Relationship between trained sensory and objective measured meat quality attributes in crossbred Canadian beef cattle after 3- and 29-days post-mortem aging
Creators: Anahid Hosseini
Publisher: name: University of Alberta Library
Year: 2022

<p>Meat quality attributes are pivotal for the beef industry. Studies across Canada showed major beef quality concerns originate from inconsistency of palatability attributes. To improve these traits genetically, they should be standardly measured, their (co)variance components and genetic parameters estimated. There are different approaches for measuring meat quality traits including objective (using Warner Bratzler Shear Force -WBSF- or color measurements) and subjective (i.e., trained sensory panel scoring) methods. Subjective methods for sensory assessment proved to closely describe eating experience of meat that influence meat purchasing preference. But on the downside these traits are time consuming, labor intensive and costly to measure while objective measurements are not. In this study, as a potential alternative for replacing sensory panel evaluation with objective methods, data for both sets of traits after 3- and 29-days post-mortem aging for 1,200 multibreed beef cattle were collected and analyzed. <br>
First, associations between meat quality traits and sensory panel scoring were investigated. Pearson phenotypic correlations, variance components (using univariate model), and genetic correlation calculation (using a two-trait model) were estimated. Fixed effects (contemporary grouping, sex, breed composition and slaughter age) and a random additive effect were fitted into the models. Results indicated that phenotypic correlations between subjective and objective measured traits were mostly weak (&lt; 0.3). This suggests that meat quality attributes are changing between day 3 and 29 post-mortem and early assessment of these traits are not good indicators of the final values. Heritability estimates at day 3 and 29 post-mortem for overall tenderness (OT), overall palatability (OP), WBSF and fat content were moderate to high. These estimates suggested the possibility of improvement through animal breeding for these traits. Genetic correlations were strong (&gt; 0.6) between WBSF and OT, OP, connective tissue (CT) and flavor intensity (FI), as well as fat content with FI, off-flavor (OF) and OP. This was also the case for OT with OF and OP. Similarly, OP was highly correlated with FI and sustained juiciness (SJ), as well as CT with OT, FI, OT and OP. These strong genetic correlations suggests that there are potentially common genes impacting these traits and in a selective breeding program they should be considered for genetic improvement.<br>
Next, genetic parameters for color attributes (lightness, Hue and Chroma) and their associations with sensory panel scoring traits were studied. Results indicated weak phenotypic Pearson’s correlations between sensory attributes and color indices (&lt;0.3), implying low consistency between these traits at day 3 and 29 post-mortem. Genetic parameter estimation showed that lightness and Hue were highly heritable. These results indicate that the lightness and Hue of beef, after 3 and 29 days of aging, can be targeted through breeding programs for improvement. Trend analysis evaluated color attributes during retail display at different shelf-life days (days 0, 2 and 4). Color measurements during retail display (day 0, 2 and 4) had negligible heritability estimates (&lt; 0.1). The results for retail color attributes indicate these traits are mostly affected by environmental factors rather than additive genetic effect. Genetic correlation estimations revealed that lightness was moderately correlated to CT, and Chroma was strongly correlated to CT, OF and OP, and moderately correlated to OT and FI. The fact that color indices are genetically correlated to palatability attributes indicates some level of pleiotropy for these traits. Color retail display, lightness, Hue and Chroma at days 0, 2 and 4 of shelf-life, had significant decline from day 0 to 4 as well as day 2 to 4 (p-value &lt;0.001). This could help to find the optimum point (day 2) of display for beef meat before the product loses its appeal due to discoloration as the largest decrease in color quality happens between day 2 to 4.<br>
Overall, meat quality attributes are not consistent through time and early measurements cannot be considered as good indicators for changes over time. Some of these traits were highly heritable implying the chance of genetic improvement with selective breeding. Strong genetic correlations between sensory and objective measured traits shows possible pleiotropic effects. We suggest that WBSF, fat content, lightness and Hue as objective measured traits are good indicators for sensory attributes. These results should be considered when designing genetic improvement strategies of meat quality attributes in Canadian crossbred beef cattle.</p>