Hydrothermal extraction of bioactives and biopolymers assisted by eutectic mixtures as modifier

Abstract

Background

Among the green technologies for the extraction of botanical bioactives with food applications, the use of both pressurized hot water under subcritical conditions and eutectic mixtures of natural compounds are highly promising. The performance of pressurized hot water extraction can be enhanced by the incorporation of modifiers and the controlled addition of water to eutectic mixtures facilitates operation, especially with continuous solvent flow operation. Based on these two facts, the combination of natural eutectic solvents (NaDES), with pressurized hot water, conforms a relatively recent approach for the extraction of bioactives and biopolymers from agricultural and food waste biomass.

Scope and approach

The NaDES assisted pressurized hot water has especial interest for the extraction of increasingly demanded bioactives for the formulation of functional foods and nutraceuticals from widely available low cost sources, such as agro-food wastes. The effect of the most influencing operational conditions and the until now few reported applications to efficiently extract bioactives and biopolymers from different underused biomass are overviewed.

Key findings and conclusions

This approach joins the advantages of both green techniques, offering the possibility of using wet biomass, avoiding drying stages, in a tunable process providing enhanced properties and stability of bioactives. The preparation of ready to use biopolymers and bioactives is feasible without requiring the costly stages for solute separation and for eutectic solvent recovery. Further studies are encouraged to address the major challenges in this field, including tools for the rational selection of solvents and operational conditions, advances in the knowledge of extraction mechanisms, solvent and solute recovery, scaling up, potential commercial applications and safety issues, particularly for food uses.