The balance between vitamin E and highly peroxidizable fatty acids in muscle and the oxidative stability of beef from cattle grown on forage- or concentrate-based rations

摘要

The effect of different feeding systems on the levels of vitamin E and highly peroxidizable polyunsaturated fatty acids (HP-PUFA) in bovine muscle and on its associated oxidative stability was determined. One-hundred heifers were divided into 4 groups and fed: outdoors at pasture (P) or concentrates indoors (C) for 11 months, or were fed grass silage indoors for 5 months followed, for 6 months, by either grazed pasture (SiP) or grazed pasture plus 50% concentrates (SiPC). Vitamin E and fatty acids were measured in the longissimus dorsi muscle (LM) which was also used for lipid oxidation (TBARS), metmyoglobin (MMb%) and hue angle (H~*) values measurements during 11 days storage in a high oxygen atmosphere. Muscle vitamin E concentration decreased (P < 0.0005) in the order: P and SiP > SiPC > C, while HP-PUFA concentration in the C treatment was lower compared to P, SiP and SiPC (P = 0.05). The SiPC and C treatments reduced meat colour stability with higher MMb% (P = 0.002) and H~* values (P < 0.0005) in LD than P and SiP treatments. Compared to the other treatments, SiPC had lower LD lipid stability (P < 0.0005), with no differences observed between P, SiP and C. These results confirm a positive effect of grass-based diets on meat colour stability and underline that pasture-based diets supplemented with concentrates could significantly impair meat oxidative stability.