Search Results (55)

Natural deep eutectic solvents (NaDESs) are emerging solvents for their yield when used for extraction of different molecules, including polyphenols. NaDESs are a cutting-edge technology that offers numerous advantages, including cheap cost, safety, effectiveness and environmental friendliness. However, due to NaDES’ high boiling point, the recovery and separation of compounds after the extraction is the bottleneck of the process. In this work, two affordable methods were tested for the recovery of phenolic compounds from three binary NaDESs (composed of choline chloride mixed separately with lactic acid, tartaric acid or glycerol as hydrogen bond donors): the antisolvent and the liquid–liquid extraction methods. The former was assessed by diluting the extracts with different aliquots of water, employed as antisolvent, which was ineffective. For the liquid–liquid extraction method, ethyl acetate (EtOAc), acetonitrile (ACN), 2-chlorobutane (2-CB) and 2-methyltetrahydrofuran (2-MeTHF) were compared. Except for ACN, all solvents were perfectly immiscible with the three NaDESs, forming biphasic systems that were analyzed by colorimetric assays and HPLC/MS. 2-MeTHF applied on a 10-fold water dilution of the NaDES extract reached recovery percentages higher than 90% for most of the non-anthocyanin phenols and good recovery (up to 80%) for some anthocyanins. 2-MeTHF appears to be the first known solvent capable of extracting anthocyanins from NaDESs. Finally, a two-step liquid–liquid extraction performed firstly with EtOAc and subsequently with 2-MeTHF is proposed for the separation of different phenolic fractions. Full article

The aim of this review is to provide a comprehensive overview of protein extraction from legume sources, with a focus on both conventional and emerging techniques. Particular attention is given to the impact of innovative methods on protein functionality, a key factor for food applications. Due to their nutritional profile and techno-functional properties, legumes are increasingly regarded as promising alternatives to animal-based protein sources in the food industry. Traditional extraction methods, such as alkaline and acidic extraction, are discussed and compared with novel approaches including enzymatic extraction, ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ohmic heating (OH), subcritical water extraction (SWE), deep eutectic solvents (DES), and dry fractionation. The potential of these emerging technologies to improve protein yield and functionality is critically assessed, alongside key challenges such as scalability, cost-effectiveness, and potential allergenicity. This review also identifies current research gaps and highlights opportunities for innovation in sustainable protein extraction. Therefore, this review contributes to the development of more efficient, functional, and sustainable protein ingredients production, highlighting the role of innovative extraction technologies in shaping the future of plant-based foods. Full article

This study explores the influence of various additives on the morphological, chemical, and thermal properties of poly(vinylidene fluoride) (PVDF) membranes prepared via the non-solvent induced phase separation (NIPS) technique. The use of a green solvent such as triethyl phosphate (TEP) was shown to be successful. A particular focus was dedicated to pore formers based on choline chloride–based deep eutectic solvents (DES) in combination with ethylene glycol and glycerol, i.e., ChCl/EG and ChCl/GLY, and its benchmark with traditional counterparts such as poly(ethylene glycol) (PEG) and glycerol (GLY). Comprehensive characterization was conducted using FESEM, FTIR, XRD, and DSC techniques to evaluate changes in membrane morphology, porosity, and crystallinity. PEG acted as a pore-forming agent, transitioning the internal structure from spherulitic to sponge-like with consistent pore sizes, while GLY produced a nodular morphology at higher concentrations due to increased dope solution viscosity. DES induced significant shifts in crystalline phase composition, decreasing α-phase fractions and promoting β-phase formation at higher concentrations. While the overall porosity remained unaffected by the addition of GLY or PEG, it was dependent on the DES concentration in the dope at lower values than those obtained by GLY and PEG. Membrane pore size with ChCl/GLY was lower than with ChCl/EG and GLY. All membranes showed performance at the hydrophobic regime. The findings demonstrate that ChCl/EG and ChCl/GLY can tailor the structural and thermal properties of TEP-driven PVDF membranes, providing a green and versatile approach to customize the membrane properties for specific applications. Full article

The purpose of this study was to extract the lipophilic fraction from one of the largest source of waste in the industrial sector, namely, the tomato residue from processing the fruit. In order to make this process more environmentally sustainable, this study used a green extraction protocol employing natural deep eutectic solvents (NADESs) combined with a less energy-consuming technology, the ultrasound-assisted extraction (UAE) method, to simultaneously recover carotenoids and tocopherol from dried powder tomato waste. Two NADESs, one hydrophilic and one hydrophobic, were prepared and compared to support high extraction efficiency and increase the stability of the extracted compounds. The optimal extraction parameters were identified as choline chloride:1,3-butanediol (1:5)-based NADES, a solid-to-liquid ratio of 1:20 (w/v), time of extraction 12 min, temperature 65 °C, radiation frequency 37 Hz, and an ultrasound power level of 70%. The extraction process was intensified and resulted in extracts rich in lycopene (215.13 ± 4.31 μg/g DW), β-carotene (206.95 ± 3.27 μg/g DW), and tocopherol (130.86 ± 8.97 μg/g DW) content, with the highest antioxidant capacity 93.84 ± 0.18 mM Trolox equivalent. Incorporating NADESs for the extraction of bioactive compounds offers numerous benefits, such as improved sustainability, enhanced extraction efficiency, better protection of sensitive compounds, and reduced environmental impact. These advantages make NADESs a promising alternative to traditional organic solvents, especially in industries that require natural, green, and efficient extraction processes for valuable bioactive molecules. Full article

Vine shoots hold promise as a biomass source for fermentable sugars with efficient fractionation and conversion processes. The study explores vine shoots as a biomass source for fermentable sugars through pretreatment with two deep eutectic solvents mixtures: choline chloride:lactic acid 1:5 (ChCl:LA) and choline chloride:ethylene glycol 1:2 (ChCl:EG). Pretreatment conditions, such as temperature/time, solid/liquid ratio, and biomass particle size, were studied. Chemical composition, recovery yields, delignification extent, and carbohydrate conversion were evaluated, including the influence of washing solvents. Temperature and particle size notably affected hemicellulose and lignin dissolution, especially with ChCl:LA. Pretreatment yielded enriched cellulose substrates, with high carbohydrate conversion rates up to 75.2% for cellulose and 99.9% for xylan with ChCl:LA, and 54.6% for cellulose and 60.2% for xylan with ChCl:EG. A 50% acetone/water mixture increased the delignification ratios to 31.5%. The results underscore the potential of this pretreatment for vine shoot fractionation, particularly at 30% solid load, while acknowledging the need for further process enhancement. Full article

Plant-based waste biomass with lignocellulose as an important component is produced in large quantities worldwide every year. The components of lignocellulose that typically exhibit high utilization value include cellulose and hemicellulose, as well as pentoses and hexoses derived from their hydrolysis. As a pretreatment for the hydrolysis process, delignification is a pivotal step to enhance cellulose/hemicellulose accessibility and achieve high yields of fermentable sugars. Additionally, deep eutectic solvents (DESs) are the most widely used solvents for delignification during biomass fractionation due to their clean and environmentally friendly attributes. DESs dissolve lignin by inducing a large amount of β-O-4 bond cleavage and partial carbon–carbon bond cleavage, retaining cellulose in the solid residue, while most of the hemicellulose is hydrolyzed in DES pretreatment. This article provides a comprehensive review of the influence of DESs in the lignocellulose separation process. Key factors such as lignin removal rate, sugar conversion rate, and product chemical structure are critically reviewed to assess the feasibility of employing DESs for lignocellulose separation. Full article

Lignocellulosic biomass is a crucial renewable energy source for producing biofuels and valuable compounds, making it an attractive alternative to fossil resources. In this study, an environmentally friendly method was developed for cellulose fractionation from sugarcane bagasse using deep eutectic solvents (DESs), focusing on achieving high cellulose purity and specific physicochemical properties. The effects of different parameters were investigated by comparing four DESs: choline chloride–lactic acid (ChCl-LA), choline chloride–glycerol (ChCl-G), choline chloride–urea (ChCl-U), and choline chloride–polyalcohol (ChCl-P), under various reaction temperatures and times. The fractionation process was conducted under standard conditions at a temperature of 100 °C for 120 min with a 1:1 molar ratio. The results indicated that all DESs produced comparable cellulose recovery, ranging from 91.83% to 97.07%. A relatively high cellulose recovery was observed in the presence of ChCl-LA, at 95.47%. In addition, ChCl-LA demonstrated the highest efficiency in removing hemicellulose and lignin, at 95.36% and 93.38%, respectively, and high recovery yields of 70.45% for hemicellulose, and 70.66% for the lignin fraction. The fractionation conditions were further optimized using response surface methodology (RSM), achieving a ChCl-LA ratio of 1:2 v/v at 120 °C for 120 min. This resulted in impressive yields: 97.86% cellulose recovery, 96.50% hemicellulose removal, 74.40% hemicellulose recovery, 77.3% lignin recovery, and 71.5% lignin yield from sugarcane bagasse. These results closely match the predicted values, emphasizing the effectiveness of the process and its potential for economic application in lignocellulosic biorefinery operations. Full article

Spilanthol is a major N-alkylamide constituent of Acmella oleracea (L.) R.K. Jansen with diverse pharmacological properties. We recently showed the applicability of NADES (natural deep eutectic solvents) for the green extraction of spilanthol. However, the purification of targets from NADES poses a challenging step due to their non-volatility. A simple green method to retrieve spilanthol with minimal instrumental effort was devised, fractioning NADES (choline chloride/methylurea, choline chloride/1,2-propanediol, choline chloride/citric acid) and dry ethanolic extracts by SPE on C18 material, eluting merely with ethanolic solutions. The relative distribution of spilanthol and organic adulteration in SPE fractions were detected by HPLC-DAD, followed by scale-up, quantification and purity determination in an NMR-based approach. Isocratic elution with 52% ethanol (v/v) proved suitable in all experiments. The three purest 10 mL fractions combined yielded 12.21 mg spilanthol at 71.65% purity from NADES extract ChCl/P (choline chloride/1,2-propanediol, molar ratio 1:2, +20% m/m water). Ethanolic extract samples showed purities ranging from 77.27 to 80.27% in combined raw fractions. For all samples, purity increased by removing non-soluble substances from organic solutions. Pooled NADES extract fractions showed 89.71% in final samples, ethanolic extracts 87.25 to 91.93%. The highest purities of individual fractions per extract were 89.23 to 94.15%. This cheap and simple purification process is promising to acquire spilanthol for research purposes or as a sample preparation step before HPLC on a semi-preparative to preparative scale, as the substance is highly priced and scarcely available on the market. Organic solvents can be reused, and preliminary scale-up possibilities are shown. Full article

Cellulose and lignin, sourced from biomass, hold potential for innovative bioprocesses and biomaterials. However, traditional fractionation and purification methods often rely on harmful chemicals and high temperatures, making these processes both hazardous and costly. This study introduces a sustainable approach for fractionating acacia wood, focusing on both cellulose and lignin extraction using a deep eutectic solvent (DES) composed of choline chloride (ChCl) and levulinic acid (LA). A design of experiment was employed for the optimization of the most relevant fractionation parameters: time and temperature. In the case of the lignin, both parameters were found to be significant variables in the fractionation process (p-values of 0.0128 and 0.0319 for time and temperature, respectively), with a positive influence. Likewise, in the cellulose case, time and temperature also demonstrated a positive effect, with p-values of 0.0103 and 0.028, respectively. An optimization study was finally conducted to determine the maximum fractionation yield of lignin and cellulose. The optimized conditions were found to be 15% (w/v) of the wood sample in 1:3 ChCl:LA under a treatment temperature of 160 °C for 8 h. The developed method was validated through repeatability and intermediate precision studies, which yielded a coefficient of variation lower than 5%. The recovery and reuse of DES were successfully evaluated, revealing remarkable fractionation yields even after five cycles. This work demonstrates the feasibility of selectively extracting lignin and cellulose from woody biomass using a sustainable solvent, thus paving the way for valorization of invasive species biomass. Full article

Separating hydroalcoholic mixtures remains a significant challenge in engineering. Liquid–liquid extraction has emerged as an appealing alternative method, because it avoids the need for the large energy inputs, volatile organic compounds, and high pressures that are typically required by other separation processes. This study explores the use of hydrophobic deep eutectic solvents (HDESs) composed of terpenes and 10-undecenoic acid as extraction agents for the liquid–liquid separation of hydroalcoholic mixtures composed of alcohols (ethanol, propan-1-ol, and propan-2-ol) and water. The water content in the solvents studied was notably low, reflecting their hydrophobic nature. For the dried HDES samples, the water content ranged from 553 to 4901 ppm. In contrast, the water-saturated samples exhibited higher water contents, ranging from 7250 to 20,864 ppm. The HDES based on thymol, DL-menthol, and L-menthol displayed a eutectic point at an x_terpenes of approximately 0.67. These mixtures maintained a liquid state up to a mole fraction of terpenes around 0.75. In contrast, the HDES composed of carvacrol, fenchyl alcohol, and α-terpineol exhibited their eutectic point at an x_terpenes near 0.5. Notably, these mixtures remained in a liquid state across the entire composition range studied. The 2:1 molar ratio (HBA:HBD) presented the best values for extracting alcohols, reaching 34.04%, 36.59%, and 39.78% for ethanol, propan-2-ol, and propan-1-ol, respectively. These results show that HDES can be applied to overcome issues with existing extraction solvents, increasing the separation efficiency and making the process eco-friendly. Full article

Green solvents, which include deep eutectic solvent-like mixtures (DES-like mixtures), are categorized as ecological and economical solvents for the pretreatment and fractionation of different types of biomasses. DES-like mixtures represent a group of the most promising green solvents for lignocellulosic pretreatment and are currently used effectively in the biomass pretreatment process. The present work describes the latest applications of DES-like mixtures in biomass delignification processes and, at the same time, summarizes the mechanism of action and influence of DES-like mixture systems on the removal of lignin from different types of biomasses. The results of this review indicate that the physicochemical properties (acidity, hydrogen bond capacity, polarity, viscosity, and water content) of DES-like mixtures have a significant effect on the biomass fractionation process. In addition to the nature of components forming DES-like mixtures, the reaction conditions (temperature, time) influence the efficiency of delignification. Active protons obtained from the hydrogen bond donor facilitate proton-catalyzed bond cleavage during fractionation, where the most significant step is the destruction of the ether and ester bonds between polysaccharides and lignin. DES-like mixtures can depolymerize lignin with subsequent breakdown of the β−O−4 bonds. Full article

Natural deep eutectic solvents (NADESs) have been shown to be selective and environmentally friendly solvents for the extraction of bioactive compounds. However, studies on the solubility of low-molecular-weight carbohydrates (LMWCs) in NADESs are scarce. In this work, new solubility data of LMWCs in NADESs are provided and a new approach based on the use of these solvents for the efficient fractionation of bioactive carbohydrates was explored for the first time. Several mono- and disaccharides and three NADESs based on choline chloride (ChCl) and different donors (2-ethylene glycol (EtG), glycerol (Gly) and ethanedioic acid dihydrate (Eth)) were considered. While the degradation of carbohydrates, mainly ketoses, was detected with ChCl:Eth due to its acidic nature, ChCl:EtG and ChCl:Gly were found to be useful alternatives for selectively separating bioactive ketoses and their corresponding aldoses (e.g., lactulose/lactose and tagatose/galactose) present in equimolar binary mixtures. In addition, the usefulness of ChCl:EtG for the selective enrichment of lactulose to be used as food ingredient or nutraceutical was proven (from a 25% in the reaction mixture to a 56% in the purified sample). NADESs could be used for the selective fractionation of value-added carbohydrates from interfering sugars for several applications, including food science, engineering or pharmaceuticals. Full article

Coriandrum sativum L. seeds are widely recognized for their traditional use in medicine. Among the most investigated components, the terpenoid linalool and monounsaturated petroselinic acid have attracted interest for their nutritional value. Instead, minor attention was paid to the polyphenolic fraction, resulting still being incomplete today. This study aimed to develop a systematic approach in which green natural deep eutectic solvents (NADES) were combined with conventional (maceration, MAC) or non-conventional (ultrasound-assisted extraction, UAE) techniques in a one-step methodology to recover polyphenols from coriander seeds. The NADES system choline chloride–citric acid (ChCl:CA, 1:1) was firstly evaluated, coupled with MAC or UAE, and then compared with ChCl–Urea (ChCl:Ur, 1:1) and ChCl–Glucose (ChCl:Glu, 1:1) under optimal conditions (20 min extraction time). The system ChCl:Ur UAE significantly improved the extraction of chlorogenic acid and its isomer (453.90 ± 4.77 and 537.42 ± 1.27 µg/g, respectively), while the system ChCl:Glu UAE improved the extraction of protocatechuic, caffeic and p-coumaric acids (131.13 ± 6.16, 269.03 ± 4.15 and 57.36 ± 0.06 µg/g, respectively). The highest levels of rutin were obtained with ChCl:CA-based NADES when the MAC technique was applied (820.31 ± 28.59 µg/g). These findings indicate that the NADES composition could be appropriately modulated to tailor extraction towards higher levels of a desirable bioactive for further applications. Full article

Deep eutectic solvents (DESs) are promising for lignin dissolution and extraction. However, they usually possess high polarity and are difficult to recycle. To overcome this drawback, a variety of switchable ionic liquids (SILs) composed of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and alcohols was synthesized and screened. According to the thermodynamic modeling suggestions, the selected DBU–HexOH SIL was coupled with hydrogen-bond donors to form switchable-DES (SDES) systems with moderated viscosity, conductivity, and pH while maintaining switchability. The SDESs produced a well-improved lignin and lignin model compound solubility compared with those of SILs; charging CO₂ into SDES (SDES_CO2) caused a further increase in solubility. The solubility (25 °C) of syringic acid, ferulic acid, and milled wood lignin in SDES_CO2 reached 230.57, 452.17, and 279.12 mg/g, respectively. Such SDES-dissolved lignin can be regenerated using acetone as an anti-solvent. The SDES-regenerated lignin exhibited a well-preserved structure with no noticeable chemical modifications. Furthermore, the SDES_CO2 lignin possessed a higher molecular weight (Mw = 10,340 g/mol; Mn = 7672 g/mol), improved uniformity (polydispersity index = 1.35), and a higher guaiacyl lignin unit content compared with the original milled wood lignin. The SDES system proposed in the present work could benefit the fractionation of lignin compounds and facilitate downstream industrial processes. Full article

Deep eutectic solvent (DES) and hot-water extraction (HWE) methods were utilized to extract polysaccharides from Polygonatum sibiricum, referred to as DPsP and WPsP, respectively. The extracted polysaccharides were purified using the Superdex-200 dextran gel purification system, resulting in three components for each type of polysaccharide. The structures of these components were characterized. The molecular weight analysis revealed that DPsP components had slightly larger molecular weights compared with WPsP, with DPsP-A showing a slightly higher dispersity index and broader molecular weight distribution. The main monosaccharide components of both DPsP and WPsP were mannose and glucose, while DPsP exhibited a slightly greater variety of sugar components compared with WPsP. FTIR analysis demonstrated characteristic polysaccharide absorption peaks in all six PSP components, with a predominance of acidic pyranose sugars. NMR analysis revealed the presence of pyranose sugars, including rhamnose and sugar aldehyde acids, in both DPsP-B and WPsP-A. DPsP-B primarily exhibited β-type glycosidic linkages, while WPsP-A predominantly displayed α-type glycosidic linkages, with a smaller fraction being β-type. These findings indicated differences in monosaccharide composition and structure between PSPs extracted using different methods. Overall, this study provided experimental evidence for future research on the structure–function relationship of PSPs. Full article