Obtaining green extracts rich in phenolic compounds from underexploited food by-products using natural deep eutectic solvents. Opportunities and challenges

Phenolic compounds have attracted scientific interest due to their bioactive properties. Moreover, the environmental awareness has increased considerably and, with it, research into valorisation processes. Food waste is a source of bioactive compounds, however, the most common methods of extracting these compounds were polluting. Recently, the use of natural deep eutectic solvents (NADES) is being studied as a way to achieve a green extraction process. This article reviews the opportunities offered by some underexploited food by-products (potato peels, grape pomace, beetroot and olive leaves) as sources of phenolic compounds and discusses the possible application of NADES for extraction. The literature reviewed concludes that these by-products are a rich source of polyphenols and that natural solvents are a real alternative for their extraction. However, further research is needed to overcome the drawbacks of NADES, as well as to study the feasibility of the application of the extracts in the food industry.

Automated summary

This article reviews the opportunities provided by underexploited food by-products as sources of phenolic compounds and discusses the potential application of natural deep eutectic solvents (NADES) for extraction. The literature suggests that these by-products are rich sources of polyphenols and that natural solvents provide a viable alternative for extraction, although further research is needed.