We aimed to establish colorimetric thresholds based upon the capacity for instrumental measures to predict consumer satisfaction with beef colour. A web-based survey was used to distribute ...standardised photographs of beef M. longissimus lumborum with known colorimetrics (L*, a*, b*, hue, chroma, ratio of reflectance at 630nm and 580nm, and estimated deoxymyoglobin, oxymyoglobin and metmyoglobin concentrations) for scrutiny. Consumer demographics and perceived importance of colour to beef value were also evaluated. It was found that a* provided the most simple and robust prediction of beef colour acceptability. Beef colour was considered acceptable (with 95% acceptance) when a* values were equal to or above 14.5. Demographic effects on this threshold were negligible, but consumer nationality and gender did contribute to variation in the relative importance of colour to beef value. These results provide future beef colour studies with context to interpret objective colour measures in terms of consumer acceptance and market appeal.
•Beef colour was considered acceptable when a* values were ≥14.5.•Demographic effects on the a* threshold were negligible.•The perceived importance of colour to beef value differed between respondent demographic groups.
The relationship between instrumental colorimetric values (L*, a*, b*, the ratio of reflectance at 630nm and 580nm) and consumer perception of acceptable beef colour was evaluated using a web-based ...survey and standardised photographs of beef m. longissimus lumborum with known colorimetrics. Only L* and b* were found to relate to average consumer opinions of beef colour acceptability. Respondent nationality was also identified as a source of variation in beef colour acceptability score. Although this is a preliminary study with the findings necessitating additional investigation, these results suggest L* and b* as candidates for developing instrumental thresholds for consumer beef colour expectations.
The aim of this study was to evaluate the effect of different forage-types on lamb carcass, meat quality and sensory attributes. Sixty-two, White Dorper lambs finished on bladder clover, brassica, ...chicory+arrowleaf clover, lucerne+phalaris or lucerne, were slaughtered at a commercial abattoir. At 24h post-mortem, the m. longissimus thoracis et lumborum (LL) was removed from the left side and sliced into three equal sub-samples, vacuum packaged and randomly assigned to ageing periods (5, 12 or 40days) and the right side was aged for 5days. The m. semimembranosus and m. adductor femoris were removed and, the former was then aged for 40days. Lambs fed chicory+arrowleaf clover or lucerne had a higher dressing percentage and fat depth. Bladder clover gave the highest level of glycogen in the LL. No sensory or other meat quality trait differences were found between the treatments. In general, no treatments showed any unfavourable effect on the traits examined.
•New forages have potential to achieve good quality lamb carcasses and meat.•These forage types do not alter the sensory attributes of lamb meat.•All forage type evaluated are valid options to finish lambs.
The effect of aperture size on the assessment of lamb meat colour values (L*, a*, b* and R630/580) was investigated. Two experiments using 2 HunterLab MiniScan colorimeters (large 25mm and small 5mm ...apertures) were conducted: 1) coloured tiles were measured and 2) unaged lamb (n=65) m. longissimus lumborum (LL) and m. semimembranosus (SM) muscles were measured over 2.5d under simulated retail display. For Experiment three, 2 different colorimeters were used on lamb (n=36) LL aged for 6weeks before measurement over 4d on simulated retail display. Coloured tile a* and b* values were unaffected by aperture size, but L* values and the R630/580 ratio were influenced by aperture size. The effect of aperture size on lamb meat colour measurements varied with display time and muscle type. The large aperture size generally provided the highest colorimetric values, and is recommended for measuring lamb meat colour.
•HunterLab colorimeter aperture size affected measurement of lamb meat colour.•Display time and cut interact with aperture size to affect colour measurements.•Large aperture size better measures lamb meat colour.•Reporting aperture size is important in colorimetric studies.
Carcase pH and temperature decline rates influence lamb tenderness; therefore pH decline parameters are beneficial when modelling tenderness. These include pH at temperature 18°C (pH@Temp18), ...temperature when pH is 6 (Temp@pH6), and pH at 24h post-mortem (pH24). This study aimed to establish a relationship between shear force (SF) as a proxy for tenderness and carcase pH decline parameters estimated using both linear and spline estimation models for the m. longissimus lumborum (LL). The study also compared abattoirs regarding their achievement of ideal pH decline, indicative of optimal tenderness. Based on SF measurements of LL and m. semimembranosus collected as part of the Information Nucleus slaughter programme (CRC for Sheep Industry Innovation) this study found significant relationships between tenderness and pH24LL, consistent across the meat cuts and ageing periods examined. Achievement of ideal pH decline was shown not to have significantly differed across abattoirs, although rates of pH decline varied significantly across years within abattoirs.
•Lamb carcase pH and temperature decline parameters can be used to predict shear force.•Loin pH at 24h post-mortem provided the best prediction parameter for shear force.•Abattoir achievement of ideal pH decline did not vary over experimental years.
Exponential decay models have been used to model pH and temperature decline in lamb carcases post mortem. Such models, once fitted to carcase data, can then be used to predict a carcase's pH at a ...temperature of 18°C and its temperature when the pH equals 6. Unfortunately, these models frequently fail when fitted to limited pH/temperature data, because of either insufficient data or inappropriateness of the exponential decay model. To overcome these problems an alternative though similar modelling approach is proposed. This alternative approach replaces the exponential decay model with a more flexible spline modelling approach for the average trend and includes in the model, as random effects, individual deviations from average trend. Including the individual deviations from average trend as random effects in the model allows information on individual carcases to be shared across carcases.
► pH/temperature decline has a large effect on tenderness. ► Modelling this decline to avoid biassed estimates is a challenge. ► A procedure is outlined that overcomes bias and provides more reliable estimates.
Assuming an exponential decay model (EDM) for pH decline as a function of temperature, ideal shortening (i.e. neither hot nor cold shortening) for an individual carcase occurs if and only if that ...carcase's model parameters fall within a specific sub-region of three dimensional space. This paper demonstrates that simply fitting EDMs to a sample of carcases and using the proportion of sampled carcases with estimated parameters within the specific sub-region can lead to seriously biassed estimates for the proportion of carcases ideally shortened. This is particularly so if the EDMs are fitted separately to each sampled carcase but also remains the case, to a lesser extent, if the models are fitted jointly using random effects modelling. A preferred estimate is based on the probability that an independently selected carcase has model parameters within the specific region, based on the distribution of the EMD parameters. The distribution of EMD parameters is obtained via the fitted random effects exponential decay model.
► pH/temperature decline has a large effect on tenderness. ► Modelling this decline to avoid biassed estimates is a challenge. ► A procedure is outlined that overcomes bias and provides more reliable estimates.
Shear force (SF) is a routine measure used in meat research to define tenderness, but the procedures are not standard. As a result, many studies have failed to include SF block weight and status ...(frozen or thawed) prior to cooking in their methods sections—potentially due to the unknown extent to which they contribute to SF and cooking loss (CL) variation. Consequently, we investigated the effects of SF block status (frozen or thawed) and weight prior to cooking (pre-cook wt) on SF and CL determination of beef. A split-plot experimental design was applied to 80 SF blocks removed from several beef
Musculus longissimus lumborum
to represent a range of weights (33.8–120.5 g) balanced by status. These were then cooked using a water bath, and assessed for SF and CL. It was found that pre-cook wt acted as a source of variation for SF and CL measurement (
P
< 0.001), and status influenced only CL (
P
< 0.01). From these, we can conclude that future beef SF studies and procedural guidelines must include descriptors for these parameters in their respective methods section to ensure reproducibility and correct contextual interpretation.
The current study investigated the effects of the supplementation of lambs with algae on the expression of genes that direct the accumulation of long chain omega-3 polyunsaturated fatty acids ...(LCn-3PUFA). The nutrition of the lamb's dam around mating was also considered. The dams were fed with either silage (SLG) or oat/cottonseed (OAT) based diets for six weeks prior to and, three weeks following conception. mRNA levels of FADS1, FADS2, CPT1, SCD, ACC and fad2 were measured in the liver, muscle and subcutaneous fat from lambs fed a control diet consisting of oat and lupin grains and chopped lucerne (CTRL) or the CTRL diet with algae (DHAgold™) added at 1.92% DM (ALG). The lambs were 117.4±2.4 days of age and weighed 37.3±3.2kg at the beginning of the experimental period, and six weeks later they were slaughtered at 160.4±2.4 days of age and a final live weight of 50.1±4.4kg. The expression of FADS1 in liver tissue was not affected (P>0.05) by the interaction between dam nutrition and algae supplementation, however it was higher (P<0.05) when lambs received the ALG diet compared with the CTRL and when their dams were fed SLG compared with OAT diet. The expression of FADS1 in muscle was negatively correlated (P<0.05) with the concentration of 20:4n-6, 20:5n-3 and 22:4n-6. The expression of FADS1, FADS2, SCD and ACC genes in lamb muscle was differentially affected by dam nutrition with the highest levels for the SLG+ALG treatment (P<0.05) compared with other treatments. The expression of SCD gene was not affected (P>0.05) by algae supplementation, but it was higher (P<0.05) when dams were fed SLG compared with OAT, however ACC was not affected (P>0.05).
•Accretion of omega-3 PUFAs is associated with a dam and lamb nutrition interaction.•Maternal nutrition affects gene expression related to fat metabolism in lambs.•Algae supplementation increases PUFA metabolism in lamb.
Carcase pH and temperature decline rates influence lamb tenderness; therefore pH decline parameters are beneficial when modelling tenderness. These include pH at temperature 18°C (pH@Temp18), ...temperature when pH is 6 (Temp@pH6), and pH at 24h post-mortem (pH24). This study aimed to establish a relationship between shear force (SF) as a proxy for tenderness and carcase pH decline parameters estimated using both linear and spline estimation models for the m. longissimus lumborum (LL). The study also compared abattoirs regarding their achievement of ideal pH decline, indicative of optimal tenderness. Based on SF measurements of LL and m. semimembranosus collected as part of the Information Nucleus slaughter programme (CRC for Sheep Industry Innovation) this study found significant relationships between tenderness and pH24LL, consistent across the meat cuts and ageing periods examined. Achievement of ideal pH decline was shown not to have significantly differed across abattoirs, although rates of pH decline varied significantly across years within abattoirs.
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