Antioxidant Efficacy of Sesame (Sesamum indicum L.) Cake Extract on Stability of Refined Sesame Oil during Storage Time

Sesame cake extract is the by-product left behind after sesame oil extraction including almost 30% of protein and phytochemicals, which possess free radical scavenging activity. In this study, antioxidant activity of sesame cake extract on the quality of refined sesame oil has been evaluated under 60 ◦C during storage time.

After extraction of ethanolic extract, sesame oil was treated with concentrations of 0, 20, 50, and 100 ppm of sesame cake extract and stored at 60 °C for 30 days. The sesame cake and refined sesame oil were taken from Yazd province and extracted with ethanol. Total Phenolic Content (TPC) (at the beginning of the study) and 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging capacity (30 days after inoculation) were evaluated. The antioxidant activity of various dilution of the Sesame Cake Ethanol Extract (SCEE) was assessed by measuring, rancimat analysis, Peroxide Value (PV), and Thiobarbituric Acid (TBA) assay, and also evaluation of the TPC. Butylated Hydroxyanisole (BHA) as a synthetic antioxidant was used. Experiments were carried out in triplicates and data were processed with ANOVA test by SPSS Software.

Radical-scavenging capabilities of SCEE were significantly larger than the group without SCEE but it was detected to be lower than the BHA group. The induction period (IP) of sesame oil raised as the concentration of SCEE increased. All concentrations of SCEE were able to decline the PV and TBA value. Also, the group containing BHA and 100 μg/ml of SCEE significantly showed the same antioxidant activity (p≤0.05).

The SCEE as a natural substance can prevent lipid oxidation of the refined sesame oil like synthetic antioxidants.