The perspectives of natural deep eutectic solvents in agri-food sector

Deep eutectic solvents in food contaminants detection: Characteristics, interaction mechanism and application advances from extracting to other roles

Food safety is crucial for public health, yet it faces growing threats from environmental and anthropogenic pollutants. Deep eutectic solvents (DESs) have emerged as green and efficient alternative solvents for detecting trace pollutants. This review highlights the characteristics of DESs, their mechanisms for extracting target analytes and applications in food analysis. Subsequently, the challenges faced by DESs in the detection of food samples and future development trends are further discussed. DESs can selectively interact with various target analytes (including pesticides, veterinary drugs, food additives, heavy metals, toxins, and other residues) during the food safety testing process by forming hydrogen bond networks. Beyond serving as extraction solvents, DESs can act as adsorbents, eluents, and reaction media, thereby simplifying sample pretreatment and enhancing the detection performance of various contaminants. Overall, as customizable functional solvents, DESs hold great promise for advancing next-generation food analysis methods, though some technical barriers remain to be addressed.

Valorization of waste tomato leaves with natural deep eutectic solvents

Waste produced during cultivation of edible plants can be a valuable source of bioactive molecules. Herein, we present the valorization of tomato leaves to obtain biologically active extracts. Deep eutectic solvents (DESs), composed of natural ingredients, were applied as extracting solvents. The extracts were rich in bioactive chemicals such as phenolics and flavonoids, with rutin as the main component (∼6 mg/g of biomass). The obtained extracts showed high antioxidative potential. Moreover, it was possible to recycle DES for subsequent extractions. Evaluation of the antimicrobial activity of the extracts against selected bacteria (Escherichia coli and Staphylococcus epidermidis) and yeast (Candida albicans) revealed that it showed strong antifungal activity, while the pure solvent did not exhibit such properties. The study revealed that by adhering to the principles of the circular economy and extracting waste tomato leaves using natural DESs, valuable antioxidants and antimicrobial agents can be obtained with high yields.

Deep eutectic solvent extraction of polyphenol from plant materials: Current status and future prospects in food applications

The increasing environmental concerns related to biomass waste have led to the exploration of sustainable methods for extracting bioactive compounds from plant materials, especially polyphenols, which are valued for their health benefits and use in functional foods and natural additives. These bioactive compounds are abundant in fruits, vegetables, tea, and herbs, and encompass flavonoids, phenolic acids, tannins, stilbenes, and lignans. Traditional extraction methods often rely on harmful petrochemical solvents, which pose significant environmental and health risks. In contrast, Deep Eutectic Solvents (DESs) have emerged as an eco-friendly alternative, offering advantages such as low toxicity, cost-efficiency, and a wide range of solubility. This review focused recent advancements in DES-based polyphenol extraction, emphasizing their applications in the food industry. It highlights the potential of DES to efficiently extract polyphenols, improving their bioavailability and stability, and exploring future prospect for enhancing food quality, safety, and functionality through functional foods and natural preservatives.

Evaluation of the Inhibition Performance of a Hybrid Depth Eutectic Solvent Used as an Inhibitor for Water-Based Drilling Fluids and Its Mechanistic Analysis

Drilling instability in oil and gas drilling has long challenged drilling safety and economics. Conventional oil-based drilling fluids offer high-temperature resistance and good inhibition. However, oil-based drilling fluids have significant problems in terms of environmental impact, cost, and waste fluid disposal. This has led to the widespread use of water-based drilling fluids. This study aims to investigate the synthesis of a new water-based drilling fluid inhibitor, a hybrid low eutectic solvent ChCl-Gly-Urea (CGU-DES), and its performance evaluation. While conventional eutectic solvents (DES) usually consist of a single type of hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD), CGU-DES extends its performance characteristics by introducing a combination of one HBA and two HBDs. The study confirmed the successful synthesis of CGU-DES using FT-IR spectroscopy. The following advantages of CGU-DES over CU-DES and CU-DES consisting of a single type of HBA and HBD were verified. Below 175 °C, the temperature resistance of CGU-DES is better, and the mass loss rate is less than 5%. The first and second rolling recoveries of CGU-DES aqueous solution with low concentration (<0.5 wt %) were greater than 95% and 85%, respectively, higher than the rolling recoveries of CG-DES and CU-DES.CGU-DES has a good ability to reduce water activity. When the dosage is 10%, the activity of DES aqueous solution is less than 0.950, and the efficiency of reducing water activity is nearly twice that of CG-DES and CU-DES. CGU-DES is compatible with sodium slurry and drilling fluids with polymer-sulfonated materials because it has little influence on rheology and fluid loss. At 180 °C, 0.7% CGU-DES was added to the polysulfonate drilling fluid system, and the fluid loss reduction rate reached 30.59%. Experiments show that CGU-DES can inhibit the hydration and dispersion of shale by inserting into the crystal spacing of montmorillonite , adsorbing onto the surface, reducing the surface tension of drilling fluid, reducing the contact angle between drilling fluid and shale, and reducing the water activity of drilling fluid. In summary, CGU-DES, a new type of green solvent, has potential application prospects in water-based drilling fluids and provides new technical support for solving the borehole instability problem during drilling.

Ultrasound assisted deep eutectic solvent-based extraction of Montepulciano d' Abruzzo grape seeds for the recovery of the grape seed oil and its biological evaluation

Grape seeds are by-products of vinification process. In this work, a green ultrasound-assisted extraction of grape seeds oil was performed by using the natural volatile deep eutectic solvent (NADES) menthol: thymol 1:1. The obtained oil was compared to that deriving from UAE with n-hexane in terms of fatty acids composition and biological activities. The content of linoleic acid was low for the DES extracted oil; the content of linolenic acid increased from 0.53 % to 5.18 %. The grape seeds oil extracted with DES showed the best total phenolic (18.65 mg GAE/g) and flavonoid (0.73 mg RE/g) contents and the highest results in FRAP, CUPRAC, MCA and Phosphomolybdenum assays. The oil extracted by DES also showed a higher amylase inhibition (0.57 mmol ACAE/g) than n-hexane extract (0.47 mmol ACAE/g). Finally, the anti-inflammatory activity was assessed in vivo through tree different assays, suggesting that their different fatty acids composition could be partially responsible for the significant anti-inflammatory effect of the grape seed oil extracted by NADES.

Impact of choline choride and sugar natural deep eutectic solvents on structure and functionality of treebean (Parkia timoriana) seed protein

This study explores the impact of natural deep eutectic solvents (NADES) on the structure and functionality of treebean (Parkia timoriana) seed protein, a novel approach to enhancing protein stability and functionality for sustainable bioprocessing. The research aims to evaluate the dynamic interactions between protein and choline chloride-sugar-based NADES, focusing on their effects on thermal properties, emulsification behaviour, and rheological characteristics. NADES were formulated using different sugars, and protein-NADES dispersions were analysed for their physicochemical and functional properties. Key findings include improved thermal stability, with sorbitol-based NADES showing the highest onset temperature (124.2 °C) and peak degradation temperature (330 °C), indicative of enhanced resistance to high-temperature processing. The sorbitol-NADES-protein dispersion also exhibited superior emulsification activity (50.42%) and stability (42.55%) compared to other formulations. Rheological analysis demonstrated non-Newtonian shear-thinning behaviour, with sorbitol-NADES providing the highest zero-shear viscosity (14.32 mPa s) and relaxation time (3.17 s). These results highlight the ability of NADES to stabilize protein structures while maintaining functionality under processing conditions. The novelty of the study lies in demonstrating the potential of NADES to sustainably enhance the structural and functional attributes of plant proteins, paving the way for innovative applications in food and bioprocessing industries. By employing green solvents, this study presents a sustainable solution for high-temperature food processing, addressing environmental concerns associated with conventional solvents.

Impact of a Novel Two-Phase Natural Deep Eutectic Solvent-Assisted Extraction on the Structural, Functional, and Flavor Properties of Hemp Protein Isolates

Defatting dehulled hemp seeds is a crucial step prior to protein extraction. However, conventional methods rely on flammable solvents, posing significant health, safety, and environmental concerns. Additionally, hemp protein has poor extractability, challenging functionality, and flavor limitations, restricting its broader application in foods. Accordingly, a two-phase natural deep eutectic solvent (NADES)-assisted extraction was evaluated as a solvent-free alternative for co-extracting protein and oil from full-fat hemp flour. In comparison to the reference hemp protein isolate (R-HPI), produced from hexane-defatted flour following conventional alkaline extraction, NADES-extracted hemp protein isolate (N-HPI) had significantly higher protein extraction yield and purity. N-HPI exhibited enhanced surface charge, lower hydrophobicity, and thus higher solubility at an acidic pH compared to R-HPI. N-HPI had a higher abundance of edestin and lower levels of vicilin-like proteins, which contributed to superior gelation compared to R-HPI. N-HPI, compared to R-HPI, contained lower levels of lipid-derived off-flavor compounds, such as aldehydes, alcohols, and ketones. These findings highlighted, for the first time, the potential of a two-phase NADES-assisted extraction as a sustainable alternate and effective process for producing high-quality, functional hemp protein. The development of such a green process is an impetus for broadening the applications of hemp protein in food systems.

Structural characterization and physicochemical properties of different hydrophilic natural deep eutectic solvents

To overcome the toxic nature of organic solvents, scientific interest in the use of green solvents, particularly natural deep eutectic solvents (NADES), has increased over the past decade, leading to new applications in the food, nutraceutical, pharmaceutical, and cosmetic industries. Understanding the physicochemical properties and molecular interactions of NADES is essential for uncovering new potential applications in these fields. In this study, several lactic and citric acid-based NADES, as well as chloride choline- and urea-based NADES, were evaluated for their physicochemical properties, including density, pH, viscosity, conductivity, and refractive index. Additionally, nuclear magnetic resonance (NMR), and in particular nuclear Overhauser enhancement spectroscopy (NOESY), was employed to investigate the intermolecular interactions between the NADES components to confirm the formation of the eutectic mixture. The extraction efficiency of the confirmed NADES was tested for extracting polyphenols as a proof of concept to highlight their relationship with the measured properties. Lactic and choline chloride-based NADES provided the highest extraction yields. These results were also compared with the predicted extraction capabilities of each NADES provided by the COSMO-RS software.

Physical field-assisted deep eutectic solvent processing: A green and water-saving extraction and separation technology

Extraction of organic and bioactive compounds from plant materials with the traditional organic solvents aided by water or oil bath heating is not sustainable, because it consumes a lot of energy, time, water/oil, solvents, and results in lower yield. This review discusses deep eutectic solvent (DES) as a green solvent, physical field technology (PFT) as a water-saving and green technology, and how the coupling of PFT (ultrasound [US], microwave [MW], infrared [IR]) to DES will improve the yield and quality of protein, polysaccharides, polyphenols, pectin, and terpenoids extracted from plant materials. Ultrasonication increases DES extraction efficiency via cavitation dislodgement and pores creation. IR coupling to DES enhances the extraction yield of polyphenols and the antioxidant and antiradical activity. MW improves DES extraction yield, reduces energy consumption, operational cost, and compound degradation, and is inferred to be the greenest technology.

The perfect match between macroalgae and eutectic solvents as a sustainable gateway to ready-to-use extracts towards a (blue + green) economy ─ A perspective review

The article discusses how aligning with the Sustainable Development Goals (SDGs) can foster a sustainable economy, mainly through the (green + blue) economy, which involves valorizing macroalgae to produce ready-to-use extracts. It focuses on the potential of eutectic solvents (commonly known as deep eutectic solvents - DES) as promising candidates for this purpose. Traditional methods for extracting bioactive compounds from macroalgae, which rely on organic solvents and aqueous buffers, often involve harsh conditions and extensive processing. These factors can lead to reduced extract quality and/or low yields. In contrast, if properly designed, DES presents a green and sustainable alternative. They offer advantages such as low volatility, adjustable polarity, and negligible toxicity, making them a more environmentally friendly and efficient option for extraction processes. They can be customized to enhance both biological and technological properties, resulting in extracts with unique characteristics such as increased antioxidant activity, antiproliferative and anti-inflammatory effects, as well as improving the viscoelasticity of polysaccharides (fucoidans, alginates, and κ-carrageenan) from macroalgae. In this sense, the tunable nature of DES enables the optimization of extraction conditions to maximize yield, purity, and bioactivity, making it a smart alternative for producing bio-based products. Despite limited literature on DES for this purpose, the article highlights their potential and outlines the main advantages and challenges needed for macroalgae valorization.

Antifungal efficacy and biofumigation potential of hydrophobic deep eutectic solvents: Postharvest treatment against Monilinia fructicola and Botrytis Cinerea

Hydrophobic Deep Eutectic Solvents (HDES), as a subclass of Natural Deep Eutectic Solvents (NADES), present a green-chemistry alternative to toxic chemicals. As HDES are based on terpenoids, these solvents could potentially be effective antifungal agents against phytopathogens Monilinia fructicola and Botrytis cinerea that frequently cause diseases in sweet cherry fruit. To contribute to the disease prevention and management goals, as a part of this study, 30 different HDES were tested in the vapor phase, at identical concentrations of 25%, 50%, and 100%. In vitro experiments were conducted on Potato Dextrose Agar medium (PDA), while in planta experiments were carried out in hermetically sealed containers with inoculated sweet cherry fruits. All tested HDES demonstrated efficacy in suppressing the growth of M. fructicola colonies (66 - 100%) and B. cinerea colonies (37 - 100%). According to the Area Under the Disease Progress Curve (AUDPC), all HDES exhibited high efficacy in preventing disease occurrence in cherry fruits by the tested phytopathogens. This research provides the first insights into the antifungal potential of HDES in the vapor phase, with promising applications as biofumigants that minimize harmful impacts on the food - human - environment complex.

A Comprehensive Review on Deep Eutectic Solvents: Their Current Status and Potential for Extracting Active Compounds from Adaptogenic Plants

Deep eutectic solvents (DESs) have attracted attention from researchers as novel compounds for extracting active substances because of their negligible toxicity, polarity, and ability to be tailored depending on the experiment. In this review, we discuss deep eutectic solvents as a promising medium for the extraction of adaptogenic compounds. In comparison to traditional methods, extraction with the use of DESs is a great alternative to the excessive usage of harmful organic solvents. It can be conducted in mild conditions, and DESs can be designed with different precursors, enhancing their versatility. Adaptogenic herbs have a long medicinal history, especially in Eastern Asia. They exhibit unique properties through the active compounds in their structures, including saponins, flavonoids, polysaccharides, and alkaloids. Therefore, they demonstrate a wide range of pharmaceutical effects, such as anti-inflammatory, antibacterial, and anticancer abilities. Since ancient times, many different adaptogenic herbs have been discovered and are well known, including Panax ginseng, Scutellaria baicalensis, and Schisandra chinensis. Active compounds can be extracted using standard methods, such as hydrolyzation, maceration, and conventional reflux extraction. However, due to the limitations of classical processing technologies, there has been a need to develop new and eco-friendly methods. We focus on the types of solvents, extraction efficiency, properties, and applications of the obtained active compounds. This review highlights the potential of DESs as eco-friendly alternatives for extracting bioactive compounds.

Assessment of oxidative stress biomarkers in Palaemon varians exposed to deep eutectic systems

In recent years, there has been extensive research within the scientific community on deep eutectic systems due to their remarkable versatility in solubilizing diverse substances and serving as effective solvents in catalytic processes. While initially regarded as non-toxic, a comprehensive toxicological assessment is essential to comprehend their behavior within organisms. In this study, seven distinct systems, composed of N,N,N-triethyl-N-(2,3-dihydroxypropyl)ammonium chloride (N00Cl) and glycerol-derived ethers with alkyl chains of varying lengths (100, 200, 3F00, 300, 3i00, and 400), in a 1:2 molar ratio were investigated for their aquatic toxicity in shrimp (Palaemon varians). The assessment involved analyzing oxidative stress biomarkers such as glutathione S-transferase, glutathione peroxidase, catalase, superoxide dismutase, total antioxidant capacity (TAC), and lipoperoxidation (MDA content). Results show an odd-even effect for LC50 values being N00Cl-300, the system showing higher values. Regarding oxidative stress, an imbalance between reactive oxygen species (ROS) and antioxidant capacity in the organisms has been observed, suggesting significant toxicity to shrimps due to the changes in oxidative stress biomarkers at high concentrations. However, at 100 mg/l all systems can be considered environmentally safe, and no negative impacts are expected on aquatic ecosystems.

Green and sustainable fabrication of DES-pretreated high-strength densified wood

Wood is a sustainable, benign, and high-performing green structural material readily available in nature that can be used to replace structural materials. However, insufficient mechanical performance (compared to metals and plastic), moisture sensitivity, and susceptibility to microorganism attack make it challenging to use wood as it is for advanced engineering applications. We here present an efficient approach to fabricating densified wood with minimal time and waste generation, demonstrating high mechanical strength, and decreased water penetration on the surface. Wood slabs were treated with deep eutectic solvents (DESs) to solubilize the lignin, followed by in-situ regeneration of dissolved lignin in the wood. Then, the slabs were densified with heat and pressure, turning the wood into a functionalized densified material. Lignin regeneration and morphological changes were observed via two-photon microscopy and Scanning Electron Microscopy (SEM), respectively. The final product is less susceptible to water absorption on the surface and has enhanced flexural strength (> 50% higher), surface hardness (100% increased), and minimal set recovery compared to natural wood. The improved mechanical performance is due to regenerated lignin which acts as a glue and fills spaces present within the interconnected cellulose network inside the wood, forming a highly dense composite during densification. Such enhancement in the properties of DES-densified wood composite makes it a favorable candidate for advanced structural and engineering applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00226-024-01594-7.

Supramolecular deep eutectic solvent: a powerful tool for pre-concentration of trace metals in edible oil

The utilization of supramolecular deep eutectic solvent eddy-assisted liquid-liquid microextraction utilizing 2-hydroxypropyl β-cyclodextrin (SUPRADES) has been identified as a successful method for pre-enriching Cu, Zn, and Mn in vegetable oil samples. Determination of each element was conducted by inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion of metal-enriched phases. Various parameters were examined, including the composition of SUPRADES species [2HP-β-CD: DL-lactic acid], a cyclodextrin mass ratio of 20 wt%, a water bath temperature of 75 °C, an extractor volume of 800 μL, a dispersant volume of 50 μL, and an eddy current time of 5 min. Optimal conditions resulted in extraction rates of 99.6% for Cu, 105.2% for Zn, and 101.5% for Mn. The method exhibits a broad linear range spanning from 10 to 20,000 μg L-1, with determination coefficients exceeding 0.99 for all analytes. Enrichment coefficients of 24, 21, and 35 were observed. Limits of detection ranged from 0.89 to 1.30 μg L-1, while limits of quantification ranged from 3.23 to 4.29 μg L-1. The unique structural characteristics of the method enable the successful determination of trace elements in a variety of edible vegetable oils.

Tunable durian seed gum-derived eutectogel as a novel coating material: Rheological, thermal, textural and barrier properties for enhanced food preservation

As a promising green and sustainable coating material, gum was extracted from durian seed to produce eutectogel, which the properties were tunable using natural deep eutectic solvent (NADES). Ten different eutectogels were successfully synthesized using durian seed gum (DSG) and xanthan gum (XG) gelators at different composition (5, 10, 15 %) to gel choline chloride-glucose (1:1), choline chloride-fructose (1:2) and betaine-glucose-water (1:1:1) NADESs. Results revealed that eutectogel was non-Newtonian and weak gel material with excellent thermostability up to 200 °C. When the gum content increased, the resulted eutectogel showed higher viscosity, yield stress, hardness, gumminess, adhesiveness, and weight holding capacity. In overall, choline chloride-fructose (1:2) NADES and 10 % of DSG formed an excellent eutectogel which remained stable and compatible upon 12 weeks of storage. It displayed superior viscoelastic, texture, gases and moisture barrier properties which were beneficial for food coating application. This eutectogel was able to extend the shelf life of fresh-cut apples during storage with lower weight loss and higher total phenolic content (TPC). The potential future of this well-characterized tunable DSG-derived eutectogel includes, but not limited to, food and pharmaceutical industries, smart sensing, flexible wearable electronics, water purification, supercapacitors and batteries.

Valorisation of Raspberry Seeds in Cosmetic Industry-Green Solutions

The fruit processing industry generates large quantities of by-products well known to be rich in bioactive compounds with numerous nutritional properties and beneficial effects for human health. We developed a strategy to valorise raspberry seeds and obtain valuable ingredients with potential application in cosmetic skincare formulas. Cold press extraction technology was applied to extract oil, and the remaining defatted raspberry seed cake was treated with three proline based deep eutectic solvents (DES) to extract polyphenols. The most potent was proline/citric acid extract, with free and total ellagic acid content (52.4 mg/L and 86.4 mg/L), total phenolic content (TPC, 550.1 mg GAE/L) and radical scavenging activity (RSA, 4742.7 mmol TE/L). After the direct mixing of the extract and after encapsulation with starch as a carrier, the skincare emulsion and microemulsion were characterised by irritation potential (Zein test), transepidermal water loss (TEWL), red blood cell (RBC), and DPPH antioxidant test. The resulting preparations were of improved quality in comparison to the control hand cream, with a low skin irritation effect, lower TEWL, and higher antioxidant potential. This work complies with circular economy principles and green technology standards, and represents the efficient model on how to reuse natural resources through waste minimization.

Deep eutectic solvents: Preparation, properties, and food applications

Deep Eutectic Solvents (DESs) emerge as innovative 21st-century solvents, supplanting traditional ones like ethanol and n-hexane. Renowned for their non-toxic, biodegradable, and water-miscible nature with reduced volatility, DESs are mostly synthesized through heating and stirring method. Physicochemical properties such as polarity, viscosity, density and surface tension of DESs influenced their application. This review paper gives the overview of application of eco-benign DESs in fruits, vegetables, cereals, pulses, spices, herbs, plantation crops, oil seed crops, medicinal and aromatic plants, seaweed, and milk for the extraction of bioactive compounds. Also, it gives insight of determination of pesticides, insecticides, hazardous and toxic compounds, removal of heavy metals, detection of illegal milk additive, purification of antibiotics and preparation of packaging film. Methodologies for separating bioactive compounds from DESs extracts are systematically examined. Further, safety regulations of DESs are briefly discussed and reviewed literature reveals prevalent utilization of DES-based bioactive compound rich extracts in cosmetics, indicating untapped potential of their application in the food industry.

Antibacterial and antifungal activities of natural deep eutectic solvents

The increasing antibiotic resistance towards a panel of microorganisms is one of the public health concerns. For this reason, the search for alternatives to the widely used antibiotic has been undertaken. In the era of sustainable chemistry, deep eutectic solvents (DESs) have emerged as promising antimicrobial agents. These solvents possess several advantages such as low volatility, low flammability, ease of preparation, and typically low cost of production. These properties make DES suitable for various applications, including extraction of biomolecules and preparation of cosmetics. Natural DESs (NADESs) are special category of DESs prepared from natural sources, which matched the recent trends of leaning back to nature, and decreasing dependence on synthetic precursors. NADES can be prepared by heating and stirring, freeze-drying, evaporation, grinding, and ultrasound-assisted and microwave-assisted synthesis. Utilizing NADESs as an alternative to traditional antibiotics, which become ineffective over time due to bacterial resistance, holds great promise for these reasons. This review aims to discuss the antimicrobial properties of multiple NADESs, including antibacterial and antifungal activities. To the best of our knowledge, this review is the first literature survey of the antimicrobial activities of NADESs. KEY POINTS: • Natural deep eutectic solvents are promising antimicrobial alternative to antibiotics • NADES holds high potential for their activity against bacterial resistance • NADES have also substantial antifungal activities.

A Sustainable Extraction Approach of Phytochemicals from Date (Phoenix dactylifera L.) Fruit Cultivars Using Ultrasound-Assisted Deep Eutectic Solvent: A Comprehensive Study on Bioactivity and Phenolic Variability

The present study aimed to evaluate the efficacy of natural deep eutectic solvents (NADESs) on the extraction of phytochemicals from eight Algerian date fruit cultivars (Phoenix dactylifera L.). In this study, lactic acid/sucrose-based NADESs were used as an alternative to conventional chemical solvents using the ultrasound-assisted extraction (UAE) method. The obtained extracts were assessed for the determination of bioactive compound contents, phenolic composition, antioxidant activity, and enzyme inhibitory potential. The results showed a considerable variation in phytochemical compositions and related activities between cultivars, where the greatest contents of total phenolics (1288.7 mg GAE/100 g), total flavonoids (53.8 mg QE/100 g), proanthocyanidins (179.5 mg CE/g), and total triterpenoids (12.88 mg OAE/100 g) were detected in the fruits of the Ourous cultivar. The same cultivar displayed the highest antioxidant capacity against DPPH• free radical (595 mg AAE/100 g), ABTS•+ cation radical (839 mg TE/100 g), and ferric reducing antioxidant potential (704 mg AAE/100 g). All extracts manifested moderate antioxidant activities tested by phosphomolybdenum, NO•, and linoleic acid lipid peroxidation assays. These extracts also exhibited interesting levels of in vitro enzyme inhibition; the Ourous cultivar gave the best inhibitory activity against α-amylase and acetylcholinesterase with 45 and 37%, respectively. HPLC-DAD-MS detected a total of five compounds, with phenolic acids and flavonoids being the main phenolics identified in the extract. The phenolic composition exhibited significant variability among cultivars. Notably, the highest amounts were revealed in the Tazizaout cultivar, with the predominance of gallic acid. The results confirmed that the combination of UAE and NADESs provides a novel and important alternative to chemical solvents for sustainable and environmentally friendly extraction and can represent a good alternative in food and pharmaceutical industry applications.

NaDES Application in Cosmetic and Pharmaceutical Fields: An Overview

Natural deep eutectic solvents (NaDES) represent a new generation of green, non-flammable solvents, useful as an efficient alternative to the well-known ionic liquids. They can be easily prepared and exhibit unexpected solubilizing power for lipophilic molecules, although those of a hydrophilic nature are mostly used. For their unique properties, they can be recommend for different cosmetic and pharmaceutical applications, ranging from sustainable extraction, obtaining ready-to-use ingredients, to the development of biocompatible drug delivery responsive systems. In the biomedical field, NaDES can be used as biopolymer modifiers, acting as delivery compounds also known as "therapeutic deep eutectic systems", being able to solubilize and stabilize different chemical and galenical formulations. The aim of this review is to give an overview of the current knowledge regarding natural deep eutectic solvents specifically applied in the cosmetic and pharmaceutical fields. The work could help to disclose new opportunities and challenges for their implementation not only as green alternative solvents but also as potential useful pathways to deliver bioactive ingredients in innovative formulations.

Nature of a Tetrabutylammonium Chloride-Levulinic Acid Deep Eutectic Solvent

A deep eutectic solvent was formed by considering the mixtures of tetrabutylammonium chloride and levulinic acid, and it is studied via a combined theoretical and experimental approach. Physicochemical properties were measured as a function of temperature, providing a macroscopic characterization of the fluid. Quantum chemistry and classical molecular dynamics simulations were carried out for the nanoscopic characterization, providing attention to the nature, extension, and dynamics of the hydrogen bonding network, which is at the root of the properties of the fluid. The reported study allows multiscale characterization of this fluid as an archetypical example of a natural, low-cost, and sustainable fluid.

From Nature to Innovation: The Uncharted Potential of Natural Deep Eutectic Solvents

This review discusses the significance of natural deep eutectic solvents (NaDESs) as a promising green extraction technology. It employs the consolidated meta-analytic approach theory methodology, using the Web of Science and Scopus databases to analyze 2091 articles as the basis of the review. This review explores NaDESs by examining their properties, challenges, and limitations. It underscores the broad applications of NaDESs, some of which remain unexplored, with a focus on their roles as solvents and preservatives. NaDESs' connections with nanocarriers and their use in the food, cosmetics, and pharmaceutical sectors are highlighted. This article suggests that biomimicry could inspire researchers to develop technologies that are less harmful to the human body by emulating natural processes. This approach challenges the notion that green science is inferior. This review presents numerous successful studies and applications of NaDESs, concluding that they represent a viable and promising avenue for research in the field of green chemistry.

Development and characterization of sustainable active pectin films: The role of choline chloride/glycerol-based natural deep eutectic solvent and lavender extracts

This study aimed to evaluate the potential effects of choline chloride: glycerol-based natural deep eutectic solvent (NADES) as a plasticizer, NADES extract (NADESext) of lavender as both plasticizer and active ingredient, as well as the lyophilized extract (LE) of lavender at different concentrations (0.5 %, 1 %, and 2 %) on the physical, mechanical, optical, thermal, barrier, morphological, and antioxidant properties of pectin films. The properties of the films were compared to those of the neat pectin film and the film plasticized with glycerol. The addition of plasticizers and LE increased thickness, water vapor permeability, and elongation at break values of the films while decreasing tensile strength and young modulus. Pectin films plasticized with glycerol, NADES, and NADESext had a similar color property but a lower opacity. The use of LE decreased lightness and increased opacity compared to the films with plasticizers. The addition of plasticizers revealed a smoother surface than neat pectin film while LE triggered the formation of agglomerates on the films. Changes in the FTIR spectra of the films showed some interactions between pectin and polyphenols in LE. The plasticizers had an insignificant effect on the antioxidant capacity of films whereas LE improved antioxidant capacity depending on the concentration. In conclusion, the results suggested that pectin films with NADES and LE could be beneficially used to improve antioxidant packaging technology along with acceptable mechanical properties.

A review on natural based deep eutectic solvents (NADESs): fundamentals and potential applications in removing heavy metals from soil

Natural based deep eutectic solvent (NADES) is a promising green solvent to replace the conventional soil washing solvent due to the environmental benign properties such as low toxicity, high biodegradability, high polarity or hydrophilicity, and low cost of fabrication process. The application of NADES is intensively studied in the extraction of organic compounds or natural products from vegetations or organic matters. Conversely, the use of the solvent in removing heavy metals from soil is severely lacking. This review focuses on the potential application of NADES as a soil washing agent to remove heavy metal contaminants. Hydrophilicity is an important feature of a NADES to be used as a soil washing solvent. In this context, choline chloride is often used as hydrogen bond acceptor (HBA) whereby choline chloride based NADESs showed excellent performance in the extraction of various solutes in the past studies. The nature of NADES along with its chemistry, preparation and designing methods as well as potential applications were comprehensively reviewed. Subsequently, related studies on choline chloride-based NADES in heavy metal polluted soil remediation were also reviewed. Potential applications in removing other soil contaminants as well as the limitations of NADES were discussed based on the current advancements of soil washing and future research directions were also proposed.

Factors Affecting the Extraction of (Poly)Phenols from Natural Resources Using Deep Eutectic Solvents Combined with Ultrasound-Assisted Extraction

Replacing conventional solvents with deep eutectic solvents (DES) has shown promising effects on the extraction yield of (poly)phenols. DES can be combined with ultrasound-assisted extraction (UAE) to further increase the extraction efficiency of (poly)phenols from natural resources compared to conventional methods. This review discusses the factors associated with DES (composition, solvent-to-sample ratio, extraction duration, and temperature) and UAE (ultrasound frequency, power, intensity, and duty cycle) methods that influence the extraction of (poly)phenols and informs future improvements required in the optimization of the extraction process. For the optimum (poly)phenol extraction from natural resources, the following parameters shall be considered: ultrasound frequency should be in the range of 20-50 kHz, ultrasound intensity in the range of 60-120 W/cm2, ultrasound duty cycle in the range of 40-80%, ultrasound duration for 10-30 minutes, and ultrasound temperature for 25-50 °C. Among the reported DES systems, choline chloride with glycerol or lactic acid, with a solvent-to-sample mass ratio of 10-30:1 shown to be effective. The solvent composition and solvent-to-sample mass ratio should be selected according to the target compound and the source material. However, the high viscosity of DES is among the major limitations. Optimizing these factors can help to increase the yield of extracted (poly)phenols and their applications.

Recovery of Polyphenols from Rosehip Seed Waste Using Natural Deep Eutectic Solvents and Ultrasonic Waves Simultaneously

Rosehips are processed and consumed in numerous forms, such as juice, wine, herbal tea, yogurt, preserved fruit, and canned products. The seeds share in fruit is 30-35% and they have recently been recognized as an important source of oil rich in unsaturated fatty acids. However, after defatting, seed waste may still contain some polar polyphenolic compounds, which have been scarcely investigated. The aim of this study was to examine the potential of the defatted seed waste as a source of polyphenols. For the defatting process, supercritical carbon dioxide extraction at 300 bar and 40 °C was applied. The capacity of eight different natural deep eutectic solvents (NADES) for the recovery of phenolics from defatted rosehip seed powder (dRSP) was examined. In the extracts obtained with ultrasound-assisted NADES extraction, twenty-one phenolic compounds were identified with LC-MS/MS, among which the most abundant were quinic acid (22.43 × 103 µg/g dRSP) and catechin (571.93 µg/g dRSP). Ternary NADES formulations based on lactic acid proved to be superior. Potential correlations between identified chemical compounds, solvent polarity and viscosity, as well as the compound distributions across studied solvent combinations in PCA hyperspace, were also investigated. PCA demonstrated that more polar NADES mixtures showed improved extraction potential. The established environmentally friendly process represents an approach of transforming rosehip seed waste into value-added products with the potential to be applied in the food industry and to contribute to sustainable production.

Natural Deep Eutectic Solvent based Ultrasound-assisted extraction: A green approach for extraction of sulfhydryl and mimosine from Leucaena leucocephala (Lam) de Wit seeds

Leucaena leucocephala (Lam.) de Wit seeds, also known as river tamarind, contain sulfhydryl compounds that exhibit antioxidant effects. However, these seeds also possess a toxic effect from mimosine. In this study, the river tamarind seeds were extracted using a natural deep eutectic solvent (NADES) based UAE. Among six NADES compositions screened, choline chloride-glycerol (ChCl-Gly) and choline chloride-sucrose (ChCl-Suc) were selected to be further optimized using a Box-Behnken Design in the RSM. The optimization of total sulfhydryl content was performed in 17 runs using three variables, namely water content in NADES (39%, 41%, and 43%), extraction time (5, 10, and 15 min), and the liquid-solid ratio (3, 5, and 7 mL/g). The highest concentration of sulfhydryls was obtained from ChCl-Gly-UAE (0.89 mg/g sample) under the conditions of a water content in NADES of 41% (v/v) and a liquid-solid ratio of 3 mL/g for 15 min, followed by that of from ChCl-Suc-UAE extract under the conditions of water content in NADES of 43% (v/v) and the liquid-solid ratio of 3 mL/g for 10 min with total sulfhydryl level was 0.67 mg/g sample. The maceration method using 30% ethanol resulted in the lowest level of sulfhydryls with a value of 0.52 mg/g. The mimosine compounds obtained in the NADES-based UAE (ChCl-Suc and ChCl-Gly) extracts were 4.95 and 7.67 mg/g, respectively, while 12.56 mg/g in the 30% ethanol-maceration extract. The surface morphology of L. leucocephala seed before and after extraction was analyzed using scanning electron microscopy. Therefore, it can be concluded that the use of ChCl-Suc and ChCl-Gly in NADES-based UAE is more selective in attracting sulfhydryl compounds than that of 30% ethanol-maceration extraction.

Green Extraction of Polyphenols via Deep Eutectic Solvents and Assisted Technologies from Agri-Food By-Products

Polyphenols are the largest group of phytochemicals with important biological properties. Their presence in conveniently available low-cost sources, such as agri-food by-products, has gained considerable attention in their recovery and further exploitation. Retrieving polyphenols in a green and sustainable way is crucial. Recently, deep eutectic solvents (DESs) have been identified as a safe and environmentally benign medium capable of extracting polyphenols efficiently. This review encompasses the current knowledge and applications of DESs and assisted technologies to extract polyphenols from agri-food by-products. Particular attention has been paid to fundamental mechanisms and potential applications in the food, cosmetic, and pharmaceutical industries. In this way, DESs and DESs-assisted with advanced techniques offer promising opportunities to recover polyphenols from agri-food by-products efficiently, contributing to a circular and sustainable economy.

Exploring carbohydrate extraction from biomass using deep eutectic solvents: Factors and mechanisms

Deep eutectic solvents (DESs) are increasingly being recognized as sustainable and promising solvents because of their unique properties: low melting point, low cost, and biocompatibility. Some DESs possess high viscosity, remarkable stability, and minimal toxicity, enhancing their appeal for diverse applications. Notably, they hold promise in biomass pretreatment, a crucial step in biomass conversion, although their potential in algal biomass carbohydrates extraction remains largely unexplored. Understanding the correlation between DESs' properties and their behavior in carbohydrate extraction, alongside cellulose degradation mechanisms, remains a gap. This review provides an overview of the use of DESs in extracting carbohydrates from lignocellulosic and algal biomass, explores the factors that influence the behavior of DESs in carbohydrate extraction, and sheds light on the mechanism of cellulose degradation by DESs. Additionally, the review discusses potential future developments and applications of DESs, particularly extracting carbohydrates from algal biomass.

The Antioxidant and Prebiotic Activities of Mixtures Honey/Biomimetic NaDES and Polyphenols Show Differences between Honeysuckle and Raspberry Extracts

In our previous research, we demonstrated that honey and its biomimetic natural deep eutectic solvent (NaDES) modulate the antioxidant activity (AOA) of the raspberry extract (RE). In this study, we evaluated the AOA behaviour of the mixture honey/NaDES-honeysuckle (Lonicera caprifolium, LFL) extract and compared it with the mixture honey/NaDES-RE. These two extracts have similar major flavonoids and hydroxycinnamic acid compounds but differ in their total content and the presence of anthocyanins in RE. Therefore, it was of interest to see if the modulation of the LFL polyphenols by honey/NaDES was similar to that of RE. We also evaluated the prebiotic activity of these mixtures and individual components on Limosilactobacillus reuteri DSM 20016. Although honey/NaDES modulated the AOA of both extracts, from synergism to antagonism, the modulation was different between the two extracts for some AOA activities. Honey/NaDES mixtures enriched with LFL and RE did not show significant differences in bacterial growth stimulation. However, at a concentration of 45 mg/mL, the honey -LFL mixture exhibited a higher effect compared to the honey-RE mixture. The antioxidant and prebiotic properties of mixtures between honey and polyphenol-rich extracts are determined by multiple interactions in complex chemical systems.

Rutin: Family Farming Products' Extraction Sources, Industrial Applications and Current Trends in Biological Activity Protection

In vitro and in vivo studies have demonstrated the bioactivity of rutin, a dietary flavonol naturally found in several plant species. Despite widespread knowledge of its numerous health benefits, such as anti-inflammatory, antidiabetic, hepatoprotective and cardiovascular effects, industrial use of rutin is still limited due to its low solubility in aqueous media, the characteristic bitter and astringent taste of phenolic compounds and its susceptibility to degradation during processing. To expand its applications and preserve its biological activity, novel encapsulation systems have been developed. This review presents updated research on the extraction sources and methodologies of rutin from fruit and vegetable products commonly found in a regular diet and grown using family farming approaches. Additionally, this review covers quantitative analysis techniques, encapsulation methods utilizing nanoparticles, colloidal and heterodisperse systems, as well as industrial applications of rutin.

Epsom Salt-Based Natural Deep Eutectic Solvent as a Drilling Fluid Additive: A Game-Changer for Shale Swelling Inhibition

Shale rock swelling poses a significant challenge during drilling a well, leading to issues related to wellbore instability. Water-based mud with specific shale inhibitors is preferred over oil-based drilling mud due to its lower environmental impact. Recently, ionic liquids (ILs) have emerged as potential shale inhibitors due to their adjustable properties and strong electrostatic attraction. However, research has shown that the most commonly used class of ILs (imidazolium) in drilling mud are toxic, non-biodegradable, and expensive. Deep Eutectic Solvents (DESs), the fourth generation of ionic liquids, have been proposed as a cheaper and non-toxic alternative to ILs. However, ammonium salt-based DESs are not truly environmentally friendly. This research explores the utilization of Natural Deep Eutectic Solvent (NADES) based on Epsom salt (a naturally occurring salt) and glycerine as a drilling fluid additive. The drilling mud is prepared according to API 13B-1 standards. Various concentrations of NADES-based mud are tested for yield point, plastic viscosity, and filtration properties for both aged and non-aged samples. The linear swell meter is used to determine the percentage swelling of the NADES-based mud, and the results are compared with the swelling caused by KCl- and EMIM-Cl-based mud. FTIR analysis is conducted to understand the interaction between NADES and clay, while surface tension, d-spacing (XRD), and zeta potential are measured to comprehend the mechanism of swelling inhibition by NADES. The findings reveal that NADES improves the yield point and plastic viscosity of the mud, resulting in a 26% reduction in mudcake thickness and a 30.1% decrease in filtrate volume at a concentration of 1%. NADES achieves a significant 49.14% inhibition of swelling at the optimal concentration of 1%, attributed to its ability to modify surface activity, zeta potential of clay surfaces, and d-spacing of clay layers. Consequently, NADES emerges as a non-toxic, cost-effective, and efficient shale inhibitor that can replace ILs and DESs.

Innovative Strategy for Aroma Stabilization Using Green Solvents: Supercritical CO2 Extracts of Satureja montana Dispersed in Deep Eutectic Solvents

The aim of this work was to establish the potential of natural deep eutectic solvents (NADES) for the stabilization of aroma volatile organic compounds from a natural source. Satureja montana was used as a source of volatile components, as it is rich in terpenes of great commercial and biological importance, such as carvacrol, thymol, and thymoquinone, among others. Supercritical CO₂ was used to extract the lipophilic fraction of S. montana, which was further directly dispersed in NADES. The stabilizing capacity of seven different NADES based on betaine and glycerol was analyzed. The stability of the components in NADES was monitored by analyzing the headspace profile during 6 months of storage at room temperature. The changes in the headspace profile over time were analyzed by using different statistical and chemometric tools and the Wilcoxon matched pair test. It was determined that alterations over time occurred such as degradation and oxidation, and they were the most prominent in the control. In addition, the indicator of decreased stability of the control was the formation of the new compounds that could compromise the quality of the product. In the stabilized NADES samples, the changes were significantly less prominent, indicating that the NADES had a stabilizing effect on the volatile compounds. According to Wilcoxon matched pair test, the most efficient stability was achieved by using betaine/ethylene glycol, glycerol/glucose, and betaine/sorbitol/water. Therefore, by applying two green solvents, a sustainable approach for obtaining pure and high-quality S. montana extracts with extended stability at room temperature was established.

The Most Potent Natural Pharmaceuticals, Cosmetics, and Food Ingredients Isolated from Plants with Deep Eutectic Solvents

There is growing interest in reducing the number of synthetic products or additives and replacing them with natural ones. The pharmaceutical, cosmetic, and food industries are especially focused on natural and bioactive chemicals isolated from plants or microorganisms. The main challenge here is to develop efficient and ecological methods for their isolation. According to the strategies and rules of sustainable development and green chemistry, green solvents and environmentally friendly technologies must be used. The application of deep eutectic solvents as efficient and biodegradable solvents seems to be a promising alternative to traditional methods. They are classified as being green and ecological but, most importantly, very efficient extraction media compared to organic solvents. The aim of this review is to present the recent findings on green extraction, as well as the biological activities and the possible applications of natural plant ingredients, namely, phenolics, flavonoids, terpenes, saponins, and some others. This paper thoroughly reviews modern, ecological, and efficient extraction methods with the use of deep eutectic solvents (DESs). The newest findings, as well as the factors influencing the efficiency of extraction, such as water content, and hydrogen bond donor and acceptor types, as well as the extraction systems, are also discussed. New solutions to the major problem of separating DESs from the extract and for solvent recycling are also presented.

Deep eutectic solvents for the food industry: extraction, processing, analysis, and packaging applications - a review

Food factories seek the application of natural products, green feedstock and eco-friendly processes, which minimally affect the properties of the food item and products. Today, water and conventional polar solvents are used in many areas of food science and technology. As modern chemistry evolves, new green items for building eco-friendly processes are being developed. This is the case of deep eutectic solvents (DESs), named the next generation of green solvents, which can be involved in many food industries. In this review, we timely analyzed the progress on applying DES toward the development of formulations, extraction of target biomolecules, food processing, extraction of undesired molecules, analysis and determination of specific analytes in food samples (heavy metals, pesticides), food microbiology, and synthesis of new packaging materials, among many other applications. For this, the latest developments (over the last 2-3 years) have been discussed emphasizing innovative ideas and outcomes. Relevantly, we discuss the hypothesis and the key features of using DES in the mentioned applications. To some extent, the advantages and limitations of implementing DES in the food industry are also elucidated. Finally, based on the findings of this review, the perspectives, research gaps and potentialities of DESs are stated.

Contemporary methods for the extraction and isolation of natural products

Extraction is a vital step in obtaining pure bioactive natural compounds for medical, scientific and commercial use. Recently, interest in extracting natural products for applications across the food, pharmaceutical, and cosmetic industries has grown rapidly, driving demand for newer, more efficient extraction methods. To develop our understanding of this field, BMC Chemistry has launched a new article Collection titled "Contemporary methods for the extraction and isolation of natural products".

NaDES as a green technological approach for the solubility improvement of BCS class II APIs: An insight into the molecular interactions

Recently, Natural Deep Eutectic Solvents (NaDES) have emerged as potential solvents for boosting drug bioavailability. In this work, the mechanism of solubility enhancement of some APIs belonging to BCS class II (tolbutamide, nimesulide, domperidone and cinnarizine) in these eutectic bio-solvents was investigated in order to get deeper insights into the molecular interactions between the NaDES components and the selected drugs. Different NaDES formulations based on choline chloride, proline, solid organic acids (citric, tartaric and malic acid), sugars (glucose and xylitol) and water were prepared by mild heating (70 °C). Characterization of unloaded NaDES (pH, Karl Fisher titration, viscosity and FTIR analysis) indicated that the type of Hydrogen Bond Acceptor (HBA) and Hydrogen Bond Donor (HBD), their molar ratio as well as water amount strongly affect the extent of H-bonding interactions. Hard gelatin capsules filled with NaDES maintained their integrity until 6 months, proving that all water molecules participate in H-bond network. APIs' solubility enhancement was significant in all NaDES with respect to buffer solutions (pH 1.2 and 6.8). Analysing NaDES having Choline as HBA, it was found that the solubility of smaller molecules increased using larger HBD, while higher molecular weight APIs can be better inserted into the network formed by smaller HBD. NOE experiments demonstrated the formation of a robust supramolecular structure among the protons of choline, those of organic acid and water. In addition, 1D ROESY spectra revealed for the first time the crucial role of choline (methyl groups) in establishing hydrophobic interactions with the relative aliphatic or aromatic portion of the drugs. These data suggest the complex structure of the API-NaDES supramolecular assembly and underline that drug solubility is dependent on a balance network of H-bonds and hydrophobic interactions as well. Understanding the type of interactions between the API and NaDES is essential for their use as effective solubilisation aid.

Green and sustainable extraction of lignin by deep eutectic solvent, its antioxidant activity, and applications in the food industry

Lignin, an amorphous biomacromolecule abundantly distributed in the plant kingdom, has gained considerable attention due to its intrinsic bioactivities and renewable nature. Owing to its polyphenolic structure, lignin has a variety of human health activities, including antioxidant, antimicrobial, antidiabetic, antitumor, and other activities. The extraction of lignin from various sources in a green and sustainable manner is critical in the food industry. Deep eutectic solvent (DES) has recently been recognized as a class of safe and environmentally friendly media capable of efficiently extracting lignin. This article comprehensively reviews the recent advances in lignin extraction using DES, discusses the influential factors on the antioxidant activity of lignin, interprets the relationship between antioxidant activity and lignin structure, and overviews the applications of lignin in the food industry. We aim to highlight the advantages of DES in lignin extraction and valorization from the nutrition and food views.

The Ability of Acid-Based Natural Deep Eutectic Solvents to Co-Extract Elements from the Roots of Glycyrrhiza glabra L. and Associated Health Risks

The roots of licorice (Glycyrrhiza glabra L.) have been widely used in traditional and officinal medicines for the treatment of different diseases. Natural deep eutectic solvents (NADES) have become popular for the extraction of active principles from medicinal plants. However, the ability of NADES to co-extract trace elements during the isolation of target active compounds is rarely investigated. The aim of this study was to analyze the content of trace elements in acid-based NADES extracts from the roots of G. glabra and the health risks associated with them. In this study, we have tested for the first time the ability of several acid-based NADES to co-extract glycyrrhizic acid (GA) and trace elements from the roots of G. glabra. GA has been identified as the dominant phytochemical in G. glabra NADES extracts (0.145-0.495 mg/g). Due to the close pKa of lactic acid and GA, the yield of GA in lactic acid-based NADES was higher in comparison with other tested NADES. The yield of GA in NADES3-NADES5 was statistically significant and surpassed the yield of GA in water. The recovery of all elements (except Li) by all tested NADES was low (less than 6%). According to an ANOVA test, the hydrogen bond donor type plays a decisive role in the extraction of elements. A strong positive correlation between the recovery of GA and MPI was noted. The metal pollution index, hazard quotient, hazard index, and chronic daily intake were calculated and suggest that all tested NADES extracts of G. glabra roots were nontoxic and possess no health risk for both ingestion and topical application.

Research Progress on the Preparation and Action Mechanism of Natural Deep Eutectic Solvents and Their Application in Food

Natural deep eutectic solvent (NADES) is the eutectic mixture which is formed by hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) with a certain molar ratio through hydrogen bonding. NADES is a liquid with low cost, easy preparation, biodegradability, sustainability and environmental friendliness at room temperature. At present, it is widely used in food, medicine and other areas. First, the composition, preparation and properties of NADES are outlined. Second, the potential mechanism of NADES in freezing preservation, the removal of heavy metals from food and the extraction of phenolic compounds, and its application in cryopreservation, food analysis and food component extraction, and as a food taste enhancer and food film, are summarized. Lastly, the potential and challenges of its application in the food field are reviewed. This review could provide a theoretical basis for the wide application of NADES in food processing and production.