Editorial: New green extraction methods for the sustainable recovery of functional plant secondary metabolites

Secondary metabolites are small molecules synthesized by plants to make them adaptive and competitive in their own environment. More than 200,000 phytochemicals are known to display a wide range of effects on living organisms, including plants, animals and humans. In this context, food, nutraceutical, pharmaceutical, cosmetic, agricultural and new material industries are actively seeking for new plant sources to recover active compounds while aiming at sustainable natural resource utilization and protection of the environment. New green extraction techniques are being developed to substitute the standard not-environmentally friendly chemical and solvent-based methodologies. Several possibilities have been explored, such as natural deep eutectic solvents (NADES), power ultrasound or microwave radiation, enzymatic hydrolysis, supercritical or pressurized liquid extractions. Depending on the final aim, the applied methods can lead to total phytochemical extract or to the selective recovery of specific classes of plant-derived compounds. Yield and extraction specificity are usually among the most important parameters considered. The interference of molecules co-extracted with the target compounds should be minimized, as well as degradation of target compounds or artifacts formation, while the techno-functional features of the targeted molecules must be ensured both during and after extraction.