Does water addition during the industrial milling phase affect the chemical-sensory quality of olive oils? The case of cv. Arbequina oils.

At olive oil industrial extraction, water addition is a practice overcoming the formation of thick pastes. The effect of water addition (0 to 6.2%, kg/kg), during the industrial milling of cv. Arbequina olives, on the oils' chemical-sensory quality, was evaluated. Despite the extra virgin olive oil classification, compared with the water incorporation (1.2-6.2%), extraction without water addition resulted into oils that showed less primary oxidation (lower peroxide values and K), greater total phenolic content (+12-22%) and higher oxidative stability (+22-31%). No water addition increased the oils secoiridoids content (+5-13%), mainly oleacein (+27-79%). Oils extracted without water addition had a more intense ripe fruity sensation (≥ +11%) but lower fruit intensities (at least -4%). Thus, the quality and stability of the cv. Arbequina oils can be favoured if extracted without adding water during the olives industrial milling.