Evaluation of Citron Peel (Citrus medica L.) Extract and Essential Oil on the Stability of Sunflower Oil

Due to the unfavorable effects of synthetic antioxidants, the use of various sources of plant antioxidants to retard or prevent oxidation of foods, especially oil-based or fat-based varieties, has today received considerable attention.

Inorder to extract the essential oil, water distillation method was applied and the extract of citron peel was obtained by ultrasound and maceration methods by using ethanol, methanol and water as solvents. Total phenolic compounds of the extracts and their antioxidant activities were measured. The chemical compounds in the extract and essential oil were identified by gas chromatography. Finally, the antioxidant effect on the stability of sunflower oil was investigated. The stability of oil to oxidation during storage for 5 days at 65 ° C was assessed using peroxide, anisidine, thiobarbituric acid, Tutox values and oxidative stability index.

The most amounts of phenolic compounds and antioxidant activity was absorved in ultrasonic-assisted ethanolic extract at 30 min. The extract concentration at 800 ppm was more effective to radical scavenging than the other concentrations. The major compounds of citron peel extract were nomilin and hesperidin. The results showed that the peroxide, anisidine, and totox value had an increasing trend over time. Ultrasonic-assisted ethanolic extract at 30 min showed the highest OSI.

The results of this study demonstrate the beneficial effects of the essential oil and extract from citron peel on sunflower oil stability and its superiority over synthetic antioxidants.