Antioxidant activity of carnosic acid and rosmarinic acid in raw and cooked ground chicken patties

BACKGROUND: Carnosic acid (CA) and rosmarinic acid (RA) are potent antioxidants. The effectiveness of an antioxidant in a food system is dependent on a range of factors such as concentration, phenolic content, physical state of the substrate, processing and storage. However, the antioxidant activity of powder vs liquid and higher vs lower phenols is not clear in different matrices. In this study, OxiKan-WS4 (4.0% RA), OxiKan-S10 (10% CA) and OxiKan-R8 (8% CA) were investigated against lipid oxidation in raw and cooked ground chicken patties during refrigerated storage. RESULTS: OxiKan-WS4 had the highest (P < 0.05) total phenolic content, whereas OxiKan-S10 and OxiKan-R8 exhibited higher DPPH radical-scavenging activity and reducing power relative to OxiKan-WS4. Lipid oxidation was minimized in meat with added extracts, as indicated by lower (P < 0.05) thiobarbituric acid-reactive substances, peroxide value and free fatty acid. Addition of natural antioxidant extracts at 10 mg equivalent total phenols per 100 g meat did not affect the sensory scores relative to non-treated controls. CONCLUSION: This study demonstrates that the physical state (powder vs liquid) of CA or RA plays an important role in determining their antioxidant efficacy.