Extraction of bioactive compounds from husks of pomegranate (Punica granatum L.) using pressurized liquids assisted by ultrasound

Abstract

The rind of pomegranate (Punica granatum L.) are rich raw material in bioactive compounds, such as punicalagins and ellagic acid, which can be extracted using the appropriate techniques and conditions. This research project will evaluate the possibility of assisting the extraction with pressurized liquid with ultrasound to improve the efficiency, selectivity and yield of the process for the isolation of these compounds from pomegranate rind. Due to the influence of process variables in the propagation of ultrasonic waves and cavitation several variables will be evaluated to determine the adequacy of combining ultrasound with pressurized liquid extraction. To maximize the effect of ultrasound application in the extraction process the use of different amounts of carbon dioxide as expansion gas will be evaluated seeking to enhance the cavitation phenomenon. The ethyl lactate will be evaluated as an alternative extraction solvent seeking a process that is not only efficient but also environmentally friendly. Initially the combined effects of temperature (60-120 ° C), solvent extraction (25-75% ethyl lactate in water and 70% ethanol in water), and ultrasound power (0-800 W) will be studied. In a second step interactions between the amount of expansion gas (0-10 wt%), pressure (50-350 bar) and ultrasound power will be evaluated. Finally, different extraction times (10-30 minutes) and number of extraction cycles (cycles 1-3) will be evaluated. The results will be analyzed based on the yield of dry extract, concentration of bioactive compounds by liquid chromatography, total polyphenol content and antioxidant activity by two different methods (FRAP and TEAC). (AU)