Production of Olive Oils Rich in Phenolic Compounds from Pastes Acidified with Food-Grade Organic Acids

This work investigates the impact of acidification on olive pastes to improve the extraction of olive oil rich in bioactive phenolic compounds, a potential new functional food. Food-grade organic acids, specifically citric, ascorbic, and acetic acid were added prior to malaxation to modulate enzymatic activity during oil extraction. A randomized experimental design was carried out using acetic, ascorbic and citric acids, and three different doses of each of them. Three replicates of each acid and dose were randomly performed, plus the control trials carried out without using acids. The use of acids does not alter the extraction efficiency of the olive oil, nor does it modify the quality parameters regulated for extra virgin olive oils. They have the highest content of phenolic compounds, 37% more than control oils. In these oils, the secoiridoids group represents 79.4% of the total phenols, and of these, more than 50% is oleacein (237.58 ± 9.18 mg/kg). The high oleacein content increases the antioxidant capacity by up to 50% (433.63 ± 38.32 mg Trolox/kg) compared to control oils. An antioxidant capacity of 4.0 µmol Trolox/mg oleacein has been determined. 1% ascorbic acid improves the content of volatile compounds of the lipoxygenase (LOX) pathway and reduces the ethanol content compared to control oils.