OLIV-006: The influence of Pulsed Electric Field on Antioxidant Components and Antioxidant Capacity of Virgin Olive Oil

The aim of the present study was to determine the influence of pulsed electric field (PEF) as a pretreatment of the malaxation process on the concentrations of antioxidants and antioxidant capacity of virgin olive oil (VOO) from four autochthonous Croatian varieties (Istarska Bjelica, Rosulja, Levantinka and Oblica). During PEF treatment, electric field strength (1-8 kV/cm) and pretreatment time (18-102 s) were varied. The concentrations of antioxidants in produced VOOs, α-tocopherol and polyphenols, were determined by the HPLC method, while their capacity to reduce the DPPH radical was measured by electron paramagnetic resonance (EPR). The variety had the greatest effect on the concentration of antioxidants. The concentration of α-tocopherol in the VOOs produced ranged from 230 to 350 mg/kg and was the highest in Levantinka and Bjelica. Bjelica, Rosulja, and Levantinka had significantly higher total polyphenol content (278.93, 258.97 and 234.19 mg/kg, respectively) compared to Oblica VOOs (92.29 mg/kg). Therefore, Rosulja, Levantinka and Bjelica had significantly higher antioxidant capacity (53.82, 46.18 and 42.84 % of DPPH radical reduction, respectively) than Oblica (21.81 %). PEF pretreatment time and electric field strength significantly affected the total polyphenol content and antioxidant capacity of the produced VOOs. The highest total polyphenol content for Rosulja, Levantinka and Bjelica was obtained at lower electric field strength and longer treatment time. The same was observed for the antioxidant capacity of Rosulja and Levantinka, while Bjelica showed the highest antioxidant capacity after longer treatment with higher electric field strength. However, PEF pretreatment had no effect on low polyphenolic content and antioxidant capacity of Oblica VOOs. Levantinka and Oblica showed the highest α-tocopherol concentration at lower electric field strength and shorter treatment duration, while Rosulja and Bjelica showed just the opposite, the highest α-tocopherol concentration was obtained after PEF treatment with higher electric field strength for longer time.