High hydrostatic pressure-assisted extraction: a review on its effects on bioactive profile and biological activities of extracts

Extraction can be described as a mass transport phenomenon, where solids present in a matrix are transferred into the solvent up to their equilibrium concentration, and it is defined as the first step for the recovery of important bioactive components from natural materials. The growing interest in bioactive compounds and high value-added ingredients from several different matrixes is due to the consumer preference of natural additives and antioxidants over synthetic ones. The major problem is that bioactive compounds, such as flavonoids, anthocyanins, etc., are enclosed in insoluble structures, making its extraction a complicated process. Several organic compounds are heat sensitive, losing their integrity and biological activity due to denaturation when subjected to heat. The most widely used extraction techniques are the conventional ones, which are easy to perform and cheap to operate, but they are mostly based on the choice of an appropriate solvent, the use of mild/high temperatures (that causes thermal degradation) and agitation in order to increase the solubility of materials and the mass transfer rate, which is reflected in long extraction times, high costs, and low extraction efficiency. Therefore, it has been necessary to develop new extraction methods, such as high hydrostatic pressure-assisted extraction since it allows the use of room temperature, low volumes of organic solvents, reduction of extraction time, and energetic consumption, with higher yields and high-quality final extracts.