Pressurized Low Polarity Water Research Articles

Extraction simulation of porous media by CFD: Recovery of trans-resveratrol from grape cane by pressurised low polarity water system

A mathematical model of coupled momentum and mass transfer including thermal degradation of trans-resveratrol from grape cane powder was developed. The experimental results, which were used for model validation, were based on a solid-liquid extraction study which was previously conducted using a semi-continuous pressurized low-polarity water (PLPW) column extraction system. During extraction, the system is considered to work under isothermal and steady-state conditions regarding heat and momentum transfer. Verification of those assumptions is also obtained by the simulation of related time-dependent physics. The used mathematical models are based on macroscopic porous medium approach with volume averaged physical properties. The resulting equations were solved using Finite Element Method by COMSOL Multiphysics® version 5.3a. The model enables the prediction of the temperature distribution at pre-heating period, and concentration and degradation of trans-resveratrol in the column. The model can also simulate the changes in temperature and ratio of ethanol in the aqueous extraction solvent.

Antioxidant activity of polyphenols from Ontario grown onion varieties using pressurized low polarity water technology

Natural by-products, especially flavonoids, are in great demand in the nutra-pharmaceutical and biomedical industries. In this study, Ontario-grown onion varieties, namely Stanley, Safrane, Fortress, Lasalle and Ruby Ring, were screened for their antioxidant properties. Pressurized low polarity water technology, an environmentally friendly technique, was employed to extract the flavonoids from the onion varieties, followed by quantification and analysis using High Performance Liquid Chromatography. The antioxidant activities in the extracted samples were determined using various antioxidant assays, such as 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), ferric reducing ability of plasma, lipid peroxidation, total antioxidant capacity and oxygen radical absorbance capacity assays. The total phenolic content extracted from the Ruby Ring variety was the highest when compared to all the other yellow onion varieties tested. Our results indicate that Ruby Ring may be chosen as a preferred variety over other onion varieties to develop functional and health food products.

Comparison of Purity and Properties of Hydroxyl Carbonate Apatite Extracted from Natural Thigh Bone by Different Physiochemical Methods

New approaches to extracting natural hydroxyl carbonate apatite from bio waste of bovine bones cortical femur have been developed. To extract pure and natural bio ceramics, three different treatments have been applied: 1-Calcination heat treatment at temperature of 700 , 2-alkaline hydrothermal at temperature of 275 and 3-Pressurized low polarity water at temperature of 250 . Raw bovine bone and obtained apatite have been characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, differential thermal and thermal gravity analyzer and fluorescent microscopy and scanning electron microscopy. The results indicate that all the proposed processes have this ability to produce pure natural hydroxyl carbonate apatite from bio-waste bovine bones. In calcinations heat treatment process, mainly all the organic component such collagen was removed at temperature of 600 and a carbonate apatite was obtained. The presence of carbonate groups led to increasing the biocompatibility and will be preferable for orthopedic and medical usages. At The degree of crystallization of powders is increased by increasing of temperature from 250°C for pressurized low polarity water processing to 600°C for calcinations treatment. Growth behavior and adhesion of cultured umbilical cord mesenchymal stem cells on the surface of 2-D hydroxyapatite scaffolds derived by these three different methods have been investigated. The results show that the stem cells could survive and attach on surface of derived carbonated hydroxyapatite scaffolds and demonstrate no negative response.

Fractionation of flax shives with pressurized aqueous ethanol

Fractionation of flax shives into major biopolymer constituents, such as cellulose, hemicelluloses, and lignin, was carried out with pressurized aqueous ethanol in a pressurized low-polarity water extractor. The effect of processing parameters such as temperature, ethanol concentration, flow rate, sample size and solvent/feed ratio on the simultaneous extraction of hemicelluloses and lignin was determined. More than 80% of total hemicelluloses and ∼78% of total lignin were removed simultaneously in a single step under the following conditions: 180 °C, 30% (v/v) ethanol concentration, 3 mL/min flow rate, and 45 mL/g solvent/feed ratio. Under these extraction conditions, cellulose degradation was negligible. Further, the separation of lignin from hemicelluloses was carried out using two simple alternative methodologies based on precipitation. Since no acidic or alkali catalysts were used, the degradation of biopolymers was negligible and the oligomer/monomer ratio of sugars was 825:1. Characterization of fractionated biopolymers was carried out with scanning electron microscopy and a Fourier-transform infrared spectrometer (FT-IR). FT-IR spectra of isolated lignin and hemicelluloses showed that both polymers were comparable to commercially available products.

Production of Carbohydrates, Lignins, and Minor Components from Triticale Straw by Hydrothermal Treatment

The effects of temperature (116 °C, 150 °C, and 183 °C) and flow rate (66, 150, and 234 mL/min) on the fractionation of triticale straw into different products was determined using a flow-through pressurized low polarity water reactor. The greatest concentration of biomass was hydrolyzed and extracted in the first two of eight 600 mL fractions (1.2 L), after which dry matter yield decreased. Carbohydrate, lignin, acetyl group, and uronic acid yield increased with temperature, but there was no effect due to flow rate. Most dry matter extracted at 116 °C was probably associated with the extractives. Xylan yields decrease slightly at the highest flow rate due to a decrease in the residence time of the acids produced in situ. Carbohydrates were extracted mostly as oligosaccharides, and the highest processing temperature resulted in the production of furans from the xylose and arabinose in the liquid extracts.

Characteristics of Lignin from Flax Shives as Affected by Extraction Conditions

Lignin, a polyphenolic molecule, is a major constituent of flax shives. This polyphenolic molecular structure renders lignin a potential source of a variety of commercially viable products such as fine chemicals. This work compares the performance of different lignin isolation methods. Lignin from flax shive was isolated using both conventional alkaline extraction method and a novel experimental pressurized low polarity water (PLPW) extraction process. The lignin yields and chemical composition of the lignin fractions were determined. The conventional alkali treatment with 1.25 M NaOH, heated at 80 °C for 5 h, extracted 92 g lignin per kg flax shives, while lignin yields from the PLPW extracts ranged from 27 to 241 g lignin per kg flax shives. The purity and monomeric composition of the lignins obtained from the different extraction conditions was assessed via UV spectroscopy and alkaline nitrobenzene oxidation. Lignin obtained from conventional alkali treatment with 1.25 M NaOH, heated at 80 °C for 5 h was of low purity and exhibited the lowest yields of nitrobenzene oxidation products. With respect to alkali assisted PLPW extractions, temperature created an opposing effect on lignin yield and nitrobenzene oxidation products. More lignin was extracted as temperature increased, yet the yield of nitrobenzene oxidation products decreased. The low yield of nitrobenzene oxidation products may be attributed to either the formation of condensed structures or the selective dissolution of condensed structures of lignin during the pressurized alkaline high temperature treatment. Analytical pyrolysis, using pyroprobe GC-MS, was used to investigate the molecular composition of the lignin samples. The total yield of pyrolysis lignin products was 13.3, 64.7, and 30.5% for the 1.25 M NaOH extracted lignin, alkaline assisted PLPW extracted lignin, and the unprocessed flax shives, respectively. Key lignin derived compounds such as guaiacol, 4-vinyl guaiacol, 4-methyl guaiacol, syringol, eugenol, isoeugenol, catechol, homocatechol, and vanillin were detected in all of the samples.

Optimization of processing conditions for the fractionation of triticale straw using pressurized low polarity water

Pressurized low polarity water (PLPW) fractionation of triticale straw was optimized to maximize hemicellulose and lignin yield, and to produce a cellulose rich fraction for biofuels production. The optimum PLPW conditions for hemicellulose yield was determined to be 165 °C, with a flow rate of 115 mL/min, and a solvent-to-solid ratio of 60 mL/g. Hemicellulose and lignin yield generally increased with increasing temperature and solvent-to-solid ratio. There was a small decrease in hemicellulose yield with an increase in flow rate. Minimum lignin content of the triticale straw residue after extraction was predicted to occur at a processing condition of 206 °C, 160 mL/min, and 67 mL/g. PLPW was successful in removing 73-78% of the hemicellulose, leaving a cellulose rich fraction (65% glucose concentration). Lignin was equally distributed between the solid residues and the extracts and most of the hemicellulose was extracted in oligomer form. Remaining solid residues after fractionation were highly digestible by cellulase enzymes.

Kinetic Modeling of Hemicellulose Hydrolysis from Triticale Straw in a Pressurized Low Polarity Water Flow-Through Reactor

Two classic and one modified kinetic models were used to study the hydrolysis of triticale straw using pressurized low-polarity water (PLPW) in a flow-through reactor. Results indicated that for these experiments hemicellulose did not follow a biphasic reaction pathway. High yields of 72% were achieved at 170 °C, but these decreased to 60% at 150 °C and only 13% at 130 °C. The kinetics were controlled more by increases in temperature than flow rate in the reactor. Increases in flow rate reduced the overall hemicellulose yields but increased the portion extracted as oligomers. The kinetic rate constants when plotted as an Arrhenius-type temperature relationship displayed a dependency with flow rate. Curvature in the Arrhenius plots of the kinetic rate constants was due to differences in acetic acid formation with temperature. A modified monophasic kinetic model which incorporated reactor geometry and fluid flow was successful at modeling the yield of xylo-oligomers and monomers in PLPW.

Extraction of Bioactive Compounds from Milled Grape Canes (Vitis vinifera) Using a Pressurized Low-Polarity Water Extractor

Trans-resveratrol and trans-e-viniferin were extracted from milled grape canes using pressurized low-polarity water. The effects of temperature were significant for both compounds (p ≤ 0.05): extraction at 160 °C resulted in a 40% loss of trans-resveratrol compared to 95 °C while reduction of trans-e-viniferin at both temperatures remained at 30%. Increasing ethanol concentration from 0% to 25% increased the extraction of total phenolics and trans-e-viniferin by 44% and 489%, respectively. Solvent flow rate also influenced trans-e-viniferin extraction. Antioxidant activity showed a strong correlation with total phenolic content of the extracts, and the two target phenolic compounds. Except for the modifier concentration, the extraction parameters studied were not statistically significant with respect to the antioxidant activity of extracts (p > 0.05). Effective diffusivities of trans-resveratrol multiplied from 3.3 × 10−11 to 10.4 × 10−11 m2/s by three times with increasing temperature. The modified Gompertz equation satisfactorily explained the extraction of the stilbenes investigated.

Extraction and characterization of hemicelluloses from flax shives by different methods

Hemicelluloses were extracted from flax shives using pressurized low-polarity water (PLPW), pressurized aqueous ethanol (PAE), microwave-assisted water (MW-Water) or aqueous ethanol (MW-EtOH), and precipitated with ethanol. Hemicelluloses still remaining in solution were further separated using ultrafiltration. All samples were characterized with chemical analysis, ion-moderated partition chromatography (IMP), size exclusion chromatography (SEC), and Fourier transform infrared (FT-IR) spectroscopy. PLPW, PAE, MW-Water and MW-EtOH extracted 90, 80, 18, and 40% of the total hemicelluloses, respectively. The molecular weight of the ethanol-precipitated hemicelluloses ranged from approximately 11,000 to 40,000 Da and the ethanol-soluble low-molecular weight hemicelluloses were about 1700 Da. High-molecular weight hemicellulose isolated from PAE extracts contained ∼23% lignin, while that from the PLPW extracts contained ∼5% lignin. Low-molecular weight hemicelluloses separated by ultrafiltration from PLPW and PAE extracts contained similar amounts of lignin (∼20%). However, the yield of low-molecular weight hemicelluloses from PLPW was higher (∼15%) compared to that from PAE (∼6%). The FT-IR results revealed the specific band maximum at 1220 cm −1 and the bands between 1175 and 1000 cm −1 which are typical of xylans.

Extraction and Separation of Carbohydrates and Phenolic Compounds in Flax Shives with pH-Controlled Pressurized Low Polarity Water

A bench-scale pressurized low polarity water (PLPW) extractor was used for the extraction and separation of hemicellulose, cellulose, lignin, and other phenolic compounds in flax shives. In the first part of this research, the key PLPW extraction process variables of temperature, pH, and flow rate, were optimized using central composite design (CCD). Temperature and pH of water had a significant affect on the fractionation of carbohydrates (cellulose and hemicellulose), lignin, and other phenolics. The optimal extraction conditions for the separation of hemicellulose and lignin, determined by the optimization using CCD, were 170 degrees C, pH 3.0, and a flow rate of 2.5 mL/min. Under these extraction conditions, 39.3% of the initial biomass or feed, 70.1% of the hemicellulose, 35.3% of the lignin, and 5.3% of the cellulose were extracted from the flax shives. In order to improve the purity and yield of the cellulose, a two-stage PLPW extraction was examined. The first stage was designed to remove hemicellulose by water at 170 degrees C and the second stage was intended for delignification by a pH 12 buffer at 220 degrees C. The two-stage PLPW extraction effectively removed 63.2% of the feed, 97.3% of hemicellulose, and 86.3% of lignin, while solubilizing 23.9% of cellulose; resulting in a solid residue containing 0.7 g of hemicellulose, 3.5 g of lignin, and 27.3 g of cellulose/100 g of DFS. The PLPW extraction is able to extract and separate components in flax shives by changing pH and temperature. The best case occurs between pH 9.5 and 12, resulting in maximum solubilization of hemicellulose and lignin.

Effects of Pressurized Low Polarity Water Extraction Parameters on Antioxidant Properties and Composition of Cow Cockle Seed Extracts

Antioxidant activity of pressurized low polarity water (PLPW) extracts of cow cockle seed and extraction residues were determined using DPPH, ABTS, and FRAP assays. The effect of extraction conditions (temperature (125, 150 and 175 degrees C) and time) on the antioxidant activity and the relationship amongst the antioxidant activity and extract composition (total phenolics and saponin content) were determined. The antioxidant activity of PLPW extracts increased with extraction temperature. Increasing activity with time was also observed at 175 degrees C. PLPW extraction residues had the highest activity suggesting antioxidant compounds were not completely extracted by PLPW. Antioxidant activity correlated well with total phenolics content of samples (R2>or=0.94), however no correlation was observed with the saponin content. A strong correlation was observed between the antioxidant activity values obtained using different methods (R2>or=0.94). These results point to the potential of PLPW extraction as a method to modify the activity of biological materials for the production of customized extracts.

Mass transfer during pressurized low polarity water extraction of lignans from flaxseed meal

The feasibility of extracting lignans from flaxseed meal using pressurized low polarity water (PLPW) in a fixed bed extraction cell was evaluated. Optimization experiments were performed using surface response methodology for flow rate, bed depth and solvent to solid ratio (S/S). Maximum yield of lignan was obtained at flow rate of 0.6–2 mL/min, bed depth to internal diameter ratio (L/ID) of 20–25, and S/S ratio of 77–150 mL/g. The effect of flow rate and the mass transfer mechanisms governing the extraction of lignans from flaxseed meal was also evaluated. A diffusion model and a two site kinetic model were used to describe the extraction of lignans from flaxseed meal by PLPW. The two models gave similar quality of data fits. The diffusion model yielded diffusivities ranging from 2 × 10 −13 to 9 × 10 −13 m 2 s −1 for extraction of lignans at 180 °C, pH 9 and a 1:1.5 meal to co-packing material ratio.

Fractionation of Flax Shives by Water and Aqueous Ammonia Treatment in a Pressurized Low-Polarity Water Extractor

Fractionation of flax shives into cellulose, hemicellulose, and lignin with a two-stage extraction process using water and aqueous ammonia was carried out in a pressurized low-polarity water extractor operated at different temperatures, flow rates, and ammonia concentrations. During the first stage with water, 84% of hemicellulose and 32% of lignin were removed at 190 degrees C at a flow rate of 1.5 mL/min for 30 min. During the second stage with aqueous ammonia, more than 77% of the lignin was removed, and hemicellulose removal reached 95% at 200 degrees C at a flow rate of 0.5 mL/min and with a solvent/feed ratio of 40 mL/g. The temperature and flow rate had a significant effect on lignin removal. The impact of additives (anthraquinone and hydrogen peroxide) and modifications (overnight soaking, reduced particle size, and elevated temperature) on lignin extraction was also studied. The combination of higher temperatures and reduced particle sizes resulted in enhanced lignin extraction. The extraction profiles of free phenolics (vanillin, acetovanillone, and vanillic acid) during the two-stage processing were monitored and compared with those of lignin.

Mass Transfer during Pressurized Low-Polarity Water Extraction of Phenolics and Carbohydrates from Flax Shives

The effects of pH-buffered water and NaOH solution on pressurized low-polarity water (PLPW) extraction were investigated to determine the optimal conditions for the extraction of lignocellulosic co...

Extraction of lignans, proteins and carbohydrates from flaxseed meal with pressurized low polarity water

This study examined the application of pressurized low polarity water (PLPW) extraction of lignans, proteins and carbohydrates from defatted flaxseed meal. Key processing conditions included temperature (130, 160, 190 °C), solvent pH (4, 6.5 and 9), solvent to solid ratio (90, 150 and 210 mL/g) and introduction of co-packing material (0 and 3 g glass beads). The addition of 3 g glass beads increased the yields for all target compounds. The maximum yield of lignans (21 mg/g meal) was obtained at 170 °C with solvent to solid ratio of 100 mL/g meal at pH 9. Optimal conditions for protein extraction were pH 9, solvent to solid ratio of 210 mL/g meal and 160 °C. Total carbohydrates recovery was maximized at 215 mg/g meal (50% recovery) at pH 4 and 150 °C with solvent to solid ratio of 210 mL/g meal. The increase of temperature accelerated extraction, thus reducing solvent volume and time to reach equilibrium. For the extraction of proteins and carbohydrates, however, a temperature of 130–160 °C is recommended, as proteins and carbohydrates are vulnerable to thermal degradation.

Optimization of Extraction of Phenolic Compounds from Flax Shives by Pressurized Low-Polarity Water

Pressurized low-polarity water (PLPW) extraction of phenolic compounds from flax shive was investigated using statistically based optimization and the "one-factor-at-a-time" method. Extraction variables examined using central composite design (CCD) included temperature, flow rate, and NaOH concentration of the extracting water. Extraction of phenolic compounds including p-hydroxybenzaldehyde, vanillic acid, syringic acid, vanillin, acetovanillone, and feruric acid was affected by temperature and NaOH concentration; and extraction of all phenolic compounds, except ferulic acid, increased with temperature and NaOH concentration of the extracting water. Flow rate had little effect on concentration of phenolic compounds at equilibrium, but the extraction rate at the early phase was higher for higher flow rates. The mechanism of PLPW extraction of flax shive phenolics was also investigated using a two-site kinetic model and a thermodynamic model. To determine the extraction mechanism, flow rate was varied from 0.3 to 4.0 mL/min while temperature and NaOH concentration were fixed at 180 degrees C and 0.47 M, respectively. The flow rate tests showed the extraction rates of total phenolic (TP) compounds increased with flow rate and can be described by a thermodynamic model. The results from the thermodynamic model demonstrated that a K(D) value of 30 agreed with the experimental data in the flow rate range of 0.3-4.0 mL/min. When the effect of the three independent variables was evaluated simultaneously using CCD, a maximum TP concentration of 5.8 g/kg of dry flax shive (DFS) was predicted from the combination of a high temperature (230.5 degrees C), a high initial concentration of NaOH (0.63 M), and a low flow rate (0.7 mL/min). Maximum TP concentration of 5.7 g/kg of DFS was obtained from extraction conditions of 180 degrees C, 0.3 or 0.5 mL/min, and 0.47 M NaOH at equilibrium. A second-order regression model generated by CCD predicted a maximum TP concentration of 5.8 g/kg of DFS under the same extraction conditions, which is well matched with the results from experimental data.

Pressurized low polarity water extraction of saponins from cow cockle seed

Pressurized low polarity water (PLPW) extraction of cow cockle seed was carried out to determine the effect of extraction conditions (temperature (125–175 °C), time (15–180 min)), and sample pre-treatment on saponin yield and composition. Accelerated solvent extractions (ASE) and ultrasonic extractions (USE) using water, methanol and ethanol (50%, 80%, 100%) were also carried out to determine the effect of extraction solvent and method on saponin recovery. A higher saponin yield was obtained by ASE compared to USE using pure and aqueous ethanol and methanol. The highest saponin yield, which was obtained by ASE using 80% ethanol, was used to calculate saponin recoveries. The saponin yield of PLPW extracts increased with extraction temperature and time. While only 33.2 wt% of total saponins was extracted from ground seeds at 125 °C in 3 h, 60.2 wt% was recovered in the first 15 min at 175 °C. Total extraction (1 h) of whole seeds yielded more saponins than ground seeds at 125–160 °C. Saponin concentration of the extracts was affected by the extraction solvent and method, sample pre-treatment and to a lesser extent by the time and temperature of PLPW extraction. The highest saponin concentration of PLPW extract was obtained at 125 °C using whole seeds (12%). The saponin composition of water extracts differed from that of aqueous ethanol and methanol extracts.

Pressurized low polarity water extraction of lignans from whole flaxseed

The application of pressurized low polarity water (PLPW) extraction to the production of flaxseed lignans-rich products has been studied, and the key geometric and process conditions, including temperature, flow rate, and total volume have been determined and optimized. Maximum amounts of lignans and other flaxseed bioactive, including proteins were extracted at 160 °C and 5.2 MPa. However, on a dry weight basis the most concentrated extracts in terms of lignans and other phenolic compounds were obtained at 140 °C and 5.2 MPa. A flow rate of 0.5 mL/min was optimal for the extraction of lignans from flaxseed ( Linum usitatissimum L.) and a total volume of 30–40 mL/g of seed was required to maximize the recovery. Higher flow rates increased the rate of the extraction but required larger water volumes. Bed depth to ID ratios of 5–18 resulted in faster extraction and maximum recovery (90–95%) at water to seed ratios of 30–50 mL/g. Larger depth to ID ratios (15–18) would allow the use of lower solvent to solid ratios (14–20 mL/g) and would still result in yields of 84–90%.