The effect of Marbling on Palatability

1. The effect of Marbling on Palatability Buenos Aires September 2008

2. Meat Standards Australia Conception Critical Control Points Genetics Nutrition/environment Pre-slaughter factors Post-slaughter factors Chilling Consumer Feedback Processing/value adding Cooking Consumption

3. AUS-Meat Marbling scores

5. Tenderness/Marbling • Relationship between marbling and tenderness is low and variable • Marbling accounts for 5-15% of variation in tenderness • Shackelford et al (1994) 1602 carcasses • Wheeler et al (1994) 1337 carcasses • Marbling does provide some assurance and so is used in a number of grading schemes

6. How does marbling impact on sensory? Tenderness • Dilution of myofibre structure • Low density fat dilutes higher density denatured protein • Dilution of connective tissue structure • IM fat is laid down in the peri-vascular cells

7. How does marbling impact on sensory? Juiciness • Lubrication • IM fat stimulates salivation • High IM fat will give a sustained impression of juiciness

8. How does marbling impact on sensory? Flavour • Lean has a meat flavour which is similar across most species • Species flavour components held in the fat

9. Does marbling protect against overcooking? • As fat conducts heat at a slower rate, high IM fat steaks thought to provide insurance against overcooking?? • Beef CRC results show no interaction evident between doneness and IM Fat% for sensory traits • Concluded that doneness was more important than IM fat% in producing tender, juicy steaks

10. Relationships between sensory and IM fat % Relationship R2 Tenderness/IM fat% 12.7 Flavour/ IM fat% 17.4 Juiciness/ IM fat% 16.3

11. Differences in flavour scoresbetween finish systems At the same shear force IM fat% At the same shear force At the same shear force IM fat% age

12. The effect of marbling in different muscles Striploin Blade Tenderness scores Topside IM Fat % 1% increase in IM Fat% resulted in a 1 unit increase in tenderness

13. How does IM Fat% grow • Classical longitudinal growth study Growing + Finishing 1.7-1.8% Conc Finishing Both treatments ad libitum Conc Growing 1.5% Conc liveweight 6 12 18 30 Age

14. Experimental design • Groups of 8 animals from • ad libitum • restricted treatments • slaughtered at 2 month intervals from 6 to 30 months • Initial slaughter group 6 • 12 slaughters each of 8 animals by 2 treatments = 192 animals

15. Carcass jointing LD thorax Chuck Tenderloin LD lumber Rump Sirloinbutt Hindshin Foreshin Brisket Rib

16. Analysis Y = AXb If “b” > 1 the component (Y) has a high growth impetus relative to the total (X) Y X

17. Analysis Y = AXb If “b” < 1 the component (Y) has a low growth impetus relative to the total (X) Y X

18. Analysis Y = AXb If “b” = 1 the component (Y) has an average growth impetus relative to the total (X) Y X

19. high impetus average impetus low impetus IMFat% distribution LD thorax b=1.09 Chuck b=1.02 LD lumber b=0.99 Fillet b=0.88 Rump b=0.95 Sirloinbutt b=1.03 Hindshin b=0.99 Foreshin b=1.00 Brisket b=0.99 Rib b=1.01

20. Correlations between joints in IMFat% Joint 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 Ad libiutm r=0.85 Restricted r=0.87

21. Correlations between joints in IMFat% Joint 1 2 3 4 5 6 7 8 9 10 MS 1 2 3 4 5 6 7 8 9 10 MS Ad libiutm r=0.85 0.73 Restricted r=0.87 0.80

22. Conclusion • IM Fat does have a small impact on palatability (tenderness, juiciness and flavour) • Difference in flavour between grain and grass feed animals is that grass fed have less IM Fat % and are older • IM Fat % does not exhibit differential growth across the musculature • IM Fat % in any cut can predict IM Fat % in other cuts