁺ and appeared to indicate a discrete aggregation of PHA molecules.     

Modification of physico-chemical and colour parameters during the marketing of 'paté'

The evolution of different physico-chemical parameters (iodine number, TBA test, residual nitrite level, pH and moisture) and CIE L^*a^*b^* colour evolution, in pork liver ‘pate’, with and without sodium ascorbate addition, were studied.

The samples were stored in an illuminated display cabinet at different lux intensities and in the dark. The regression equations were obtained for each one of the parameters under study, from the first day of exposure to light.

The sodium ascorbate showed a protective effect on the photo-oxidation mechanism (measured by TBA test), but it did not have an influence on the samples in darkness.

In both types of paté exposed to light, fading takes place and the most important variations in colour parameters are produced during the first 24 h of exposure to light.     

Predicting variability of ageing and toughness in beef M. Longissimus lumborum et thoracis

The object of this study was to determine muscle characteristics which might predict meat toughness. Eleven Charolais cattle were slaughtered at approximately 26 months of age and the Longissimus lumborum et thoracis muscle was taken 1 hr post mortem and stored at 12 °C for 24 hr and then at 4 °C.

The average half-life for ageing in these raw muscles was 4.6 days but the toughness varied widely between the animals. Toughness varied 3-fold and the rate of ageing varied 20-fold between animals.

Correlations were done to determine which characteristics might explain this variability. Toughness was correlated positively with increase in oxidative status of muscle and the initial levels of calpastatin. Toughness was correlated negatively with the initial levels of μ- and m-calpains and cysteine and serine proteinase inhibitors, the initial pH values and the rates of their decline. The rates of ageing were highly correlated positively with the initial levels of proteinase inhibitors and the rates of decline of calpastatin and negatively with the ultimate amounts of expressible juice.

There was a wide variability in tenderness in M. Longissimus lumborum et thoracis from similar animals. Variations in metabolism and enzyme activity controlled by inhibitors and calpains appear to be largely responsible for this variability.     

Colour and texture characteristics in meat of male and female foals

The effect of livestock production system and sex was studied on the colour and on the texture profile of the longissimus dorsi muscle (LD) from 16- and 24-month-old foals aged 4 days. Besides, the effect of ageing time was also studied on the texture profile between 4 and 8 days. Females from the 16-months group were darker than their counterparts and the 4-day aged steaks of the 24-month-old foals were lighter, redder and yellower. LD muscle of the 24-month-old foals was tougher after 4 and 8 days ageing than that of the younger foals besides in the 24-month-old foals the toughness may have been accentuated by lower growth rate prior to slaughter. Ageing improved tenderness but the rate of tenderisation was different according to age. The colour coordinates a^* and b^* could differentiate the 4-day aged steaks of the foal samples according to production system to a higher degree than did the compression or WBSF values being b^* values the most important colour coordinate which could discriminate the origin of the animals.     

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.