Modern Techniques Used in Solid-Liquid Extraction and the Place of Ultrasound Assisted Extraction Among These Techniques

In recent years, biomolecules have attracted attention due to their nutraceutical potentials and studies on development of techniques for the extraction of these components from various natural sources are increasing. the presence of polysaccharides such as hemicelluloses, starch, pectin inside the plant cell wall, reduces the extraction efficiency of conventional extraction techniques. also, conventional techniques has negative aspects namely, long extraction times, large amount of solvent, low extraction selectivity, high cost and the necessity of solvent evaporation in excess amounts. therefore, there is a need for the development of green and new extraction techniques for the efficient recovery of biomolecules. by ultrasound application which is a modern extraction technique, micron sized cavites cause degradation in the cell wall and a decrease in particle size and so it accelerates mass transfer and increase the extraction rates. ultrasonic extraction shortens the processing time and provides a higher product purity, reduces energy consumption and results in an environmentally friendly technology with less solvent usage. in this review, modern extraction techniques are considered from a holistic point of view and the location of the ultrasonic extraction among these techniques is expressed in detail.