Pressurized liquid extraction of polyphenols from olive leaf and olive pomace

The aim of this study was to obtain polyphenols from Pirina and olive leaves by pressurized solvent extraction method. Using 50% ethanol as solvent and an extraction pressure of 1500 psi, the influence of the parameters of pressurized liquid extraction parameters (temperature, extraction time, and pH) on the quality and quantity of oleuropein and phenolic compounds, as well as on the activity of DPPH radical scavenger was studied by response surface design. The results showed that the extraction yield varied between 22.55-36.5% for olive leaves and 2.54-17% for pirina, the total phenolic yield varied between 9.77-41.52% for olive leaves and 0.5-4.68% for pirina, and the total flavanol yield varied between 1.42-6.19% for olive leaves and 0.25-1.92% for pirina. The highest DPPH scavenging activity of 11.24 μg leaf extract/ml (EC50) was obtained at 75°C, pH 4.5 and for 22.5 min.