Effect of dietary vitamin E supplementation on beef colour stability

The effect of dietary vitamin E upon colour, waterholding capacity, bacterial growth and lipid oxidation of beef longissimus thoracis (LT) and psoas major (PM) muscle were examined during aerobic display of fresh muscle and after aging in vacuum for 26 days. Forty crossbred beef bulls received a whole crop corn silage, supplemented with concentrate. Twenty bulls were each supplemented with 2025 mg vit E per day (added to the concentrate) for 136 day prior to slaughter and compared with non-supplemented control animals (n=20). In fresh LT muscle drip loss did not differ between treatment groups, while in PM muscle drip loss was significantly higher for the supplemented group. The treatment did not affect bacterial growth in fresh and aged muscles. Lipid oxidation during 12 day storage of fresh muscle was significantly lower for the supplemented group, as indicated by the lower TBA-values. No effect of the vitamin E treatment was observed on a∗-values of both fresh and aged LT muscle during display for 8 and 5 days, respectively. In PM muscle, supplemented beef had lower a∗-values in fresh (at day 1) and aged (at days 1 and 2) muscle, due to a lower oxygenation. The reason for this lower oxygenation is unclear. After aging, colour stability was decreased and more variable than in fresh muscle. Similar results were obtained when the difference in reflection values at 630 and 580 nm (R630-580), instead of the a∗ value, was used as a parameter for colour stability. The absence of an effect of vit. E on the rate of discoloration, might possibly be explained from the observation that α-tocopherol levels in control muscle were relatively high (LT: 2.1 and PM: 3.2 μg/g muscle), compared with data from literature. Analysis of the feed for vit. E suggests that this was due to a relatively high natural vit. E uptake from the feed, which was calculated to be approx. 330 mg vit. E per animal per day for the control group.