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International audience; Over the last two decades, proteomics have been employed to decipher the underlying factors contributing to variation in the quality of muscle foods, including beef tenderness. One such approach is the application of high throughput protein analytical platforms in the identification of meat quality biomarkers. To broaden our understanding about the biological mechanisms underpinning meat tenderization across a large number of studies, an integromics study was performed to review the current status of protein biomarker discovery targeting beef tenderness. This meta-analysis is the first to gather and propose a comprehensive list of 124 putative protein biomarkers derived from 28 independent proteomics-based experiments, from which 33 robust candidates were identified worthy of evaluation using targeted or untargeted data-independent acquisition proteomic methods. We further provide an overview of the interconnectedness of the main biological pathways impacting tenderness determination after multistep analyses including Gene Ontology annotations, pathway and process enrichment and literature mining, and specifically discuss the major proteins and pathways most often reported in proteomics research.

Post-mortem (p-m) muscle undergoes a myriad of complex physical and biochemical changes prior to its conversion to meat, which are influential on proteolysis and hence tenderization. A more in-depth understanding of the mechanisms underpinning these dynamics is a key to consistently providing tender beef. Using an LC-MS/MS approach, with state-of-art mass spectrometry Q Exactive HF-X, the proteome and associated pathways contributing to the appearance of the proteolytic breakdown products appearing over 14 days p-m, at two important molecular weights (110 and 30 kDa) on 1D SDS-PAGE gels, have been investigated in beef longissimus thoracis et lumborum muscles exhibiting four rates of pH decline differentiated on the basis of time at pH 6 (fast glycolysing, or = medium > slow > very slow. The day 2 p-m appearance of the 30 kDa band was most evident for the fast glycolysing muscle with little or no evidence of appearance in slow and very slow. For days 7 and 14 p-m, the strength of appearance was dependent on glycolysing groups fast > medium > or = slow > very slow. LC-MS/MS analysis yielded a total of 22 unique proteins for the 110 kDa fragment and 13 for the 30 kDa, with 4 common proteins related to both the actin and fibrinogen complex. The Gene Ontology analysis revealed that a myriad of biological pathways are influential with many related to proteins involved primarily in muscle contraction and structure. Other pathways of interest include energy metabolism, apoptotic mitochondrial changes, calcium and ion transport, and so on. Interestingly, most of the proteins composing the fragments were so far identified as biomarkers of beef tenderness and other quality traits.

This study evaluated the contributions of sensory traits to overall liking in Europe. Perceptions by untrained consumers of tenderness, juiciness, flavor liking and overall liking were determined using the Meat Standards Australia protocols. According to European consumer testing with European beef samples, flavor liking was the most important contributor (39%) to beef overall liking, followed by tenderness (31%) and juiciness (24%) (P0.94). The improvement in tenderness over the last decades may explain the highest contribution of flavor liking nowadays. Flavor liking is therefore the main driver of variability in overall liking. Juiciness is the least robust trait which could be influenced by other traits during consumer perception. For outstanding steaks, each sensory trait should have excellent scores and high contributions to overall liking. For medium cuts, one sensory trait with a low score has the potential to be compensated by other traits with higher scores and more emphasis will be placed on the trait with the lowest perception.

The ability of brown seaweed extracts, Ascophyllum nodosum, Laminaria hyperborea, Pelvetia canaliculata, Fucus vesiculosus and Fucus serratus to protect against tert-butyl hydroperoxide (tert-BOOH) induced stress in Caco-2 cells was investigated. Oxidative stress was determined by measuring alteration in the enzymatic activity of catalase (CAT) and superoxide dismutases (SOD) and cellular levels of glutathione (GSH). L. hyperborea, P. canaliculata and F. serratus significantly protected against tert-BOOH induced SOD reduction but did not protect against the reduction in CAT activity or the increased cellular levels of GSH. The ability of F. serratus and F. vesiculosus to protect against H(2)O(2) and tert-BOOH induced DNA damage was also assessed. The DNA protective effects of the two seaweed extracts was compared to those of three metal chelators; deferoxamine mesylate (DFO), 1,10-phenanthroline (o-phen) and 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (BAPTA-AM). F. serratus and F. vesiculosus significantly protected (P

To examine the effect of a modification of a typically Irish dairy calf-to-beef production system, Charolais × Friesian steers were offered a finishing ration of grass silage ad libitum and 5.6 kg concentrates daily for 174 days prior to slaughter at 25 months of age or grass silage ad libitum for 174 days, followed by pasture for 167 days and slaughter at 30 months of age. Finishing at pasture increased carcass weight (376 vs. 342 kg) but did not affect intra-muscular lipid concentration (28 vs. 24 g/kg). Finishing at pasture decreased Longissimus thoracis et lumborum lightness (35.6 vs. 36.9) and increased shear force of muscle at 2 (8.54 vs 4.32) and 7 days (5.21 vs 3.64 kg) post-mortem but not at 14 days post-mortem (4.45 vs. 3.42 kg). Finishing at pasture did not affect the sensory characteristics of tenderness, juiciness, firmness or chewiness and tended (P

The antioxidant potential of methanolic extracts of brown seaweeds was assessed by Total Phenol Content, Ferric Reducing Antioxidant Power (FRAP), β-carotene bleaching and the DPPH scavenging assays. Ascophyllum nodosum, Pelvetia canaliculata, and Fucus serratus contained the highest phenol concentrations while Fucus vesiculosus and F. serratus exhibited the highest FRAP activities. F. vesiculosus and A. nodosum were the most effective extracts at scavenging DPPH radicals and preventing β-carotene bleaching. The antioxidant activity of the seaweed extracts was also evaluated in Caco-2 cells. All extracts significantly (P

Connective tissue of three porcine muscles (M. infraspinatus, IS; M. longissimus dorsi, LD; M. semimembranosus, SM) from 27 animals [populations A (n = 13, reared in Ireland) and B (n = 14, reared in Finland)] was studied by measuring the collagen content, collagen solubility and thermal shrinkage temperature of the connective tissue. Colour and pH were also determined. Collagen solubility was highest in IS (p < 0.05) and lowest in SM (p < 0.05) although no difference between LD and SM was found in population B. The onset and peak temperatures of thermal shrinkage (To and Tp) were highest in IS (p < 0.05). The lowest To and Tp were found in SM from population B whereas no differences were seen between LD and SM muscles in population A. It was concluded that the thermal stability of the connective tissue in the three porcine muscles differ. IS, as a dark muscle has high thermal shrinkage temperatures and high collagen solubilities in comparison to the lighter LD and SM muscles which have lower thermal shrinkage temperatures and collagen solubilities. Collagen contents were highest in IS and lowest in LD.

The objective of this study was to evaluate the importance of proteolysis and sarcomere length in determining the tenderness of bovine M. longissimus dorsi (LD) muscle over a 21-day period. This was done by altering the pre-rigor glycolytic behaviour of hot-boned LD muscles using different early post-mortem temperature regimes. Hot-boned LD muscles (n=8) were cut in two, randomised, placed in polythene bags and submerged in a water bath set at 5°C (rapidly chilled) and 15°C (slowly chilled) for 8h post-mortem. All muscles were then stored at 2°C for up to 21 days post-mortem. The temperature regimes altered the glycolytic behaviour of the muscles in the pre-rigor period. The slowly chilled muscles exhibited a faster (P0.01) pH fall than rapidly chilled muscles. Cold shortening was induced in rapidly chilled muscles as they had shorter (P0.01) sarcomere lengths than slowly chilled muscles up to day 21 post-mortem. Warner Bratzler shear force values (WBSF) deemed cold-shortened muscles as tougher than noncold shortened up to day 14 post-mortem. Both cold-shortened and noncold-shortened muscles tenderised over time to an extent where there was no significant difference in WBSF values by day 21 post-mortem. SDS-PAGE protein profiles indicated that the rate of proteolysis was faster in slowly chilled muscles when compared to rapidly chilled muscles. However by day 21 post-mortem it appeared that rapidly and slowly chilled muscles underwent proteolysis to the same extent.

Pork loins were pumped to 110% of original weight with solutions containing 5.5% salt and 3.3% sodium tripolyphosphate, 5.5% salt and 3.3% β-lactoglobulin (β-lg) enriched fraction or 5.5% salt and 3.3% whey protein concentrate 80% (WPC80) for comparison with non-enhanced control loins. The enhancement of pork loins significantly increased (p

This study characterised the lipid classes of Longissimus dorsi (LD) muscle and the fatty acid profiles of the LD intramuscular fat and subcutaneous (SC) adipose tissue of male and female foal mixed populations. Two animal groups were studied based on slaughter ages of 16 and 24 months. The sex of the animals had no statistical significance in the lipid fractions of the LD muscle or in the intramuscular fatty acids (p⩾0.05). In contrast, there was a significant effect of sex on the fatty acid profile of the SC adipose tissue. Furthermore, the livestock production system showed difference in both lipid class and fatty acid profiles from the LD and SC adipose tissues. The LD of 24-month old foals had lower phospholipids content (p⩽0.001), displayed little difference in saturated fatty acids (SFA) (p⩽0.1), exhibited higher levels of monounsaturated fatty acids (MUFA) (p⩽0.05) and lower levels of polyunsaturated fatty acids (PUFA) (p⩽0.05) compared with that of the 16-month old foals. Furthermore, the fatty acid profile of the SC adipose tissue of the 24-month old foals had higher SFA (p⩽0.05) and PUFA (p⩽0.01) with lower amounts of MUFA (p⩽0.001) relative to the 16-month old foals.

Loose structure and PSE like zones on the lateral surface of porcine semimembranosus muscle have beenobserved by other researchers. However the role of connective tissue in this abnormally loose structure insemimembranosus muscle has not yet been clarified. We collected about 100g samples from 7 loosestructured and 7 normal structured Irish commercial porcine semimembranosus muscles in order tocompare the onset and peak of thermal transition temperature of intramuscular connective tissue betweenthe samples from the two groups. Meat quality parameters, ultimate pH, rough estimate for drip loss,lightness (L), redness (a) yellowness (b) and as well as electrical conductivity and reflectance were alsomeasured on the samples. Four of the samples characterized as normal by visual assessment showed DFDcharacteristic so the statistical analysis was carried out both including and excluding those samples. Inboth cases the onset (p

Variation in quality traits may occur between the different muscles within a carcass and also within a muscle. This study examined inter- and intramuscular variation and the resulting effect on measurements (pH, conductivity and colour) taken within 24 h post mortem. The effect of shackling on these quality prediction measurements was also determined. Finally the inherent variability of quality attributes within porcine M. longissimus thoracis et lumborum (LTL) was examined at 4 days post mortem. Significant intermuscular variation was detected at 24 h post mortem, with higher pH and conductivity values recorded in the M. semimembranosus (SM) than in the LTL. pH and conductivity measurements in both muscle types were correlated (r = 0.46–0.88, P < 0.05) at 45 min and 3 h post mortem. CIE L* and a* values, % reflectance and Japanese pork colour scores were significantly (P < 0.001) different in the neck region (M. biventer cervicis and M. splenius) than on the surface of the SM and M. gluteus medius. An intramuscular effect was not observed in either SM or LTL muscles. Shackling did not introduce a significant variation between sides for pH, conductivity and colour measurements taken up to 24 h post mortem. At 4 days post mortem it was determined that the water-holding capacity, tenderness (Warner–Bratzler Shear force) and composition of the LTL are not dependent on sampling location within the muscle. These results suggest that meat quality measurements are uniform throughout the LTL (loin) and that a significant relationship exists between the LTL and SM muscles. Copyright © 2005 Society of Chemical Industry

Meat products manufactured from low-value cuts may be unacceptably tough because of the high connective tissue content of meats used in their manufacture. The effects of shin beef treated with lactic acid at two concentrations (0.5 mol/L and 0.05 mol/L) and citric acid (0.05 mol/L) on cook loss, colour, textural and sensory characteristics of frankfurters were investigated. The results were compared to two controls containing high and low-value beef. Results indicate that the acids had little or no effect on cook loss and at the low concentrations had no apparent tenderising effect in comparison to the control shin beef. However, a significant effect on tenderness (P

Hereford cross heifers ( n =3) were slaughtered and hung conventionally. At 1 h post-mortem the M. longissimus dorsi (LD) was excised, vacuum packaged in plastic bags and stored at 4°C. Samples were taken from each of eight different locations along the length of the LD muscle at 1 h, 1, 3 and 15 days post-mortem for extraction using 5% TCA. Supernatants were stored at −20°C until analysis by HPLC. Peptides produced during the storage of beef were isolated by high performance liquid chromatography (HPLC). Results show that these components increase in quantity from 1 h to 15 days post-mortem. Five fractions were collected which correspond to various peaks of interest. These fractions were subsequently analysed by mass spectrometry and amino acid sequencing to reveal their identity. Fractions 1 and 2 were found to be mixtures of low molecular components. Fractions 3, 4 and 5 were found to be proteolytic fragmentation products of glyceraldehyde-3-phosphate dehydrogenase, troponin T and creatine kinase, respectively. Enhanced appearance of proteolytic fragments from these parent proteins with muscle ageing suggest that they may be useful indicators of meat quality. Further work incorporating sensory and/or texture evaluation of muscle tissue is required to investigate this issue

Proteolysis of myofibrillar proteins results in an increase in substrate made available for the release of free amino acids. Levels of these amino acids have previously been determined in different muscles over the post mortem ageing period in beef. However, there is a shortage of information available regarding variations within a muscle over this ageing period. The objective of this study was to carry out preliminary investigations into the free amino acid levels in eight locations along the M. longissimus dorsi (LD) over the post mortem ageing period. Free amino acids were analysed in the LD of three Hereford cross heifers at 1 h, 1, 3 and 15 day post mortem. In general most amino acids increased in all locations over the ageing period while a 100% increase was observed in total amino acids averaged over the eight locations. More variations occurred between locations in the earlier post mortem period, however, there were no consistent differences during ageing which might suggest variations in proteolytic activity along the LD. As these analyses were carried out on three animals a larger number of animals would need to be sampled to verify these results.

The optimising of the composition of ingredients has a major effect on the properties of low-fat products. The purpose of this research was to assess the effects of added tapioca starch (ranging from 0–30 g/kg), oat fibre (ranging from 0–20 g/kg) and whey protein (ranging from 0–20 g/kg) on the physical and organoleptic characteristics of low-fat beef burgers. Response surface methodology (RSM) was used to study the simultaneous effects of these three ingredients. Significant models of regression were ascertained for cooking properties (yield and water holding capacity), the sensory attributes of tenderness and juiciness, and all mechanical texture attributes. The level of tapioca starch (TS) influenced the models to the greatest extent. Its effect on the cooking properties was highly significant, positive and linear. The presence of TS had a large negative linear effect on Warner-Bratzler and Kramer shear forces. For each significant regression model, TS exerted a linear effect, and in some cases a quadratic effect. Both oat fibre and whey protein had a limited influence. There was no evidence of interactions among the variables. The results indicate that as the TS in low-fat beef burgers increases a succulent and tender low-fat product is obtained.

Heifers (n = 70) were slaughtered and hung conventionally in an industrial meat plant. Near infrared (NIR) spectroscopy was studied for its ability to predict selected meat quality attributes, i.e. Warner-Bratzler shear force (WBSF), sensory tenderness, texture, flavour and acceptability. Freshly cut steaks (2.5 cm thick) were taken from the longissimus dorsi (LD) muscle at 1, 2, 7 and 14 days post mortem for NIR analysis. Other samples (also 2.5 cm thick) were taken at 2, 7 and 14 days post mortem, vacuum-packaged in plastic bags and stored at -20 °C for WBSF measurement and sensory analysis. Heifers were slaughtered in two groups; between slaughterings, replacement of the spectrophotometer lamp and lamp assembly was necessitated by a bulb failure. Using principal component regression (PCR), correlation coefficients of 0.82 and 0.73 were obtained for the prediction of WBSF in sample sets 1 and 2, respectively. On merging both sample sets, this value was lowered slightly (r = 0.61). Correlation coefficients obtained for the prediction of tenderness, texture, flavour and acceptability were 0.67, 0.53, 0.51 and 0.46 respectively (set 1); 0.72, 0.71, 0.45 and 0.67 (set 2); 0.53, 0.54, 0.24 and 0.42 (combined sets).

The objective was to determine the effect of pre-slaughter growth rate on feed efficiency, components of body growth and on the tenderness of longissimus muscle from steers reared to a common age and carcass weight. Sixty Friesian steers were group-housed and offered grass silage ad libitum and 3.5 kg concentrates per animal daily for 5 months and then 5 kg concentrates and 1 kg grass hay for 1 month before the experiment began. The animals were then weighed and in a randomised block were assigned to one of 5 groups, for slaughter at the beginning of the experiment or to be offered concentrates and hay (900 and 100 g/kg total diet, respectively) to achieve target growths of: 0.72 kg/day continuously for 17 weeks, 0.36 kg/day for the first 8 weeks and 1.08 kg/day for the final 8 weeks (low–high), 1.08 kg/day for the first 8 weeks and 0.36 for the final 8 weeks (high–low) or 0.36 kg/day for the first 2 weeks, 0.72 kg/day during weeks 4 and 14 and 1.08 kg/day for the final 2 weeks (pulse). One week was allowed for transition to the different dietary allowances within each energy supply pattern. The mean age at the beginning and end of the study was 18 and 22.5 months, respectively. After slaughter, the weight of the carcass and kidney + channel fat depot were recorded, the pistola hind quarter was dissected into fat, lean and bone and the tenderness of the m. longissimus thoracis et lumborum (LTM) muscle was measured instrumentally and using a trained taste panel after 2, 7 or 14 days ageing. The pattern of energy supply did not affect carcass weight, fat score or kidney + channel fat weight. The pistola hind quarter from animals offered the low–high energy pattern had a similar composition to the continuously-fed animals but contained more muscle than that from animals offered high–low or pulse energy patterns. After 14 days ageing, LTM from the continuously-fed animals was more tender than that from animals offered the other energy supply patterns but shear force did not differ between supply patterns. The data do not support the hypothesis that pre-slaughter growth rate increases tenderness but suggest that energy supply pattern can influence body composition of finishing cattle.

The objective of this study was to determine if there is an association between tenderness in bovine M. longisimus dorsi (LD) and polymorphisms in the bovine calpain I (exons 9 & 14), calpain II (regulatory subunit) or growth hormone (intron 3) genes. Genomic DNA was isolated from bovine LD (n=281) on which quality attributes (Warner Bratzler shear force (WBSF), sarcomere length and composition) were also characterised. DNA polymorphisms were analysed using polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis. Association analyses were performed between genotypes at the four polymorphic loci and day 14 WBSF values. It was found that the calpain 1 exon 9 genotypes had an association with WBSF such that animals with the GA genotype exhibited decreased WBSF and increased tenderness when compared to animals with the GG genotype (P

The objective of this study was to determine the effects of hot-boning, low voltage electrical stimulation (ES) and chilling temperature on the tenderness of bovine M. longissimus dorsi (LD) and M. semimembranosus (SM) muscles. LD (n=32) and SM (n=32) muscles were subjected to different post-mortem treatments; hot-boning (before 90min post-mortem), cold-boning (at 48h post-mortem), low voltage ES and rapid or slow chilling. Hot-boned muscles which were not electrically stimulated (NES) had higher Warner Bratzler shear force (WBSF) values (P0.001) and shorter sarcomeres (P0.001) than cold-boned muscles. Hot-boned muscles subjected to ES had lower pH values (P0.001) post-stimulation and up to 8h post-mortem than NES muscles. At both chilling temperatures WBSF values were lower in ES hot-boned LD and SM muscles at days 2, 7 and 14 post-mortem than NES muscles. Hot-boned muscles subjected to slow chilling had longer sarcomeres (P0.001) than those subjected to fast chilling. In hot-boned SM muscles, ES resulted in longer sarcomere lengths (P0.001). However, ES did not have a significant effect on the sarcomere length of LD muscles. As indicated by WBSF values all muscles tenderised during ageing, including muscles which were 'cold shortened'. Proteolysis was not the main reason for differences in WBSF values between ES and NES muscles as judged by qualitative sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). A combination of slow chilling and ES had a positive effect on hot-boned muscles with respect to WBSF values.

The aim of this study was to monitor the effects of the alteration of the pre-rigor environment of the bovine LD muscle using controlled temperature regimes in order to gain an insight into the early post-mortem pH/temperature/time interactions which are important from the point of view of tenderness and to identify possible reasons for inconsistencies in beef tenderness. LD muscles (n=12) were hot-boned within 90min post-slaughter, cut into three pieces which were randomly placed in polyethylene bags and submerged in water baths pre-set at the following temperatures; 0, 5, 10, 15, 20 and 25°C for 8 h post-mortem then stored at 2°C for up to 14-days post-mortem. The rate of pH decline increased with increasing temperature. Muscles incubated at 0 and 5°C were cold shortened however not all of these muscles were tough as indicated by Warner Bratzler shear force values (WBSF). A pH range of 5.9-6.2 at 3 h post-mortem (pH(3)) produced consistently tender beef where cold-shortening was avoided. Cold shortened muscles showed the greatest variation in tenderness at 14 days post-mortem and underwent the greatest amount of tenderisation (ΔWBSF) and proteolysis between days 2 and 14 post-mortem. Proteolysis of cold shortened muscle may induce variation in tenderness in these muscles.

Four Beta-lactoglobulin (β-lg) enriched fractions containing different mineral contents were prepared and evaluated in frankfurters. Frankfurters were assessed for cook loss, water holding capacity (WHC), textural and sensory characteristics. The addition of the β-lg fractions reduced the cook loss (p0.001) in comparison to the control (6.63% vs 3.98%). The fractions (β-lg 1 and 2) with the lowest calcium level significantly reduced WHC (p0.01). The β-lg fractions had no detrimental effect on the sensory characteristics (p0.05). All of the fractions increased the TPA value of hardness in comparison to the control (p0.001) while the springiness decreased in the fractions (p0.001) with the lowest mineral level. This study showed that the mineral composition of the β-lactoglobulin fractions affected cook loss, tenderness and hardness (TPA) of the frankfurters and the addition of the β-lactoglobulin enriched fraction did not affect the organoleptic quality of frankfurters in comparison to the control. This study shows the potential for next generation whey protein fractions and their application in meat products.

Proteolytic degradation of muscle, which occurs post-mortem as part of the meat-ageing process, results in the production of protein fragments. In beef, degradation of skeletal muscle troponin T (TnT) results in the generation of a 16-residue long peptide (TnT (16-31)), identified in trichloroacetic acid (TCA) soluble extracts. We report the development of a competitive enzyme-linked immunosorbent assay (ELISA) for the quantification of TnT (16-31), using polyclonal antibodies raised against synthetic TnT (16-31). The ELISA procedure is based on inhibition of binding of the antibodies to immobilised TnT (16-31) by TnT (16-31) present in solution. Its useful range is 30 pmol to 2 nmol TnT (16-31)/ml. Quantification of TnT (16-31) in TCA muscle extracts showed that its concentration was enhanced with ageing. Moreover, a correlation between TnT (16-31) levels and meat tenderness was observed. The ELISA developed herein may prove advantageous for future use at the research and industrial level.

Probes, which can be used on-line to rapidly and efficiently detect beef quality attributes (colour and tenderness), are currently being considered to predict ultimate beef quality. The contribution of the inherent sampling variability (due to factors such as muscle location) needs to be evaluated in order to optimise the sampling procedure for these measurements. The main objective of this trial was to monitor some sampling factors which may contribute to variation in pH and various quality attributes in bovine M. longissimus thoracis et lumborum (LTL). Location along the muscle did not impact on colour measurements ( P ⩾0.05). Location had no effect on cook loss, Warner Bratzler shear force (WBSF) and sarcomere length values ( P ⩾0.05). The moisture and intramuscular fat contents did vary ( P ⩾0.05); however, as the differences were very small this may not be of practical significance. Different models of pH meters/probes had a significant influence ( P ⩽0.01) on recorded pH values. However pH did not differ significantly ( P ⩾0.05) along the length of the LTL. The type of meter used also had a significant impact on colour readings and 1 h ‘blooming’ time was observed as optimal for measuring colour on beef.

Rapid chilling of lamb has major economic advantages for the meat industry. Rapid chilling can reduce weight loss from approximately 2% in normally chilled lamb to approximately 1.2%. These weight loss reductions are a major financial incentive for rapid chilling. With rapid chilling, the requirement for overnight chilling can be eliminated and carcasses can be dispatched to commercial markets on the day of slaughter. When properly carried out, rapid chilling results in lamb carcasses that are not tougher than normally chilled lamb. During the work, considerable variation in shear force values for individual lamb carcasses was encountered irrespective of the chilling treatment. This variation in tenderness appears to be due mainly to animal variation rather than external environmental factors. Continuous monitoring of carcass weight during chilling and subsequent storage indicated that rapidly chilled carcasses gained weight appreciably when moved at the end of the rapid chilling period to the storage chill (4 °C). This increase in weight was the main cause of decreased weight loss associated with rapid chilling. The differences found in weight loss between rapidly chilled carcasses and normally chilled carcasses can be maintained over 5 days of chilled storage when the carcasses are stored at 4 °C and > 90% relative humidity.

The perception of healthiness and/or safety, tenderness, juiciness and aroma or flavour are important quality criteria that influence the decision of a consumer to purchase beef. Beef production systems represent the combined and interacting effects of genotype, gender, age at slaughter and nutrition before slaughter. The present paper highlights recent information on how beef production systems can be modified to enhance the tenderness, flavour and healthiness of beef. Carcass management post-slaughter has a larger effect on meat tenderness than gender, genotype or feeding systems. Optimum ‘pasture to plate’ management systems are being established to ensure beef tenderness. The chemistry underlying beef flavour is complex, with in excess of 140 components identified in cooked beef volatiles. Flavour of beef is influenced by cattle diet, but assessment of flavour by a taste panel is subject to the previous experiences and preferences of the panellists. Modern lean beef can have an intramuscular fat concentration of 25–50 g/kg and can be considered a low-fat food. As the quantity of grass in the diet of cattle is increased, there is a decrease in saturated fatty acid concentration, and an increase in then-3 polyunsaturated fatty acid and conjugated linoleic acid concentrations. It is concluded that there is opportunity to exploit the diet of cattle to produce tender flavoursome beef that has an increased conjugated linoleic acid concentration, a lower fat concentration and a fatty acid profile more compatible with current human dietary recommendations.

The objective of this experiment was to determine the effect of varying the proportions of autumn grass and concentrates and grass silage and concentrates on the quality of meat from cattle with similar rates of carcass growth. Fifty continental crossbred steers were assigned to five treatments. The experimental diets offered were (1) grass silage ad libitum plus 4 kg concentrate (SC), (2) 1 kg hay plus 8 kg concentrate (CO), (3) 6 kg grass dry matter (DM) plus 5 kg concentrate (CG), (4) 12 kg grass DM plus 2.5 kg concentrate (GC) and (5) 22 kg grass DM (GO). The experiment lasted 85 days after which all animals were slaughtered. The right side m. longissmus dorsi was excised from all animals 24 h post slaughter for assessment of meat quality. Treatments SC and CO resulted in animals with whiter (P

Heifers (n=47) were slaughtered and hung conventionally in an industrial meat plant. Electrical impedance (Py) and conductivity (EC) were studied for their ability to indicate or predict selected meat quality attributes i.e. Warner-Bratzler shear force (WBSF), sensory tenderness, texture, flavour and acceptability, water holding capacity (WHC) and colour. pH, electrical impedance (meat check) and electrical conductivity (pork quality meter) measurements were taken at hourly intervals up to 8 h and again at 1 and 2 days postmortem. Electrical measurements were taken again at 7 and 14 days postmortem. Freshly cut steaks (2.5 cm thick) were taken from the longissimus dorsi (LD) muscle at 2, 7 and 14 days postmortem, vacuum-packaged in plastic bags and stored at -20°C for WBSF and sensory analysis. Freshly cut steaks were used for WHC and colour measurements. During the development of rigor and over the ageing period, electrical changes occur in muscle tissue. Electrical measurements were found to change significantly between 1 and 14 days postmortem and when measured over the ageing period (at 2, 7 and 14 days postmortem) were significantly correlated to WBSF, sensory tenderness and Hunter 'a' and 'b' values (r=±0.56-±0.68, p

The activities of lysosomal cathepsins and the calpain-calpastatin system were measured to determine their involvement in the more rapid tenderisation of fast glycolysing muscle. The rate of pH fall of M. longissimus dorsi (LD) of Hereford cross Friesian heifers (n = 52, Experiment 1; n = 36, Experiment 2) was measured. Muscles were selected according to their rate of glycolysis; slow and fast (n = 16, Experiment 1; n = 10, Experiment 2). Fast glycolysing muscles were rated more tender in sensory analysis and had a lower shear force than slow glycolysing muscles. Slow glycolysing muscles had shorter sarcomere lengths. Low pH conditions in fast glycolysing muscle correlated with the enhanced release of cathepsins B and L from lysosomes. Calpain I activity was higher and calpastatin activity was lower in fast glycolysing muscle early post mortem. SDS-PAGE electrophoresis patterns showed increased proteolysis, such as the earlier appearance of the 30 kDa fragment in fast glycolysing muscle. Transmission Electron Microscopy (TEM) results showed a greater degree of ultrastructural breakdown early post mortem in fast glycolysing muscle. The results suggest that the increase in tenderness in muscles that undergo fast glycolysis early post mortem may be caused by proteolysis by released lysosomal cathepsins and calpain I uninhibited by calpastatin.

The rate of early post-mortem pH fall in bovine muscle was studied to determine its influence on the rate and extent of the tenderisation process. The pH of M. longissimus dorsi (LD) and M. semimembranosus (SM) muscles of Hereford cross Friesian heifers (n = 127) was taken up to 24 h post mortem. Twenty-four LD and 24 SM muscles were selected according to their rate of pH fall; slow (n = 8), intermediate (n = 8) and fast (n = 8) and were sampled at 2, 7 and 14 days post mortem for sensory, mechanical, physicochemical and biochemical analysis. Fast glycolysing LD muscles were rated more tender in sensory analysis and texture assessment whereas slow glycolysing muscles were considered significantly tougher (p < 0.001). Fast glycolysing LD had a significantly lower shear force (p < 0.001) at each stage of ageing. Slow glycolysing LD and SM had the highest shear force values. No significant difference was found in intramuscular fat or moisture content between the groups. Slow glycolysing LD muscles had shorter sarcomere lengths at 2 days post mortem. SDS-PAGE electrophoresis patterns showed increased proteolysis, such as the earlier appearance of the 30 kDa fragment, which is believed to be a good indicator of tenderness, in fast glycolysing muscle. These results suggest that the rate of post-mortem pH fall plays an important role in proteolysis and tenderisation.

three changes of PBS, and incubated for 1 h in an appropriate dilution of patients serum in PBS/Tween 20 (1/200 dilution for IgG detection, 1/100 dilution for IgA or IgM detection). After washing, strips were incubated in peroxidase-labelled goat-anti-human IgG, IgA or IgM antibody (Tago) (1/500 dilution in PBS/Tween 20), and substrate added (1 5 mg of 3-amino-9-ethyl carbazole in 4 ml of dimethylsulphoxide, 46 ml of 0.02 M-acetate buffer, pH 5, 100 pl of H202) . Serum from patients, with candida septicaemia (n = lo), candida urinary tract infection (UTI) (n = 32), oral candidiasis (n = 20) and healthy controls (n = 60), was used. The IgG, IgA and IgM antibody responses of patients (adults, children, neonates) were analysed, and a representative profile of each group is shown in Fig. 1. A marked heterogeneity in the antibody response to cytoplasmic antigens in candida-infected individuals was observed. The antibody response of both adults and children with candida septicaemia, or candida UTI, was predominantly of the IgG class, and was directed against a wide range of antigens of molecular masses 93-1 8 kDa. Serum from all patients reacted with a 45 kDa band. However, the response seen in neonates with UTI differed significantly since the antibodies produced were predominantly IgM, and reacted with 21 kDa and 18 kDa bands. This IgM response may represent a primary immunization with candida. The antibody responses of patients with oral candidiasis differ from other groups in that the IgG and IgA antibody levels are often of equal strength. The 45 kDa band is recognized by most patients, but in 60% of patients with oral candidiasis no antibodies were detected. This may reflect a less serious disease state in these individuals. Thirty-eight per cent of controls had IgG antibodies to the 45kDa band, and to other minor bands, while 62% of controls were negative. The level of positivity in controls may reflect cross-reacting antibodies recognizing candida antigens, or may be the result of a previous subclinical infection. These results emphasize the need to identify infection specific antigens for accurate diagnosis of severe candida infections.