The effect of ultrasound on extraction yield and quality characteristics of olive oil

In our study, the influence of ultrasound on the extraction yield and quality characteristics of Virgin Olive Oils (VOO) extracted from of Edremit, Uslu and Gemlik cultivar were studied. The extraction yield, free acidity, peroxide value, p-anisidin value, total oxidation value, K232 and K270, total phenol compound, the content of total chlorophyll, total carotenoid compounds and sensorial properties of oils were determined. Different sonication treatments did not induce significant difference in the oil yield and extractability indexes of Edremit olive oils, however they were significantly different those extracted from Uslu and Gemlik olive oils. The oil obtained from Gemlikolive pastes treated with 4 and 8 minute ultrasound improved oil yield, by 1.63% and 1.53% and the oil extractability by 8.3% and 7.8%, respectively. Moreover, the content of chlorophylls and carotenoids were highest in samples subjected to 8 minutes sonication treatmentwhereas they were lowest in olive oilssubjected to 12 minute ultrasound. Oils extracted by 8 minute sonication showed higher oxidative stability as proven by their lower acidity value (FFA), p-anicidine value (p-AV), peroxide value (PV) and total oxidation (TOTOX) values than those extracted by 4 and 12 minute sonication. In this study, effect 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, keeping a maximum of commercial quality. The optimal conditions were found to be 50°C, 2 min and 44.74 min for ultrasound initial temperature, sonication time and malaxation time, respectively. The optimal condition resulted in extraction yield of 8.39 % and the acidity value of 0.28 mg oleic acid/ 100 g olive oil. The experimental values obtained under optimal conditions were in agreement with the theoretical values.