Search Results (51)

The current research aims to develop a simple, sensitive, and green analytical method for the group extraction/monitoring of 19 organochlorine and organophosphorus pesticides from fruit juices using microwave radiation to assist a cloud point extraction (MW-CPE) in combination with re-extraction in hexane and GC-MS/MS detection. The main experimental factors affecting the CPE and re-extraction have been optimized. The matrix-matched calibration was performed, and the limit of quantification (LOQ) for all studied pesticides at optimized conditions ranged between 5 and 47 ng L⁻¹. When applying only 0.25 mL of hexane for re-extraction, the proposed method shows good accuracy and precision. The “greenness” of the developed MW-CPE-GC-MS/MS method was assessed using the AGREE prep software. The method has been successfully implemented in pesticide analysis in commercially available fruit juices (lemon concentrate and red apple juice). The recovery values obtained for most analytes were within the range of 71% and 114% and RSD below 20% (exept Heptahlor, Aldrin, o,p-DDD, p,p-DDD and o,p-DDT, p,p-DDT). The developed method combines a preconcentration with a sample clean-up step due to the extraction of the pigments into the non-polar micelles during the extraction step, and deposition in the intermediate layer of MgSO₄ during the re-extraction step. Full article

By proportionally blending fresh latex from PR107, Reyan 72059, and Reyan 73397, and employing both acid- and enzyme-assisted microbial coagulation methods, this study analyzed the effects of the specific latex formulation on the following: physicochemical properties, non-rubber components, molecular weight and distribution, vulcanization characteristics of compounded rubber, and physical–mechanical properties of vulcanized natural rubber. The results indicate that, compared to acid-coagulated natural rubber, enzyme-assisted microbial coagulated natural rubber exhibits slightly lower levels of volatile matter, impurities, plasticity retention index (PRI), nitrogen content, calcium ions (Ca²⁺), iron ions (Fe³⁺), and fatty acid content. Conversely, it demonstrates higher values in ash content, initial plasticity (P₀), Mooney viscosity (M_L(1+4)), acetone extract, magnesium ions (Mg²⁺), copper ions (Cu²⁺), manganese ions (Mn²⁺), gel content, molecular weight and distribution, and glass transition temperature (Tg). With the increase in the proportion of PR107 and Reyan 72059 fresh latex, the ash content, volatile matter content, fatty acid content, gel content, and dispersion coefficient (PDI) of natural rubber gradually decrease, while the impurity content, PRI, nitrogen content, weight-average molecular weight (Mw), and number-average molecular weight (Mn) gradually increase. Compared to acid-coagulated natural rubber compounds, enzyme-assisted microbial-coagulated natural rubber compounds exhibit higher minimum torque (M_L) and maximum torque (M_H), but shorter scorch time (t₁₀) and optimum cure time (t₉₀). Furthermore, as the proportion of PR107 and Reyan 72059 fresh latex increases, the ML of the compounds gradually decreases. In pure rubber formulations, enzyme-assisted microbial-coagulated natural rubber vulcanizates demonstrate higher tensile strength, tear strength, modulus at 300%, and Shore A hardness compared to acid-coagulated natural rubber vulcanizates. When the fresh latex ratio of PR107, Reyan 72059, and Reyan 73397 is 1:1:3, the tensile strength and 300% modulus of the natural rubber vulcanizates reach their maximum values. In carbon black formulations, the tensile strength and tear strength of enzyme-assisted microbial-coagulated natural rubber vulcanizates are significantly higher than those of acid-coagulated natural rubber vulcanizates in pure rubber formulations, with the increase exceeding that of other samples. Full article

Pectin is a multifunctional polysaccharide whose structural attributes, including degree of esterification (DE), molecular weight (MW), and branching, directly affect its gelling, emulsifying, and bioactive properties. Conventional pectin extraction relies on acid- or alkali-based methods that degrade the pectin structure, generate chemical waste, and alter its physicochemical and functional properties. Although novel methods such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and enzyme-assisted extraction (EAE) are recognized as environmentally friendly alternatives, they frequently use acids or alkalis as solvents. This review focuses on pectin extraction methods that do not involve acidic or alkaline solvents such as chelating agents, super/subcritical water, and deep eutectic solvents (DESs) composed of neutral components. This review also discusses how these alternative extraction methods can preserve or modify the key structural features of pectin, thereby influencing its monosaccharide composition, molecular conformation, and interactions with other biopolymers. Furthermore, the influence of these structural variations on the rheological properties, gelling behaviors, and potential applications of pectin in the food, pharmaceutical, and biomedical fields are discussed. This review provides insights into alternative strategies for obtaining structurally intact and functionally diverse pectin by examining the relationship between the extraction conditions and pectin functionality. Full article

In this study, the ultrasonic-assisted extraction of deep eutectic solvents (UADES) for tea polysaccharides was optimized, and their physicochemical properties and antioxidant activities were analyzed. The optimal DES comprised choline chloride (CC) and ethylene glycol (EG) in a molar ratio of 1:3, with a water content of 40%. The optimized condition was an extraction temperature of 61 °C, an ultrasonic power of 480 W, and an extraction time of 60 min. The UADES extraction rate of polysaccharides (ERP) was 15.89 ± 0.13%, significantly exceeding that of hot water (HW) extraction. The polysaccharide content in the UADES-extracted tea polysaccharides (UADESTPs) was comparable to that of hot-water-extracted tea polysaccharides (HWTPs) (75.47 ± 1.35% vs. 74.08 ± 2.51%); the UADESTPs contained more uronic acid (8.35 ± 0.26%) and less protein (12.91%) than HWTP. Most of the UADESTPs (88.87%) had molecular weights (Mw) below 1.80 × 10³ Da. The UADESTPs contained trehalose, glucuronic acid, galactose, xylose, and glucose, with molar ratios of 8:16:1:10. The free radical scavenging rate and total reducing power of the UADESTPs were markedly superior to those of the HWTPs. Moreover, the UADESTPs had a better alleviating effect on H₂O₂-induced oxidative injury in HepG2 cells. This study develops an eco-friendly and efficient extraction method for tea polysaccharides, offering new insights for the development of tea polysaccharides. Full article

American ginseng (Panax quinquefolium L.) residue from the extraction industry can be dried and mixed with rice bran as media for black truffle solid-state fermentation to enhance reuse and bioactive functions. Different ratios of rice bran (R) and American ginseng residue (G) mixtures were used as solid-state media for 5 weeks of black truffle fermentation, and then their bio-component contents and whitening effects were analyzed. Finally, four drying methods—hot air drying (HA), microwave drying (MW), hot air-assisted radio frequency (HARF) drying, and radio frequency vacuum (RFV) drying—were assessed to optimize drying efficiency for fermented medium. The results showed that using a 3:1 ratio of rice bran and American ginseng residue as the medium increased the crude polysaccharide and flavonoid contents by approximately threefold and enhanced the ginsenoside Rg3 content about twelvefold. Additionally, the 100 µg/mL ethanol extract of the fermented product inhibited 70% of tyrosinase activity and reduced the melanin area on zebrafish embryos by 42.74%. In the drying study, RFV drying R2G1 required only 13 min without exceeding 70 °C, demonstrating superior drying efficiency, temperature control, and low energy consumption. Overall, this study demonstrates the potential of black truffle fermentation of solid-state media from rice bran and American ginseng residue mixtures for whitening applications and highlights RFV drying as an efficient method for by-products. Full article

This study investigates the recovery of bioactive polyphenolic compounds from the pomace of two white winemaking grape varieties, Moschofilero and Rhoditis. The pomace was subjected to two drying techniques: air drying (AD) and solar drying (SD). Extraction methods included microwave-assisted extraction (MW), ultrasound-assisted extraction (US), and Soxhlet extraction (S), using water and water–ethanol (WE) solvents. Antioxidant activity (IC50), total phenolic content (TPC), and total flavan-3-ol content (TFC) were determined. For Moschofilero, SD pomace extracted with US-WE showed the highest antioxidant activity (IC50: 0.59 mg/mL) and the highest phenolic recovery (TPC: 285.76 mg gallic acid equivalents (GAE)/g) and flavan-3-ol content (TFC: 46.21 mg catechin equivalents (CE)/g). For Rhoditis, AD pomace extracted with US-WE demonstrated superior antioxidant activity (IC50: 1.08 mg/mL), phenolic content (TPC: 216.51 mg GAE/g), and flavan-3-ol content (TFC: 35.96 mg CE/g). HPLC analysis identified quercetin-3-glucuronide, myricetin, and quercetin as the main flavonols in both grape varieties, with Moschofilero also containing isorhamnetin-3-glucoside and syringetin-3-glucoside. Drying and extraction methods significantly influenced the recovery of bioactive compounds, with US combined with AD or SD yielding the best results for both grape varieties These findings show that improved drying and extraction methods can add value to grape pomace for use in functional foods and nutraceuticals. Full article

This study aimed to optimize the ultrasound-assisted extraction (UAE) of polysaccharides from fermented Astragalus membranaceus (FAPS) and to investigate the physicochemical properties and antioxidant activities of the extracted polysaccharides. Using a combination of single-factor experiments and response surface methodology based on a Box–Behnken design, we improved the extraction of crude FAPS without deproteinization. Under optimal conditions (50 °C, 60 min, 8 mL/g, 480 W), the yield of crude FAPS obtained by UAE (7.35% ± 0.08) exceeded the yield from convectional hot water extraction (6.95% ± 0.24). After protein removal, the FAPS was subjected to comprehensive chemical analyses, including HPLC, HPGPC, FT-IR, UV spectroscopy, and a Congo red assay. The results showed that FAPS had a significantly higher carbohydrate content compared to the non-fermented group (95.38% ± 6.20% vs. 90.938% ± 3.80%), while the protein content was significantly lower than that of the non-fermented Astragalus polysaccharides (APS) group (1.26% ± 0.34% vs. 6.76% ± 0.87%). In addition, FAPS had a higher average molecular weight and a lower Mw/Mn ratio compared to APS. The primary monosaccharides in FAPS were identified as Glc, Ara, Gal and GalA, with a molar ratio of 379.72:13.26:7.75:6.78, and FAPS lacked a triple helix structure. In vitro, antioxidant assays showed that FAPS possessed superior antioxidant properties compared to APS. These results emphasize the significant potential of FAPS as an antioxidant, possibly superior to that of APS. The results of this study suggest that fermentation and UAE offer promising applications for the development and utilization of Astragalus membranaceus for human and animal health. Full article

In this paper, citrus pomace was used as a source of pectin and polyphenols extracted in one pot solution by microwave-assisted extraction (MAE) and conventional extraction (CE) methods. MAE parameters were optimized to maximize yield and adjust in situ final physicochemical properties of extracted pectins, such as the methylation degree (DM), significantly influencing pectin functionality and application. Citric acid (CA) and acetic acid (Hac) were employed as solvents to mitigate pectin degradation. Extracted pectins were structurally (GPC and FTIR-ATR), morphologically (SEM), and thermally (TGA) characterized. From the reaction batch, the bioactive compounds (AOs) were separated and recovered, and their yield and antioxidant activities were evaluated with a DPPH assay. Moreover, by strategically selecting pH and solvents, this research enabled precise control over the final properties of pectin. The various characterization techniques employed show that the extraction conditions significantly influence the physicochemical and morphological properties of the material. Molecular weight (Mw) values range from 218 kDa to 567 kDa, surface morphology varies from compact/aggregated structures to three-dimensional network-like formations, and the DM spans from 34% (low DM) to 83% (high DM). This highlights a novel approach for predicting and tailoring in situ characteristics of extracted pectin to meet specific application requirements. Full article

Rare earth elements (REEs) possess unique physical and chemical properties that render them indispensable in various industries, including electronics, energy production and storage, hybrid and electric vehicles, metallurgy, and petro-chemical processing. The criticality of REE underscores the need to enhance the efficiency of primary resource extraction and promote circularity through increased recycling from secondary sources. This paper provides a brief overview of REE recovery from secondary sources, particularly waste from electronic and electric equipment (WEEE). The discussion encompasses direct reuse of magnets, short-loop recycling (direct recycling), hydro- and pyrometallurgical processes, highlighting microwave (MW) technology. Original results are presented, focusing on the recovery of neodymium (Nd) from permanent magnet scraps from hard disk drives (HDD-PC) using microwave-assisted liquid metal extraction (LME) with magnesium (Mg) as the extractant. The subsequent separation of Nd from the Mg-Nd alloy via vacuum Mg distillation that is reused in the process is described. The experimental study demonstrates that the LME process, conducted in a microwave furnace, is a viable method for recovering Nd from permanent magnet scraps, which are essential for reducing the environmental impact of REE extraction and promoting a circular economy. By separating Nd from the alloy through vacuum distillation (450–550 mmHg), at temperatures of 850–900 °C for 8 h, a Nd sponge with a content of 95–98 wt.% Nd was obtained. The extracted content of Nd in the Mg alloy increases with increasing temperature and holding time. It was found that ≈ 97% of the Nd in the scrap was extracted from 2 to 5 mm crushed scrap at 800 °C for 8 h, using a LiF-LiCl-MgF₂ protecting flux in a furnace Ar atmosphere. Full article

In response to the significant waste of bioresources from passion fruit peels in the current market, aiming to enhance the economic benefits of soluble dietary fiber (SDF) derived from passion fruit peels in the food industry, this study extracted the SDF from passion fruit peels using six different methods and assessed how these methods affected its physicochemical properties. The results indicated that the acid-assisted extraction method (AAE-1) was the most effective at protein removal among the six methods, and the SDF derived from this method had the highest extraction yield (17.05%), cation exchange capacity (1.17 mL/g), total monosaccharide content (92.6620 µg/mg), xylose (3.2187 µg/mg), and mannose (3.7334 µg/mg). The SDF extracted by enzyme-assisted extraction method (EAE) showed the highest DPPH free radical scavenging capacity (66.67%), reducing sugar content (5.71%), oil-holding capacity (5.86 g/g), and glucose content (55.9662 µg/mg). The SDF extracted by alkali-assisted extraction method (AAE-2) provided the highest water-holding capacity (7.82 g/g), solubility (4.24 mL/g), and rhamnose content (3.0854 µg/mg). The SDF extracted by microwave-assisted extraction method (MAE) possessed the highest total sugar content (20.15%), ABTS radical scavenging capacity (65.46%), ferric ion-reducing capacity (58.83%), and galactose content (7.8912 µg/mg). The SDF extracted by hot water-assisted extraction method (HWE) of soluble fiber from passion fruit peels had the highest arabinose content (5.3775 µg/mg) and galacturonic acid content (35.6795 µg/mg), as well as the highest weight-average molecular weight (Mw) and number-average molecular weight (Mn). These findings provide a theoretical foundation for the development and utilization of passion fruit peels. Full article

This study presents the synergistic application of ultrasound- and microwave-assisted extraction (UAE–MAE) as a novel and efficient method for recovering bioactive compounds from the medicinal plants oregano, rosemary, Hypericum perforatum, and chamomile. Extraction parameters, including microwave (MW) power, ultrasound (US) power, and extraction time, were optimized using the response surface methodology (RSM), with ethanol as the solvent. Extracts were evaluated for total phenolic content (TPC) via the Folin–Ciocalteu method and antioxidant activity (IC50) using the DPPH assay. High-performance liquid chromatography with diode array detection (HPLC–DAD) identified the main bioactive compounds contributing to their antioxidant and therapeutic potential. The optimized UAE–MAE conditions enhanced phenolic recovery and antioxidant potential across all plants. Notably, Hypericum perforatum exhibited the highest TPC (53.7 mg GAE/g) and strongest antioxidant activity (IC50 29.8 mg extract/g) under 200 W MW, 450 W US, and 12 min, yielding 14.5%. Rosemary achieved the highest yield (23.36%) with a TPC of 26.35 mg GAE/g and an IC50 of 40.75 mg extract/g at 200 W MW, 700 W US, and 8 min. Oregano’s optimal conditions (500 W MW, 700 W US, 12 min) produced a TPC of 34.99 mg GAE/g and an IC50 of 50.31 mg extract/g. Chamomile extracts demonstrated lower phenolic content and antioxidant activity but achieved significant yields under 500 W MW, 700 W US, and 5 min. This study highlights UAE–MAE’s superior efficiency, showcasing its potential to maximize phenolic recovery sustainably, making it a promising technique for industrial and therapeutic applications. Full article

Lithium (Li), a leading cathode material in rechargeable Li-ion batteries, is vital to modern energy storage technology, establishing it as one of the most impactful and strategical elements. Given the surge in the electric car market, it is crucial to improve lithium recovery from its rich mineral deposits using the most effective extraction technique. In recent years, both industry and academia have shown significant interest in Li recovery from various Li-bearing minerals. Of these, only extraction from spodumene has established a reliable industrial production of Li salts. The current approaches for cracking of the naturally occurring, stable α-spodumene structure into a more open structure—β-spodumene—involve the so-called decrepitation process that takes place at extreme temperatures of ~1100 °C. This conversion is necessary, as β-spodumene is more susceptible to chemical attacks facilitating Li extraction. In the last several decades, many techniques have been demonstrated and patented to process hard-rock mineral spodumene. The objective of this review is to present a thorough analysis of significant findings and the enhancement of process flowsheets over time that can be useful for both research endeavors and industrial process improvements. The review focuses on the following techniques: acid methods, alkali methods, carbonate roasting/autoclaving methods, sulfuric acid roasting/autoclaving methods, chlorinating methods, and mechanochemical activation. Recently, microwaves (MWs), as an energy source, have been employed to transform α-spodumene into β-spodumene. Considering its energy-efficient and short-duration aspects, the review discusses the interaction mechanism of MWs with solids, MW-assisted decrepitation, and Li extraction efficiencies. Finally, the merits and/or disadvantages, challenges, and prospects of the processes are summarized. Full article

The development of products with skin-protective effects has been driven by the increasing incidence of skin diseases that are exacerbated by increasing pollution, urbanization, poor living, working, fatigue, dietary habits, and general treatment. The ability of antioxidants to protect the skin from oxidative stress and its effects makes them one of the most important ingredients in today’s cosmetics. This article aims first to characterize the plant extracts obtained from Acmella oleracea (A. oleracea) and then to evaluate the preliminary criteria for a new marketed product: the stability, antioxidant activity, and in vitro behavior of certain serums based on A. oleracea plant extract and hyaluronic acid. The extracts were obtained by liquid–solid extraction methods (maceration (M), ultrasound-assisted extraction (UEA), and a combined method between these two (UEA + M) using an aqueous solution of ethyl alcohol as the extraction solvent. The determination of the amounts of compounds with antioxidant activity highlighted the fact that the extract obtained from the whole plant of A. oleracea using maceration in conditions of S/L = 1:30, 20 days, and an extraction solvent percentage of 50% led to obtaining the highest amount of polyphenols (30.42 μg GAE/g), while using the combined UAE + M method under conditions of S/L = 1:30, 6 min + 20 days, and 50% extraction solvent led to obtaining the highest amount of flavonoids (32.88 mg QE/g). The tests performed on dermato-cosmetic serums based on the plant extract and multimolecular hyaluronic acid (HA) (1 HA with HMW—1.0 mDa–1.6 mDa; HA with LMW—10 kDa–200 kDa; and HA OLIGO, MW < 10 kDa) led to the conclusion that they exhibit structural stability, good shear behavior revealing a satisfactory texture, and high physical stability during storage. These results encourage the transition to in-depth testing, both microbiological and dermatological, as a final step in the consideration of a new commercial product. Full article

Olive oil production is characterized by large amounts of waste, and yet is considerably highly valued. Olive pomace can serve as a cheap source of bioactive compounds (BACs) with important antioxidant activity. Novel technologies like Pulsed Electric Fields (PEF) and High Pressure (HP) and microwave (MW) processing are considered green alternatives for the recovery of BACs. Different microwave (150–600 W), PEF (1–5 kV/cm field strength, 100–1500 pulses/15 µs width), and HP (250–650 MPa) conditions, in various product/solvent ratios, methanol concentrations, extraction temperatures, and processing times were investigated. Results indicated that the optimal MW extraction conditions were 300 W at 50 °C for 5 min using 60% v/v methanol with a product/solvent ratio of 1:10 g/mL. Similarly, the mix of 40% v/v methanol with olive pomace, treated at 650 MPa for the time needed for pressure build-up (1 min) were considered as optimal extraction conditions in the case of HP, while for PEF the optimal conditions were 60% v/v methanol with a product/solvent ratio of 1:10 g/mL, treated at 5000 pulses, followed by 1 h extraction under stirring conditions. Therefore, these alternative extraction technologies could assist the conventional practice in minimizing waste production and simultaneously align with the requirements of the circular bioeconomy concept. Full article

The mushroom industry should implement green extraction technologies; however, there is not enough information on the differences between these techniques expressed as the chemical composition of the resulting extract. In this study, selected types of green extraction techniques (GETs) were used on Chaga (Inonotus obliquus) (Fr.) Pilát from Serbia (IS) and Mongolia (IM) to examine the differences that would enable the composition-based technology choices in the mushroom supplement industry. Subcritical water extraction (SWE), microwave-assisted (MW) extraction, and ultrasonic-assisted extraction (VAE) were used to prepare the extracts. SWE was performed at two different temperatures (120 and 200 °C), while 96% ethanol, 50% ethanol, and water were used for MW and VAE. The yield, the content of total phenols, total proteins, and carbohydrates, qualitative and quantitative analysis of phenolic compounds, carbohydrates, including α- and β- and total glucans, and fatty acids, were determined in the obtained extracts. SWE resulted in a significantly higher yield, total polysaccharide, and glucan content than any other technique. Glucose was the most dominant monosaccharide in the SWE samples, especially those extracted at 200 °C. The MW 50% EtOH extracts showed the highest yield of total phenols. Among the tested phenolic compounds, chlorogenic acid was the most dominant. SWE can be recommended as the most efficient method for extracting commercially important compounds, especially glucans and phenols. Full article