Endogenous and exogenous α-tocopherol supplementation: Effects on lipid stability (TBARS) and warmed-over flavour (WOF) in porcine M. longissimus dorsi roasts held in aerobic and vacuum packs

The effects of exogenous and endogenous supplementation with α-tocopheryl acetate on lipid stability of cooked porcine M. longissimus dorsi was examined with respect to aerobic and vacuum packaging. Large White pigs (n = 8) were fed a control diet (n = 4; 20 mg α-tocopheryl acetate/kg of feed) or supplemented (n = 4; 500 mg α-tocopheryl acetate/kg of feed) diet for 70 d prior to slaughter. Portions of each of the M. longissimus dorsi muscles were removed from the same location and separated into four treatment groups. Treatment groups were non-supplemented (20 mg α-tocopheryl acetate/kg of feed) (C), supplemented (500 mg α-tocopheryl acetate/kg of feed) (E), non-supplemented, oil (20 mg α-tocopheryl acetate/kg of feed plus 5% soya oil) (CO) and non-supplemented, oil (20 mg α-tocopheryl acetate/kg of feed plus 5% soya oil containing 500 mg/kg α-tocopherol (COE). Samples from the four groups were roasted in an oven to an internal temperature of 70°C and then stored in aerobic and vacuum packaging. TBARS values were determined on days 0, 2, 4, 6 and 8 of refrigerated (4°C) display. Samples in vacuum packs were also assessed for TBARS after weeks 0, 1, 2, 4, 6 and 8 of refrigerated (4°C) display. Warmed-over flavour (WOF) was assessed on days 0, 2, 4 and 8 for both packaging conditions. Samples in the vacuum-packaged group displayed the lowest (p ≤ 0.05) levels of lipid oxidation in all four treatment groups. The supplemented group (E) was the least (p ≤ 0.05) susceptible to oxidation in aerobic packaging and to WOF development in both packaging groups. Addition of vitamin E (COE) was moderately effective in preventing oxidation under aerobic packaging conditions. However, greater (p ≤ 0.05) levels of WOF were observed in this group than the dietary α-tocopherol supplemented group under both packaging conditions.