Hydrothermal Extraction Research Articles

Mechanistic insights into lipid extraction from wet microalgae using hydrophobic deep eutectic solvents under hydrothermal conditions

Hydrophobic deep eutectic solvents (HDESs) were first employed under hydrothermal conditions to form a two-phase system for instantaneous and efficient lipid extraction from wet microalgae, preventing lipid degradation and avoiding the use of toxic solvents. Ten HDESs were assessed for their efficiency and selectivity in lipid extraction. Among them, OCT-DEC, composed of octanoic acid and decanoic acid, achieved the highest extraction efficiency at 95.42 %, while also preventing the co-extraction of proteins and reducing sugars. Molecular dynamics simulations revealed that lipid extraction efficiency is primarily influenced by lipid-HDES interactions, which drive lipid diffusion, and the interfacial properties of the two-phase hydrothermal system, which resist lipid diffusion. The superior performance of OCT-DEC is attributed to its high hydrogen bond density and short bond lifetimes, which, combined with its structural stability, synergistically reduce resistance to lipid diffusion at the interface. Additionally, OCT-DEC significantly enhances the thermal stability of unsaturated fatty acids, such as C20:5, effectively preventing the degradation of high-value lipids and highlighting its potential for hydrothermal extraction of these valuable compounds.

Massa Medicata Fermentata, a Functional Food for Improving the Metabolic Profile via Prominent Anti-Oxidative and Anti-Inflammatory Effects.

Massa Medicata Fermentata (MMF) is a naturally fermented product used to treat indigestion and increase stomach activity in traditional medicine. This study examined the ability of the hydrothermal extract of MMF to scavenge free radicals corresponding to biological oxidative stresses, further protecting essential biomolecules. The anti-inflammatory effects of MMF were evaluated in LPS-induced RAW264.7 macrophages and zebrafish. In addition, the effects of MMF on the body mass index (BMI) and cholesterol accumulation in adult zebrafish fed a high-cholesterol diet (HCD) for three weeks were examined. MMF prevented the DNA and lipid damage caused by oxidative stress, inhibited LDL oxidation, and reduced the expression of cytokines and related proteins (MAPK and NFκB), with prominent anti-oxidative pathway (NRF2-HO-1) activation properties. LPS-induced NO production was reduced, and the increase in BMI and TC caused by the HCD diet was suppressed by MMF in zebrafish embryos or adult zebrafish. The bioactive aglycone of quercetin may be contributing to the mechanisms of systemic effects. MMF has excellent antioxidant properties and is useful for improving inflammation status and metabolic profile, thus highlighting its potential as a healthy, functional food.

Numerical study on the fluid flow and condensation heat transfer characteristics of two-phase NaCl-H2O fluids on the external swept spiral coil in a hydrothermal vent

The substantial thermal energy of two-phase NaCl-H2O hydrothermal fluids makes them a significant target for utilizing deep-sea energy. A fundamental understanding of the thermal performance of two-phase NaCl-H2O hydrothermal fluids during condensation is crucial for heat energy harnessing. It aims to obtain the flow and condensation heat transfer characteristics of two-phase NaCl-H2O fluids during the heat transfer process outside a spiral coil structure in this paper. The properties of the NaCl-H2O binary systems were adopted instead of pure water, and the salt transport equation was considered to reflect the impact of salinity change on heat transfer, making the simulation more representative of natural venting fluids. The results indicated a significant tangential velocity when the fluids externally swept the spiral coil. Secondly, the heat transfer area can be divided into the “normal region” and the “island region,” of which convection and condensation contribute to the heat transfer mechanisms. The “island region” formation was attributed to both vapor condensation and the spoiler effect caused by the spiral structure. Moreover, the heat flux increased with decreasing salinity in the “island region,” and a weak interaction was observed between heat flux and salinity in the “normal region.” Finally, the spiral structure's heat transfer performance was superior to the straight structure's. This investigation may provide a basis for designing and optimizing the heat transfer equipment for deep-sea hydrothermal extraction.

ANTI-OXIDANT, ANTI-BACTERIAL, AND ANTI-INFLAMMATORY ACTIVITY OF Scutellaria baicalensis ROOT SUPERCRITICAL FLUID EXTRACTS

Scutellaria baicalensis (S. baicalensis) root extract has been used for a long time in Oriental medicine and the cosmetics industry due to its natural anti-oxidant properties in disease treatment. However, comprehensive studies comparing the physiological activities of different S. baicalensis root extracts are lacking. Specifically, there is a need to compare S. baicalensis root hydrothermal extract (SBHE), S. baicalensis root 75% ethyl alcohol extract (SBAE), and S. baicalensis root supercritical fluid extracts (SBSEs) simultaneously. In this study, we extracted S. baicalensis roots using three different methods: hydrothermal, 75% ethyl alcohol, and supercritical fluid extraction. We then evaluated their radical scavenging activities, SOD-like activity, anti-bacterial activities, and the production of inflammatory factors. Among the extracts tested, the S. baicalensis root supercritical fluid 35°C extract (SBSE35) exhibited superior overall physiological activities. Notably, only the SBSEs demonstrated anti-bacterial activity against Staphylococcus aureus, whereas SBHE and SBAE did not. SBHE and SBAE increased interleukin (IL)-6 levels (p ≤ 0.05). Additionally, SBHE and SBAE showed a slight decrease in IL-8 at low concentrations, but an increase in IL-8 production in a concentration-dependent manner. In contrast, SBSE35 significantly reduced both IL-6 and IL-8 levels (p ≤ 0.05). These findings suggest that SBSE35 has greater potential for improving human health in the cosmetics and pharmaceutical fields. Keywords: Scutellaria baicalensis root; supercritical fluid extraction; anti-oxidant; anti-bacterial; anti-inflammation

Study on the hydrothermal gradient extraction of hemicellulose by a flow-through reactor

The hydrothermal gradient extraction process based on the hemicellulose constituent units is important for obtaining high quality hemicellulose products. The hydrothermal extraction of sawdust hemicellulose was performed under both non-isothermal and isothermal operations using a flow-through reactor for investigating the extraction patterns. The results show that there were significant differences in the major forms of hemicellulose units at different extraction stages. For glucose, xylose, and galactose units, the selectivity of oligomeric form decreased gradually with increasing temperature, whereas it decreased and then increased under thermostatic operation. The selectivity of the mannose oligomeric form decreased and then increased in both operation modes, reaching a trough at 170 °C (96.81 %) and 60 min (55.21 %), respectively. The molecular weight of extracted hemicelluloses were mainly distributed below 70,000 Da, and gradually decreased with temperature, but increased with time. The results contribute to the quantitative and qualitative understanding of the hemicellulose gradient extraction process.

Hydrothermal extraction of microcrystalline cellulose from post-consumer indigo denim fabrics and evaluation of its UV blocking property

Abstract Waste cotton clothes, including post-consumer denim fabrics, are abundant biopolymer sources due to their high cellulose content. These waste materials commonly end up in landfills, posing health and environmental concerns and losing valuable cellulosic materials. To address these, this study aims to extract and characterize microcrystalline cellulose (MCC) from post-consumer indigo denim fabrics using a one-step hydrothermal method and evaluate its UV-blocking properties. FTIR and TGA analysis of raw and bleached denim confirmed the presence and purity of cotton cellulose and the indigo dye. Extracted MCC yielded 70-84%, with a degree of polymerization (DP) of 281-299. XRD analysis of the MCC showed a cellulose Type I structure. FTIR suggests the removal of amorphous phases of cellulose, leaving the crystalline structure. SEM meanwhile revealed rod-shaped and rough-surfaced MCC particles with diameters of 10-20 μm and lengths of 45-60 μm. Both FTIR and SEM indicated the retention of indigo dye on MCC surface. Increased acid hydrolysis time led to smaller particle sizes and higher degree of crystallinity (CrI). Indigo PVA-MCC films showed good transparency and effective UV blocking. These results indicate the successful conversion of denim to MCC via the hydrothermal method and the stability of indigo dye in the cellulose matrix.

Sustainable valorisation of freshwater fish by‐products to gelatin and fish oil by hydrothermal extraction

SummaryThis study explores the potential of hydrothermal extraction as an innovative valorisation method for the simultaneous production of gelatin and fish oil from fish byproducts. It offers an environmentally friendly alternative to conventional solvent‐based techniques by minimising the use of chemical solvents and water. We researched various major commercial freshwater fish species: striped catfish, catfish, and tilapia, and achieved a gelatin product that reflects commercial standards in chemical structure, gel strength, and pH level. The striped catfish gelatin showed the highest gel strength and viscosity (66.01 ± 0.83 g bloom and 15.3 ± 0.1 cP), but was produced at a lower yield than the catfish gelatin. On the other hand, striped catfish produced the highest yield of fish oil (13.56 ± 0.21%) and has the highest omega 3 content (3.72 ± 0.02%) than other fish oil. This innovative study demonstrates the potential of hydrothermal extraction as a sustainable method for producing gelatin and fish oil, offering eco‐friendly and nutritional benefits across a range of applications.

Evaluation of carrageenans extracted by an eco-friendly technology as source for gelled matrices with potential food application

Red macroalgae are considered an immense source of hydrocolloids (agar and carrageenan) that are gaining momentum in the food industry as an alternative to animal-based ones, like gelatin. This work evaluates carrageenans extracted from four different red macroalgae (Chondrus crispus, Mastocarpus stellatus, Sarcopeltis skottsbergii and Gigartina pistillata) by an eco-friendly process (hydrothermal extraction), for their possible employment as food additives considering purity requirements stated by the European Regulation. In general, carrageenans presented a suitable composition, although some sample presented lower sulfate content than 15 % and higher As content than 3 mg/kg, being only carrageenans from Chondrus crispus and Sarcopeltis skottsbergii appropriate for gelled matrices formulation. Different concentrations of hydrocolloids (1–5 %) and salts (0.1–1 M NaCl, CaCl2 and KCl) were evaluated to reach a desired consistency. Rheological behavior of said gels revealed a gel-like behavior, with G' > G” and practically frequency independency of the parameters. Overall, gels formulated with KCl achieved higher G' with maximum values of 100–1000 Pa, whereas the commercial gelled dessert (used as control) only achieved values of around 10 Pa. After 3 months of cold storage, all gels exhibited a strengthening of the gelled matrix, without water syneresis. The colorimetric parameters were also evaluated, showing higher inclination for red and yellow tones with modest lightness values (around 60 %). In this work, hydrothermally extracted carrageenans from Chondrus crispus and Sarcopeltis skottsbergii were assessed, laying the groundwork for further studies in this area.

Hydrothermal extraction of ulvans from Ulva spp. in a biorefinery approach

A simple cascade process based on the hydrothermal fractionation of Ulva spp. biomass was proposed. Considering the overall extraction yields (50 %), ulvan recovery (23 %), and ulvan composition, structural, mechanical and cytotoxic properties, the selected optimal final heating temperature was 160 °C. Ethanol precipitation provided the highest ulvan recovery yields but choline chloride precipitated ulvans showed stronger mechanical properties, G´ moduli 1.5·104 Pa and 3·104 Pa for ethanol and for choline chloride, respectively. Both products were safe on NCTC 929 mouse fibroblasts and after a cooling stage, formed films without requiring any additives. From the ulvan-free liquid fraction, one product with 43 % (wt, d.b.) phenolics and moderate antiradical properties and a byproduct containing nutrients and minerals were separated. The methane potential of the corresponding residual solids was influenced by the hydrothermal heating temperature and was doubled compared to than for the untreated seaweed biomass (60 mL/g VS). This scheme could be also applied to the wet algal biomass, in a chemical free alternative to provide ready to use ulvan biopolymers, bioactives, nutrients, salts and biogas, conforming a biorefinery approach.

Soybean extract inhibits influenza virus entry: Mechanistic insights.

Influenza viruses pose significant public health threats because they can cause seasonal outbreaks and global pandemics. Current preventive measures, including vaccines and antiviral drugs, are limited by their low efficacy and the emergence of drug-resistant viruses. Addressing these issues necessitates the development of novel preventive and treatment methods. Our previous work highlighted the inhibitory effects of soybean hydrothermal extract on influenza virus growth. In this study, we aimed to delve into the mechanism underlying the antiviral activity, specifically the inhibition of viral entry. Our findings reveal that soybean extract significantly inhibited the stages of viral entry during a viral infection and hindered virus uptake by cells. Fluorescence microscopy of stained viral nucleoproteins demonstrated viral localization on the cell membrane in soybean-treated cells, highlighting a distinctive pattern compared to the control cells where the virus was internalized. Soybean extract targeted the clathrin-dependent endocytosis pathway, as evidenced by 76% inhibition using a clathrin-dependent marker (transferrin). The identification of soybean inhibitors underscores the need for further investigation and offers potential for innovative antiviral interventions.

Comparative analysis of biological potential of acerola by-product extracts obtained by hydrothermal and gas-expanded liquid extraction

The acerola non-pomace, a by-product from the juice clarification step and rich in phenolic compounds and ascorbic acid, was investigated for its biological potential through in vitro tests. Extracts were obtained using hydrothermal extraction (HT) at 121°C as well as CO2-expanded ethanol (GXL) at 40°C. The GXL extract contained 159 mg/g of ascorbic acid, while the HT extract showed 70 mg/g. Catechin was found only in the HT extract, and quercetin only in the GXL extract. Both extracts exhibited similar antiglycemic potential, but the GXL extract showed twice the neuroprotective potential against acetylcholinesterase (AChE, IC50=302 μg/mL) and lipoxygenase (LOX, IC50=227 μg/mL) activities. In human breast cancer cells (MDA-MB-231), the GXL extract demonstrated better antitumor potential with an IC50 of 100 μg/mL compared to 250 μg/mL for the HT extract.

Hydrothermal extraction and thorough characterization of carrageenans and proteins from Gigartina pistillata

Carrageenan, an interesting biopolymer from red seaweed, possesses a myriad of applications in food, nutraceutical, or pharmaceutical industries. Although its conventional extraction used to be performed with alkaline solvents, water extraction under subcritical conditions is an alternative eco-friendly technique that has gained popularity in recent years. This work evaluates the recovery and characterization of carrageenan and proteins from Gigartina pistillata. The highest number of proteins was identified at the lowest processing tempeartures. Extracted carrageenan exhibits molecular weights greater than 500 kDa and good rheological behaviour, with interest for food applications and for the formulation of hydrogels when mixed with KCl. The carrageenans and carrageenan hydrogels presented interesting properties such as good thermal stability until 170 °C (TGA-DTG) and show characteristic bands of kappa/iota carrageenans in FTIR studies. Greater cell viability than 70% were achieved on NIH/3T3 fibroblast at carrageenan concentrations of 0.05 and 0.025%, whereas carrageenan extracted at 160 °C (concentration of 0.025%) displays a lower inflammatory action than other samples. In this sense, in this work the eco-friendlier extracted carrageenan was thoroughly characterized and its potentiality to be used in the biomedical field was evaluated.

Optimizing the microwave-assisted hydrothermal extraction of pectin from tangerine by-product and its physicochemical, structural, and functional properties

Microwave-assisted hydrothermal extraction (MAHE) was optimized using a Box-Behnken design (BBD) of the response surface methodology (RSM) for optimal recovery of pectin from tangerine peel (TPP). The effects of three factors (pH, irradiation time and temperature) on extraction yield (EY), galacturonic acid content (GAC) and degree of esterification (DE) of pectin were investigated. The optimal extraction conditions were as follows: pH 1.7, irradiation time 12 min and temperature 109 °C. Under these conditions, the EY, GAC and DE were 30.4, 72.3 and 45.2%, respectively. The low methoxyl content of MHAE (45.2%) compared to CE is confirmed by the 1H NMR and FTIR spectra, and the emulsifying activity is 57.65% and 50.56% for CE and MHAE, respectively. The total phenolic content (TPC) of pectin produced using MAHE is 41.2 mg GAE/g, thus indicating higher antioxidant properties compared to pectin produced with CE, which had a TPC of 38.4 mg GAE/g. In addition, the X-ray diffraction (XRD) and surface morphological analysis (SEM) results showed that TPP had a rough surface and crystalline structure. Overall, our findings show that TTP from MAHE can be used as a natural antioxidant ingredient in the functional food and pharmaceutical industries.

Accelerating Sulfated Polysaccharides Extraction from Fast-Growing Ulva Green Seaweed by Frequency-Controlled Microwaves.

Ulva sp. is a type of green algae and is widely distributed in coastal areas around the world due to eutrophication. Effective utilization of Ulva sp. is expected for the establishment of carbon-neutral biochemical production. Microwave-assisted hydrothermal extraction is one of the most efficient ways of extracting highly functional polysaccharides called ulvan. Here, we demonstrate the importance of microwave frequency in enhancing ulvan extraction from Ulva meridionalis. We found that microwaves (2.45 GHz) selectively heat water solvent, while radio frequency (200 MHz) selectively heats ionic ulvan. Moreover, 2.45 GHz was more effective for extracting ulvan than 200 MHz. Then, we analyzed the conformational change in ulvan during microwave irradiation using in situ small-angle X-ray scattering. Microwaves initiated the loosening of ulvan bundles at temperatures lower than those of conventional heating. As a result, microwaves at 2.45 GHz selectively heat water and initiate ulvan structural change to enhance the extraction of ulvan from U. meridionalis.

Application of red mud in hydrothermal remediation of Cd- and petroleum-contaminated soil

Developing a technique to simultaneously remove the harmful effects of organic matter and heavy metals from composite-polluted soil is of great importance, as it could reduce the time required for land restoration. In this study, red mud was used as an additive to remediate Cd- and petroleum-contaminated soil (CPCS) using hydrothermal technology, and its effects on the total organic carbon (TOC), total Cd, and available Cd (CdA) in the soil were evaluated. During hydrothermal extractions, when the temperature increased from 150 °C to 350 °C, the TOC removal efficiency increased from 16.32 % to 61.29 %, while the ratio of CdA (RCdA) decreased from 32.28 % to 10.72 %, and after adding 2 g of red mud, the RCdA decreased from 46.54 % to 20.30 %. During hydrothermal oxidations, adding red mud increased the TOC removal efficiency from 78.44 % at 0 g to 84.62 % at 3 g when the amount of oxidant was 30 mL, and RCdA decreased from 31.62 % to 19.46 %. These results indicate that hydrothermal treatments could significantly affect the organic substances in soil, and red mud played the roles of a catalyst and passivator during hydrothermal oxidation. The passivation of Cd by red mud was promoted under high-temperature conditions and an appropriate increase in the oxidant concentration and reaction time could promote the removal of organic matter and the reduction of CdA. However, excessive oxidants and reaction time could cause further decomposition of organic matter, leading to a decreased ability to capture Cd.

Characterization of a novel sulfated-rhamnoglucuronan isolated from Korean seaweed Ulva pertusa and its efficacy for treatment of inflammatory bowel disease in mice

This study aimed to isolate Ulva pertusa polysaccharide (UPP), which elicits anti-inflammatory bowel disease (IBD) effects, from the Korea seaweed U. pertusa and identify its structure. Firstly, UPP was isolated from U. pertusa using hydrothermal extraction and ethanol precipitation. UPP is a novel polysaccharide that exhibits unique structural features such as 3-sulfated rhamnose, glucuronic acid, iduronic acid, and 3-sulfated xylose, which are repeated in 1,4-glycosidic bonds. Prophylactic oral administration of UPP in mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) suppressed the levels of inflammatory cytokines and MAPK- and NF-κB-related factors in the serum and colon tissue. Tight junction (TJ)-related factors such as occludin, claudin-1, and mucin were effectively augmented by UPP in the colon tissue. In addition, UPP administration prevented the DSS treatment-led cecal short chain fatty acid imbalance, and this effect was most evident for propionic acid. In conclusion, UPP isolated from the Korean U. pertusa demonstrates potent anti-IBD activity. Characterization of this ulvan revealed its unique structure. Moreover, its efficacy may be associated with its anti-inflammatory effects and regulation of gut microbiota and TJ proteins. Thus, this study provides new insights into the biological effects of UPP in IBD.

Hydrothermally Stimulated Molecular Interfaces for Augmented Electron Delocalization in Wet-Chemical Phosphorus Recovery from Incineration Ash of Sewage Sludge.

Wet-chemically recovering phosphorus (P) from sewage sludge incineration ash (SSIA) has already become a global initiative to address P deficit, but effectively isolating P from these accompanying metals (AMs) through adsorption in a SSIA-derived extract remains elusive. Here, we devised a hydrothermal stimulus-motivated thermodynamic and kinetic enhancement to gain anionic ethylenediaminetetraacetic acid (EDTA) molecular interfaces for AM enclosure to resolve this conundrum. A new dosage rule based on the EDTA coordination ratio with AMs was established for the first time. Upon hydrothermal extraction at 140 °C for 1 h, the P extraction efficiency reached 96.7% or higher for these obtained SSIA samples, and then exceptional P sequestration from these EDTA-chelated AMs was realized by the peculiar lanthanum (La)-based nanoadsorbent (having 188.86 mg P/g adsorbent at pH ∼ 3.0). Relevant theoretical calculations unraveled that these delocalized electrons of tetravalent EDTA molecules boosted the enclosure of liberated AMs, thereby entailing a substantially increased negative adsorption energy (-408.7 kcal/mol) of P in the form of H2PO4- through intruding lattice-edged carbonates to coordinate La with monodentate mononuclear over LaCO5(1 0 1). This work highlights the prospect of molecular adaptation of these common extractants in wet-chemical P recovery from various P-included wastes, further sustaining global P circularity.

A comparative study on enhanced anti-inflammatory activity of Cannabis root extract prepared by combined processing process

Objectives: Cannabis root is a medicinal plant that has been used in traditional medicine around the world. However, in previous studies using simple extracts, the biological activity was not relatively prominent compared to other herbal medicines. The aim of the present study is to confirm the enhancement of anti-inflammatory activity and bioactive compound of Cannabis root extract prepared by combined processing process.Methods: A series of processes including repeated steam and dry, fermentation, hydrothermal extraction and ethanol extraction was applied to Cannabis root. The antioxidant content of cannabis root extracts obtained through a combined processing process was investigated by analyzing the total phenolic, tannin, and flavonoid contents. Anti-inflammatory effects were tested in LPS-treated RAW264.7 cells. The anti-inflammatory mechanism was examined by western blot. Finally, the component profile of Cannabis root extract was analyzed using High Performance Liquid Chromatography (HPLC) and Thin layer chromatography (TLC).Results: The cannabis root extract prepared by complex processing process had higher antioxidant and anti-inflammatory effects than simple extract. Total phenolic and tannin contents were significantly increased, and DPPH free radical inhibition activity was strengthened by combined processing process. Increased NO production and iNOS expression in LPS-treated RAW264.7 cells were decreased in a concentration-dependent manner upon extract treatment by complex processing process. Additionally, the Stigmasterol content of Cannabis root extract was increased through a complex processing process.Conclusions: Further research is needed on the mechanisms and substances that exhibit the anti-inflammatory effects of Cannabis roots extract prepared by complex processing process.

Sustainable valorisation of bioactive molecules from rice husks through hydrothermal extraction for chitosan-based bioplastic production

Rice husks are a low value byproduct, even though it possesses molecules with great potential, such as arabinoxylans, proteins, and silica. These molecules can be used to improve mechanical and physicochemical properties of materials for food packaging. In this work, hydrothermal treatment was used for a sustainable extraction of the valuable molecules present in rice husks. Various extraction temperatures (180, 200, and 220 °C) were performed targeting to extract fractions with distinct compositions. The water extract obtained at 220 °C demonstrated the highest extraction yield, 3 times superior to conventional hot water extraction. These extracts exhibited high content of proteins, phenolic compounds, and carbohydrates, particularly arabinoxylans. This extract was incorporated in chitosan-based films in different ratios, 1:0.1, 1:0.3, and 1:0.5 (chitosan:extract, w:v). The film with the lowest extract ratio presented the highest flexibility (higher elongation and lower Young's modulus) when compared to the pristine chitosan film. The antioxidant capacity was also increased, achieving an antioxidant capacity of >10-fold in comparison to control film. The results revealed that hydrothermal extraction emerges as an environmentally friendly and sustainable methodology for extracting valuable compounds from rice industry byproducts. This method exhibits significant potential to impart flexible and antioxidant properties to biobased materials.

High-Temperature Hydrothermal Extraction of Phenolic Compounds from Brewer's Spent Grain and Malt Dust Biomass Using Natural Deep Eutectic Solvents.

Aligned with the EU Sustainable Development Goals 2030 (EU SDG2030), extensive research is dedicated to enhancing the sustainable use of biomass waste for the extraction of pharmaceutical and nutritional compounds, such as (poly-)phenolic compounds (PC). This study proposes an innovative one-step hydrothermal extraction (HTE) at a high temperature (120 °C), utilizing environmentally friendly acidic natural deep eutectic solvents (NADESs) to replace conventional harmful pre-treatment chemicals and organic solvents. Brewer's spent grain (BSG) and novel malt dust (MD) biomass sources, both obtained from beer production, were characterized and studied for their potential as PC sources. HTE, paired with mild acidic malic acid/choline chloride (MA) NADES, was compared against conventional (heated and stirred maceration) and modern (microwave-assisted extraction; MAE) state-of-the-art extraction methods. The quantification of key PC in BSG and MD using liquid chromatography (HPLC) indicated that the combination of elevated temperatures and acidic NADES could provide significant improvements in PC extraction yields ranging from 251% (MD-MAC-MA: 29.3 µg/g; MD-HTE-MA: 103 µg/g) to 381% (BSG-MAC-MA: 78 µg/g; BSG-HTE-MA: 375 µg/g). The superior extraction capacity of MA NADES over non-acidic NADES (glycerol/choline chloride) and a traditional organic solvent mixture (acetone/H2O) could be attributed to in situ acid-catalysed pre-treatment facilitating the release of bound PC from lignin-hemicellulose structures. Qualitative 13C-NMR and pyro-GC-MS analysis was used to verify lignin-hemicellulose breakdown during extraction and the impact of high-temperature MA NADES extraction on the lignin-hemicellulose structure. This in situ acid NADES-catalysed high-temperature pre-treatment during PC extraction offers a potential green pre-treatment for use in cascade valorisation strategies (e.g., lignin valorisation), enabling more intensive usage of available biomass waste stream resources.