Ultrasound-assisted extraction of Osmanthus fragrans fruit oil and evaluation of its fatty acid composition, physicochemical properties and antioxidant activity

In this work, optimization of ultrasound-assisted extraction (UAE) of Osmanthus fragrans (OF) fruit oils from four representative species of OF groups was firstly performed. A Box-Behnken design was applied to investigate and optimize the process variables. Among them, the specie of OF var. latifolius Makino (OFL) had the highest oil yield (18.53 %) by UAE under the optimal conditions with an ultrasound extraction time of 33 min, ultrasound temperature of 52 ℃ and liquid-to-solid ratio of 12 mL/g. Furthermore, the fatty acid composition, physicochemical characteristics, and antioxidant activity of OFL fruit oil extracts obtained through UAE and Soxhelet extraction (SE) were determined and compared. The results demonstrated that the oil yield and fatty acid composition between UAE and SE were similar, while the oil obtained by UAE displayed superior physicochemical properties and antioxidant activity. These findings suggest that UAE represents an effective method for OF fruit oil extraction.