In the optimization of pretreatment study, hexane was used as a solvent. Two levels of four parameters including temperature (20∘C and 40∘C), time (10 min and 300min), orange peel wastes and hexane ratio (1 : 2 and 1 : 12),
and the wastes size (homogenized or chopped) were selected. Forty grams of thewasteswas dissolvedwith a certain amount
of hexane in the flasks, followed by shaking vigorously for a determined period of time. After the settlement, the extracts
were removed from residuals by vacuum filtration.