Oleosomes: Insights into structure, sources, extraction methods, and current applications to pharmaceuticals and beyond

Oleosomes, also known as oil bodies, are nutrient substances that exist as oil-in-water (O/W) emulsions in the form of triacylglycerols surrounded and protected by a specialized membrane of proteins embedded with a monolayer of phospholipid mixtures. These naturally occurring compounds are widely present in plants, serving as an energy reservoir during germination and providing resilience to stresses in severe environmental conditions. Moreover, as naturally pre-emulsified emulsions, oleosomes have shown promising applications in the fields of food and nutrition and pharmaceutical sciences. An increasing number of researchers are focusing on the extraction of oleosomes from conventional plant-based sources, such as rapeseed, soybeans, sunflower, and flaxseed, due to their attractive advantages. Meanwhile, many other plant species, microalgae, microorganisms, and mammals can also accumulate triacylglycerols in the form of oleosomes. This review presents new perspectives on the structure, composition, and traditional aqueous extraction techniques of oleosomes, as well as the alternative extraction methods, such as twin-screw press, enzyme-assisted, and ultrasound-assisted extractions of oleosomes in both conventional plants and sources such as nuts, fruits, and algae. Furthermore, the broad applications of oleosomes from the food industry to pharmaceutical fields are discussed.