Addition of synthetic and natural antioxidants to alpha-tocopheryl acetatesupplemented beef patties: effects of antioxidants and packaging on lipid oxidation

Friesian steers (n = 5), aged 26-27 months, were fed a diet containing 2000 (supplemented) IU alpha -tocopheryl acetate/head/day for approximately 50 days prior to slaughter. Muscularis semimembranosus muscles from supplement ed cattle were held in frozen storage (-20 degrees Cx12 weeks) following wh ich they were minced and divided into five batches. The batches contained: (1) control, containing only vitamin E supplemented beef(C); (2) vitamin E supplemented beef with 4% soya oil (S); (3) vitamin E supplemented beef mix ed with 0.2% Duralox NMC dissolved in 4% soya oil (R1); (4) vitamin E suppl emented beef mixed with 0.25% Herbalox type 25 (containing 25 natural antio xidant extracts of rosemary) dissolved in 4% soya oil (R2); and (5) vitamin E supplemented beef mixed with a 1:I mixture of 0.01% (w/w) BHA and 0.01% (w/w) BHT dissolved in 4% soya oil (B). The meat was then aerobically packa ged (A) or packaged under the following modified atmospheres (MAP); 30:70 ( M-1); 70:30 (M-2) or 80:20 (M-3) (O-2:CO2) Oxidative stability (TBARS) and Hunter 'a' values (redness) were determined in all beef patties over 8 days of refrigerated (4 degreesC) storage. Under MAP or aerobic packaging condi tions, elevated oxygen levels brought about increased (P < 0.05) TEARS numb ers during refrigerated storage. However, the addition of rosemary extracts or BHA/BHT significantly (P < 0.05) improved the oxidative stability of di etary a-tocopheryl acetate supplemented beef. Rosemary extracts were as eff ective in reducing TEARS as the combination of synthetic antioxidants, BHA/ BHT. (C) 2001 Elsevier Science Ltd. All rights reserved.