A note on the effect of post-mortem maturation on colour of bovine Longissimus dorsi muscle

peer-reviewedFinancial support to P.G. Dunne was provided under the Walsh Fellowship programme of Teagasc.Fifteen heifers were housed and fed a concentrate diet while 54 counterparts grazed at pasture for 90 days at which stage six heifers from each group were slaughtered. The remaining animals in the pasture group were then housed and offered either: concentrate only; concentrate plus grass silage with silage accounting for either 20% or 50% of the total dry matter offered; or zero-grazed grass plus concentrate with grass accounting for 83% of the dry matter offered. Heifers (3/diet) were slaughtered 28, 56, 91 and 120 days thereafter. Colour characteristics of M. longissimus dorsi (LD) were measured at 48 h post mortem. The LD was then vacuum-packaged and stored at between 0 and 4 °C in darkness for 12 days, when colour characteristics were again measured. Maturation of LD resulted in meat that had higher redness values (‘a’ value; P<0.001) and a more intense red colour (higher ‘C’ value; P<0.001) at 14 days post mortem than at 2 days, regardless of diet/duration of feeding. Maturation also resulted in a brighter colour (higher ‘L’ value; P<0.001) but this difference was greatest when cattle were slaughtered the day-56 time point

The Tenderisation of Shin Beef Using a Citrus Juice Marinade

The effectiveness of organic acids (acetic, citric, lactic) and a citrus juice marinade as tenderising agents in shin beef muscle was investigated. At 0.2 M, citric acid was more effective as a tenderising agent than acetic or lactic acid. Immersion of shin beef strips in citric acid (0–0.05 M) showed that a significant tenderising effect was obtained above a concentration of 0.013 M. When shin beef strips were immersed in the citrus juice marinade (31% orange juice, 31% lemon juice, 38% distilled water) mean pH decreased from 5.7 to 3.1 and mean sample weight increased by ∼65%. The mean Warner–Bratzler shear force value decreased from 178 to 44 N cm−2 following marination while mean sensory analysis scores for tenderness and juiciness increased following marination. A mean total collagen content of 1.4 g/100 g was recorded in shin beef of which 9% was soluble in unmarinated samples and 29% was soluble in marinated samples. The results indicated that the tenderisation of beef samples using a citrus juice marinade could be attributed to marinade uptake by muscle proteins and also to solubilisation of collagen

Confirmation of the Dietary Background of Beef from its Stable Isotope Signature

End of project reportConsumers are increasingly demanding information on the authenticity and source of the food they purchase. Molecular DNA-based technology allows animal identification, but without certification or a “paper-trail” but does not provide information about feed history or the production system under which the animal was reared. The stable isotopes of chemical elements (e.g.13C/12C, 15N/14N) are naturally present in animal tissue and reflect the isotopic composition of the diet. The overall aim of this project was to determine the feasibility of using the stable isotopic composition as an intrinsic, biochemical marker to gain information about feed components used in the production of beef. Factors likely to affect the isotopic signature such as source of tissue, duration of feeding and production systems were examined. It is expected that this highly innovative and original technique will permit the identification of country of origin and dietary history of beef and so greatly assist efforts to market Irish beef, particularly in lucrative European markets. Sequential sampling and stable isotope analysis of bovine tail hair and hoof revealed that the two tissues can provide a detailed and continuous record of animal dietary history. Because hair can be sampled repeatedly and noninvasively, we anticipate that this approach will also prove useful for the investigation of short-term wildlife movements and changes in dietary preferences

Meat provenance: Authentication of geographical origin and dietary background of meat

peer-reviewedThe authenticity of meat is now an important consideration in the multi-step food chain from production of animals on farm to consumer consumption of the final meat product. A range of techniques, involving analysis of elemental and molecular constituents of meat, fingerprint profiling and multivariate statistical analysis exists and these techniques are evolving in the quest to provide robust methods of establishing the dietary background of animals and the geographical origin of the meat derived from them. The potential application to meat authentication of techniques such as stable isotope ratio analysis applied to different animal tissues, measurement in meat of compounds directly derived from the diet of animals, such as fatty acids and fat soluble vitamins, and spectroscopy is explored. Challenges pertaining to the interpretation of data, as they relate to assignment of dietary background or geographical origin, are discussed

The fatty acid profile and stable isotope ratios of C and N of muscle from cattle that grazed grass or grass/clover pastures before slaughter and their discriminatory potential

peer-reviewedConsumption of grazed pasture compared to concentrates results in higher concentrations, in beef muscle, of fatty acids considered to be beneficial to human health. Little information is available on the influence of the type of grazed forage. Our objectives were to determine 1) the effect of inclusion of white clover in a grazing sward on the fatty acid profile of beef muscle and 2) the potential of the fatty acid profile and stable isotope ratios of C and N to discriminate between beef from cattle that grazed grass-only or grass/clover swards before slaughter. A total of 28 spring-born Charolais steers grazed from March until slaughter in October, either on a perennial ryegrass (Lolium perenne L.) sward that received approximately 220 kg N/ha or a perennial ryegrass–white clover (Trifolium repens L.) sward that received 50 kg N/ha. The longissimus muscle from cattle finished on grass/clover had a higher (P < 0.05) proportion of C18:2 and C18:3 but a lower (P < 0.05) proportion of conjugated linoleic acid and δ15N value than animals finished on the grass-only sward. Discriminant analysis using the fatty acid data showed that, after cross-validation, 80.7% of grass/clover and 86.1% of grass-only muscle samples were correctly classified. Discriminant analysis using the stable isotope data showed that, after cross-validation, 95.7% of grass/clover and 86.5% of grass-only muscle samples were correctly classified. Inclusion of white clover in pasture is likely to have little effect on healthiness of meat for consumers. However, changes in fatty acids and stable isotopes can be used to distinguish between grass/clover-fed and grass-only-fed beef

A validated method for cholesterol determination in turkey meat products using relative response factors

The objective of this study was to develop a precise and accurate method to quantify cholesterol in turkey meat products using relative response factors, based on a modification of a previously published method for plant sterols determination. Validation was performed using neat solutions to determine linearity, precision, and accuracy. The method was linear in the concentration range considered (1–20 µg/mL, r2 ≥ 0.991). Precision and accuracy were within the acceptability guidelines of the U.S. Food and Drug Administration (FDA) for method validation (<20% relative standard deviation (RSD) at the lower limit of quantification (LLOQ) and <15% RSD for other standards). Turkey meat was spiked with cholesterol at two levels (low = 3 µg/mL and high = 18 µg/mL), either before or after saponification, to establish the recovery and matrix effects. Recovery ranged from 94% to 105%, with a mean value of 105% at the low spike level and 95% at the high spike level. No significant matrix effects were found (90% to 112% recovery). This method is reliable for the quantification of cholesterol in turkey meat products in the range 0.4–8 mg/g

Enhancement of the Nutritional Value and Eating Quality of Beef

End of Project ReportThis project was supported by the European Commission (Healthy Beef, QLRT-CT-2000-31423).Consumer interest in the nutritional aspects of health has increased interest in developing methods to manipulate the fatty acid composition of ruminant products. Ruminant meats such as beef and lamb are often criticised by nutritionists for having high amounts of saturated fatty acids (S) and low polyunsaturated fatty acids (P).The P:S ratio in beef is approximately 0.1, the ideal being about 0.4. This project is part of a larger EU-supported project entitled Healthy Beef (Enhancing the content of beneficial fatty acids in beef and improving meat quality for the consumer: QLRT-CT-2000-31423). The Teagasc contribution, which was a collaboration between Grange Research Centre and The National Food Centre, focussed on nutritional manipulation of beef cattle. In particular, on exploiting grazing and fishoil as tools to enhance the concentration of “healthy” fatty acids in beef. The conclusions were: • The beneficial effect of a grazed grass-based diet on the fatty acid composition of beef was confirmed • The scale of this beneficial effect is strongly dependent on the duration of grazing • The optimum concentration of beneficial fatty acids was not achieved suggesting that feeding management prior to grazing is important • Grazing influenced beef colour and drip-loss in a durationdependent manner • Animals finished off grass for 40 or 98 days produced meat that was tougher than that from animals finished on silage and concentrates or fed grass for the last 158 days. • Fish oil supplementation enhanced the concentration in beef, of fatty acids that are beneficial to human health • The linear response to increasing level of fish oil consumption indicates scope to further enhance the concentrations of beneficial fatty acids in beef Wilting of grass prior to ensiling did not impact negatively on the overall content of n-3P in muscle, but it increased the concentration of conjugated linoleic acid • Dietary inclusion of fish oil or wilting of grass prior to ensiling did not affect muscle appearance • Fish oil seemed to increase tenderness but only at the high level of inclusion. This merits further study • There was some evidence that wilting of grass prior to ensiling enhanced meat tenderness. This needs to be confirmed.European Unio

The State Of Higher Education In 2012

The higher education sector is experiencing an escalating pace of change. Even colleges and universities with the greatest resources and strongest brands are confronting change, particularly as a result of the digital revolution that is radically impacting modes of learning and accessibility to knowledge. These changes are driven by market pressures — i.e., by the demands and expectations of students and faculty. At the same time, all of higher education continues its evolution in response to ongoing price pressures, to reduced governmental support, to growing competition from the for-profit higher education sector, to its own ethical challenges, and to changes in the regulatory environment. Boards, presidents, provosts and CFOs are addressing these risks and challenges with new strategies and unique action plans that are a far cry from traditional approaches to higher education

Long-term stability of RNA in post-mortem bovine skeletal muscle, liver and subcutaneous adipose tissues

peer-reviewedBackground: Recovering high quality intact RNA from post-mortem tissue is of major concern for gene expression studies in animals and humans. Since the availability of post-mortem tissue is often associated with substantial delay, it is important that we understand the temporal variation in the stability of total RNA and of individual gene transcripts so as to be able to appropriately interpret the data generated from such studies. Hence, the objective of this experiment was to qualitatively and quantitatively assess the integrity of total and messenger RNA extracted from bovine skeletal muscle, subcutaneous adipose tissue and liver stored at 4°C at a range of time points up to 22 days post-mortem. These conditions were designed to mimic the environment prevailing during the transport of beef from the abattoir to retail outlets. Results: The 28S and 18S rRNA molecules of total RNA were intact for up to 24 h post-mortem in liver and adipose tissues and up to 8 days post-mortem in skeletal muscle. The mRNA of housekeeping genes (GAPDH and ACTB) and two diet-related genes (RBP5 and SCD) were detectable up to 22 days post-mortem in skeletal muscle. While the mRNA stability of the two housekeeping genes was different in skeletal muscle and liver, they were similar to each other in adipose tissue. After 22 days post-mortem, the relative abundance of RBP5 gene was increased in skeletal muscle and in adipose tissue and decreased in liver. During this period, the relative abundance of SCD gene also increased in skeletal muscle whereas it decreased in both adipose tissue and liver. Conclusion: Stability of RNA in three tissues (skeletal muscle, subcutaneous adipose tissue and liver) subjected to long-term post-mortem storage at refrigeration temperature indicated that skeletal muscle can be a suitable tissue for recovering biologically useful RNA for gene expression studies even if the tissue is subjected to post-mortem storage for weeks, whereas adipose tissue and liver should be processed within 24 hours post-mortem.This research was part funded by the Irish Government under the National Development Plan 2000-2006. Support to BB under the Walsh Fellowship Programme of Teagasc is acknowledged