Subcritical water extraction of essential oils and plant oils

Subcritical water extraction is a green technology with interesting advantages in relation to the possibility of processing fresh raw materials to sustainably obtain natural valuable products. The potential of this technology for the aqueous extraction of lipophilic fractions from plant biomass is well known and has recently attracted renewed interest. This review presents an update of the advances on the extraction of two valuable types of lipophilic products, essential oils and vegetal lipids from various plant biomasses. It also emphasizes the effect of process variables as particle size, time, liquid to solid ratio, pressure and temperature as well as the operation tunability to select optimal conditions for different solutes. The optimal operation conditions play a key role to efficiently recover these natural products with potential applications in cosmetic, food, agricultural and pharmaceutical/medical industries.