PROPOLIS EXTRACT COULD BE RECOMMENDED AS A NATURAL ANTIOXIDANT TO IMPROVE VEGETABLE OIL OXIDATIVE STABILITY

Abstract

Objective: In this study, the total phenolic content, individual phenolic components, and total antioxidant capacity of the ultrasonically assisted ethanolic extract of propolis were investigated in detail. Another aim of our study was to reveal the effects of propolis extracts on olive oil lipid oxidation compared to synthetic antioxidants (BHA, BHT) with tests performed under accelerated thermal conditions. Material and Method: We determined the total antioxidant capacity of propolis extract by CUPRAC assay. On the other hand, the polyphenolic content of propolis extract was determined by the Folin assay. Identification of phenolic compounds of propolis was performed using reversed phase high performance liquid chromatography (RP-HPLC). The effect of propolis on the oxidative stability of extra virgin olive oil under accelerated storage conditions was studied using the Shall oven test. Result and Discussion: The results revealed that propolis is rich in phenolic components. According to the CUPRAC assay, the total antioxidant capacity of propolis extract was calculated to be 2.013 ± 0.03 mmol TR/g-propolis extract. The total phenolic content of the propolis extract was calculated to be 1.67 ± 0.008 mmol TR/g-propolis extract. The oils with propolis extract incorporated exhibited much better chemical stability, including lower peroxide value and partly decreased tocopherols content. Data showed that propolis extract was more effective in delaying the oxidation of olive oil compared to synthetic antioxidants such as BHA and BHT.