*2.1. Phenolic Extract Preparation*

Olive of Ottobratica cv were processed by a three-phase centrifugation apparatus in an olive oil mill located in the province of Reggio Calabria. The obtained olive Mill Wastewater (OMWW) were transferred in Food Technologies laboratory of the Mediterranean University of Reggio Calabria (Italy) where were submitted to two different extraction methods.

Method A*:* was carried out following the method reported by Romeo et al. [4]. An aliquot of OMWW was acidified to pH 2 with HCl and washed three times with hexane (1:1, *v*/*v*) in order to remove the lipid fraction. After shaken and centrifuged (Nüve, Ankara, Turkey) the extraction procedure was carried out by means of ethyl acetate three times and the solvent was recovered in a separating funnel (1:4 *v*/*v*). The ethyl acetate was separated and evaporated using a rotary vacuum evaporator at 25 ◦C. Finally, the dry residues were again dissolved in 100 mL of water, filtered using PTFE 0.45 μm (diameter 15 mm) syringe filter. The obtained sample, named PE A, was then stored at 4 ◦C until subsequent analyses.

Method B*:* an aliquot of OMWW was acidified to pH 2 with citric acid. After 30 min of shaken and 5 min of centrifugation (6000 rpm) the sample was filtrated with a paper filter and concentrated in an oven at 50 ◦C. The final residue characterized by gelatinous consistency was extracted with water (1:5, *w*/*v*) in an ultrasound system (Sonoplus Ultrasonic homogenisers, Series 2000.2, HD 2200.2. BANDELIN, Ultraschall seit 1955) for 30 min. Finally, the obtained extract was filtered using PTFE 0.45 μm (diameter 15 mm) syringe filter. The sample, named PEB, was then stored at 4 ◦C until subsequent analyses.
