Evaluation of Antioxidant Activity of Grapefruit Seed Extract on the Stability of Anchovy Oil

The aim of this study was to determine the types and amounts of phenolic compounds present in the grapefruit seeds as a source of natural antioxidant and to examine the antioxidant activity of grapefruit seed extract (GSE) in anchovy oil. Free and bound phenolic compounds of grapefruit seeds were extracted by methanol and alkaline hydrolysis respectively and then were measured by HPLC method. Antioxidant activities of GSE at different concentrations were compared with the synthetic antioxidant; TBHQ.The antioxidant activity was assessed by determination of peroxide value (PV), Thiobarbitoric Acid value (TBA) and induction periods (IP) measurements using Rancimat apparatus. Phenolic acids (Coumaric, Ferulic, Caffeic and Sinapic) and lutein, naringin and flavonoids were identified as the main phenolic compounds in grapefruit seeds. Total amount of phenolic compounds in grapefruit seeds was 485 ppm. The antioxidant activity increased with the increase in GSE level. GSE at 2000 ppm exhibited the highest antioxidant activity and the activity was better than TBHQ at 100 ppm. This study indicated that GSE is an antioxidant which might be used as an alternative to TBHQ to preserve the oil at low temperature. GSE might be suggested as a substitute for synthetic antioxidants for oils stored for a long time at room temperature.