A Box-Behnken design for optimization of ultrasound-assisted solvent extraction of hazelnut oil

This study aims to increase the hazelnut oil yield using ultrasound as initial treatment in hexane solvent extraction. A Box-Behnken design was applied to optimize the ultrasound amplitude (30%, 60%, and 90%), solvent to solid ratio (6:1, 8:1, and 10:1) and extraction temperature (28, 38, and 48 degrees C). The results showed that increasing all these variables would increase the oil yield. The oil extraction were optimum at 90% ultrasound amplitude, 10:1 solvent to solid ratio, and 48 degrees C of extraction temperature. Effect of extraction time on oil yield was studied at optimum conditions. The maximum oil yield was achieved at 75 min of extraction time with 15-min initial sonication. The maximum oil yield in ultrasound-assisted extraction was around 88%. Ultrasound treatment had increased 4% of oil yield from the control. Fourier-transform infrared spectroscopy results showed that the extracted hazelnut oil has the similar functional groups as other edible oils.