Antioxidant Properties of Avicennia marina Leaf Extract in Soybean Oil System

Abstract

Background: Despite the widespread use of antioxidants during the storage of oils, oxidation of fats and fatty foods is still reported to be the main reason for their quality drop. Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) completely escape and easily decompose at high temperatures. There are serious problems in relation to the toxicity of BHA, BHT and tertiary butylhydroquinone (TBHQ), possibly due to their metabolism and accumulation in organs and tissues. So finding a useful natural antioxidant is of great importance, and due to the considerable presence of mangrove plant on the Southern Coasts of Iran, this study aims to investigate the antioxidant properties of Avicennia marina leaves. Objective: Evaluation of the antioxidant activity of the Avicennia marina leaf extract and its comparison with synthetic antioxidant TBHQ. Methods: By adding the ethanolic extracts of Avicennia marina leaves at different concentrations (2, 4 and 6 mg/mL) into soybean oil system at room temperature during 20 days and at different intervals, their peroxide (PV), thiobarbituric acid (TBA), conjugated dienes (CD) and conjugated trienes (CT), as well as fatty acid profile were measured. Antioxidant activity of the samples was compared with that of TBHQ sample. Data analysis was performed using SAS, and a comparison of average data was carried out using least significant difference (LSD) at a level of 0.01. Results: The antioxidant activity of 2 and 4 mg/mL concentrations of Avicennia marina leaf extract in soybean oil was comparable with that of 0.2 mg/mL concentration of synthetic TBHQ. As a result, this natural antioxidant can be used for the preservation of soybean oil. Conclusion: Due to the presence of phenols in the leaves, Avicennia marina leaf extract can be used as a rich source of natural antioxidants.