The high power ultrasound frequency: Effect on the virgin olive oil yield and quality. (August 2017) - Bejaoui, Mohamed Aymen
Abstract: In this work a pilot-scale device for continuous High Power Ultrasound (HPU) application was employed for its use at experimental plant level. The experiment consisted in the sonication treatment of olive paste at three frequencies of 20, 40, and 80 kHz. After treatments, the Virgin Olive Oil (VOO) was extracted at 'ABENCOR' laboratory scale extraction system. Two extraction conditions were compared, malaxation and centrifugation, against direct paste centrifugation. The first effect observed of the HPU application on the olive paste, for all the frequencies used when compared with the untreated paste, was the instantaneous heating. Regarding to the process efficiency, in general the application of HPU improves the process yield with respect to the untreated paste. HPU treatment at 40 kHz frequency followed by kneading produced higher olive oil extractability. With respect to the VOO quality and nutritional compounds no alteration was noted with the HPU treatment. Highlights: High Power Ultrasound treatments allowed increase of oil yield. High Power Ultrasound treatments at 40 kHz allowed equivalent yield than malaxation. No alteration of oil quality with the High Power Ultrasound treatments. No significant change were observed between treatments for minor compounds.