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Several bioactive compounds that hold a potential interest in the food industry as phenolic compounds, polysaccharides, proteins and vitamins, among others, are present in seaweeds. Green extraction technologies are the preferred way to obtain these compounds. Pressurized hot water extraction, from 160 to 220 °C, was tested to achieve high yields of these components from the edible brown seaweed, Undaria pinnatifida. The maximum fucoidan content was recovered at 160 °C, while the phloroglucinol content and antioxidant activity were maximum at 220 °C. The possibility of encapsulating these bioactive fractions using mannitol was assessed. The highest production yield of the polymeric particles was found using the 220 °C fraction (close to 75%). In order to formulate microparticles with bioactive potential, several ratios of liquid phases were assessed, 3:1, 1:1 and 1:3 (w:w), using the liquid fractions obtained at 160 °C and 220 °C. The yield production was always above 67%, being in the 1:3 ratio (160 °C:220 °C) and close to 75%. The rheological results indicated that the presence of microparticles enhanced the apparent viscosity of the aqueous dispersions with non-Newtonian profiles, achieving the highest viscosity for those formulated with microparticles from 160 °C:200 °C (3:1). [ABSTRACT FROM AUTHOR]

In this study, pressurized hot water extraction (PHWE) was evaluated for the recovery of anti-diabetic borapetoside C (BPC) from T. crispa stems. The maximum BPC extraction efficiency obtained at 100 ˚C, 2.5 MPa and 5.0 mL/min was considerably higher than that obtained by the conventional methods. Under optimized conditions, one-site kinetic desorption model could most accurately describe the PHWE behavior, suggesting an intra-particle diffusion-controlled mechanism. The undesirable compounds in the extract were further removed by micelle-mediated separation (MMS), in which Tween 80 was added, followed by NaCl addition and slight temperature increase to induce phase separation. At the most suitable MMS condition, with 0.028 mM Tween 80, 0.4 M NaCl, at 85 ˚C, the majority (87 %) of BPC could be recovered in the aqueous phase after 40 min. After MMS, the resulting extract exhibited low cytotoxicity against L6 and HepG2 cells while maintaining significant α-glucosidase and α-amylase inhibition activities. [Display omitted] • Pressurized hot water extraction (PHWE) of BPC from T. crispa was optimized. • Optimal PHWE conditions were found to be 100 °C, 5 mL/min and 2.5 MPa. • The optimized PHWE conditions accurately fit the one-site kinetic desorption model. • Micelle-mediated separation with Tween 80 selectively removes undesirable compounds from PHWE extracts. • PHWE/MMS extracts exhibit comparable activity to acarbose with low toxicity to L6 cells. [ABSTRACT FROM AUTHOR]

Although sweet tea is rich in bioactive polysaccharides, the knowledge regarding their structures, bioactivities, and gut microbial metabolism is still limited. Therefore, in order to promote the application of sweet tea polysaccharide (STP) in the food industry, the pressurized hot water extraction (PHWE) of STP was optimized, and its structural properties and biological effects as well as microbial fermentation characteristics were investigated. The maximum extraction yield (4.64 % ± 0.03 %) of STP extracted by PHWE was obtained under the optimal conditions. Both homogalacturonan and arabinogalactan might exist as major polysaccharide fragments in STP. Additionally, STP exerted obviously in vitro antioxidant, anti-diabetic, and immunostimulatory effects, which might be related to its chemical properties, such as uronic acids, conjugated polyphenolics, and esterification degree. Furthermore, STP could be consumed by intestinal microbiota, and its fermentability was about 54 % at the end stage of fecal fermentation. Indeed, STP could modulate the microbial composition via improving the growth of several beneficial microbes, causing the release of beneficial short-chain fatty acids. Collectively, the findings indicate that the PHWE is an efficient method for extracting bioactive polysaccharides from sweet tea, and results can also provide a scientific basis for developing STP into functional foods or functional ingredients. • Pressurized hot water extraction of sweet tea polysaccharide (STP) was optimized. • STP was mainly composed of HG and AG fragments. • STP exerted multiple health-promoting effects in vitro. • The potential metabolic behavior of STP by gut microbiota was revealed. • STP could modulate the gut microbial composition to improve intestinal health. [ABSTRACT FROM AUTHOR]

A large amount of waste from Bambusa chungii culms is generated from the bamboo pulping industry, causing disposal problems. Nevertheless, bamboo culms are a suitable source of functional ingredients, such as antioxidant compounds. However, because of the high compactness and tightness in their material structure, obtaining phytochemicals from bamboo culms using conventional organic solvent extraction methods can be inefficient. In this research, we developed a pressurized hot water extraction (PHWE) method to recover 19 target phenolic compounds from Bambusa chungii culms. The extracted compounds were determined by ultra-high performance liquid chromatography–quadrupole time-of-flight–mass spectrometry (UPLC–QTOF–MS). The antioxidant potential of the extracts was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2' -Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays. We investigated the effects of temperature, extraction time, and the material-to-liquid ratio on PHWE, and these parameters were optimized with a Box–Behnken design experiment and response surface tool. The optimal extraction condition was found at 170 °C, with a 1:30 g/mL material-to-liquid ratio and a 14 min extraction time. Following these optimal parameters, the total yield of target phenolic compounds (TYPC) reached 3.85 mg/g of raw material, and the half-maximal inhibitory concentrations (IC50) for the DPPH and ABTS tests were 94.7 mg/L and 21.88 mg/L, respectively. The FRAP value was 1.23 µmol FSE/mg of dried extract. A strong correlation between TYPC and the antioxidant activity of the extract was confirmed. The TYPC and antioxidant capacity of the optimal PHWE extract of the Bambusa chungii culms were both considerably higher than those of extracts obtained from conventional solvent extractions. These results indicated that PHWE is an excellent green technique for recovering phenolic compounds from bamboo culms, and the PHWE extracts of Bambusa chungii culms may be a good source of natural antioxidants. [ABSTRACT FROM AUTHOR]

The present study extracted total saponins from quinoa husks with pressurized hot water extraction and optimized the extraction conditions. The response surface methodology (RSM) with a Box–Behnken design (BBD) was employed to investigate the effects of extraction flow rate, extraction temperature and extraction time on the extraction yield of total saponins. A maximal yield of 23.06 mg/g was obtained at conditions of 2 mL/min, 210 °C and 50 min. The constituents of the extracts were analyzed by liquid chromatography–mass spectrometry (LC-MS). A total of twenty-three compounds were identified, including five flavonoids, seventeen triterpenoid saponins and a phenolic acid. Moreover, we performed an in vitro assay for the α-glucosidase activity and found a stronger inhibitory effect of the quinoa husk extracts than acarbose, suggesting its potential to be developed into functional products with hypoglycemic effect. Finally, our molecular docking analyses indicated triterpenoid saponins as the main bioactive components. [ABSTRACT FROM AUTHOR]

A significant amount of bioactive compound-rich solid waste is released during the industrial phycocolloid-centric extraction of Gelidium sesquipedale. The impact of mild pressurized hot water extraction on repurposing this waste for the recovery of agar with an adjustable gel texture is investigated. A two-factor interaction response surface model assessed the influences of the operating temperatures (80 to 130 °C), times (45 and 150 min), pressures (1 to 70 bar), and algae concentrations (3 to 10% (w:v)). At a temperature of 100 °C, a pressure of 10.13 bar, a recovery time of 45 min, and a 10% algae concentration, the working parameters were considered ideal (w:v). Agar with a hardness of 431.6 g, an adhesiveness of −13.14 g.s−1, a springiness of 0.94, a cohesiveness of 0.63, and a gumminess of 274.46 g was produced under these conditions. A combined desirability of 0.78 was obtained for the exposed technology that retrieved gels with a minimum agar yield of 10% and thermal hysteresis between 39 ± 1 and 52 ± 0.5 °C. The fitted design can provide a high techno-commercial value to the agri-food industrial waste stream. [ABSTRACT FROM AUTHOR]

This study aimed to utilize enzymatic treatment and pressurized hot water extraction (PHWE) to recover soluble food-grade protein and collagen peptides from mechanically deboned chicken meat (MDCM), a side-stream from the meat industry. Food-grade enzyme blends Ermitase 1 and Ermitase 2 were used to fractionate the mechanically deboned meat into fat, soluble protein, and solids. Response surface methodology was utilized to optimize treatments to maximize the protein yield. At the optimum conditions (hydrolysis time 240 min, E:S 0.27%, and a hydromodule 1 L/kg), the enzymatic treatment produced high protein yield, approximately 90%. The protein hydrolysates showed a good solubility index, but weak gelling properties. The PHWE of the bones resulted in a high nitrogen yield, approximately 87%, at the optimum conditions of 190 °C and 83 min. Peptides in the bone extract were in the range of 0.5–13.7 kDa. Overall, our study highlights the importance of response surface methodology to optimize parameters for mechanically deboned chicken meat enzymatic and PHWE treatments to achieve high yields of protein for food applications and low-molecular-weight collagen peptides for cosmetic applications. The crucial role of protein and peptide prices was observed in preliminary profitability analysis. [ABSTRACT FROM AUTHOR]

Several bioactive compounds that hold a potential interest in the food industry as phenolic compounds, polysaccharides, proteins and vitamins, among others, are present in seaweeds. Green extraction technologies are the preferred way to obtain these compounds. Pressurized hot water extraction, from 160 to 220 °C, was tested to achieve high yields of these components from the edible brown seaweed, Undaria pinnatifida. The maximum fucoidan content was recovered at 160 °C, while the phloroglucinol content and antioxidant activity were maximum at 220 °C. The possibility of encapsulating these bioactive fractions using mannitol was assessed. The highest production yield of the polymeric particles was found using the 220 °C fraction (close to 75%). In order to formulate microparticles with bioactive potential, several ratios of liquid phases were assessed, 3:1, 1:1 and 1:3 (w:w), using the liquid fractions obtained at 160 °C and 220 °C. The yield production was always above 67%, being in the 1:3 ratio (160 °C:220 °C) and close to 75%. The rheological results indicated that the presence of microparticles enhanced the apparent viscosity of the aqueous dispersions with non-Newtonian profiles, achieving the highest viscosity for those formulated with microparticles from 160 °C:200 °C (3:1).

Abstract Background Safety, environmental and economic setbacks are driving industries to find greener approaches to extract bioactive compounds from natural resources. Pressurized hot water extraction (PHWE) is among the solvent free and efficient methods for extracting bioactive compounds. Experimental In this study, the suitability of PHWE for extracting bioactive compounds such as phenolics, hydrolysable tannins and flavonoids from Phyllanthus tenellus was investigated by UPLC-qTOF-MS. Results Solvent properties of water are significantly increased through imposing temperature at 121 °C and pressure at 15 p.s.i. Pressurized hot water extraction obtained 991-folds higher hydrolysable tannins than methanol extraction. Conclusion The extraction yields of hydrolysable tannins with PHWE was almost double of absolute methanol extraction.

The present study extracted total saponins from quinoa husks with pressurized hot water extraction and optimized the extraction conditions. The response surface methodology (RSM) with a Box–Behnken design (BBD) was employed to investigate the effects of extraction flow rate, extraction temperature and extraction time on the extraction yield of total saponins. A maximal yield of 23.06 mg/g was obtained at conditions of 2 mL/min, 210 °C and 50 min. The constituents of the extracts were analyzed by liquid chromatography–mass spectrometry (LC-MS). A total of twenty-three compounds were identified, including five flavonoids, seventeen triterpenoid saponins and a phenolic acid. Moreover, we performed an in vitro assay for the α-glucosidase activity and found a stronger inhibitory effect of the quinoa husk extracts than acarbose, suggesting its potential to be developed into functional products with hypoglycemic effect. Finally, our molecular docking analyses indicated triterpenoid saponins as the main bioactive components.

A significant amount of bioactive compound-rich solid waste is released during the industrial phycocolloid-centric extraction of Gelidium sesquipedale. The impact of mild pressurized hot water extraction on repurposing this waste for the recovery of agar with an adjustable gel texture is investigated. A two-factor interaction response surface model assessed the influences of the operating temperatures (80 to 130 °C), times (45 and 150 min), pressures (1 to 70 bar), and algae concentrations (3 to 10% (w:v)). At a temperature of 100 °C, a pressure of 10.13 bar, a recovery time of 45 min, and a 10% algae concentration, the working parameters were considered ideal (w:v). Agar with a hardness of 431.6 g, an adhesiveness of −13.14 g.s−1, a springiness of 0.94, a cohesiveness of 0.63, and a gumminess of 274.46 g was produced under these conditions. A combined desirability of 0.78 was obtained for the exposed technology that retrieved gels with a minimum agar yield of 10% and thermal hysteresis between 39 ± 1 and 52 ± 0.5 °C. The fitted design can provide a high techno-commercial value to the agri-food industrial waste stream.

Moringa oleifera leaves are widely used in traditional medicine as a food supplement because they are high in essential and nutritious content. Pressurized hot water extraction (PHWE), which is a green approach, was used for the recovery of the macro-nutrient and micro-nutrient elements from dried leaf powder of Moringa oleifera. In this study, response surface methodology was applied to assess the influence of temperature (50–200 °C) and time (5–60 min) on the extractability pattern of macro-nutrient and micro-nutrient elements from the leaves of Moringa oleifera when processed by PHWE. The quantification of macro-nutrient elements such as Ca, K and Mg and micro-nutrient elements like Al, Co, Cr, Cu, Fe, Ni and Zn from the leaves was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Obtained results revealed that the extraction of macro-nutrient elements from the Moringa oleifera leaves was enhanced by increasing the extraction time more than the extraction temperature. On the contrary, the amounts of extractable micro-nutrient elements were increased by increasing the extraction temperature. Hence, the recovery for macro-nutrient elements ranged from 88 to 98% while for micro-nutrients it ranged from 21 to 46%. This implies that macro-nutrient elements are extracted with relatively high selectivity in relation to micro-nutrient elements in Moringa dried leaf powder using the PHWE technique. [ABSTRACT FROM AUTHOR]

Moringa oleifera is an excellent source of bioactive compounds which exhibit nutritional and medicinal properties. Pressurized hot water extraction is known as a green, environmentally, faster and efficient extraction technique. However, it is facing a challenge with the degradation of thermolabile compounds at higher temperature. This research was performed to investigate the influence of extraction temperature, time and flow rate of pressurized hot water extraction in the recovery of Vitamin C and phenolic compounds from Moringa oleifera leaves. Response surface methodology (RSM) and artificial neural network (ANN) were used as estimates and predictive models with maximum responses. The optimal pressurized hot water extraction conditions were identified at: 91°C for temperature, 60 min for extraction time and 0.3 mL min− 1 for flow rate, giving a predicted concentration of 3.92 ± 0.30, 4.74 ± 0.32 and 0.357 ± 0.19 g per 100 g of dry powder for kaempferol, quercetin and vitamin C, respectively. Evaluation of the two models through the statistical error parameters showed that ANN model gave a good predictive and estimation capabilities than RSM. Therefore, ANN can be recommended for use optimization method in the pressure hot water extraction. • Moringa oleifera leave source of bioactive compounds with antioxidant activities. • Pressurized hot water extraction technique for phenolic and thermolabile compounds. • Response surface methodology and Artificial neural network as optimization modeling. [ABSTRACT FROM AUTHOR]

This study aimed to utilize enzymatic treatment and pressurized hot water extraction (PHWE) to recover soluble food-grade protein and collagen peptides from mechanically deboned chicken meat (MDCM), a side-stream from the meat industry. Food-grade enzyme blends Ermitase 1 and Ermitase 2 were used to fractionate the mechanically deboned meat into fat, soluble protein, and solids. Response surface methodology was utilized to optimize treatments to maximize the protein yield. At the optimum conditions (hydrolysis time 240 min, E:S 0.27%, and a hydromodule 1 L/kg), the enzymatic treatment produced high protein yield, approximately 90%. The protein hydrolysates showed a good solubility index, but weak gelling properties. The PHWE of the bones resulted in a high nitrogen yield, approximately 87%, at the optimum conditions of 190 °C and 83 min. Peptides in the bone extract were in the range of 0.5–13.7 kDa. Overall, our study highlights the importance of response surface methodology to optimize parameters for mechanically deboned chicken meat enzymatic and PHWE treatments to achieve high yields of protein for food applications and low-molecular-weight collagen peptides for cosmetic applications. The crucial role of protein and peptide prices was observed in preliminary profitability analysis.

Abelmoschus esculentus L. Moench (okra) is a commonly consumed vegetable that consists of the seeds and peel component which are rich in polyphenolic compounds. The aim of this study is to utilize pressurized hot water extraction (PHWE) for the extraction of bioactive phytochemicals from different parts of okra. A single step PHWE was performed at various temperatures (60 °C, 80 °C, 100 °C and 120 °C) to determine which extraction temperature exhibits the optimum phytochemical profile, antioxidant and antidiabetic activities. The optimum temperature for PHWE extraction was determined at 80 °C and the biological activities of the different parts of okra (Inner Skin, Outer Skin and Seeds) were characterized using antioxidant (DPPH and ABTS), α-glucosidase and vasoprotective assays. Using PHWE, the different parts of okra displayed distinct phytochemical profiles, which consist of primarily polyphenolic compounds. The okra Seeds were shown to have the most antioxidant capacity and antidiabetic effects compared to other okra parts, likely to be attributed to their higher levels of polyphenolic compounds. Similarly, okra Seeds also reduced vascular inflammation by downregulating TNFα-stimulated VCAM-1 and SELE expression. Furthermore, metabolite profiling by LC/MS also provided evidence of the cytoprotective effect of okra Seeds in endothelial cells. Therefore, the use of PHWE may be an alternative approach for the environmentally friendly extraction and evaluation of plant extracts for functional food applications.

Background: Safety, environmental and economic setbacks are driving industries to find greener approaches to extract bioactive compounds from natural resources. Pressurized hot water extraction (PHWE) is among the solvent free and efficient methods for extracting bioactive compounds. Experimental: In this study, the suitability of PHWE for extracting bioactive compounds such as phenolics, hydrolysable tannins and flavonoids from Phyllanthus tenellus was investigated by UPLC-qTOF-MS. Results: Solvent properties of water are significantly increased through imposing temperature at 121 °C and pressure at 15 p.s.i. Pressurized hot water extraction obtained 991-folds higher hydrolysable tannins than methanol extraction. Conclusion: The extraction yields of hydrolysable tannins with PHWE was almost double of absolute methanol extraction. [ABSTRACT FROM AUTHOR]

Pressurized liquid extraction (PLE) is a tool able to provide green extraction methods to further determine contaminants in food and the environment. The aim of this review is to offer a critical overview of the recent developments within this field and can be considered as an update of the previous that we published in 2015. Trends regarding sample treatment, solvents, in-cell clean-up approaches used in the extraction of organic contaminants are addressed. Special attention deserve those methods that include on-line clean up in the extraction cell. Comparison with other green techniques is also presented. The final objective of this review is to clearly define the role that this technique plays in the analysis of organic pollutants, their strengths and weaknesses, as well as the updated spectrum of applications for which PLE is an essential tool. • Update review of the PLE to extract contaminants in food and the environment. • Establishment of the applications for which PLE is advantageous. • Main analytical parameters of the different PLE procedures are discussed. • Advantages and limitations in the analysis are considered and evaluated. • Future trends and prospects are envisaged. [ABSTRACT FROM AUTHOR]

The aim of this study was to produce ready to drink (RTD) iced teas from sage and linden. For this purpose, phenolics of sage and linden were extracted by pressurized hot water extraction (PHWE) and then the extracts obtained were spray dried by the addition of maltodextrin. The powders produced by spray drying were processed into RTD sage and linden iced teas by adding sucrose and citric acid. The optimum conditions of PHWE of sage and linden were at 160 °C and for 10 min and 5 min, respectively. The solubility and microencapsulation efficiency of spray dried powders were found to be greater than 97%. In addition, total phenolic content and antioxidant activity of RTD iced teas are parallel with those of microencapsulated sage and linden powders after pasteurization at 80 °C for 5 min. The sensory analysis of RTD iced teas showed that products were well-accepted by the panelists. [ABSTRACT FROM AUTHOR]

In existing processes, the extraction of steviol glycosides from stevia leaves involves many process steps often including extraction by organic solvents. The purpose of the present study was to develop a process for the effective extraction of steviol glycosides, which can provide a concentrated juice exhibiting a high level of recovery with regard to the target compounds, rebaudioside A and stevioside. Pressurized Hot Water Extraction (PHWE) was first optimized with Response Surface Methodology in terms of maximized rebaudioside-A yield and minimized colour components. PHWE was then combined with pressing in a wine-press, resulting higher efficiency for extracting both steviol glycosides in comparison to the reported methods in the literature. Finally, spray drying was applied for both product stabilization and removal of contaminants. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present in the most comprehensive way the facts about the application of PLE in the analysis of secondary metabolites in plants. It is true that due to its specific extraction conditions, PLE is one of the most effective and versatile techniques of plant constituents isolation. It is also true that it has popularized the use of aqueous organic mixtures, and even water alone, for the extraction of nonpolar compounds. Yet, the same specific extraction conditions can lead to erroneous results of plant constituent content analysis. Disclosure of new facts about the application of PLE in the analysis of secondary plant metabolites provides an insight into an often overlooked aspect of extraction of active compounds from plants. • This review updates knowledge about the applicability of PLE. • It discusses the effectiveness and usefulness of PLE in the context of its achievements. • It discloses the limitations of PLE in the plant constituents content analysis. • Knowing all these facts can lead to the creation of a perfect method with a good method. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hemp fibers were retted with continuous steam treatment while extracting compounds. • The extraction temperature affects the composition of the hemp extracts obtained. • With the continuous steam treatment the hemicellulose content of hemp decreases. • The extracts contained compounds with potential to be used by the chemical industry. Abstract The overarching aim of this study was to investigate the possibility of extracting carbohydrates and other compounds from hemp (Cannabis sativa L.) using a continuous steam treatment that would also separate the fibres from the hurd. Different parts of hemp, such as stalk, leaves, and decorticated hemp with hurd, were extracted by a steam treatment. After processing, the fibers in the stalk could be easily separated. The products obtained at different extraction temperatures were characterized using multiple techniques. The hemicellulose content of untreated dry hemp was reduced from 275 mg/g to 237 mg/g at 160 °C treatment while the corresponding cellulose content increased from 376 mg/g to 418 mg/g. For example, the iron (Fe) content of the extracts increased with elevated treatment temperatures; for dry hemp at 100 °C, the Fe content in extracts was 1.33 mg/kg, whereas at 160 °C, it was much higher, 16.58 mg/kg. The results demonstrate that the extraction temperature influences the composition of the extracts. Compounds with potentially useful applications, such as in medicine and in the chemical industry, were also identified in the extracts. However, more research will be needed to optimize the treatment and the further processing of the products in order to estimate the commercial potential of this technique. [ABSTRACT FROM AUTHOR]

Two green chemistry extraction systems, an in-house stainless-steel column Pressurized Hot Water Extraction system (PHWE) and a commercially available Espresso machine were applied for analysing 23 active pharmaceutical ingredients (APIs) in sewage sludge. Final analysis was performed on UPLC-MS/MS using two different chromatographic methods: acid and basic. When analysing all 23 APIs in sewage sludge both extraction methods showed good repeatability. The PHWE method allowed for a more complete extraction of APIs that were more tightly bound to the matrix, as exemplified by much higher concentrations of e.g., ketoconazole, citalopram and ciprofloxacin. In total, 19 out of 23 investigated APIs were quantified in sewage sludge, and with a few exceptions the PHWE method was more exhaustive. Mean absolute recoveries of 7 spiked labelled APIs were lower for the PHWE method than the Espresso method. Under acid chromatographic conditions mean recoveries were 16% and 24%, respectively, but increased to 24% and 37% under basic conditions. The difference between the PHWE method and the Espresso method might be interpreted as the Espresso method giving higher extraction efficiency; however, TIC scans of extracts revealed a much higher matrix co-extraction for the PHWE method. Attempts were made to correlate occurrence of compounds in sewage sludge with chemical properties of the 23 APIs and there are strong indications that both the number of aromatic rings and the presence of a positive charge is important for the sorption processes to sewage sludge. [ABSTRACT FROM AUTHOR]

Cooperage woods are rich in volatile compounds responsible for pleasant aromas described as coconut, vanilla, spice, caramel, toasty, etc. In the present work, the hot water extraction under 103 bar pressure of natural flavoring compounds from cooperage wood residues is described. It was possible to obtain aqueous extracts rich in diverse volatile compounds from the following wood species: oak (Quercus alba and Quercus petraea), chestnut (Castanea sativa), cherry (Prunus avium), false acacia (Robinia pseudoacacia) and lenga (Nothofagus pumilio), while the concentration of the components is similar to that obtained with organic solvents. The gas chromatography-mass spectrometry (GC-MS) analysis of aqueous extracts shows a wide spectrum of natural flavoring compounds, the composition of which are species dependent. The extracts exhibit antioxidant properties. Water extraction under subcritical conditions offers the possibility of a sustainable recovery of natural flavorings and antioxidant compounds from cooperage woods, which are well suited for application in the food industry. [ABSTRACT FROM AUTHOR]

Abstract Background Pressurized hot water extraction (PHWE) technique has recently gain much attention for the extraction of biologically active compounds from plant tissues for analytical purposes, due to the limited use of organic solvents, its cost-effectiveness, ease-of-use and efficiency. An increase in temperature results in higher yields, however, issues with degradation of some metabolites (e.g. tartrate esters) when PHWE is conditioned at elevated temperatures has greatly limited its use. In this study, we considered possibilities of optimizing PHWE of some specific functional metabolites from Bidens pilosa using solvent compositions of 0, 20, 40 and 60 % methanol and a temperature profile of 50, 100 and 150 °C. Results The extracts obtained were analyzed using UPLC-qTOF-MS/MS and the results showed that both temperature and solvent composition were critical for efficient recovery of target metabolites, i.e., dicaffeoylquinic acid (diCQA) and chicoric acid (CA), which are known to possess anti-HIV properties. It was also possible to extract different isomers (possibly cis-geometrical isomers) of these molecules. Significantly differential (p ≤ 0.05) recovery patterns corresponding to the extraction conditions were observed as recovery increased with increase in methanol composition as well as temperature. The major compounds recovered in descending order were 3,5-diCQA with relative peak intensity of 204.23 ± 3.16 extracted at 50 °C and 60 % methanol; chicoric acid (141.00 ± 3.55) at 50 °C and 60 % methanol; 4,5-diCQA (108.05 ± 4.76) at 150 °C and 0 % methanol; 3,4-diCQA (53.04 ± 13.49) at 150 °C and 0 % methanol; chicoric acid isomer (40.01 ± 1.14) at 150 °C and 20 % methanol; and cis-3,5-diCQA (12.07 ± 5.54) at 100 °C and 60 % methanol. Fitting the central composite design response surface model to our data generated models that fit the data well with R2 values ranging from 0.57 to 0.87. Accordingly, it was possible to observe on the response surface plots the effects of temperature and solvent composition on the recovery patterns of these metabolites as well as to establish the optimum extraction conditions. Furthermore, the pareto charts revealed that methanol composition had a stronger effect on extraction yield than temperature. Conclusion Using methanol as a co-solvent resulted in significantly higher (p ≤ 0.05) even at temperatures as low as 50 °C, thus undermining the limitation of thermal degradation at higher temperatures during PHWE.

Phytochemicals of Cannabis sativa mainly for the use in the different industries are that of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Pressurized hot water extraction (PHWE) is seen as an efficient, fast, green extraction technique for the removal of polar and semi-polar compounds from plant materials. The PHWE technique was applied to extract cannabinoid compounds from Cannabis sativa seed. Response surface methodology was used to investigate the influence of extraction time (5−60 min), extraction temperature (50−200 °C) and collector vessel temperature (25−200 °C) on the recovery of delta-9-tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD), cannabichromene (CBG) and cannabigerol (CBC) from Cannabis sativa seed by PHWE. The identification and semi quantification of cannabinoid compounds were determined using GCXGC-TOFMS. The results obtained from different extractions show that the amount of THC and CBN was drastically decreasing in the liquid extract when the temperature rose from 140 to 160 °C in the extraction cell and the collector′s vessel. The optimal conditions to extract more CBD, CBC, and CBG than THC and CBN were set at 150 °C, 160 °C and 45 min as extraction temperature, the temperature at collector vessel, and the extraction time, respectively. At this condition, the predicted and experimental ratio of THCt (THC + CBN)/CBDt (CBD + CBC+ CBG) was found to be 0.17 and 0.18, respectively. Therefore, PHWE can be seen as an alternative to the classic extraction approach as the efficiency is higher and it is environmentally friendly.

Phenolics and essential oil of peppermint were obtained by pressurized hot water extraction (PHWE). The best extraction conditions were found to be 130 °C for temperature, 10 min for extraction time, and 3 cycles for extraction number. There were no statistically significant differences between 130 and 160 °C in terms of essential oil content. Total phenolic contents (TPC) of the extracts were higher at 160 °C than that of 130 °C. However, further HPLC analysis of the extracts revealed that hydrolysis and/or decomposition of phenolics were observed in the extracts obtained at 160 °C. The main phenolic of peppermint was determined as eriocitrin by HPLC-DAD, while menthol was the dominant component in essential oil fraction of peppermint by GC-FID. The present study demonstrated that PHWE was a suitable technique for simultaneous extraction of phenolics and essential oil from peppermint. The technique might be used as an analytical extraction tool for determination of phenolics and essential oil. Moreover, the extracts of PHWE could directly be evaluated for the enrichment of liquid food formulations or be transformed into solid form by suitable techniques such as spray drying for easy storage and subsequent enrichment of food products. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hydrolysates were produced at different conditions by subcritical water treatment. • Physico-chemical and bio-functional parameters of the hydrolysates were studied. • Hydrolysates obtained at 225 °C/100 bar showed significant results. • Best condition showed rich in antioxidants, ACE-I activities, and total amino acids. • SDA-PAGE and MALDI-TOF analysis revealed modification in molecular weight. Abstract Pacific oyster muscle hydrolysates were prepared by pressurized hot water extraction (PHWE) at process conditions ranging 125 °C/20 bar ∼ 275 °C/140 bar to investigate various physico-chemical and bio-functional parameters. Degree of hydrolysis was increased with increasing temperature and pressure and at 275 °C/140 bar, hydrolysis was found to be highest. Glycogen, protein, reducing sugar, and phenolic content of the hydrolysates were increased obtained from 125 °C/20 bar to 225 °C/100 bar, but decreased after raising over 250 °C/120 bar. Total and free amino acid contents were subsequently decreased as temperature and pressure increased over 175 °C/60 bar. Radical scavenging activity and antihypertensive activity was found to be highest at 225 °C/100 bar at which condition, the protein molecular size and carbohydrate molecular weight of the hydrolysates were 15 kDa or lower and 300–1000 Da, respectively. This study suggests the 225 °C/120 bar conditions for bio-functional Pacific oyster hydrolysate preparation. [ABSTRACT FROM AUTHOR]

World quinoa production is increasing due its high nutritional value. As a consequence, large quantities of stalks accumulate as unused byproducts. Here, we verify the presence of saponins in the stalks and present a biorefinery approach with quinoa stalks as feedstock, using an integrated processing scheme to separate saponins, xylan and cellulose. Saponins were extracted using pressurized hot water extraction (PHWE), optimized by a central composite experimental design (rotatable 2 2 ) with temperature and extraction time as factors. Xylan was extracted from the residual solid material after PHWE by an alkaline method using 0.5 M NaOH at 80 °C. Cellulose was purified from the remaining residuals using acetic and nitric acid at 120 °C, which resulted in recovery of white cotton-like cellulose, showing no need of further bleaching. The saponin yield was significantly increased at temperatures exceeding 110 °C, with highest amounts obtained at 195 °C (15.4 mg/g raw material). The yield in the following xylan extraction (maximum 120 mg/g raw material) was however significantly reduced when preceded by PHWE above 110 °C, indicating degradation of the polymer. Cellulose recovery (maximum 296 mg/g raw material) was less affected by variations in temperature and time in the preceding PHWE. The results obtained shows that tuning between saponin and xylan extraction is critical. This approach is foreseen to be applicable to the valorisation of residual fiber-rich biomass from various types of crops, besides quinoa. [ABSTRACT FROM AUTHOR]

An investigation of the previously unexamined ancient Tasmanian clone Lomatia tasmanica W. M. Curtis (Proteaceae) and two other endemic species Lomatia tinctoria R. Br. and Lomatia polymorpha (Labill.) R. Br. was undertaken . This represents the first extensive natural products study in which individual phytochemical components have been isolated and identified from these three Lomatia species. Extraction of L. tasmanica leaves provided the naphthoquinone juglone (0.34% w/w), and n -alkanes nonacosane and heptacosane (0.30% w/w combined). L. polymorpha afforded the flavonoid glycosides dihydroquercetin 3- O -β-D-xyloside (0.22% w/w) and quercetin 3- O -β- d -glucose (0.14% w/w), as well as the naphthalene glucoside 1,4,8-trihydroxynaphthalene-1- O -β- d -glucose (0.04% w/w) and 4- O - p -coumaroyl- d -glucose (0.03% w/w). In addition, both L. polymorpha and L. tinctoria contained juglone (0.32% w/w and 0.58% w/w, respectively). L. polymorpha provided tetracosan-1-ol, hexacosan-1-ol and octacosan-1-ol (0.07% w/w combined), while L. tinctoria gave nonacosane (0.13% w/w). Analysis of three individual specimens from each of the three species demonstrated consistency in the respective phytochemical profiles of these populations and tentatively suggests limited intraspecific variation. [ABSTRACT FROM AUTHOR]

The effects of sediment contamination on fish are of high significance for the protection of ecosystems, human health and economy. However, standardized sediment bioassays with benthic fish species, that mimic bioavailability of potentially toxic compounds and comply with the requirements of alternative test methods, are still scarce. In order to address this issue, embryos of the benthic European weatherfish ( Misgurnus fossilis ) were exposed to freeze-dried sediment (via sediment contact assays (SCA)) and sediment extracts (via acute fish embryo toxicity tests) varying in contamination level. The extracts were gained by accelerated solvent extraction with (i) acetone and (ii) pressurized hot water (PHWE) and subsequently analyzed for polycyclic aromatic hydrocarbons, polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofurans. Furthermore, embryos of the predominately used zebrafish ( Danio rerio ) were exposed to extracts from the two most contaminated sediments. Results indicated sufficient robustness of weatherfish embryos towards varying test conditions and sensitivity towards relevant sediment-bound compounds. Furthermore, a compliance of effect concentrations derived from weatherfish embryos exposed to sediment extracts (96 h-LC 50 ) with both measured gradient of sediment contamination and previously published results was observed. In comparison to zebrafish, weatherfish embryos showed higher sensitivity to the bioavailability-mimicking extracts from PHWE but lower sensitivity to extracts gained with acetone. SCAs conducted with weatherfish embryos revealed practical difficulties that prevented an implementation with three of four sediments tested. In summary, an application of weatherfish embryos, using bioassays with sediment extracts from PHWE might increase the ecological relevance of sediment toxicity testing: it allows investigations using benthic and temperate fish species considering both bioavailable contaminants and animal welfare concerns. [ABSTRACT FROM AUTHOR]

Pressurized hot water extraction (PHWE) is a sustainable technique that represents an alternative to conventional extraction methods using organic solvents. It enables the recovery of bioactive compounds, such as phenolic compounds, proteins, and polysaccharides, among others, from different natural sources. Hence, the primary objective of this review is to offer a brief overview on the PHWE fundamentals, providing an up-to-date account of its applications in the recovery of bioactive compounds from 2019 to present. This review builds upon the previous works (Plaza and Turner (Trends in Analytical Chemistry 71 (2015) 39–57) and Plaza and Marina (Trends in Analytical Chemistry 116 (2019) 236–247)). Additionally, the review highlights the latest trends in PHWE, including its combination with other advanced extraction techniques as well as the use of natural deep eutectic solvents as modifiers, to enhance extraction yields. These advances aim to improve the efficiency and versatility of PHWE as an extraction technique. • Review of pressurized hot water extraction (PHWE) of bioactive compounds, 2019 to present. • Application of PHWE to obtain phenolics, proteins, and polysaccharides, among others. • Last trend in PHWE is its combination with natural deep eutectic solvents as modifiers. • PHWE combined with other advanced extraction techniques to improve extraction efficiency. [ABSTRACT FROM AUTHOR]

The search for useful compounds from plants is an important research area. Traditional screening that involves isolation and identification/quantitation is tedious, time consuming, and generates a significant amount of chemical waste. Here, we present a simple, fast, and green strategy to assess ≥0.1% wt/wt quantities of useful compounds in plants/spices using pressurized hot water extraction using a household espresso machine followed by chemical analysis using capillary electrophoresis. Three demonstrations with polygodial, cinnamaldehyde, coumarin, and shikimic acid as target metabolites are shown. Direct analysis of extracts was by the developed micellar electrokinetic chromatography and capillary zone electrophoresis methods. The approach, which can be implemented in less developed countries, can process many samples within a day, much faster than traditional techniques that would normally take at least a day. Finally, 0.8−1.1% wt/wt levels of shikimic acid were found in Tasmanian-pepperberry and Tasmanian-fuschia leaves via the approach.

Two green chemistry extraction systems, an in-house stainless-steel column Pressurized Hot Water Extraction system (PHWE) and a commercially available Espresso machine were applied for analysing 23 active pharmaceutical ingredients (APIs) in sewage sludge. Final analysis was performed on UPLC-MS/MS using two different chromatographic methods: acid and basic. When analysing all 23 APIs in sewage sludge both extraction methods showed good repeatability. The PHWE method allowed for a more complete extraction of APIs that were more tightly bound to the matrix, as exemplified by much higher concentrations of e.g., ketoconazole, citalopram and ciprofloxacin. In total, 19 out of 23 investigated APIs were quantified in sewage sludge, and with a few exceptions the PHWE method was more exhaustive. Mean absolute recoveries of 7 spiked labelled APIs were lower for the PHWE method than the Espresso method. Under acid chromatographic conditions mean recoveries were 16% and 24%, respectively, but increased to 24% and 37% under basic conditions. The difference between the PHWE method and the Espresso method might be interpreted as the Espresso method giving higher extraction efficiency; however, TIC scans of extracts revealed a much higher matrix co-extraction for the PHWE method. Attempts were made to correlate occurrence of compounds in sewage sludge with chemical properties of the 23 APIs and there are strong indications that both the number of aromatic rings and the presence of a positive charge is important for the sorption processes to sewage sludge.

In this work we have characterized a mild soda pulped birch ( betula pendula ) lignin after a novel pressurized hot water extraction pilot process. In the process hemicelluloses are first isolated from woods chips with hot water at oxygen-starved conditions, followed by mild alkali pulping at oxygen-starved conditions to remove lignin from the cellulose. Lignin was precipitated, washed and fractionated from the black liquor and characterized by quantitative 13 C NMR, 13 C DEPT experiments, 31 P NMR, 2D HSQC, FTIR, size exclusion chromatography (SEC), elemental analysis, pyrolysis-gas chromatography-mass spectrometry ( py -GC–MS), methoxyl group quantification and residual carbohydrate analysis after methanolysis. The structure was compared to a MWL of birch obtained from the same wood chips and the differences were an increase in phenolic hydroxyl groups, carboxylic groups, polydispersity index, and reduction of aliphatic hydroxyl groups. The process resulted in β-O-4 cleavage and condensation of the structure. This lignin is therefore suitable to be used in its polymeric form, rather than for degradation of the structure to small building blocks. [ABSTRACT FROM AUTHOR]

The investigation of high-value compounds found in plants has been of increasing interest in recent years. Elderberry is an example of such a plant and elderberry proteins, namely ribosome inactivating proteins, are an example of compounds of increased interest. In particular, elderberry branches are rich in these proteins. Since extraction is usually the first step involved in the analysis of plant bioactive compounds, this study investigates the feasibility of pressurized hot water extraction (PHWE) for the recovery of proteins from elderberry branches. The branches were extracted by PHWE at temperatures ranging from 40 to 100 °C. Other parameters influencing the effectiveness of the extraction process such as the size of the elderberry branches, extraction time, and number of extraction cycles were also investigated. The optimal conditions were found and the obtained results confirmed that the PHWE technique is an efficient way to extract proteins from biological material. [ABSTRACT FROM AUTHOR]

In this study, the solvent based extraction of artemisinin from Artemisia annua L. using acetone in percolation mode is compared to the method of pressurized hot water extraction. Both techniques are simulated by a physico-chemical process model. The model as well as the model parameter determination, including the thermal degradation of artemisinin are shown and discussed. For the conventional extraction, a solvent screening is performed considering various organic solvents. A temperature screening is presented for the systematic design of the pressurized hot water extraction. The best temperature with regards to thermal decomposition and high productivity was found to be 80 °C. Both, conventional percolation and Pressurized Hot Water Extraction (PHWE) are suitable for the extraction of artemisinin. The extraction curves show a high conformity with the simulation results. [ABSTRACT FROM AUTHOR]

The occurrence of pharmaceutically active compounds (PhACs) in the environment may pose a potential risk for humans and ecosystems. Wastewater treatment plants (WWTPs) are recognized as one of the main sources of these chemicals into both aquatic and terrestrial environments. The objectives of the study were to determine the presence of a wide variety of PhACs (n = 45) in sewage-impacted sediments and soils from the Guadalete River basin (SW Spain) by developing and applying an environmentally friendly multi-residue method based on pressurized hot water extraction (PHWE). Different parameters were optimized, including extraction temperature, pH, solvents, and clean-up. Extraction recoveries were analyte dependent, varying between 50% and 140% for most of the analytes when using pure water as extraction solvent at 100 °C. Determination of PhACs was performed by ultra-high performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS), enabling method detection (mLODs) and quantification (mLOQs) limits between <0.01 and 0.83 ng g −1 and from 0.02 to 2.75 ng g −1 , respectively. Regarding the sampling area, 14 out of 45 target compounds were detected in soils and sediments. Analgesic/anti-inflammatories was the therapeutic group most commonly detected, reaching concentrations up to 20 ng g −1 . [ABSTRACT FROM AUTHOR]

This study evaluates the feasibility of using sub-critical water extraction (SWE) processes to obtain antioxidant phenolic compounds from peanut skins. Theoretical models were tested against experimental data in order to optimize extraction conditions and antioxidant activity of target compounds. The maximum concentration of total phenolics was achieved by using 60.5% ethanol as co-solvent, at 220 °C extraction temperature and 7 g/min solvent flow. Under these extraction conditions, a large number and variety of polyphenols were identified. Phenolic profile was dominated largely by monomeric and condensed flavonoids, particularly procyanidin and proanthocyanidin oligomers. Extracts obtained under those conditions also gave the best radical scavenging capacities, which were higher to those reached by using a synthetic antioxidant (BHT, butylhydroxytoluene). Kinetic studies showed a high extraction rate of polyphenols until the first 30 min of extraction, and it was in parallel with the highest antioxidant activity. [ABSTRACT FROM AUTHOR]

Cocoa and cocoa products have broad and well-proven health benefits, most of which are associated with the high antioxidant capacity of cocoa flavonoids. Most extraction methods for flavonoids in cocoa products use several steps including a defatting step and large amount of organic solvents. Moreover, they are labor-intensive and time-consuming. In this work, a pressurized hot water extraction (PHWE) method has been compared to conventional sonication extraction (CSE) method. The contribution of individual compounds to the total antioxidant capacity of the extracts was evaluated by developing an analytical technique consisting of high-performance liquid chromatography (HPLC) with photodiode array coupled to electrochemical and to charged aerosol detectors and HPLC-mass spectrometry for the confirmation of the identity of compounds present. Additionally, procyanidins were analyzed by fluorescence detection. PHWE turned out to be more efficient in extracting phenolics and methylxanthines, as compared to the conventional method, in addition to being more 'green' in terms of using less organic solvents. [ABSTRACT FROM AUTHOR]

Pressurized hot water extraction (PHWE) was optimized for the determination of selected polyphenols (catechin, epicatechin, rutin, quercetin and chlorogenic acid) in Sambucus nigra L. branches. Pressure 15 MPa, temperature 100 °C and extraction time 1 × 5 min were found to be sufficient for the extraction of target polyphenols from the matrix. Chlorogenic acid and rutin were the most abundant substances, the highest contents of them were observed in December (922 mg·kg-1 for rutin and 108 mg·kg-1 for quercetin). [ABSTRACT FROM AUTHOR]

In this study, two strains of Kappaphycus alvarezii were treated with pressurized hot water extraction (PHWE) at conditions ranging from 150 °C/1 MPa to 300 °C/10 MPa using three different solvents including water, 1% formic acid, and 1% sodium hydroxide. Hydrolysates obtained from the extraction were investigated for their hydrolysis efficiency, pH, radical scavenging activity (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH)), total phenolic content (TPC), total flavonoid content (TFC), total sugar, reducing sugar, monosaccharide composition, Maillard reaction products (MRPs), total protein, emulsifying properties, and foaming properties. The highest hydrolysis efficiency ranged from 81.47 to 97.18% showing a consistent increase with increasing temperature and pressure conditions. Major monosaccharide compounds recovered from the hydrolysates were glucose and galactose with concentrations of 156.21 and 155.49 mg L, respectively. Radical scavenging activity, polyphenol content, and proteins increased from 150 °C/1 MPa to 270 °C/8 MPa but decreased at 300 °C/10 MPa due to decomposition and protein denaturation. Foaming and emulsifying properties were influenced by variation of protein with relation to temperature and protein-polysaccharide electrostatic interactions. Thus, this study showed that the best condition for all sugars and foaming properties is 150 °C/1 MPa, while antioxidants, TPC, TFC, total protein, and emulsifying properties are best recovered at 270 °C/8 MPa for both strains. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the potential of pressurized hot water extracted hemicellulose fractions from various wood species as feeds for ruminants. In Experiment 1, the fermentability of several hemicellulose extracts was screened using an in vitro gas production method. The samples were extracted from spruce (Picea abies) including mainly galactoglucomannan (GGM), from birch (Betula pendula) consisting mainly of xylan and from larch (Larix sibirica) consisting mainly of arabinogalactan. The GGM and xylan samples were readily fermented by rumen microbes while arabinogalactan was not. Based on the in vitro study, GGM was chosen for an in vivo digestibility trial using sheep, where it was fed at increasing proportions of diet dry matter (0, 47, 94 and 141 g kg-1) in a Latin Square design. The in vivo organic matter digestibility of GGM was relatively low, 0.58, but PHWE extracted hemicellulose has some potential as a feed for ruminants.

In this work we have analyzed the pine and spruce softwood lignin fraction recovered from a novel pressurized hot water extraction pilot process. The lignin structure was characterized using multiple NMR techniques and the thermal properties were analyzed using thermal gravimetric analysis. Acetylated and selectively methylated derivatives were prepared, and their structure and properties were analyzed and compared to the unmodified lignin. The lignin had relatively high molar weight and low PDI values and even less polydisperse fractions could be obtained by fractionation based on solubility in i-PrOH. Condensation, especially at the 5-position, was detected in this sulphur-free technical lignin, which had been enriched with carbon compared to the milled wood lignin (MWL) sample of the same wood chips. An increase in phenolic and carboxylic groups was also detected, which makes the lignin accessible to chemical modification. The lignin was determined to be thermally stable up to (273–302 °C) based on its Tdst 95% value. Due to the thermal stability, low polydispersity, and possibility to tailor its chemical properties by modification of its hydroxyl groups, possible application areas for the lignin could be in polymeric blends, composites or in resins.

In this study, five flavonoid glycosides were extracted from defatted Camellia oleifera seeds by using a pressurized hot water extraction (PHWE) method. The independent experimental factors (temperature, time and pressure) influencing the PHWE efficiency of the flavonoid glycosides were optimized and quantified using an orthogonal array design and high-performance liquid chromatography – negative mode electron spray ionization/mass spectrometry (HPLC/(−)ESI–MS-MS), respectively. Based on the result of experimental design, the maximum extraction efficiency of flavonoid glycosides were obtained by selecting temperature at 140 °C, pressure at 600 psi, and time for 10 min. The recovery and overall yield of the flavonoid glycosides were greater than those in ultrasonic extraction (UE) (78.5% vs 68.4% and 18.8 mg/g vs 15.91 mg/g). In particularly, compounds 1 and 2, which are kaempferol derivatives, were higher 1.19–1.23 times than those of the compounds obtained through UE (6.63 mg/g vs 5.56 mg/g; 11.89 mg/g vs 9.66 mg/g, respectively). These two compounds have higher polarities and antioxidant capacities than the other three flavonoid glycosides. Thus, PHWE is an excellent alternative method for the extraction of flavonoid glycosides that are highly polar and potent antioxidants. [ABSTRACT FROM AUTHOR]

A green platform based on a three-step downstream processing including the use of supercritical carbon dioxide (ScCO 2 ), carbon dioxide-expanded ethanol (CXE) and pressurized hot water (PHWE) extractions has been developed to obtain different fractions from Moringa oleifera leaves. Each process was optimized based on the extraction yield. Optimal extracts were functionally characterized by measuring total phenolic (TPC) and total flavonoid contents (TF). The antioxidant activity by TEAC assay was also tested. Moreover, a chemical characterization of the extracts was performed by GC–MS and HPLC–ESI–QTOF–MS. The extraction yields of the optimized process were 3.1, 29.5 and 30.2% respectively. The extraction of total phenolics was higher in PHWE than in CXE extract (62.4 vs. 20.3 mg GAE/g leaves) while TF showed the opposite (3.8 vs. 9.6 mg quercetin/g leaves respectively). ScCO 2 fraction was rich in fatty acids such as α-linoleic acid and alkanes. CXE fraction was richer in glycosylated flavonoids than PHWE while the latest fraction was richer in phenolic acids, which could explain the higher antioxidant activity of this fraction (13.4 mmol Eq trolox/100 g dry leaves) compared to CXE (6 mmol Eq trolox/100 g dry leaves). [ABSTRACT FROM AUTHOR]

This study investigates the influence of process conditions on pressurized hot water extraction (PHWE) to maximize the bioactive compounds, including total saponins (TS), total phenolic compounds (TP) and total antioxidants (TA), produced from ginseng by-product (GBP). Response surface methodology (RSM) was employed to study the influences of temperature [180–240 °C], pressure [15–45 bar], solid to liquid (S/L) ratio [0.04–0.09 g/mL], agitation speed [100–200 RPM], and reaction time [5–15 min]. Box-Behnken design (BBD) was used with five variables and three levels. The optimal conditions were 207 °C, 43.45 bar, S/L ratio of 0.04 g/mL, agitation speed of 199 RPM, and reaction time of 15 min. The obtained values of TS, TP and TA under these conditions were: 7.12 g Gin Re/100 g, 49.11 mg GAE/g, and 5.31 g TE/100 g, respectively. The optimized ginseng hydrolysate showed good antimicrobial and antihypertensive activities. Homogentisic and gentisic acid were the main phenolic compounds present in the ginseng hydrolysate. [ABSTRACT FROM AUTHOR]

Background: Pressurized hot water extraction (PHWE) technique has recently gain much attention for the extraction of biologically active compounds from plant tissues for analytical purposes, due to the limited use of organic solvents, its cost-effectiveness, ease-of-use and efficiency. An increase in temperature results in higher yields, however, issues with degradation of some metabolites (e.g. tartrate esters) when PHWE is conditioned at elevated temperatures has greatly limited its use. In this study, we considered possibilities of optimizing PHWE of some specific functional metabolites from Bidens pilosa using solvent compositions of 0, 20, 40 and 60 % methanol and a temperature profile of 50, 100 and 150 °C. Results: The extracts obtained were analyzed using UPLC-qTOF-MS/MS and the results showed that both temperature and solvent composition were critical for efficient recovery of target metabolites, i.e., dicaffeoylquinic acid (diCQA) and chicoric acid (CA), which are known to possess anti-HIV properties. It was also possible to extract different isomers (possibly cis-geometrical isomers) of these molecules. Significantly differential (p ≤ 0.05) recovery patterns corresponding to the extraction conditions were observed as recovery increased with increase in methanol composition as well as temperature. The major compounds recovered in descending order were 3,5-diCQA with relative peak intensity of 204.23 ± 3.16 extracted at 50 °C and 60 % methanol; chicoric acid (141.00 ± 3.55) at 50 °C and 60 % methanol; 4,5-diCQA (108.05 ± 4.76) at 150 °C and 0 % methanol; 3,4-diCQA (53.04 ± 13.49) at 150 °C and 0 % methanol; chicoric acid isomer (40.01 ± 1.14) at 150 °C and 20 % methanol; and cis-3,5-diCQA (12.07 ± 5.54) at 100 °C and 60 % methanol. Fitting the central composite design response surface model to our data generated models that fit the data well with R values ranging from 0.57 to 0.87. Accordingly, it was possible to observe on the response surface plots the effects of temperature and solvent composition on the recovery patterns of these metabolites as well as to establish the optimum extraction conditions. Furthermore, the pareto charts revealed that methanol composition had a stronger effect on extraction yield than temperature. Conclusion: Using methanol as a co-solvent resulted in significantly higher (p ≤ 0.05) even at temperatures as low as 50 °C, thus undermining the limitation of thermal degradation at higher temperatures during PHWE. [ABSTRACT FROM AUTHOR]