Ultrasound-assisted extraction of oil from macauba pulp using alcoholic solvents

Ultrasound-assisted extraction (UAE) of macauba pulp oil was investigated using ethanol and isopropanol as solvents and compared with the conventional extraction technique. An experimental design was applied to evaluate the influence of the experimental variables (temperature, solvent to pulp ratio, and time) on the oil extraction and to optimize them. The optimum conditions were then evaluated in relation to the extraction kinetics and the effect of the application of ultrasound in the process was determined. For both techniques, higher yields were obtained with the use of ethanol as the solvent. The results showed that increasing the temperature, the amount of solvent used and the extraction time leads to greater oil removal from macauba pulp (p<.05), and the amount of solvent used in the process had the greatest influence. The maximum oil yields obtained by UAE were 49.2 and 38% with ethanol and isopropanol, respectively, obtained at 60 degrees C, with a 90-min extraction time and solvent to pulp ratio of 10, which represent approximate to 86 and approximate to 77% of the yield obtained by conventional extraction. The UAE provided better yields when compared to the process without ultrasound. The fatty acids composition was not influenced by the extraction method and solvent used; however, UAE provides oils with higher levels of -carotene and flavonoids using ethanol and isopropanol, respectively. Practical applicationsThe optimization of UAE for macauba pulp oil extraction is presented in the present study and the results demonstrate the efficiency of the method for obtaining this oil in low extraction time and solvent consumption. The oil obtained by this technique has higher levels of -carotene and flavonoids. Additionally, macauba pulp oil obtained using ethanol and isopropanol with solvent may be used as a food, because these solvents are considered of food grade.