Partition of phenolic compounds during the virgin olive oil industrial extraction process

Phenolics have been considered an important group of natural antioxidants. The type and quantity of phenolics vary in olive matrices (leaves, fruit, stones, seeds, and paste). However, the relationships linking the products from the olive oil extraction process are poorly studied. This manuscript deals with the partition of phenolic compounds during olive oil production season at three times. Samples were taken during malaxation to determine the phenolic content in the olive paste at 0, 15, and 45 min. The wet pomace and oil phases were analyzed and the phenolics quantified in terms of kilogram of olive paste. Malaxation time had an important effect on the alcohols and secoiridoids. Hydroxytyrosol and tyrosol decreased, and their hydrophilic character was proved through their presence in the wet pomace and wastewater. Oleuropein and ligstroside degradation results in the formation of secoiridoid derivatives, mainly the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA). A molar transfer index (MTI) was established between the 3,4-DHPEA-EDA in the olive paste and olive oil (as the liquid phase) and wet pomace (as the solid phase). An increasing trend was observed for the molar transference to virgin olive oil with the advance of the crop season.