A Critical Review of Emerging Hydrophobic Deep Eutectic Solvents’ Applications in Food Chemistry: Trends and Opportunities

Abstract

Due to their low cost, biodegradability, and ease of preparation, deep eutectic solvents (DESs) are considered promising green alternatives to conventional solvents, as exploiting green solvents has been a research focus for achieving sustainable development goals. Most DESs in published studies are hydrophilic. On the other hand, the DES’s hydrophilicity restricts its practical applicability to just polar molecules, which is a vital disadvantage to this extractant. Hydrophobic DES (HDES) has been developed as a new extractant adept at extracting nonpolar inorganic and organic compounds from aqueous systems. Although there has been little research on HDESs (HDES publications account for <10% of DES), specific intriguing applications have been discovered, requiring investigation and comparisons. As a result, this review covers the applications of emerging HDES in detecting pesticide residues, food additives, contaminants in food packaging, heavy metals, separation and extraction processes in food. According to the available literature, HDESs have the potential to overcome the limitations of hydrophilic DESs and be used in a broader range of applications in food with greater efficiency, which has received little attention. HDES is expected to substitute a lot of harmful organic extractants used for analytical reasons (food chemistry) in the future. Besides, the limitations of HDES were reviewed, and future studies were provided. This will serve as a reference for green chemistry advocates and practitioners in food science who want to minimize pollution and improve efficiency and benefit from the further development of HDESs.

Hydrophobic Deep Eutectic Solvents as Greener Substitutes for Conventional Extraction Media: Examples and Techniques

“…VFAs can be produced via fermentation, , can be extracted from water with the help of the liquid–liquid extraction (LLE) method, , and so on. Recently, HDESs have been successfully used as solvent media in the extraction of VFAs due to their advantages over their counterparts. In 2015, the first use of HDESs for removing VFAs from a diluted aqueous solution was tested .…”

Mass spectrometry‐based approaches to assess the botanical authenticity of dietary supplements

“…The results showed that the extraction efficiency was comparable, but MSPD presented the advantages of allowing the extraction and cleanup in a single run, requiring less time and solvents. Recently, different works have suggested the use of deep eutectic solvents (DES) as alternatives to conventional organic solvents for extracting phytochemicals from plant material and foods (Boateng, 2022; Wang et al., 2020). Although the use of such solvents is still very limited and mostly focused on the optimization of bioactive compound extraction, it is likely that their use will increase in the future for the extraction steps of different analytical methodologies as they are considered nontoxic, biodegradable, environmentally friendly, and inexpensive.…”

A comparative study of lupeol extraction from a by‐product of lupin processing by hydrophobic natural deep eutectic solvents and their precursor components

“…[27] Besides, although these environment-friendly solvents bring overwhelming advantages, the recovery of target compounds from the mixtures after the extraction process has not yet been solved, and their recycling is one of the barriers to profitable commercial use. [28] The separation of target compounds from HNADES is difficult, as the evaporation of the solvent is not possible due to its low vapor pressure. [29] To address this problem, several techniques have been proposed to efficiently recover target compounds from HNADES, such as crystallization, antisolvent addition, solid-liquid extraction, membrane filtration, distillation, liquid-liquid extraction, supercritical fluid extraction, and separation based on density differences.…”