Impact of Using Ultrasound on Chemical Properties and Bioactive Compounds of Olive Oil Extracted from Olive Paste

Impact of using ultrasound technology on quality and extraction yield of Coratina and koroneiki olive oil was studied. The application of ultrasound treatment was done to olive paste for 0, 2, 4, 6, 8 and 10 minutes. Oil yield significantly increased 16.65, 18.33% for Coratina and Koroneiki, respectively. Olive paste temperature was increased from 22oC (after crushing) to about 23, 25, 26.5, 28 and 30 oC after 2, 4, 6, 8 and 10 minutes of ultrasound, respectively. All examined samples had low contents of FFA, PV, K232 and K270 and there are no differences in FFA, K232, K270 and lipid profile between untreated sample and treated sample with ultrasound for both cultivars. Furthermore, obtained olive oil by ultrasound showed total tocopherols, chlorophyll and carotenes significantly higher than untreated one. Total tocopherols were significantly increased from 5.81 and 4.62% after 10 minutes of sonication for Coratina and Koroneiki, respectively. Chlorophylls were increased after sonication. Carotenes were increased 20.13 and 39.68% after 10 minutes of sonication for Coratina and Koroneiki, respectively. Also, sonicated samples showed decrease in total phenols. It significantly decreased total phenols by 14.53 and 14.24% after 10 min for Coratina and Koroneiki, respectively. Results indicated that the increment time of ultrasound had an increase in fruity attribute and had a decrease in bitterness and pungency intensities. The use of ultrasound had not altered olive oil quality, as extra virgin olive oil in accordance with International Olive Council. So, ultrasound could be a suitable technology for improving olive oil yield.