Hexane-oil mixtures were collected after ultrasonication. The samples were centrifuged at1000 rpm for 20 min to separate the fine solid particles that may still be present in the sample. After centrifugation, 1 ml of supernatant was collected from the sample and weighed using a precision scale. Hexane was evaporated by placing the samples in an oven at 105 °C for 2 hours. The initial and final weight of the samples were measured and recorded. The oil yield (Y) was determined by using the following formula (Equation 1).