Colour stability, under simulated retail display conditions, of M. longissimus dorsi and M. semimembranosus from steers given long-term daily exercise and supplemented with vitamin E

The objective was to determine if exercise has a negative impact on the colour stability of beef and if dietary vitamin E (VE) supplementation could counteract any negative effect. Steers were not exercised or were walked 4.41 km/day for 18 weeks. Within exercise treatment animals consumed, on average, either 450 or 1050 IU/day of VE. Muscle α-tocopherol increased (P = 0.004) from 2.35 to 3.15 μg/g with VE supplementation. Following ageing M. longissimus dorsi (LD) and M. semimembranosus (SM) steaks were packaged under 80%O2:20%CO2 and stored at 4 °C. The LD of exercised steers was more red and more saturated (both P < 0.05) after 0 and 2 days of storage than LD of unexercised steers. While redness of both muscles decreased over the display period, LD retained a higher redness than SM from day 2 to 7 (P < 0.05). Colour shelf-life of LD was extended by 0.75 days, to 3.25 days, due to VE supplementation.