ACTION OF ORIGANUM MAJORANA L. EXTRACT ABOUT THE OXIDATIVE STABILITY OF SOYBEAN OIL

Objective: The objective of this work was to evaluate the efficiency of the marjoram extract when applied to the soybean oil and also to compare it with the TBHQ antioxidant in the same conditions, as well the synergistic effect of both. Methods: The marjoram extract, suspended in a hydroethanolic medium, was obtained from the freeze-dried plant. The treatments: Control (soybean oil 100%), TBHQ100 (soybean oil + 100 mg/kg TBHQ), Extract100 (soybean oil + 100 mg/kg phenolic compound of marjoram extract) and Mixture (soybean oil + 50 mg/kg phenolic compound of marjoram extract + 50 mg/kg TBHQ) were subjected to an accelerated storage test in an oven at 60°C for 20 days. Results: The Extract100 presented 10.53 mg GAE/g of phenolic compounds, being able to eliminate 52.1% of the DPPH radical. The TBHQ100 presented elevated efficiency against lipidic oxidation in the soybean oil due to lower peroxide indexes, 8.79 meq/kg in 20 days. However, the Mixture retained larger quantities of total tocopherols within the storage. Conclusion: It was concluded that it is possible to decrease the amount of synthetic antioxidant in substitution of the natural and, consequently, to reduce the lipidic oxidation of the soybean oil.