Response surface optimization of ultrasound-assisted oil extraction from autoclaved almond powder

An investigation into ultrasound-assisted extraction and autoclaving pretreatment was conducted for the oil extraction from almonds. The best possible combination of extraction parameters was obtained with the response surface methodology (RSM), at a three-variable, three-level experiment Box–Behnken design (BBD). The optimum extraction parameters were as follows: extraction time, 55 min; extraction temperature, 51 °C; and solvent/sample ratio, 19:1, at a fixed ultrasonic frequency of 40 kHz and power of 150 W. Under these conditions, the oil recovery was 81.89 ± 0.23% for the autoclaved almonds, which well matches with the predicted value. Furthermore, the oil composition was analyzed with GC–MS, and the effect of the autoclaving on the oil extraction was evaluated. The results showed that the autoclaving pretreatment increased the oil recovery, without affecting the oil composition, by 8.69%, which confirmed the efficacy of the autoclaving on the oil extraction from almond powder.