Liselotte Pannier

The impact of increasing lean meat yield (LMY) on consumer eating acceptance and its association with intramuscular fat (IMF) of lamb products was evaluated. Consumer sensory scores (overall liking, tenderness, juiciness, flavour liking) of the loin and topside were obtained from 3119 lambs, in addition to the knuckle, leg, outside, rack, rump and shoulder from a subset of these animals (n = 824). LMY indicators included GR tissue depth (measured 110 mm from dorsal midline of 12th rib), whole carcass and section (fore, saddle, hind) computed tomography (CT) lean% and cut weight of the loin and topside (as a percentage of the total carcass weight). Loin IMF was measured on all animals, with topside, outside, rump and shoulder IMF obtained from a subset of animals. Linear mixed models demonstrated a reduction in eating quality with increasing LMY in all cuts (P < 0.05) except the knuckle and leg. The impact on eating quality varied depending on the method used to estimate LMY, with the strongest association observed when using CT lean% measures, particularly section CT lean% from which the cut was taken. The effect of LMY on consumer eating quality was fully driven by IMF within the loin and rump cuts (P > 0.05) but only partially in the rack, outside and shoulder (P < 0.05). Results confirm the importance for simultaneous selection of LMY and IMF as key drivers of sheepmeat eating quality and the importance for the inclusion of on-line predictions of LMY in eating quality grading systems.

Untrained consumer-determined sensory scores of tenderness, juiciness, flavour liking, and overall liking possess a level of dependency due to poorer consumer ability to discriminate between these traits. Given that overall liking is strongly correlated to all traits, this study evaluated the contributions of sensory traits to the overall liking scores of Australian lamb. Tenderness, juiciness, flavour liking and overall liking of a range of lamb cuts were assessed by untrained Australian consumers (n = 18,720) following Meat Standards Australia protocols. The most important contributor to lamb overall liking was flavour liking (44.7%), followed by tenderness (28.3%) and juiciness (27.0%) (P < 0.05; R = 0.88). The contribution of the sensory traits to overall liking varied between meat quality categories, although the contribution of juiciness varied minimally. The contribution of flavour liking to overall liking became more important as loin intramuscular fat content increased. Whilst small differences in the contribution of tenderness and juiciness were present between cooking methods, untrained consumers evaluated overall liking in a similar manner regardless of cut type, demonstrating consumers' inherent ability to consistently evaluate meat products.

This study evaluated the impact of high oxygen modified atmosphere packaging (MAP) in four different combinations, 80 % oxygen and 20 % carbon dioxide (MAP80), 40 % oxygen, 20 % carbon dioxide and 40 % nitrogen (MAP40(20CO2)), 40 % oxygen, 60 % carbon dioxide (MAP40(60CO2)), and vacuum skin packaging (VSP) under different retail display times (3 or 8 days) on the sensory scores of lamb meat. Untrained consumer sensory scores for overall liking, tenderness, juiciness and liking of flavour were assessed on the M. longissimus lumborum (loin) and M. semimembranosus (topside) of 144 lambs. In general, MAP40(20CO2) samples received higher sensory scores than MAP80 (P < 0.05). While the high carbon dioxide MAP mixture MAP40(60CO2) scored similar to MAP80 (P > 0.05). Therefore, MAP40(20CO2) minimised the detrimental effects on eating quality and is a viable alternative to the widely used MAP80. However, the highest eating quality scores were still obtained with VSP (P < 0.05).

The current sheep Meat Standards Australia (MSA) model is a pathways system designed to improve the overall eating quality of Australian lamb, yet it is unable to predict individual consumer-based eating quality scores for specific cuts. This paper describes the methodology of using consumer sensory scores to create an objective composite eating quality prediction score linked to individual quality grades for different cuts. This methodology accounts for objective carcass measures that are being commercialised within the industry, such as intramuscular fat percentage and a measure of lean meat yield percentage. The model demonstrated that through utilising these carcass grading traits, an eating quality prediction can be made with an accuracy of 75 % and 72 % for the grill and roast cooking method respectively, however individual consumer variation remained substantial. The model will allow the supply chain to allocate cuts to different marketing strategies (branding) based on their eating quality performance whilst also reducing the chances of consumers being offered products that do not meet their expectations.

This study investigated how modified atmosphere packaging (MAP) with lower oxygen concentrations affects meat surface redness compared to standard 80% oxygen MAP for sheepmeat. Colour measuring instruments assessed redness (oxymyoglobin to metmyoglobin ratio and a*) in M. longissimus lumborum (loin) and M. semimembranosus (topside) from 50 Merino lambs. After 5 or 20 days of vacuum storage, meat samples were re-packaged into one of five MAP treatments (0, 20, 40, 60, or 80% oxygen), and colour was measured after 2, 6, or 10 days of retail display. Decreasing oxygen from 80% to 40% showed no negative impact on loin redness during retail display. Topside samples under 40% oxygen exhibited lower oxy/met values than 80% oxygen MAP at 2 and 6 days, with no difference after 10 days. This finding highlights the potential to reduce MAP oxygen content to 40% without compromising surface redness, potentially mitigating adverse effects on eating quality.

Implications

The Australian beef and lamb industries have shifted from utilizing a carcass classification system to consumer-focused carcass grading, through the Meat Standards Australia grading system.

Grading systems must be dynamic to meet changing consumer preferences.

Objective technologies can increase the accuracy and precision of yield and eating quality measurement inputs into grading models.

Combining carcass yield estimates with consumer value can underpin transparent value-based trading systems.

Value-based trading can generate significant industry benefits by delivering the desired product to the consumer, improving processing efficiency and optimization, and providing more precise carcass feedback and market signals to livestock suppliers.

Hotpot is a widely popular cooking method for sheepmeat in China. This study measured the sensory responses of 720 untrained Chinese consumers to Australian sheepmeat cooked using a hotpot technique with methods based on Meat Standards Australia protocols. Shoulder and leg cuts of 108 lambs and 109 yearlings were scored on tenderness, juiciness, flavour and overall liking with linear mixed effects models used to analyse the influence of muscle type and animal factors on these scores. On average, shoulder cuts were more palatable than legs cuts for all sensory traits (p < 0.01) and lambs compared to yearlings (p < 0.05). Intramuscular fat and muscularity were identified as strong drivers of eating quality (p < 0.05), with greater palatability for both cuts as intramuscular fat increased (range 2.5 to 7.5%), and muscularity decreased (as measured through loin weight adjusted for hot carcase weight). Consumers were unable to detect differences between animal sire type and sex in sheepmeat hotpot. These findings suggest shoulder and leg cuts performed comparatively well in hotpot compared to previously tested sheepmeat cooking methods and emphasise the importance of balanced selection for quality and yield traits to ensure that consumer satisfaction is maintained.

Lamb eating quality was measured using untrained consumer sensory panels to determine the difference in intrinsic eating quality scores of grilled and roasted leg cut muscles. The Knuckle, Outside flat, and Topside from both legs of 65 mixed-sex lambs from diverse genetic backgrounds were prepared using alternative grill and roast cook methods. Each sample was eaten by 10 consumers and scored for tenderness, juiciness, flavor, and overall liking. All cuts scored higher (p < 0.001) when grilled compared with when roasted for all traits except for Topside tenderness. Grilled Knuckle scored higher than roast Knuckle by 13.6%, 23.9%, 14.4% and 15.8% for tenderness, juiciness, flavor, and overall liking, respectively. The grilled Outside flat scored higher than roast Outside flat by 14.1%, 27.1%, 10.9%, and 14.3% for tenderness, juiciness, flavor, and overall liking, respectively. Finally, grilled Topside scored higher than roast Topside by 21.3%, 7.4%, and 6.6% for juiciness, flavor, and overall liking, respectively. Carcass traits for intramuscular fat and shear force had a significant (p < 0.001) effect on all eating quality traits for both grill and roast cuts. Girth rib fat had a significant effect (p = 0.01) on tenderness and juiciness (p = 0.03) for Outside flat and Topside but had no effect (p > 0.05) on Knuckle for both grill and roast. This study identified that specific cooking methods can improve sensory traits for individual cuts and suggests that a cut-by-cook method eating quality model for sheepmeat can therefore increase consumer satisfaction.

Anecdotal suggestions that US consumers perceive Australian sheepmeat as more “gamey” or “stale” compared to US sheepmeat are potentially attributable to the extended chilled shipping times contributing to longer-aged meat and predominately pasture-fed grazing systems. This study evaluated the impact of diet and extended storage times on Australian sheepmeat using sensory scores as assessed by US consumers. Meat samples from Australian sheep (n = 80) fed a grass or grain diet were aged in a vacuum at 1–2 °C for 5, 21 or 45 days. Untrained consumers (n = 960) at Texas Tech University (Lubbock, Texas) assessed samples for overall liking, tenderness, juiciness and flavour using a scale from 1 (worst) to 100 (best). In general, US consumers scored grain- and grass-fed samples within the same storage period similarly (p > 0.05). Furthermore, storage from 5 to 21 days improved sensory scores by a maximum of 28.6 for tenderness for grass-fed outside cuts (p < 0.05), while storage for 21 to 45 days did not improve eating quality for most cuts of both diets (p > 0.05). This is an interesting finding for the Australian sheepmeat industry as long storage time has no negative effect on eating quality and US consumers enjoyed grass- and grain-fed sheepmeat equally.