Semi-industrial ultrasound-assisted virgin olive oil extraction: Impact on quality

This is the first effort to implement a continuous VOO ultrasound-assisted extraction system on a semiindustrial scale, studying its impact on product quality. Four sets of control/treated monovarietal VOOs were produced from Carolea and Ottobratica cultivars, at two maturation stages, in a low-scale mill plant (Wcap=150 kg/h). Thirty minutes of traditional malaxation were set for control trials, whereas UAE tests underwent 15min of traditional malaxation and 15 min of sonication, performed in a continuous ultrasonic reactor placed between the malaxer and decanter. Basic VOO quality parameters, antioxidant content, and volatile profiles were studied. In the tested conditions, UAE treatment did not affect free acidity or peroxide values. A consistent and significant increase in the content of minor compounds, namely phenols (lignans, secoiridoids) and C6 and C5 volatile compounds, was generally observed when UAE was applied. However, UAEmay have been responsible for a reduction in tocopherol content.UAEgenerally lead to higher extraction yields and higher intensities of positive sensory notes of fruity, bitter, and pungent. The results of semi-industrial trials support the application of UAE for VOO production, rendering its industrial implementation tangible.