Effect of ultrasound on olive oil extraction and optimization of ultrasound-assisted extraction of extra virgin olive oil by response surface methodology (RSM)

Abstract

In this study, the effects of different extraction parameters including ultrasound time, temperature and malaxation time on olive oil quality were investigated. The extraction variables ultrasound initial temperature (20–50 °C), ultrasound time (2–10 min) and malaxation time (30–50 min) were studied to obtain ideal conditions of ultrasonic treatment on the olive paste for obtaining of a greater yield in the extraction of oil, while maintaining a maximum level of commercial quality. To evaluate the level of commercial quality, absorbance in the UV region, peroxide (PV) and free acidity values (AV), the total chlorophyll, carotenoid, phenol contents, total antioxidant activity and sensory analysis of EVOOs extracted from Edremit cultivar were determined. The optimum conditions were found to be 50 °C, 2 min and 43.23 min for ultrasound initial temperature, sonication time and malaxation time, respectively. This optimal condition gave an extraction yield of 8.25 % and the acidity value of 0.24 mg oleic acid/100 g olive oil. The experimental values obtained under optimal conditions were in agreement with the theoretical values.