Min Extraction Time Research Articles

Modelling and optimization of polyphenol and antioxidant extraction from Rumex hastatus by green glycerol-water solvent according to response surface methodology

Rumex hastatus (RH) is an edible wild herb abundantly distributed in many parts of the world. With the increasing realization of the environmental threats corresponding to the use of conventional organic solvents, the realization to explore efficient green solvents for the extraction of valuable natural products from plants is increasing. The present project, therefore, aimed to discover an optimized efficient and green process for obtaining antioxidant phytochemicals from R. hastatus using aqueous glycerol as a green and low-cost extraction medium. For modelling and optimization according to RSM (response surface methodology), the independent factors were glycerol concentration, temperature and time, and the responses included TPC (total phenolic content), TFC (total flavonoid content), and anti-radical activity (ARA) and iron chelating activity (ICA). The predicted optimum conditions were 52.155% glycerol concentration, 41.303 min extraction time and 50 °C extraction temperature with the predicted values for TPC, TFC, ARA and ICA as 21.65 mg GA/g DW, 95.78 mg RE/g DW, 84.93% and 46.47%, respectively. For responses, well-fitted quadratic models were suggested. Thus, aqueous glycerol is an efficient, green, and cost-effective solvent and its around 50% solution can effectively be used as an extracting medium for antioxidants from R. hastatus. The discovered model should be viable for large scale extraction of bioactive compounds from this plant.

Optimization of ultrasonic-assisted extraction of phenolic compounds and antioxidant activities From Pistacia atlantica Desf. galls using response surface methodology

In the present study, the response surface methodology (RSM) using Box-Behnken design (BBD) was employed to optimize conditions for the extraction of phenolic compounds from Pistacia atlantica Desf. leaf galls. Three variables were evaluated at three levels (15 experimental runs): the extraction time (40 min, 45 min, and 50 min), the solid-to-liquid ratio (1:10 g/ml, 1: 20 g/ml, and 1:30 g/ml) and temperature (40 °C, 50 °C, and 60 °C). According to the three-dimensional response surface, the optimum extraction phenolic compounds were found at 40 min extraction time, 1:20 g/ml solid-liquid ratio, and 60 °C extraction temperature. In these conditions, the content of TPC, TFC, CTC, and antioxidant activity (DPPH and iron chelation) were 139.88 mg GAE/g DW, 2.43 mg QE/g DW, 121.32 mg CE/g DW, 65.94 mg AAE/g DW, and 501.38 mg TE/g DW, respectively. The results indicate an agreement between the prediction values and experimental ones, which points the success of the optimization. Moreover, they indicate that P. atlantica galls produce a high amount of antioxidants and antiradicals under optimized conditions determined by RSM. Actually, the used method is a simple, reliable one that serves as an alternative to various other extraction techniques.

Supercritical Carbon Dioxide Extraction of Nicotiana tabacum Leaves: Optimization of Extraction Yield and Nicotine Content

The employment of supercritical carbon dioxide extraction for obtaining the chemical compounds from N. tabacum leaves, especially nicotine, is advancing. The supercritical carbon dioxide extraction of dried N. tabacum cv. Samsun and N. tabacum cv. Virginia at different process parameters was performed to obtain the highest extraction yield and nicotine relative amount. The optimal extraction conditions concerning the highest extraction yield and nicotine relative amount were determined by response surface methodology. The highest extraction yield for N. tabacum cv. Samsun was 2.99% and for N. tabacum cv. Virginia 2.33% at 23.41 MPa, 50 °C and 90 min of extraction time. The highest nicotine relative amount in N. tabacum cv. Samsun and N. tabacum cv. Virginia was at 15 MPa, 50 °C and 90 min extraction time and was 242.1 mg per 100 g of plant material and 32.4 mg per 100 g of plant material, respectively. The pressure, temperature and time influenced the extraction yield and nicotine relative amount recovery in N. tabacum cv. Samsun and N. tabacum cv. Virginia. A general inclusive concept in respect to pressure, temperature and time of the supercritical carbon dioxide extraction and a report on phytochemicals present in two N. tabacum varieties is presented.

High-Yield Recovery of Antioxidant Compounds from Bambusa chungii Culms Using Pressurized Hot Water Extraction.

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.

Unraveling the relationship between conditions of ultrasonic-assisted extraction of chia mucilage and viscosity.

The application of chia mucilage still remains restricted due to the difficulty in achieving high extraction yields. The effect of ultrasonic-assisted extraction (UAE) conditions (temperature, seed:water ratio and time) on the rheological properties of chia mucilage extracts and the relation to the proportion of translucent phase (TP) and opaque phase (OP) of the mucilage in the extract were evaluated. UAE allowed the efficient extraction of chia mucilage from chia seeds. The desired overall optimal combination to maximize both yield and apparent viscosity was achieved at a seed:water ratio 1:10, a temperature of 25.3 °C and 53.7 min extraction time; the optimal conditions to obtain the maximum yield and minimum apparent viscosity were a seed:water ratio close to 1:20, temperature of 48.8 °C and 208.4 min extraction time. The results obtained in the present work demonstrated that the differences in rheological properties of chia mucilage extracts are due to the extraction methods used. Therefore, it is possible to modulate the extraction conditions in order to obtain different characteristics of the mucilage, maintaining a high extraction yield. © 2022 Society of Chemical Industry.

Effects of Different Deproteinization Methods on the Antioxidant Activity of Polysaccharides from Flos Sophorae Immaturus Obtained by Ultrasonic Microwave Synergistic Extraction

Flos Sophorae Immaturus (FSI) serves as one of the Chinese medicinal herbs of homologous provenance, whose polysaccharides constitute part of the active compounds that exert their pharmacological properties. Single-factor and response surface methodology were employed to investigate optimal extraction conditions for the ultrasonic-microwave synergistic extraction (UMSE) of polysaccharides from FSI (PFSI), which were deproteinized by Sevage, papain, and trichloroacetic acid methods, and the antioxidant potential of PFSI by contrasting deproteinization methods based on free-radical scavenging capacity. The optimum conditions for UMSE extraction of PFSI were 500 W microwave power, 265.887 W ultrasonic power, 20.078 min extraction time, and 94.995:1 liquid-to-material ratio. Meanwhile, the sequence of the single factors on the yield of polysaccharides indicated that microwave power > extraction time > D liquid to material ratio > B ultrasonic power, and that the obtained average value of polysaccharide yield was 37.05%, which was analogous to the predicted value of 37.17%, indicating that the optimization method was reasonable. In vitro, the antioxidant assay demonstrated that PFSI, with or without deproteinization, had a definite capability to scavenge oxidative free radicals. This research provides a theoretical basis for the industrial production of PFSI as a natural antioxidant, and a scientific basis for its industrial development.

Polyethylene glycol assisted mechanical amorphous dispersion using water for the extraction of hydrophobic anthraquinones from aloe

In this study, a rapid, environmental, economical, and practical method, polyethylene glycol (PEG) assisted mechanical amorphous dispersion using water for the extraction of hydrophobic anthraquinones in crops was first proposed. In order to fully understand the factors affecting the extraction yield, a systematic study was carried out by single factor tests and response surface methodology (RSM). The corresponding influence parameters including the type of dispersant, the amount of dispersant, grinding time, extraction time, and solid-liquid ratio were optimized. Subsequently, RSM was used for multifactor experiments and the optimum conditions were 242.67 mg of PEG 100000, 4.91 min of grinding time, 4.60 min of extraction time, and 10 mL of water, respectively. To verify the feasibility of this method, the solution extracted was then analyzed by high performance liquid chromatography/quadrupole-time of flight mass spectrometry. The results showed that this method had good linearity (R2 higher than 0.99), stable intra-day precision, and inter-day precision with relative standard deviations ranging from 0.04 to 2.07% and 0.22–3.00%, satisfactory reproducibility of 0.02–6.23% for all analytes. Finally, this method was successfully used for the extraction and analysis of anthraquinones from aloe.

Antioxidant and antidiabetic activities of a polyphenol rich extract obtained from Abelmoschus esculentus (okra) seeds using optimized conditions in microwave-assisted extraction (MAE).

Functional foods have gained popularity in recent decades. They are exploited for their bioactive compounds like polyphenols, which are highly demanded in cosmetic, pharmaceutical and nutraceutical industries. However, extractive techniques and conditions used up to recently are almost obsolete and must be optimized for higher efficiency. The current study aimed to evaluate the antidiabetic potential of an optimized extract of Abelmoschus esculentus (okra) seeds. The optimal conditions for extracting polyphenolic compounds from okra seeds were determined using Microwave Assisted Extraction (MAE). A Face Center Composite Design (FCCD) was used for optimization. Solvent/dry matter ratio, wavelength and time were considered while the response studied was the polyphenolic content. The extract obtained at optimal conditions was characterized using Thin Layer Chromatography (TLC) and Fourier Transform Infra-Red (FTIR) spectroscopy, then tested for its antioxidant, alpha amylase inhibitory and antidiabetic activities. Response Surface Methodology (RSM) permitted the determination of the optimal conditions for phenols extraction as: microwave power 330 W, with a solvent ratio of 97.04/1 mL/g for 9.5 min of extraction time. The optimized extract showed a phenolic content up to 86.37 ± 1.13 mg GAE/g containing quercetin and catechin as revealed by the TLC. Functional groups characteristic of polyphenols were identified on FTIR spectra, and the extract exhibited good in vitro antioxidant capacities with DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging capacity and FRAP (Ferric Reducing Antioxidant Power Assay). An IC50 of 3.99 ± 0.15 μg/mL was obtained with the DPPH scavenging test. Alpha amylase inhibitory assay revealed that the optimized okra extract behaved as a non-competitive inhibitor of porcine pancreatic amylase with an IC50 of 484.17 ± 2.33 μg/mL. Antidiabetic activity of the extract was observed in streptozotocin-induced diabetic males Wistar rats, as shown by the fasting blood glucose levels, food intake, changes in body weight and serum lipid profile among others.

Switchable-hydrophilicity solvent liquid-liquid microextraction combined with smartphone digital image colorimetry for the determination of palladium in catalytic converters.

Switchable-hydrophilicity solvent liquid-liquid microextractionwas coupled with smartphone digital image colorimetry for the determination of palladium as its metal chelate with N,N-diethyl-N'-benzoylthiourea. Images of the colored extract were captured in a homemade colorimetric box, which were split into their red-green-blue channels. The blue channel was used to determine the concentration of palladium. Optimum extraction conditions were achieved using 600 μL of triethylamine as the extraction solvent and 4.0mL of 10M sodium hydroxide as the hydrophilicity-switching trigger within 1.0min extraction time. Optimum complexation conditions were obtained at a sample pH of 4.50, andmetal/ligand mole ratio of 1:2 within 3.0min. Optimum detection conditions were achieved at a distance of 7.0cm between the sample solution and the detection camera, a region of interest of 175.0 px2 at a detection wavelength of 480.0nm and 30.0% brightness of the monochromatic light source. Limits of detection and quantitation were found to be less than 0.7 and 1.8µgg-1, respectively. A good linearity with coefficients of determination above 0.9974 was obtained. Accuracy was checked via a single-factor analysis of variance (ANOVA) test by comparing the results with the ones obtained using flame-atomic absorption spectrometry and the results were statistically in a good agreement (P > 0.05). The proposed method was applied for the determination of palladium in catalytic converters with percentage relative recoveries ranging between 95.7 and 103.7% and percentage relative standard deviations below 4.0%.

An efficiency strategy for cobalt recovery from simulated wastewater by biphasic system with polyethylene glycol and ammonium sulfate

Today, biphasic aqueous systems have received more attention than conventional separation methods due to their advantages, such as biocompatibility, low cost, and easy operation. The extraction of cobalt ions from the aqueous phase with the absence and the presence of other ions was investigated using polyethylene glycol, and ammonium sulfate salt without using an extractant. The efficiency was evaluated using operating parameters such as aqueous pH, salt and polymer concentrations, phase volume ratio, and initial metal concentration. The higher temperature, and the lower aqueous pH showed a maximum transfer rate for cobalt ions into the PEG1000 phase. Extraction efficiency under optimal conditions equal to 50% (w/w) polyethylene glycol 1000, 4 M ammonium sulfate, aqueous pH = 2, and 15 min extraction time was over 98%. Results from infrared spectroscopy, and thermo-gravimetric analysis illustrated the presence of the PEG-cobalt ion complex. The observation demonstrated that the biphasic system is the proper technology for wastewater purification.

Rapid and Sensitive Determination of Polycyclic Aromatic Hydrocarbons in Green Tea Samples by Dispersive Liquid-Liquid Microextraction Coupled to High-Performance Liquid Chromatography-Diode Array Detection

A rapid and sensitive dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of selected polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene (PHE) and fluoranthene (FLA) in green tea beverage samples. The extracted PAHs were separated and determined by using high-performance liquid chromatography diode array detection (HPLC-DAD). An experimental design using response surface methodology (RSM) and central composite design (CCD) was performed to evaluate the interactive effects of the 2 most significant parameters, namely extraction time and sample pH. The optimal conditions were sample pH of 6.5 with 1.25 min extraction time. The analysis of variance (ANOVA) showed that the most influential parameter was the extraction time. The predicted values were obtained in good agreement with the actual value (R2 ≥ 0.9086). Under the optimal extraction conditions, the method demonstrated acceptable linearity (R2 ≥ 0.9996) over a concentration range (10 - 1,000 µg L−1) for different PAHs. The limits of detection and quantifications were in the range of (4 - 10 µg L−1) and (18 - 50 µg L−1), respectively. Good analytes recovery (102 - 110 %) and excellent precision level with relative standard deviations (RSD %, n = 3) were obtained between 1.53 and 4.52 %. The method was successfully applied to the analysis of spiked green tea beverage samples. The proposed method is rapid, reliable, sensitive, and environmentally friendly for the detection of PAHs.
 HIGHLIGHTS
 
 A more efficient sample preparation method is required to measure interferences and enrich target analysis of PAHs residues in green tea, as existing methods are time-consuming, significant tendency to form emulsions, consume large volumes of solvents, and involve disposal of toxic or flammable chemicals
 Dispersive liquid-liquid microextraction (DLLME) method coupled with a high-performance liquid chromatography diode array detector (HPLC-DAD) was developed for the analysis of selective PAHs, namely fluoranthene (FLA) and phenanthrene (PHE) in green tea beverage samples
 RSM optimized DLLME parameters based on CCD, and the optimal conditions used during the analysis of PHE and FLA in the green tea samples extracted the non-polar PHE and FLA with good sensitivity. The procedure was simple, rapid, sensitive, and minimized the consumption of organic solvent
 
 GRAPHICAL ABSTRACT

Optimization of Microwave-Assisted Pectin Extraction from Cocoa Pod Husk.

Optimization of pectin extraction from cocoa pod husk was carried out to examine independent variables that affect the quality of pectin obtained and determine the best conditions for the extraction process. In this study, three independent variables thought to contribute to microwave-assisted pectin extraction were used, namely, extraction time (20, 25, and 30 min), microwave power (180, 300, and 450 W), and citric acid concentration (2.5%, 5%, and 10%). Response surface methodology was applied using central composite design (CCD) to examine the effect of independent variables on the parameter measured. Among the seven parameters measured, namely, yield, temperature, moisture content, ash content, equivalent weight, methoxyl content, and galacturonic acid content, the statistical analysis test showed that the model equations that were suitable for predicting response values were temperature, moisture content, and ash content. Therefore, the optimization of conditions was only reviewed for these three parameters. Optimization results concluded that the factors that had the most significant effect on temperature, moisture content, and ash content were extraction time and microwave power. Optimal conditions for pectin extraction were at 30 min extraction time, 450 W microwave power, and 10% solvent concentration, resulting in a temperature of 104 °C, moisture content of 6%, and ash content of 8%. Other parameter values measured under these conditions were a yield of 21.10%, equivalent weight of 602.40 mg/mol, methoxyl content of 6.07%, and galacturonic acid content of 72.86%. Pectin extracted from cocoa pod husk using this method has the potential to be further applied, especially in the food and pharmaceutical industries.

Optimization of Accelerated Solvent Extraction of Ginsenosides from Cultivated Wild Ginseng Using Response Surface Methodology.

This study’s aim is to apply response surface methodology (RSM) to model and optimize the accelerated solvent extraction (ASE) technique for extracting the sum of ginsenosides (Rg1, Rb1, and Rg3) and total ginsenosides from cultivated wild ginseng. To extract ginsenosides from cultivated wild ginseng, a new ASE-based method, combined with RSM modeling and optimization, was developed. The RSM method, which was based on a five-level, three-factor central composite design, was used to obtain the optimal combination of extraction conditions. Briefly, the optimal extraction conditions for the sum of ginsenosides (Rg1, Rb1, and Rg3) and total ginsenoside were as follows: 88.64% ethanol for each extraction solvent, 105.98°C and 129.66°C of extraction temperature, 28.77 and 15.92 min of extraction time, extraction pressure of 1,500 psi, nitrogen purge of 60 s, flush volume of 60%, and one extraction cycle. A 3D response surface plot and contour plot derived from the mathematical models were applied to obtain the optimal conditions. Under the above conditions, the experimental extraction yields of the sum of ginsenosides (Rg1, Rb1, and Rg3) and total ginsenoside content were 7.45 and 32.82 mg/g, respectively, which closely agrees with the model’s prediction values.

Extraction of phenolics and anthocyanins from purple eggplant peels by multi-frequency ultrasound: Effects of different extraction factors and optimization using uniform design

In this work, multi-frequency ultrasound (working modes for the single-, dual- and tri-frequency in simultaneous ways) was applied to extract bioactive compounds from purple eggplant peels. The single-factor experiments were performed by varying six independent variables. A six-level-five-factor uniform design (UD) was further employed to evaluate the interaction effects between different factors. It was found that extraction temperature and extraction time significantly affected the total phenolic content (TPC), whereas the total monomeric anthocyanins (TMA) was mainly influenced by ethanol concentration, extraction temperature and solid-liquid ratio. Based on partial least-squares (PLS) regression analysis, the optimal conditions for TPC extraction were: 53.6 % ethanol concentration, 0.336 mm particle size, 44.5 °C extraction temperature, 35.2 min extraction time, 1:43 g/mL solid-liquid ratio, and similar optimal conditions were also obtained for TMA. Furthermore, the TPC and TMA extraction were investigated by ultrasound in different frequencies and power levels. Compared with single-frequency (40 kHz) and dual-frequency ultrasound (25 + 40 kHz), the extraction yield of TPC and TMA with tri-frequency ultrasound (25 + 40 + 70 kHz) increased by 23.65 % and 18.76 % respectively, which suggested the use of multi-frequency ultrasound, especially tri-frequency ultrasound, is an efficient strategy to improve the TPC and TMA extracts in purple eggplant peels.

Comparison of Alliin Recovery from Allium sativum L. Using Soxhlet Extraction and Subcritical Water Extraction

Garlic (Allium sativum L.) is an herbaceous plant and is recognised for its numerous medicinal and culinary properties, and it is used in diverse food preparations for its characteristic flavour and aroma. High alliin content increases the formation of allicin, a bioactive compound of garlic. Therefore, this research aimed to compare different extraction methods for garlic (Allium sativum L.) between subcritical water extraction (SWE) and Soxhlet extraction to obtain a high extraction yield and alliin content. The SWE conditions were 120 °C and 180 °C temperatures and 2 mL/min and 6 mL/min flow rates at a constant pressure of 15 MPa for a 10 min extraction time, respectively. In the meanwhile, the extraction time for Soxhlet extraction with various solvents, namely, distilled water, ethanol–water (1:1), and 100% ethanol, was two hours. High-performance liquid chromatography (HPLC) was used to analyse alliin. Soxhlet extraction had the best yield (1.96 g) using ethanol–water (1:1) as the solvent in comparison to SWE extraction (1.28 g) at 180 °C and 6 mL/min. In contrast, SWE yielded a greater concentration of alliin (136.82 mg/g) at 120 °C and 2 mL/min than the Soxhlet method when using distilled water as the solvent (65.18 mg/g). Therefore, SWE may replace Soxhlet extraction as the conventional method for extracting alliin from garlic at a high concentration, and SWE has advantages that favour garlic extracts.

Potential of sodium dodecyl sulfate micellar solutions as eluents in magnetic dispersive micro-solid phase extraction with polydopamine-coated magnetite nanoparticles. Application to antidepressant drugs

In this paper, the potential of micellar solutions of the anionic surfactant sodium dodecyl sulfate (SDS) as eluents in dispersive micro-solid phase extraction (D-μSPE) using polydopamine-coated magnetite nanoparticles (Fe3O4@PDA NPs) for the extraction and preconcentration of seven basic drugs (bupropion, citalopram, fluoxetine, mianserin, nomifensine, trimipramine, and viloxazine) is explored for the first time (to the best to our knowledge) and compared with conventional hydro-organic eluents. The impact of the sample solution pH, Fe3O4@PDA NPs and PDA coating amounts and extraction time on the extraction efficiency (EE), as well as the composition of the eluent on the overall efficiency (OE) are studied. Under the selected experimental conditions (50 mg of Fe3O4@PDA NPs, 100 μL of 1 M NH3, 5 min of extraction time and 0.15 M SDS at pH 2.6 as eluent), EE and OE values were higher than 90% for all compounds and for the most hydrophobic compounds (trimipramine, fluoxetine and mianserin), respectively. The results shown in this paper demonstrate the suitability of Fe3O4@PDA NPs as a sorbent for the extraction of antidepressants as well as the advantages of using SDS micellar solutions over classic hydro-organic eluents containing methanol, acetonitrile or tetrahydrofuran. Finally, the stability and reusability of the Fe3O4@PDA NPs is proven.

Development of solid-state fermentation process of spent coffee grounds for the differentiated obtaining of chlorogenic, quinic, and caffeic acids.

Spent coffee grounds (SCGs) are a good source of chlorogenic acid (CGA), which can be hydrolyzed to quinic acid (QA) and caffeic acid (CA). These molecules have antioxidant and neuroprotective capacities, benefiting human health. The hydrolysis of CGA can be done by biotechnological processes, such as solid-state fermentation (SSF). This work evaluated the use of SSF with Aspergillus sp. for the joint release of the three molecules from SCGs. Hydroalcoholic extraction of the total phenolic compounds (TPCs) from SCGs was optimized, obtaining 28.9 ± 1.97 g gallic acid equivalent (GAE) kg-1 SCGs using 0.67 L ethanol per 1L, a 1:9 solid/liquid ratio, and a 63 min extraction time. Subsequently, SSF was performed for 30 days, achieving the maximum yields for CGA, QA, and TPCs on the 16th day: 7.12 ± 0.01 g kg-1 , 4.68 ± 0.11 g kg-1 , and 54.96 ± 0.49 g GAE kg-1 respectively. CA reached its maximum value on the 23rd day, at 4.94 ± 0.04 g kg-1 . The maximum antioxidant capacity was 635.7 mmol Trolox equivalents kg-1 on the 14th day. Compared with unfermented SCGs extracts, TPCs and CGA increase their maximum values 2.3-fold, 18.6-fold for CA, 14.2 for QA, and 6.4-fold for antioxidant capacity. Additionally, different extracts' profiles were obtained throughout the SSF process, allowing us to adjust the type of enriched extract to be produced based on the SSF time. SSF represents an alternative to produce extracts with different compositions and, consequently, different antioxidant capacities, which is a potentially attractive fermentation process for different applications. © 2022 Society of Chemical Industry.

Ultrasound assisted cyanotoxin extraction for nematode inhibition in soil

Root-knot nematodes are one of the plant damaging nematodes in agriculture causing a projected annual yield loss of ∼12 % (∼$160 billion) worldwide. Conventional solutions to control these plant-parasitic nematodes involve chemical nematicides. To reduce the use of harmful chemicals, microalgal extracts can be used as greener alternatives for nematode management. Microalgae produce valuable metabolites, including cyanotoxins which can aid in nematode suppression.In this study, two microalgae species, Trichormus variabilis and Nostoc punctiforme, were treated with ultrasound for intensified recovery of secondary metabolites. Ultrasound results in cell wall disruption of the microalgal species, thus resulting in enhanced release of secondary metabolites. Microalgal biomass was treated with an ultrasound probe at 50 % amplitude, 20 kHz frequency, using water as the extraction medium, for 5–30 min. The extraction efficiency was determined in terms of the total chlorophyll (Chl) content of the extract. Microscopic images of the treated cells were also investigated to gain insight into the effect of the ultrasonication time on the cell morphology. Our results suggest that ultrasonication resulted in the intensified release of secondary metabolites, as established through the total chlorophyll content of the ultrasonicated microalgal samples as well as the microscopic images of the ruptured cells. The best extraction for Trichormus variabilis was achieved with 15 min extraction time where the Total Chl content increased by 29 times (compared to the non-ultrasonicated sample), and for the Nostoc punctiforme, 30 min extraction time gave the highest metabolite recovery of 6.4 times higher than the non-ultrasonicated sample.Ultrasonicated algal extracts were then tested for their nematicidal potential against root-knot nematode, Meloidogyne hapla, in infested field soil samples. Experimental study was conducted using different concentrations of each microalga, Trichormus sp. and Nostoc sp., individually, as well as in combination. The nematode count for the treated soil was compared with that of the control (untreated soil). Ultrasonicated microalgal extracts showed 66% to 100% inhibition on root-knot nematodes in the soil samples tested.

The Separation of Chlorobenzene Compounds from Environmental Water Using a Magnetic Molecularly Imprinted Chitosan Membrane.

In this work, a magnetic molecularly imprinted chitosan membrane (MMICM) was synthesized for the extraction of chlorobenzene compounds in environmental water using the membrane separation method. The optimal extraction amount for chlorobenzene (9.64 mg·L−1) was found to be a 1:2 solid to liquid ratio, with a 20 min extraction time and 35 °C extraction temperature. This method proved to be successfully applied for the separation and trace quantification of chlorobenzene compounds in environmental water, with the limit of detection (LOD) (0.0016–0.057 ng·L−1), limit of quantification (LOQ) (0.0026–0.098 ng·L−1), and the recoveries ranging (89.02–106.97%).

Ultrasound‐assisted alkaline extraction of proteins in several algae and their nutritional characteristics

SummaryUltrasound‐assisted alkaline extraction (UAAE) and the nutritional quality of proteins from five algae (Arthrospira platensis, Cladophora glomerata, Porphyra tenera, Laminaria japonica and Undaria pinnatifida) were investigated. The UAAE of the A. platensis protein using a 60% amplitude level and 30 min extraction time provided the highest protein yield (81.86%) and altered the surface of A. platensis. Amino acid profiles revealed that lysine and branched‐chain amino acids (BCAAs) were dominant in most algal proteins. The C. glomerata protein had the highest digestibility (94.09%) and protein digestibility‐corrected amino acid scores for the BCAAs. The L. japonica protein demonstrated a rich source of aspartic and glutamic acids, giving an umami taste. The algal proteins contained low contents of carbohydrates (3.87–44.83 mg glucose equivalents g−1) and nucleic acids (0.60–8.57 mg g−1), while total phenolics were 6.13–70.13 mg gallic acid equivalents g−1. Algal proteins could be a good ingredient in developing vegan and vegetarian foods.