Search Results (81)

This study evaluates how different purification methods influence the antioxidant properties of polyphenol-rich berry pomace extracts, taking into account both the source of the pomace and the purification strategy used. The extracts were obtained from raspberry, blackberry, strawberry, and wild strawberry pomaces derived from the production of unclarified juices and purées. The extracts were analyzed in three states: crude (CEX), purified using Amberlite XAD 1600N adsorbent resin (XAD), and purified via size-exclusion chromatography (SEC) on a gel filtration resin. Ellagitannins, flavanols, and anthocyanins were determined using HPLC-DAD-FD methods. Antioxidant properties were determined based on: total antioxidant compounds, DPPH radical scavenging activity, and Fe³⁺ ion reduction power. Purification significantly enhanced the concentration of antioxidant compounds, which increased 2-fold with the XAD method and more than 3-fold using SEC. The extracts exhibited strong DPPH radical scavenging activity, ranging from 65% to 90% for raspberry and blackberry extracts and from 34% to 95% for strawberry and wild strawberry extracts, depending on the degree of purification. Similarly, Fe³⁺-reducing power increased 2- to 6-fold in extracts purified using XAD and SEC compared to crude extracts. Purification via size-exclusion chromatography enabled the separation of tannin-rich and anthocyanin-rich extract fractions. Ellagitannins were the main class of polyphenols contributing to the enhanced antioxidant potential. Anthocyanins contributed significantly to antioxidant activity only in the case of blackberry extracts. Full article

Background: Pomegranate peel (Punica granatum L.) is a rich source of phenols, particularly ellagitannins, highlighting punicalagin, a bioactive compound with recognized antioxidant potential. However, efficient recovery and purification methods are required to enable its application in food and health-related products. This study aimed to obtain a partially purified fraction of punicalagin from pomegranate peel using optimized extraction and purification strategies. Methods: A Taguchi L9 (3)³ experimental design was employed to optimize ultrasound-assisted extraction, evaluating extraction time (10, 20, 30 min), ethanol concentration (20, 40, 80%), and solid-to-solvent ratio (1:12, 1:14, 1:16). Total polyphenol content was quantified using the Folin–Ciocalteu method. Extracts obtained under optimized conditions were concentrated by rotary evaporation and subjected to semipurification using flash chromatography with Amberlite XAD-16 resin. Subsequently, the fractions were lyophilized and analyzed by HPLC/ESI/MS. Results: The Statistica software determined the optimal conditions for polyphenol extraction (20 min, 40% ethanol, 1:12), with the signal-to-noise (S/N) ratio reaching 88.43 ± 0.66, surpassing the predicted value of 77.42. Flash chromatography yielded four fractions, and HPLC/ESI/MS analysis revealed the presence of ellagitannins in all of them, with fraction number 2 showing the highest relative abundance of punicalagin (89.25%). Conclusions: The combination of ultrasound-assisted extraction and flash chromatography proved effective for obtaining punicalagin-rich fractions from pomegranate peel, supporting its potential for nutraceutical applications. Full article

Developing highly efficient and cost-effective immobilized biocatalysts is essential for optimizing diacylglycerol (DAG) production via biotransformation of natural oil. To address this, the 1,3-regiospecific MAS1-H108W lipase, derived from marine Streptomyces sp. strain W007, was produced through high-density fermentation (20 °C, pH 7.0, 132 h). This lipase was immobilized by XAD1180 resin adsorption, yielding an immobilized MAS1-H108W lipase with a lipase activity of 4943.5 U/g and a protein loading of 201.5 mg/g under selected conditions (lipase/support ratio 100 mg/g, initial buffer pH of 8.0). After immobilization, the lipase maintained its optimal temperature at 70 °C and shifted its optimal pH from 7.0 to 8.0, along with enhanced thermostability. The immobilized MAS1-H108W lipase demonstrated superior efficiency in DAG synthesis compared to non-regiospecific immobilized MAS1 lipase and commercial lipases (Novozym 435 and Lipozyme RM IM). Under the optimized reaction conditions (reaction temperature 60 °C, olive oil/glycerol molar ratio 1:2, adding amount of immobilized MAS1-H108W lipase 1.0 wt.%), a maximum DAG content of 49.3% was achieved within 4 h. The immobilized lipase also exhibited excellent operational stability, retaining 81.9% of its initial production capacity after 10 reuse cycles. Furthermore, in the glycerolysis of various vegetable oils (corn oil, rapeseed oil, peanut oil, sunflower oil, and soybean oil), the DAG content catalyzed by immobilized MAS1-H108W lipase consistently exceeded 48%. This work provides a highly efficient and economical immobilized biocatalyst for DAG production, and highlights the significant potential of regioselective lipases in promoting efficient DAG synthesis via glycerolysis. Full article

Aryl diazonium salt chemistry offers a robust and versatile approach for the modification of material surfaces via the covalent immobilization of reactive functional groups under mild conditions. In this study, this strategy was successfully applied to graft the chelating agent 4-(2-pyridylazo)resorcinol (PAR) onto Amberlite XAD-4 resin. Initially, 4-nitrobenzenediazonium tetrafluoroborate (NBDT) was covalently anchored onto the resin surface using hypophosphorous acid as a reducing catalyst to introduce aryl nitro groups. These nitro groups were subsequently reduced to aniline functionalities, enabling diazo coupling with PAR. The successful modification of the resin was confirmed by ATR-FTIR spectroscopy, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The synthesized chelating resin exhibited sorption capacities of 0.152, 0.167, and 0.172 mM g⁻¹ for Co(II), Ni(II), and Cu(II), respectively. The functionalized resin was packed into standard SPE cartridges and employed as a selective sorbent for the extraction and preconcentration of trace metals from groundwater samples collected from Dhalamah Valley, Al-Madinah Al-Munawwarah, prior to quantification by inductively coupled plasma mass spectrometry (ICP-MS). These results demonstrate the effectiveness of rapid diazonium-based surface functionalization for the preparation of selective polymeric metal chelators suitable for the extraction of trace metals from complex groundwater matrices. Full article

Bis(2-ethylhexyl) phosphate (P204) is widely used in extraction processes in the nuclear and rare earth industries. However, its high solubility in water results in high levels of total organic carbon and phosphorus in aqueous environments, and may also lead to radioactive contamination when it is used to combine with radionuclides. In this paper, we characterized a coconut shell activated carbon (CSAC) and a coal-based activated carbon (CBAC) for the adsorption of P204 and then evaluated their adsorption performance through batch and column experiments. The results found that, except for the main carbon matrix, CSAC and CBAC carried rich oxygen-containing functional groups and a small amount of inorganic substances. Both adsorbents had porous structures with pore diameters less than 4 nm. CSAC and CBAC showed good removal performance for P204 under low pH conditions, with removal efficiencies significantly higher than those of commonly used adsorption resins (XAD-4 and IRA900). The adsorption kinetics of P204 conformed to the pseudo-second-order kinetic model, and the adsorption isotherms conformed to the Langmuir model, indicating a monolayer chemical reaction mechanism. Both adsorbents exhibited strong anti-interference capabilities; their adsorption performance for P204 did not change greatly with the ambient temperature or the concentrations of common interfering ions. Column experiments demonstrated that CSAC could effectively fix dissolved P204 with a removal efficiency exceeding 90%. The fixed P204 could be desorbed with acetone. The findings provide an effective method for the recovery of P204 and the regeneration of spent activated carbon, which shows promise for practical applications in the future. Full article

Olive mill wastewater (OMW), a byproduct of the olive oil industry, is a potential source of natural bioactive phenolic polymers. In this work, a column chromatography technique was used for the isolation of a new complex polymer (named OMW-2000XAD) from OMW via fractionation on Amberlite^® XAD16 resin. The developed procedure was simple and proved to be reproducible using OMW from two different sources. OMW-2000XAD was further characterized by elemental, glycosidic, and amino acid composition analysis, as well as spectroscopic techniques. The polymer’s molecular size, which was estimated via gel filtration chromatography, was 1960 kDa, which is significantly larger than other high-molecular weight fractions previously isolated from OMW or other agro-industrial wastes. OMW-2000XAD was mainly composed of phenolic compounds (89.8%). It also contained polysaccharides (16.1%) and proteins (10.3%), with glucose (12.25%) and cysteine (1.71%) being the most abundant sugar and amino acid, respectively, as well as metals (1.29%, primarily potassium). However, due to its low solubility, complexity, and heterogeneous composition, it was not possible to identify all phenolic compounds or elucidate a definitive structure via MS, FTIR, and NMR. OMW-2000XAD exhibited strong radical scavenging antioxidant capacity (ABTS^•+, DPPH^• and peroxyl radicals), with results up to 7415 µmol Trolox equivalent/mol (ORAC method), but showed no antiproliferative effects, highlighting the need for further research. Full article

Cocoa is a rich source of health-promoting polyphenols such as flavanols. These compounds can be separated from other matrix constituents using various adsorbents or resins. Seven different macroporous resins (Amberlite^® XAD-2, XAD-4, XAD-7, XAD-7HP, XAD-16, Sepabeads^TM SP207, and Diaion^® HP2-MG) were evaluated for their adsorption and desorption properties for the enrichment of flavonoids from an aqueous cocoa (Theobroma cacao L.) extract. The influence of adsorption and desorption temperatures and the concentration of the desorption solvent (a hydroalcoholic solution) were investigated by static adsorption and desorption methods. The results of the resin comparison showed that the adsorbent XAD-7HP had the best adsorption characteristics, with an adsorption capacity of 39.8 mg ECE/g. XAD-7HP was found to be the most suitable adsorbent, and 70% ethanol was the best desorbing solvent, based on static experiments. In addition, the optimal conditions for the adsorption of flavonoids were obtained at a temperature of 30 °C, where equilibrium was reached after 80 min. The static adsorption process was well-described by a pseudo-second-order kinetics model, while the adsorption isotherm data were fitted well by the Freundlich isotherm model. Further dynamic adsorption and desorption characteristics were evaluated on a packed glass column, and it was shown that XAD-7HP could enrich the flavanol content by 5.03-fold, with a dry matter content of 456.05 mg/mL (as estimated by the degree of DP1–DP7 procyanidin polymers using ultra-pressure liquid chromatography). Full article

Berberine, palmatine, and coptisine are bioactive alkaloids commonly found in medicinal plants, including Coptis chinensis Franch. (Ranunculaceae). To address the limitations of conventional volatile organic solvents, this study employed eco-friendly solvents—aqueous solutions of surfactants, carboxylic acids, and deep eutectic solvents—to extract these alkaloids. Among the solvents tested, lactic acid, malic acid, and pyruvic acid exhibited the highest extraction efficiencies. Optimal extraction conditions for ultrasound-assisted extraction were determined via response surface methodology. For lactic acid, optimal conditions included a concentration of 96% (w/w), a liquid-to-solid ratio of 30.0 mL/g, and a temperature of 60.0 °C, yielding 139.6 ± 0.2 mg/g of total alkaloids. Malic acid at 40.0% (w/w), 30.0 mL/g, and 80.0 °C produced 133.0 ± 0.5 mg/g, while pyruvic acid at 88.0% (w/w), 30.0 mL/g, and 75.0 °C resulted in 146.3 ± 0.4 mg/g. The recovery efficiencies of these alkaloids were further enhanced using macroporous resins. The XAD-8 and AB-8 resins achieved recovery rates of 80.11 ± 0.78% and 79.00 ± 1.06%, respectively, for lactic acid extracts. The LSA-40 resin yielded efficiencies of 95.58 ± 1.40% and 89.86 ± 0.90% for malic and pyruvic acid extracts, respectively. Notably, the combination of malic acid as an extraction solvent and the HPD-400 resin achieved an impressive alkaloid recovery yield of 79.52% from C. chinensis. This work represents the first reported application of this approach and highlights the potential of green solvents and macroporous resins for sustainable and efficient alkaloid extraction from C. chinensis. Full article

In this study, polyphenols in the crude extract (CE) from red onion peel were recovered by macroporous resin, and their antioxidant and anti-inflammatory activities were evaluated. Among the four resins screened (SP850, XAD2, XAD7HP, and XAD16N), XAD7HP showed the highest desorption and recovery ratios, and it was used to optimize polyphenol recovery through single-factor experiments. The optimal conditions were established as 1 g resin, pH 4, 25 °C, 7 h for adsorption, followed by desorption with 70% ethanol for 1 h at 25 °C. These conditions achieved 85.00% adsorption ratio, 87.10% desorption ratio, and 20.9% yield of the macroporous resin-recovered extract (MRE) from the CE. HPLC analysis revealed that rosmarinic acid, quercetin, and myricetin were major compounds in the MRE, with the content of these compounds higher (about 7-fold) compared to the CE, confirming enhanced recovery of polyphenols by macroporous resin. Moreover, FT-IR and ¹H-NMR analysis confirmed the successful recovery of these polyphenol compounds in the MRE. Furthermore, the MRE displayed significantly improved antioxidant activities (DPPH, ABTS, and FRAP) and anti-inflammatory activities (inhibition of nitric oxide synthesis and reactive oxygen species production) compared to the CE. In summary, our findings suggest that macroporous resin can effectively recover polyphenol compounds from red onion peel extract and enhance their biological activities. Full article

Background/Objectives: Plants species of the Epilobium genus are traditionally used to treat prostatitis and other urinary tract disorders and are particularly rich in ellagitannins and flavonol 3-O-glycosides. The aim of this work was to evaluate the inhibitory activity of different extracts from E. angustifolium L. and E. parviflorum Schreb. and their major bioactive compound, oenothein B, against a panel of Gram-positive (Enterococcus faecalis ATCC 29212, Enterococcus faecalis BS, Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 29213, and Staphylococcus aureus ATCC 43300) and Gram-negative (Escherichia coli ATCC 25922, Escherichia coli ATCC 35218, Escherichia coli BS, Klebsiella pneumoniae ATCC 13883, Klebsiella pneumoniae ATCC 70063, Klebsiella pneumoniae BS, Proteus mirabilis BS, and Pseudomonas aeruginosa ATCC 27853) bacteria responsible for prostatitis. Methods: Aqueous and ethanolic raw extracts were prepared, and the latter were further purified using the resin Amberlite^TM XAD7HP. Then, an HPLC-MS/MS method was developed for the quantification of the marker bioactives and their levels were correlated with the antimicrobial activity. Results: Purified extracts were richer in polyphenols (330.80 and 367.66 mg/g of dry extract for E. angustifolium and E. parvifolium, respectively) than the raw extracts. Oenothein B was the predominant compound in all the extracts (119.98 to 327.57 mg/g of dry extract). The minimum inhibitory concentrations (MICs) in the range of µg/mL indicated significant antibacterial activity, which was higher for the purified extracts and oenothein B (MIC values from 4 to 16 and 8 to 1024 µg/mL on Gram-positive and Gram-negative strains, respectively). Conclusions: These results outline the outstanding potential of E. angustifolium and E. parviflorum extracts and oenothein B as therapeutic alternatives or complementary agents to conventional antibiotic treatments of prostatitis and other urinary tract infections. Full article

This study evaluated the antioxidant efficacy of ellagitannins from a pomegranate husk in preventing vegetable canola oil (VCO) oxidation during French fry preparation. Ellagitannins were extracted using 80% acetone, purified via Amberlite XAD-16 resin chromatography, and incorporated into VCO at 0.05%, 0.1%, and 0.2% concentrations. VCO oxidation was assessed at 145 °C, 160 °C, and 190 °C, with frying experiments conducted at 160 °C for five 10 min cycles. Primary lipid oxidation (peroxide values) was measured using the AOCS Cd 8-53 method, and molecular structural changes were analyzed by infrared spectroscopy. Results showed that ellagitannins significantly mitigated VCO oxidation across all temperatures, with 0.05% identified as the optimal concentration. This concentration reduced peroxide values to 4.66 ± 1.15 meq O/kg, remaining stable and below acceptable limits during frying. Infrared spectroscopy confirmed no significant structural changes in VCO. These findings highlight ellagitannins as effective antioxidants for enhancing VCO oxidative stability during frying, offering a natural, sustainable solution for improving oil quality and extending its usability in the food industry. Full article

Owing to the intensive development of electrical and electronic equipment, there is an increasing demand for precious metals, which are often used for its production. Due to their scarce supply, it is important to recover them from secondary sources. A promising way to recover precious metals are impregnated resins. In this research, Amberlite XAD-16 was impregnated with TBP at the weight ratios of 1:2 and 1:3 using the ‘warm impregnation’ method. Studies were carried out on the sorption of Au(III), Pd(II), Pt(IV), and Rh(III) ions from the model chloride solutions as well as the real solution formed after leaching the smart card chips. Only Au(III) ions were efficiently sorbed on the prepared impregnated sorbents. The best results were obtained at 6 M HCl and the sorbent mass: 0.1 g/25 mL. The maximum sorption capacity for the impregnated sorbents was: 147.91 mg/g (ratio 1:2) and 149.66 mg/g (ratio 1:3). Recovery of Au(III) ions from the real leaching solution was: 97.36% and 97.77%, respectively. The Langmuir isotherm was the best-fit model for the experimental results. Thermodynamic studies proved that the investigated sorption process is spontaneous and exothermic. The desorption process can be easily carried out with 1 M HCl/1 M TU. Full article

This paper proposes a simple, environmentally friendly, and efficient procedure for preparing natural water samples for the voltammetric determination of trace amounts of Se(IV). The method is based on premixing a sample with Amberlite XAD-7 resin at 50 °C. The composition of the 10 mL solution consists of the sample to be analysed, 0.1 mol L⁻¹ of acetate buffer at pH = 4.0, and 0.5 g of Amberlite XAD-7. After 2 min of stirring, a voltammetric measurement is carried out using a fixed bismuth microelectrode using the following potentials: −2.5 V for 2 s and −0.55 V for 30 s. The voltammetry is recorded by varying the potential from −400 mV to −1000 mV. An undisturbed Se(IV) signal is obtained in the presence of 10 mg L⁻¹ of Triton X-100, 5 mg L⁻¹ of SDS, 10 mg L⁻¹ of CTAB, 5 mg L⁻¹ of Rhamnolipid, 5 mg L⁻¹ of HA, 10 mg L⁻¹ of FA, and 2 mg L⁻¹ of NOM. The validity of the developed procedure is checked by analysing the certified reference materials SPS-SW1 (surface water) and TM-25.5 (Lake Ontario water) additionally enriched with surfactants and humic substances. Full article

The objective of this study was to investigate the umami characteristics of soy sauce using electronic tongue evaluation and amino acid composition and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI−TOF MS) analysis. The soy sauce peptides were isolated from soy sauce using XAD−16 macroporous resin combined with ethanol solution. The results showed that the soy sauce peptide fraction eluted by 60% ethanol (SS−60%) exhibited a prominent umami taste, and the umami scores were highly positively correlated with the amino acid nitrogen contents of soy sauces. The umami scores of SS−60% were significantly positively correlated with the contents of free amino acids. Especially, Phe showed the highest positive correlation with the umami scores. In addition, five characteristic ion peaks with m/z at 499, 561, 643, 649, and 855 were identified in the peptide mass fingerprinting. Therefore, this study provides new insights into the umami characteristics for the taste evaluation and reality identification of soy sauce. Full article

The aim of this paper was to investigate the effect of temperature on the removal efficiency of surfactant-induced interferences. Surfactants were removed as a result of mixing with XAD-7 resin. The study was carried out using the example of Cr(VI) determination by adsorption stripping voltammetry (AdSV). Measurements were carried out using a solution containing Cr(VI), acetate buffer (pH = 6.2), DTPA, KNO₃, and different surfactants. Ten mL of the solution was mixed with 0.5 g of XAD-7 resin at different temperatures for 5 min prior to voltammetric measurement. The effect of the mixing temperature of the sample with the resin on the voltammetric Cr(VI) signal in the presence of different surfactants was studied in the range from 20 to 60 °C. The proposed method of removing interference from surfactants by mixing the sample with the XAD-7 resin at 60 °C was used for the determination of trace amounts of Cr(VI) in river water containing non-ionic, anionic, cationic surfactants, and biosurfactants. Full article