A Review of New Methods for Extracting Oil from Plants to Enhance the Efficiency and Physicochemical Properties of the Extracted Oils

Abstract

In general, there are three methods for extracting oil from various sources: mechanical, solvent, and pre-press-solvent. Each of these methods has its own advantages and disadvantages, with extraction efficiency depending on key factors such as the extraction technique, the properties of the plant component matrix, and the solvent used. Factors like temperature, pressure, and time also play a role. Researchers have consistently sought to replace or complement these methods to reduce residual oil in products. This study introduces new oil extraction methods that have gained attention in recent years, including the microwave, pulsed electric field, ultrasound, supercritical fluid, enzymatic, ohmic, and combined methods to enhance efficiency. The research demonstrates that these methods increase oil extraction efficiency and bioactive compound extraction from plant sources, resulting in improved oil quality. Most methods also reduce extraction time, offering researchers and industrialists a variety of options for their oil extraction needs. However, the study notes contradictions in the results, such as varying acidity levels in the oil, which may be attributed to raw materials and study conditions. In the end, it was determined that ultrasound, pulsed electric field, and enzyme methods can be used industrially to extract oil from olives, while supercritical fluid can be used to extract oil from certain seeds.