ANTIOXIDANT ACTIVITIES OF ROSEMARY AND SAGE EXTRACTS AND VITAMIN-E IN A MODEL MEAT SYSTEM

Thiobarbituric acid (TEA) assay and capillary gas chromatography (GC) were used to assess the effects of storage and the potential antioxidants, vitamin E and rosemary and sage extracts, on lipid peroxidation of a cooked beef homogenate. Increased levels of malondialdehyde (MDA) or TBA-reactive substances (TEARS) were observed in samples during a 5-day period. TEARS levels ranged from 2.0 to 3.9 times higher than GC-analyzed MDA levels, indicating the presence of other reactants in the TEA assay. Despite elevated levels, TEARS formation is similar to the actual MDA formation. Addition of vitamin E at 25-100 mu g/g in the homogenate showed a concentration dependence in inhibiting lipid peroxidation. Samples containing either herbal extract (30 mu g/g) showed effective inhibition since MDA levels of treated samples were 62 and 53% of the control. Improved antioxidative activity was not observed when the antioxidants were mixed together in equal amounts.