2:00 pm - 3:00 pm
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Anahid Hosseini. This seminar is open to the general public to attend.
Meeting ID: 952 3520 9137 Passcode: 790073
Relationship between trained sensory and objective measured meat quality attributes in crossbred Canadian beef cattle after 3- and 29-days post-mortem aging.
MSc with Dr. Graham Plastow
Meat quality attributes are pivotal for the beef industry. Studies across Canada show 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. Both objective (using Warner Bratzler Shear Force -WBSF- or color measurements) and subjective (i.e., trained sensory panel scoring) methods are used to determine meat quality. Sensory assessment closely describes the eating experience that influences meat purchasing preference. On the downside their measurement is time consuming, labor intensive and costly while objective measurements are less so. In this study, I investigated the potential to replace 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.
Pearson phenotypic correlations, variance components (using univariate model), and genetic correlation calculation (using a two-trait model) were estimated between meat quality traits and sensory panel scoring. 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 (< 0.3). This suggests that meat quality attributes are changing between day3 and 29 post-mortem and early assessment of these traits are not good indicators of the final values. Heritability estimates at day3 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 (> 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.
Genetic parameters for color attributes (lightness, Hue and Chroma) and their associations with sensory panel scoring traits were then studied. Results indicated weak phenotypic correlations between sensory attributes and color indices (<0.3), implying low consistency between these traits at day3 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. 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. Retail display color measurements at days 0, 2 and 4 of shelf-life, lightness, Hue and Chroma had significant decline from day 0 to 4 as well as day 2 to 4 (p-value <0.001). The optimum point (day2) 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.
Overall results suggest that the objective measures for WBSF, fat content, lightness and Hue are good indicators for sensory attributes. These results can be useful for improving beef quality in the future through selective breeding.