Ultrasound-assisted Water Extraction Research Articles

Effects of alkaline and ultrasonication on duckweed (Wolffia arrhiza) protein extracts’ physicochemical and techno-functional properties

Wolffia is a protein-rich aquatic plant with the potential to help address food sustainability issues; however, a more efficient extraction process must be sought due to limited yield with conventional methods. This study aimed to investigate the effects of duckweed forms (fresh and dried), duckweed-to-aqueous solution ratio (DSR), as well as alkaline and ultrasonication extractions on yields, physicochemical and techno-functional properties of duckweed protein extracts (DPE). Three extraction methods were used: alkaline extraction (AE), ultrasound-assisted alkaline extraction (UAAE), and ultrasound-assisted water extraction (UAWE). The study showed fresh duckweed resulted in a 2.5-fold higher yield and protein recovery than oven-dried duckweed. UAE significantly enhanced extraction yield and protein recovery. The optimal extraction process was a DSR of 1:6 using UAAE at pH 8.5, resulting in a 16% yield and 34% protein recovery. Furthermore, the study found that UAE facilitated the extraction of non-polar/hydrophobic amino acids while AE proved to be efficient in extracting sulfur-containing amino acids. This study, for the first time, revealed the role of UAE and AE in promoting the extraction of different profiles of amino acids. The DPE produced using UAAE contained 65% protein, meeting the WHO/FAO/UNU recommended protein intake for preschool-aged children. Furthermore, the DPE exhibited excellent emulsifying properties and oil-holding capacity comparable to commercial soy protein isolates. Overall, UAAE was identified as a promising approach for producing techno-functional and nutritious protein ingredients from Wolffia. The resulting DPE proved to show great potential for functional plant-based food and feed applications.

Chemical Composition of Different Extracts from Echinacea purpurea (L.) Moench Roots and Evaluation of Their Antimicrobial Activity

This research aimed to reveal the chemical composition of different fractions obtained by sequential extraction of purple coneflower (Echinacea purpurea) roots and to evaluate the antimicrobial activity of some of them. Hexane, chloroform, ethyl acetate, and water were used as solvents to obtain the corresponding extracts. A GC-MS analysis was employed to reveal the chemical composition of hexane, chloroform, and ethyl acetate fractions. Conventional and ultrasound-assisted water extraction was performed to isolate inulin-type polysaccharides. Eighteen microorganisms were used for testing the antimicrobial activity of the obtained organic extracts. From GC-MS analysis more than forty compounds were detected in the fractions, including fatty acids, organic acids, fatty alcohols, sterols, and terpenes. Only in ethyl acetate extract were found mannitol and fructose isomers, while in chloroform extract were detected α- and β-amyrin, and betulin. Ethyl acetate fraction demonstrated the highest antimicrobial activity against 11 microorganisms (Bacillus cereus, B. amyloliquefaciens, Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritis, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Candida albicans, Saccharomices cerevisiae, and Peniclium sp.). The polysaccharide fractions were structurally characterized by FT-IR and NMR studies as linear inulin having β-(2→1)-linked Fru units and a T-Glc unit linked α-(1→2). Inulin from coneflower roots showed poor flowability, promising bulk and tapped density, swelling properties, and better oil-holding than water-holding capacity. This study demonstrated the potential of coneflower root fractions as a rich source of phytochemicals with antimicrobial activities and potential prebiotic activity due to inulin content (15% yield) and echinacea root as a useful biobased industrial crop/material.

Ultrasound-Assisted Water Extraction of Gentiopicroside, Isogentisin, and Polyphenols from Willow Gentian "Dust" Supported by Hydroxypropyl-β-Cyclodextrin as Cage Molecules.

The residue after sieving ("dust") from the willow gentian underground parts is an unexploited herbal tea by-product, although it contains valuable bioactive compounds. Cyclodextrins as efficient green co-solvents, cage molecules, and multifunctional excipients could improve the extraction and contribute to the added value of the resulting extracts. The objective of this study was to determine the optimal conditions for the extraction of gentiopicroside, isogentisin, and total phenolics (TPC) from willow gentian "dust" using ultrasound-assisted water extraction coupled with hydroxypropyl-β-cyclodextrin (HPβCD). The influence of extraction temperature (X1: 20-80 °C), time (X2: 20-50 min), and HPβCD concentration (X3: 2-4% w/v) was analyzed employing the response surface methodology (RSM). The optimal extraction conditions for simultaneously maximizing the extraction yield of all monitored responses were X1: 74.89 °C, X2: 32.57 min, and X3: 3.01% w/v. The experimentally obtained response values under these conditions (46.96 mg/g DW for gentiopicroside, 0.51 mg/g DW for isogentisin, and 12.99 mg GAE/g DW for TPC) were in close agreement with those predicted, thus confirming the suitability and good predictive accuracy of the developed RSM models. Overall, the developed extraction system could be an applicable alternative strategy to improve the extraction of bioactive compounds from the underutilized "dust" of willow gentian underground parts.

Turnip peel extract as green corrosion bio-inhibitor for copper in 3.5% NaCl solution

In this study, for the first time, we report turnip peel extract (TPE) as an eco-friendly, inexpensive vegetable waste and green bio-inhibitor for copper corrosion in 3.5 wt% NaCl solution. Ultrasound-assisted water extraction was used to prepare the TPE, and this method allows us to naturally and directly use this substance as a green inhibitor in corrosive media. GC-MS analysis was utilized to detect the main chemical compounds of TPE. EIS tests and potentiodynamic polarization techniques were used to determine the resistance of copper against corrosion in 3.5 wt% NaCl solution. SEM-EDS analysis was utilized to analyze the surface morphology and elemental identification of the copper surface. It was found that by the increment of the amount of TPE, the inhibition efficiency (IE) increased, the maximum IE was almost 92% which is promising. Also, the inhibition efficiency of TPE was studied in different corrosive solution temperatures (298–338 K) that showed the increment of temperature, reduces the inhibition efficiency, although IE is almost 64% at 338 K which is acceptable. The adsorption mechanism of TPE molecules on the copper surface is considered as physical adsorption due to the positive value of ΔH and adsorption isotherm which was matched with the Langmuir isotherm model.

Sequential Extraction of Hydroxytyrosol, Mannitol and Triterpenic Acids Using a Green Optimized Procedure Based on Ultrasound.

Olive-derived biomasses contain bioactive compounds with health promoting effects as well as antioxidant and sweet-tasting properties. However, their sequential extraction has not been attained. In the present study, firstly antioxidants and mannitol were extracted from exhausted olive pomace (EOP) by an eco-friendly method, ultrasound-assisted water extraction (UAWE). The amplitude (20–80%), extraction time (2–18 min) and solid loading (2–15%, w/v) were evaluated according to a Box–Behnken experimental design. Using the response surface methodology, the optimal conditions for extraction were obtained: 80% amplitude, 11.5% solid loading and 16 min. It enabled the multi-response optimization of the total phenolic content (TPC) (40.04 mg/g EOP), hydroxytyrosol content (6.42 mg/g EOP), mannitol content (50.92 mg/g EOP) and antioxidant activity (ferric reducing power or FRAP, 50.95 mg/g EOP; ABTS, 100.64 mg/g EOP). Moreover, the phenolic profile of the extracts was determined by liquid chromatography-UV and mass spectrometry, identifying hydroxytyrosol as the main phenolic compound and other minor derivatives could be characterized. Scanning electron microscopy was used to analyze the morphological changes produced in the cellular structure of EOP after UAWE. In addition, the chemical composition of the extracted EOP solid was characterized for further valorization. Then, a second extraction step was performed in order to extract bioactive triterpenes from the latter solid. The triterpenes content in the extract was determined and the effect of the previous UAWE step on the triterpenes extraction was evaluated. In this case, the use of ultrasound enhanced the extraction of maslinic acid and oleanolic acid from pelletized EOP with no milling requirement. Overall, UAWE can be applied to obtain antioxidant compounds and mannitol as first extraction step from pelletized EOP while supporting the subsequent recovery of triterpenic acids.

Influence of ultrasound and extraction conditions on the intensity of extraction of anthocyanin pigment from berry raw materials

The effect of ultrasound and extraction conditions on the degree of anthocyanin pigment extraction from berry raw materials has been studied. It has been shown that the use of ultrasound for extraction allows increasing the anthocyanin pigment yield. The ultrasound-assisted water extraction at 25°C for 30 minutes increases the yield of pigment in aqueous solution by 22 %. The increase in the ultrasound-assisted extraction temperature to 65°C reduces the extraction time down to 15 minutes. It has been shown that the use of ultrasound reduces the extraction degree in 96 % ethanol and in the ethanol/water/hydrochloric acid system and increases the amount of anthocyanin pigment into the solution containing water as an extraction agent. In this case, the use of the ultrasound-assisted extraction reduces the anthocyanin pigment extraction time to 20 minutes with the use of the 96 % ethanol as an extraction agent, and to 15 minutes in an aqueous solution. The study of the ultrasound-assisted extraction effect, as well as the frequency and power of ultrasonic vibrations on the anthocyanin pigment extraction intensity has shown that the indirect ultrasound-assisted extraction (ultrasonic bath) with the ultrasound exposure frequency of 35 kHz and the power of 80 W allows allocating the anthocyanin pigment to the fullest extent possible within 30 minutes. With the direct ultrasound exposure (ultrasonic homogenizer) with the frequency of 20 kHz and the power of 75 W, the extraction time with an aqueous solution is reduced to 15 minutes, and with 96 % ethanol - to 20 minutes.

Ultrasound-Assisted Water Extraction of Mastocarpus stellatus Carrageenan with Adequate Mechanical and Antiproliferative Properties.

Ultrasound-assisted water extraction was optimized to recover gelling biopolymers and antioxidant compounds from Mastocarpus stellatus. A set of experiments following a Box–Behnken design was proposed to study the influence of extraction time, solid liquid ratio, and ultrasound amplitude on the yield, sulfate content, and thermo-rheological properties (viscoelasticity and gelling temperature) of the carrageenan fraction, as well as the composition (protein and phenolic content) and antiradical capacity of the soluble extracts. Operating at 80 °C and 80 kHz, the models predicted a compromise optimum extraction conditions at ~35 min, solid liquid ratio of ~2 g/100 g, and ultrasound amplitude of ~79%. Under these conditions, 40.3% carrageenan yield was attained and this product presented 46% sulfate and good mechanical properties, a viscoelastic modulus of 741.4 Pa, with the lowest gelling temperatures of 39.4 °C. The carrageenans also exhibited promising antiproliferative properties on selected human cancer cellular lines, A-549, A-2780, HeLa 229, and HT-29 with EC50 under 51.9 μg/mL. The dried soluble extract contained 20.4 mg protein/g, 11.3 mg gallic acid eq/g, and the antiradical potency was equivalent to 59 mg Trolox/g.

Optimization of Aqueous Extraction Conditions of Inulin from the Arctium lappa L. Roots Using Ultrasonic Irradiation Frequency

Ultrasound-assisted extraction is a promising technique to obtain active compounds from plants with high efficiency. The present study was conducted in two sections. In the first phase, the effect of solvent type (methanol, ethanol, water, and water-ethanol (50 : 50, v/v)) on inulin extraction yield from burdock roots (Arctium lappa L.) was investigated by the conventional method. The second phase aim was to optimize the condition of inulin and phenolic compounds including sonication time (10–40 min), sonication temperature (40–70°C), and solid/solvent ratio (1 : 20–1:40 g/ml) using response surface methodology (RSM). The results demonstrated that the highest inulin efficiency was extracted by water in the conventional method, which is equal to 10.32%. The optimum conditions of ultrasound-assisted water extraction for independent variables including sonication time and temperature as well as solid/water ratio were 36.65 min, 55.48°C, and 1 : 35 g/ml, respectively, which were determined on the maximization of inulin and total phenol content and minimization of IC50. At this optimum condition, inulin yield, phenolic compounds, and IC50 were found to be 12.46%, 18.85 mg GA/g DW, and 549.85 µg/ml, respectively. Regarding the results of this research, ultrasound-assisted extraction can be used as an alternative to the conventional extraction methods in extracting bioactive compounds from medicinal plants because it may improve the mass transfer, reducing the extraction time and the solvent used.

Preparation, characterization, and antibacterial properties of “green” synthesis of Ag nanoparticles and AgNPs/kaolin composite

The present work describes "green" method of silver nanoparticles (AgNPs) synthesis using an aqueous extract of grape pomace (GPE)as a reducing and capping agent and preparation of Ag-NPs/kaolin composite. The grape pomace extract (GPE) was prepared by the ultrasound-assisted water extraction with subsequent oxidation by oxygen purge and characterized by liquid chromatography–mass spectroscopy (LC–MS), total phenolic (TPC) and total flavonoid contents (TFC). AgNPs were characterized by UV–vis spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX). The prepared GPE– AgNPs/Kaolin composite contained 1.26% of silver nanoparticles as was estimated using SEM and EDX techniques. The GPE– AgNPs/Kaolin composite exhibited an antimicrobial activity on the growth of Escherichia coli and Bacillus subtilis.

Valorization of Food Waste to Produce Eco-Friendly Means of Corrosion Protection and “Green” Synthesis of Nanoparticles

Agrifood by-products are a key element within Europe’s sustainable strategies. Valorization and reuse of zero-waste technologies are becoming more popular, and they are commonly named as “second-generation food waste management.” The present study is directed to the valuable extracts of “green” organic compounds from the by-products of fruit and berry/vegetable crops, which can be revalorized in sustainable chemical technology and engineering, namely, in the production of “green” synthesis of nanoparticles and for the inhibition of corrosion and scaling of metals in corrosive media. Numerous types of agrifood by-products (rapeseed pomace, sugar beet pulp, fodder radish cake, grape pomace, and pomegranate peels) were investigated. The waste extracts for corrosion and scale inhibitors of mild steel in tap water were prepared by the conventional extraction method that uses 2-propanol and characterized by gas chromatography-mass spectroscopy (GC-MS). Inhibition of scaling and corrosion was investigated in thermal scaling conditions on the surface of the electrode manufactured from mild steel. The LPR technique was applied to measure the corrosion rate, and the scaling rate was determined gravimetrically. The extracts were found to inhibit the corrosion rate 2-3 times, while only radish cake extract inhibited both the corrosion and scaling rates. The waste extracts to produce nanoparticles were prepared by the ultrasound-assisted water extraction with subsequent oxidation by oxygen purge and characterized by liquid chromatography-mass spectroscopy (LC-MS). The aqueous grape pomace and pomegranate peel extracts were screened for total phenolic content (TPC) and total flavonoid content (TFC). The reduction capacity of the extracts was assessed using ferric reducing power (FRAP) and phosphomolybdenum (PM) assays. AgNPs were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The particle size of AgNPs ranged between 40 and 50 nm. The antimicrobial activity of AgNPs was tested against Escherichia coli using the agar diffusion method and optical density.

Effect of Pterocladia capillacea Seaweed Extracts on Growth Parameters and Biochemical Constituents of Jew’s Mallow

We performed field experiments to evaluate the influence of two extraction treatments, seaweed (Pterocladia capillacea S.G. Gmelin) water extraction (WE) and ultrasound-assisted water extraction (USWE) at three concentrations (5%, 10%, and 15%), as well as control NPK traditional mineral fertilizer on the growth, yield, minerals, and antioxidants of Jew’s Mallow (Corchorus olitorius L.) during the two seasons of 2016 and 2017 in Egypt. Plant height, number of leaves, and fresh weight of WE10 treatment were the highest (p < 0.05) as 59.67 cm, 10.67 and 2.41 kg m−2 in 2016, respectively, and 57.33 cm, 11.00 and 2.32 kg m−2 in 2017, respectively. WE10 and USWE5 treatments produced the highest dry matter (17.07%) in 2016 and (16.97%) in 2017, respectively. WE10 plants had an increased water productivity of 41.2% relative to control plants in both seasons. The highest chlorophyll ‘a’ was recorded after the WE10 treatment in 2016 and 2017 (17.79 μg g−1 and 17.84 μg g−1, respectively). The highest levels of total antioxidant capacity, total phenolics, and total flavonoids were also recorded after the WE10 treatment. Application of WE10 boosted growth, yield, minerals, and antioxidants of Jew’s Mallow. The CROPWAT model was used to estimate the evapotranspiration, irrigation water requirements, and yield response to irrigation scheduling. Our data showed a yield reduction in the initial growth stage if a limited amount of water was provided. Therefore, irrigation water should be provided during the most important stages of crop development with the choice of effective irrigation practices to avoid water losses, as this helps to maximize yield.

Optimization of ultrasound‐assisted water extraction conditions for the extraction of phenolic compounds from black mulberry leaves (Morus nigra L.)

AbstractMultiple response optimizations of ultrasound‐assisted water extraction (UAWE) conditions for the extraction of phenolic compounds from Morus nigra L. leaves were investigated. The experimental design and optimization of the UAWE were performed using response surface methodology (RSM) coupled with a central composite design (CCD). The optimum conditions of UAWE were determined as extraction time: 15 min, solvent:solid ratio: 85 mL/g and extraction temperature: 55°C. The optimized UAWE was compared with conventional extraction (CE) and it was observed that TPC (21.78 ± 0.50 mg GAE/g dw), TFC (11.70 ± 0.26 mg CAT/g dw), and TAA (66.37 ± 0.66% 1,1‐diphenyl‐2‐picrylhydrazyl [DPPH]) in UAWE were higher than CE. The polyphenolic profile of the extracts obtained from both methods was evaluated and most of the 16 phenolic compounds especially chlorogenic acid (3.47 ± 0.06 mg/g dw), kaempferol (1.39 ± 0.02 mg/g dw) and quarcetin hydrate (1.92 ± 0.01 mg/g dw) were found in higher amounts in UAWE extracts.Practical applicationsBlack mulberry leaf extract, which is an important source for antioxidants and especially phenolic compounds, has a potential to become a supplement and functional food. Herbal infusion or tea prepared from black mulberry leaves can be an alternative to mostly consumed tea. The extraction and purification of natural antioxidant substances from plant sources make it possible to use these substances in the food industry. It is therefore important to optimize the extraction conditions of natural antioxidants and identify the substances in the extracts obtained. In this study, UAWE for high extraction yield at low temperature was also preferred to extract high quantities of phenolic compounds, which are heat sensitive. UAWE for phenolic extraction from black mulberry leaves was optimized by RSM. The optimized and improved extraction technique obtained from this study can contribute to the food industry by being used in large‐scale industrial applications.

Optimization of Ultrasound-Assisted Extraction of Anthocyanins and Phenolic Compounds from Black Soybeans (Glycine max L.)

Black soybeans have been reported to contain high antioxidant content, including anthocyanins. Ultrasound-assisted water extraction of antioxidants from Korean black soybeans (Glycine max [L.] Merr. Cheongja4ho) was investigated for the first time. A three-level, three-factor Box-Behnken design using a response surface methodology (RSM) was employed to optimize the conditions for the maximum yields of three dependent variables, including total anthocyanin content, total phenol content, and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, based on 17 different experiments. The solid-liquid ratio (X1, 1/30–1/50 g mL−1), extraction time (X2, 1–9 min), and amplitude (X3, 20–100%) significantly affected three dependent variables. The optimized conditions were solid-liquid ratio of 49.1 g mL−1, extraction time of 8.59 min, and amplitude of 81.4%. At the optimum point, the total anthocyanin content, total phenol content, and ABTS•+ scavenging activity were 66.44, 940.96, and 242.45 mg 100 g−1. The difference (%) between the predicted and experimental values was less than 6.40%, indicating that the model fits well. The conditions optimized for ultrasound-assisted water extraction of antioxidants from black soybeans can be applied as an efficient technique for extracting anthocyanins in plants on a larger scale.

Optimization of ultrasound-assisted water extraction of flavonoids from Psidium guajava leaves by response surface analysis

Psidium guajava leaves are rich in health-promoting flavonoids compounds. For better utilization of the resource, the ultrasound-assisted aqueous extraction was investigated using Box-Behnken design under response surface methodology. A high coefficient of determination (R2 = 97.8%) indicated good agreement between the experimental and predicted values of flavonoids yield. The optimal extraction parameters to obtain the highest total flavonoids yield were ultrasonic power of 407.41 W, extraction time of 35.15 min, and extraction temperature of 72.69 °C. The average extraction rate of flavonoids could reach 5.12% under the optimum conditions. Besides, HPLC analysis and field emission scanning electron microscopy indicated that the ultrasonic treatment did not change the main component of flavonoids during extraction process and the higher flavonoids content was attributed by the disruption of the cell walls of guava particles. Thus, the extraction method could be applied successfully for large-scale extraction of total flavonoids from guava leaves.

Structure and radio‐protective effects of sulfated Auricularia auricula polysaccharides

Radiation-protective effects of sulfated polysaccharides (SNAAP80) from Auricularia auricular were studied. Crude polysaccharides were extracted using ultrasound-assisted water extraction. Bioactive polysaccharide fragments were screened using ethanol precipitation with an in vitro antioxidant activity test. The chlorosulfonic acid-dimethylformamide method was used to obtain the sulfated polysaccharide. Monosaccharide composition and molecular weight were determined using GC-MS and HPLC-GPC, respectively. IR, UV, and SEM were used for structural characterization. The antiradiation effect of SNAAP80 was studied using a 60Co-γ radiation model in mice. The results showed that the SNAAP80, with a degree of substitution of 0.514, was composed of glucose and mannose. A bioactivity analysis showed that the SNAAP80 increased the organ indexes, phagocytosis index, stimulation index, and the superoxide dismutase, glutathione peroxidase, catalase, and lactate dehydrogenase activity. The SNAAP80 decreased TBARS, IL-2, IL-12, INF-γ, protein carbonyls, creatinine, and blood urea nitrogen. The results suggested that SNAAP80 had an effective radiation-protective effect. Practical applications Auricularia auricula is a commonly cultivated commercial mushroom in East Asia; it is also called “wood ear” in China and “black fungus” in Russia. Many published studies regarding polysaccharides from A. auricula have shown their beneficial health effects for both humans and animals. A. auricula is acknowledged for its pharmaceutical effects such as inhibiting lipid peroxidation, decreasing liver damage, hypolipidemic properties and so on. Functional activity of polysaccharides is related to their solubility. The activities of polysaccharide NAAP80 from A. auricular were restricted because of its poor solubility. Therefore, it was modified by chlorosulphonic acid-N,N dimethylformamide to obtain SNAAP80 which has a significantly higher solubility. Antiradiation effect of SNAAP80 has been studied in this paper, and its potential application in antiradiation may be relevant to space exploration, the military, daily health care, and therapeutic medications.

Static, Kinetic, and Isotherm Adsorption Performances of Macroporous Adsorbent Resins for Recovery and Enrichment of Bioactive Procyanidins from Cranberry Pomace.

This study examined the ability of five Amberlite resins coupled with ultrasound-assisted water extraction for the recovery and enrichment of bioactive procyanidins and total phenolics from cranberry pomace. Static adsorption showed that XAD-7HP had the highest adsorption capacity for procyanidins (52.2mg/g resin) and total phenolics (99.1mg/g resin) whereas XAD-761 had the lowest. Adsorption of procyanidins fitted better to pseudo-second-order kinetics than pseudo-first-order kinetics. Isotherm adsorption on XAD-7HP suggested that Langmuir isotherm was a better model to describe the adsorption of procyanidins while Kemkin-Pyzhev equation was better for total phenolics based on higher coefficient of determinations (R2 ). Dynamic tests on XAD-7HP suggested that the flow rate of 7 and 8 mL/min were the optimum conditions for adsorption and desorption of procyanidins, respectively. Measurements using HPLC revealed that adsorption increased the contents of procyanidins and total phenolics by 4.57- and 4.73-folds, respectively, compared to the initial extracts. This research showed that Amberlite XAD-7HP resin adsorption coupled with ultrasound-assisted water extraction is an efficient method to separate and concentrate procyanidins from cranberry pomace.

Detection of over 100 selenium metabolites in selenized yeast by liquid chromatography electrospray time-of-flight mass spectrometry.

The characterization of the selenometabolome of Selenized(Se)-yeast, that is the fraction of water soluble low-molecular weight Se-metabolites produced in Se-yeast is of paramount interest to expand the knowledge on the composition of this food supplement. In this work, we have applied liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS) to search for Se-species from the low molecular weight range fraction of the selenized yeast used for food supplements. Prior to LC-TOFMS, sample treatment consisted of ultrasound assisted water extraction followed by size exclusion fractionation assisted with off-line inductively coupled plasma mass spectrometry detection of isotope 82Se. The fraction corresponding to low-molecular weight species was subjected to LC-TOFMS using electrospray ionization in the positive ion mode. The detection of the suspected selenized species has been based on the information obtained from accurate mass measurements of both the protonated molecules and fragments from in-source CID fragmentation; along with the characteristic isotope pattern exhibited by the presence of Se. The approach enables the detection of 103 selenized species, most of them not previously reported, in the range from ca. 300-650Da. Besides the detection of selenium species, related sulphur derivate metabolites were detected based on the accurate mass shift due to the substitution of sulphur and selenium.

Simultaneous ultrasound-assisted water extraction and β-cyclodextrin encapsulation of polyphenols from Mangifera indica stem bark in counteracting TNFα-induced endothelial dysfunction

This study proposes an alternative technique to prevent heat degradation induced by classic procedures of bioactive compound extraction, comparing classical maceration/decoction in hot water of polyphenols from Mango (Mangifera indica L.) (MI) with ultrasound-assisted extraction (UAE) in a water solution of β-cyclodextrin (β-CD) at room temperature and testing their biological activity on TNFα-induced endothelial dysfunction. Both extracts counteracted TNFα effects on EAhy926 cells, down-modulating interleukin-6, interleukin-8, cyclooxygenase-2 and intracellular adhesion molecule-1, while increasing endothelial nitric oxide synthase levels. β-CD extract showed higher efficacy in improving endothelial function. These effects were abolished after pre-treatment with the oestrogen receptor inhibitor ICI1182,780. Moreover, the β-CD extract induced Akt activation and completely abolished the TNFα-induced p38MAPK phosphorylation. UAE and β-CD encapsulation provide an efficient extraction protocol that increases polyphenol bioavailability. Polyphenols from MI play a protective role on endothelial cells and may be further considered as oestrogen-like molecules with vascular protective properties.

Polyphenol extraction and characterization of Justicia secunda Vahl leaves for traditional medicinal uses

Water extracts of Justicia secunda leaves are used by village communities in southern countries to prepare traditional medicines at home. The beverage is usually obtained by boiling the plant in water. On a pilot plant scale, water extracts were processed using an extraction–concentration procedure achieved in a three-step process, including ultrasound-assisted water extraction followed by cross-flow microfiltration of the crude extract and its concentration by reverse osmosis. As the processing conditions were milder than for homemade preparations, the extract obtained was enriched in natural leaf flavonoids. At each step of the pilot plant process, the co-products obtained were analyzed for total polyphenol and total flavonoid contents by the UV–vis spectrophotometric method. The process allowed a better leaf water-extraction of polyphenol compounds than the homemade extraction. The crude extract was concentrated 28 times (v/v) at room temperature by membrane volume reduction, and the total content of polyphenol compounds of the concentrated extract was 17 times higher than those of the crude extract. Individual polyphenol compounds were characterized by HPLC-DAD analysis at λmax=325nm. Additional structure characterization was carried out for the two major flavonoid compounds found (65% of total HPLC-DAD peak area of the flavones-type compounds) in the water extracts by tandem mass spectrometry (LC–ESI-MS2) and by nuclear magnetic resonance (1H NMR, 13C NMR). They were identified as luteolin 7-O-[β-glucopyranosyl-(1→2)-β-rhamnosyl-(1→6)] β-glucopyranoside and luteolin 7-O-[β-apiofuranosyl-(1→2)]-β-xylopyranoside.

Lab and pilot-scale ultrasound-assisted water extraction of polyphenols from apple pomace

Apple pomace, a residue from juice or cider production, shows high content of exploitable polyphenols. In this work, apple pomace was submitted to an Ultrasound-Assisted Extraction (UAE) in order to produce extracts rich in antioxidants. After a preliminary study, a solid/liquid ratio of 150mg of dry material per mL was used, and optimized conditions obtained by response surface methodology for polyphenols water-extraction were 40°C, 40min and 0.764W/cm2. A comparison showed Total Phenolics Content (TPC) obtained by UAE was 30% higher than the content obtained by Conventional Extraction (CE)(555 and 420mg of catechin equivalent per 100g of dry weight, respectively) and both methods presented the same extraction kinetics. Furthermore, extracts obtained by ultrasound showed higher antioxidant activity, which was confirmed by HPLC analysis, that revealed main polyphenols were not degraded under the applied conditions. The large scale experiments of this ultrasound procedure showed a potential industrial application.