Method for phenol recovery from “alperujo”: numerical optimization and predictive model

Abstract

“Alperujos” of Arbequina olives harvested in 2010 and 2011 and of Nevadillo olives in 2012 were evaluated in order to reduce their pollutant load by recovering the phenols with antioxidant properties. First, three successive extractions with water (4 °C, 120 min) were carried out to evaluate by spectrophotometry the total phenol contents, which significantly varied with cultivar and harvest year. The combined aqueous extracts of “alperujo” (combined-AEA) showed high pollutant loads with volatile solids to total solids ratios close to 1 suggesting high organic material contents and very low total phenols to chemical oxygen demand ratios. Second, phenols were recovered from the combined-AEA using ethyl acetate. By experimental design, the following conditions were found to maximize phenol recovery: temperature = 20 °C, time = 120 min, pH of aqueous extract = 2.00 and solvent/extract ratio (v/v) = 3:1. Up to 41.6% of the phenols were recovered from the combined-AEA after three successive extractions using recycled solvent.