Search Results (61)

The aim of the present study was to investigate the bioactive composition of pomegranate peel and to produce a phenolic-rich extract for encapsulation using vibrating nozzle technology. Conventional heat- and advanced microwave-assisted extraction of phenolic compounds were investigated, and the extract with the highest phenolic content was used to perform encapsulation with alginate-based delivery solutions containing fava bean proteins, mucin, carboxymethyl cellulose, nutriose, and collagen hydrolysates. The formulated beads were characterized for their physico-chemical (morphology, size distribution parameters, and FT-IR spectra) and bioactive (encapsulation efficiency and simulated gastrointestinal digestion) properties. The highest yields of punicalin, punicalagin, and ellagic acid (9.40, 44.51, and 3.95 mg g⁻¹ DM, respectively) were achieved by heat-assisted extraction at 80 °C. The addition of fava bean proteins and carboxymethyl cellulose to the alginate-based delivery solutions resulted in the highest encapsulation efficiency of total phenols (83.99 and 83.78%, respectively). However, the beads formulated with fava bean proteins were irregularly shaped, while those with carboxymethyl cellulose were predominantly spherical. All beads showed limited phenolic release under simulated gastric conditions, followed by enhanced release in the intestinal phase. Overall, the obtained results indicate that encapsulation efficiency was governed by the combined effects of rheological parameters, bead morphology, and molecular interactions, highlighting the importance of a multi-parameter design approach in the development of effective delivery systems. Full article

Chromium-related hazard in mine wastes depends strongly on oxidation state, with hexavalent chromium [Cr(VI)] representing the most mobile and toxicologically relevant chromium form. Abandoned tailings dumps can develop sharp pH and redox gradients that favour either Cr(VI) persistence or attenuation, yet field-based evidence from Eastern European post-mining sites remains limited. This study evaluates the Defor Petrila tailings dump, Jiu Valley, Romania, as a first-tier environmental hazard-screening case study based on repeated monitoring performed during 2022–2024 at twelve permanent sampling points and two local operational control samples. Field pH and redox potential (Eh), moisture, organic matter, acid-extractable Mn and Fe, pseudo-total Cr, and method-defined extractable Cr(VI) were determined. Here, pseudo-total Cr refers to chromium released by microwave-assisted acid digestion and does not represent complete decomposition of the silicate matrix, while extractable Cr(VI) refers to the operationally defined fraction obtained by alkaline extraction. In addition, a conservative redox-based prioritisation score (R_redox) was applied only as an internal ranking layer to identify sectors where Cr(VI) is more likely to persist. The upper dump sector (P1–P4) was alkaline (pH 7.5–8.2), strongly oxidising (+280 to +412 mV), and enriched in Mn and Fe, whereas the lower sector (P9–P12) was wetter, slightly acidic to near-neutral, and reducing (−59 to −10 mV). Extractable Cr(VI) reached 18.7 mg kg⁻¹ at P2 in 2024, while both control samples remained below the quantification limit. Exploratory repeated-site statistics, sector-based comparison, and correlation analysis supported a coherent association between Eh, Mn enrichment, and extractable Cr(VI), but these relationships are interpreted as spatially structured screening evidence rather than proof of a single mineralogical oxidation pathway. No direct exposure, leachability, bioaccessibility, ecotoxicity, airborne dust, water, vegetation, or biomonitoring measurements were included; therefore, the results identify priority zones for confirmatory toxicological and exposure-based assessment, not receptor-specific risk estimates. This study demonstrates that combining chromium speciation with field redox zonation can support conservative monitoring prioritisation at abandoned mine-waste sites where the toxic form of chromium may remain environmentally active. Full article

Growing concern over the presence of microplastics in food has led to the development of numerous methods for their extraction and analysis. However, many of these methods are time-consuming and limited to specific food types. In this study, we present a novel and quick approach involving microwave-assisted acid extraction of microplastics from food, followed by Raman microscopy analysis. The method’s performance was evaluated through determination of its digestion efficiency, particle mass and number recovery, limit of detection (LOD), and the digestion protocol’s effect on polymer physicochemical characteristics. The extraction protocol achieved 99.74–100.01% digestion of four different food matrices within 2 h, with 81.4–110.7% mass and 80–108% number recoveries of added polymer particles, both being within the 80–120% range. Importantly, DSC, TGA, DLS and Raman analyses of added particle polymers showed no significant change in PE, PP and PTFE polymer structure, while some structural changes were found for PET and PMMA. This method’s good analytical performance, high throughput and suitability for quick digestion of several different food matrices make it a promising step towards reliable monitoring of microplastics in food. Full article

Table grapes are commonly consumed fresh, and their market value is largely determined by ripeness, grape color, mineral composition, and variety-specific aroma. This study integrated physicochemical ripening indicators (°Brix%, pH, titratable acidity, maturity index), CIELAB color parameters measured on the outer skin and inner sections, multi-element mineral profiling following microwave-assisted digestion (ICP-MS), and volatile organic compound (VOC) profile by HS-SPME/GC-MS to characterize five table grape varieties (Thompson Seedless, Isabella, Mevlana, Pepita Alfonso, and Red Globe). Significant differences in ripeness were found among the varieties (p < 0.01). Isabella had the highest soluble solids content (22.91 °Brix%), while Pepita Alfonso had the highest maturity index (79.89) and the lowest titratable acidity (0.22%). Color measurements also showed significant differences among the varieties (p < 0.01). Thompson Seedless exhibited the highest peel lightness/yellowness and chroma values, while Pepita Alfonso and Red Globe had a darker, lower chroma profile. Color index values differed between the peel and the inner cross-section depending on the variety (p < 0.01). Mineral composition was found to be variety-specific (p < 0.01). The dominant macroelements among the samples were K, P, and Mg, and statistically significant differences were also determined in trace elements (p < 0.01). A total of 42 volatile organic compounds (VOCs) were identified. Aldehydes were dominant in the volatile fraction (39.07–64.96%), nonanal contributed a significant percentage, and terpenoids (floral aroma note) were found in the highest percentage in the Isabella variety (28.87%). PCA applied to the integrated physicochemical, color, and mineral dataset enabled the clear discrimination of the five table grape cultivars. Pepita Alfonso was positioned toward positive PC2, and Red Globe occupied the opposite segment. Thompson Seedless and Isabella were separated mainly along PC1, while Mevlana showed an intermediate profile. SIMCA class-distance results confirmed the visual separation. All pairwise interclass distances were above the decision threshold (ICD > 3), ranging from 62,922 (Red Globe–Mevlana) to 806,425 (Isabella–Pepita Alfonso). Findings indicated robust cultivar-level classification for authenticity and quality control purposes. Overall, the integrated multi-domain approach is considered to provide a solid foundation for variety differentiation and quality-oriented harvesting and market management. Full article

The study explored the impact of Microwave-Assisted Extraction (MAE) on the physicochemical, structural, functional, and antioxidant properties of protein concentrates from white pea (Lathyrus sativus), red gram (Cajanus cajan), and black gram (Vigna mungo). The objective was to evaluate the efficiency of MAE as a sustainable green extraction technique compared to the conventional method. Total amino acid content increased in MAE protein from 69.23 to 72.78 g/100 g powder in white pea protein (WPP), 69.41 to 72.39 g/100 g powder in red gram protein (RGP), and 65.56 to 70.30 g/100 g powder in black gram protein (BGP). Functionally, MAE significantly improved solubility and emulsifying capacity and water- and oil-holding capacities. Bioactive evaluation showed a significant increase in total phenolic and flavonoid contents, followed by improved DPPH, ABTS, and FRAP activities. A reduction in tannins and phytic acid correlated with enhanced in vitro protein digestibility. These enhanced MAE-derived proteins further demonstrated superior performance when incorporated into wheat flour, improving its nutritional and functional properties. Overall, MAE protein demonstrated improved structural integrity, antioxidant potential, and digestibility, highlighting white pea protein as the most responsive legume to MAE, followed by red and black gram. Full article

The presence of trace and toxic elements in milk and dairy products is an important food safety issue, as contamination can occur along the dairy supply chain and may be influenced by animal species, production system, and processing conditions. This study aimed to investigate and compare the multi-elemental composition of milk and selected dairy products obtained from organic, conventional, and commercial production systems in north-western Romania. A total of 307 samples, including raw milk from different animal species (cow, goat, buffalo, donkey) as well as yogurt, cheese, and mozzarella, were collected from farms and retail outlets. Samples were subjected to standardized microwave-assisted acid digestion and analyzed for toxic and essential elements (Pb, Cd, Hg, As, Cr, Ni, Al, Sn, Cu, and Zn) using inductively coupled plasma mass spectrometry (ICP–MS), with quality assurance ensured through certified reference materials and proficiency testing. The results indicated low concentrations of toxic metals across all dairy matrices, with Pb ranging from 0.0047 to 0.0117 mg/kg, Cd from 0.0008 to 0.0011 mg/kg, and As from 0.0007 to 0.0664 mg/kg, depending on animal species and production system. Mercury was consistently below the limit of detection in all datasets (LCD = 100%). Essential and transition elements were systematically quantified, occurring within expected ranges (Al: 0.021–0.264 mg/kg; Cu: 0.078–0.270 mg/kg; Zn: 3.245–7.963 mg/kg; Sn ≈ 0.0030–0.0035 mg/kg). All toxic element concentrations were below the maximum limits established by European Union legislation. Variations in elemental profiles were observed between animal species and production systems, with organic cow milk showing the most homogeneous composition. All toxic element concentrations were below the maximum limits established by European Union legislation. Overall, the findings confirm the safety of the analyzed dairy products and emphasize the relevance of multi-elemental monitoring as a practical tool for dairy supply chain surveillance and risk assessment. Full article

Condensed tannins from grape seed residues show high antioxidant activity but low oral bioavailability because of their high degree of polymerization and covalent interactions with proteins. This study aimed to improve their bioaccessibility through depolymerization and encapsulation. Depolymerization was carried out using microwave-assisted SN1 reactions with gallic acid as a nucleophile under food-grade conditions, mainly producing epicatechin monomers with 99.8% polymer degradation efficiency. Importantly, the inhibition of ABTS●+ and DPPH● radicals remained unaffected (p > 0.05), indicating that depolymerization preserved the antioxidants’ redox function, maintaining about 90% of their inhibition activity. The products were encapsulated in phosphatidylcholine liposomes, which had nanometric sizes and high encapsulation efficiency (83.11%), and remained stable for up to 60 days. In vitro release of nanoliposomal epicatechin in a D1 simulant was less than 10% after 48 h, fitting a Weibull model (β = 0.07), suggesting sub-diffusive transport and demonstrating high bioactive retention capacity in aqueous systems. During in vitro digestion, bioaccessibility of gallic acid and epicatechin reached 95.61 ± 0.58% and 98.56 ± 0.81%, respectively, with a 2333% increase in the bioaccessible mass of flavan-3-ols in native liposomal condensed tannins, which otherwise showed no detectable bioaccessibility. These findings highlight the potential of polyphenols from agro-industrial waste with enhanced bioaccessibility for applications in nutraceuticals and functional foods. Full article

In the present study, ultrasound-assisted extraction using deep eutectic solvents was proposed for the preparation of uniced and iced gingerbread cookies prior to the determination of four macronutrients (potassium, sodium, magnesium, calcium), four micronutrients (manganese, zinc, iron, copper), the presence of toxic metal (cadmium), and antioxidant capacity. With the addition of 30% water in each green solvent, three acidic deep eutectic solvents, comprising xylitol with malic acid, choline chloride with malic acid, and choline chloride with lactic acid, were tested for their efficiencies in the simultaneous extraction of elements and antioxidants. The synthesized deep eutectic solvents were characterized by infrared spectroscopy, which provided evidence of generating new hydrogen bonds between two components of these solvents. Element profiles were analyzed by inductively coupled plasma–mass spectrometry after the extraction using green solvents and the microwave-assisted acid digestion of gingerbread samples. It was found that two deep eutectic solvents containing malic acid exhibited high abilities for solubilization of macronutrients and manganese from the samples studied, while the best extraction efficiencies for Zn, Fe and Cu micronutrients were achieved when the lactic acid-based deep eutectic solvent was used. However, the antioxidant capacity, evaluated by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and cupric reducing antioxidant capacity (CUPRAC) methods, led to the selection of choline chloride–lactic acid as the most promising green solvent for extracting antioxidants from two types of gingerbread cookies. The deep eutectic solvent-based extraction conforms to the principles of green chemistry and is suitable for releasing elements and antioxidants from gingerbread cookies. Full article

Mango (Mangifera indica L.) is a very popular tropical drupe that can be consumed fresh or dried. It is rich in essential nutrients such as vitamins, dietary fibre, and minerals, as well as biologically active substances, with a positive effect on health. However, it can also contain potentially toxic elements, which justifies the need of properly investigating this food product. Commercially available samples of dried mango, as well as the mesocarp and peel of fresh mango, were analysed. Prior to the multi-element analysis by inductively coupled plasma mass spectrometry (ICP-MS), the microwave-assisted sample digestion method using various reagents and reagent mixtures was optimised, showing that a mixture of nitric acid and hydrogen peroxide gave the best recoveries. The results obtained were processed by chemometric methods. The content of elements in the peel was higher than in the mesocarp. The macroelements Ca, K, Mg, and Na were found in the largest proportion, and the micronutrients present in significant quantities were Cu, Zn, and Mn (>3 mg/kg), while toxic elements, which according to the guidelines of The European Food Safety Authority) would represent a danger to human health, were not found in mass fractions above the permissible values. Full article

Heavy metal contamination in food has become a significant global food safety concern. This study assessed the concentrations of As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mn, K, Mg, Na, Ni, Se, Pb, and Zn in 13 locally grown vegetables using microwave-assisted acid digestion and ICP-MS. The potential human health risks associated with their consumption were also evaluated. Vegetable samples were collected from the local farmer’s market in Grand Forks, North Dakota. The mean levels (μg/g) of Na, Mg, K, Ca, Fe, Se, Mn, Cu, Zn, Co, Hg, Cr, Ni, As, Cd, and Pb were 1001, 2935, 30474, 686.0, 52.90, 0.171, 37.63, 4.936, 21.33, 0.069, 0.0030, 0.049, 0.736, 0.083, 0.298, and 0.019, respectively, having the following decreasing trend: K > Mg > Na > Ca > Fe > Mn > Zn > Cu > Ni > Cd > Se > As > Co > Cr > Pb > Hg. The highest total metals level was found in spinach, with the following decreasing order: spinach > tomato > sugar beet > white eggplant > cucumber ~ kale > green chili > green bean > dill ~ potato > capsicum > onion > corn. Spinach exhibited the highest concentrations of Cd, Cr, Pb, and Hg, which suggests a higher risk of metal exposure from its consumption. Toxic metals except Cd were found to be lower than the maximum allowable concentrations set by international agencies among the analyzed vegetables, while Cd levels were higher than maximum allowable levels in most of the vegetables. Health risks associated with metal intake by vegetable consumption were evaluated in terms of estimated daily intake (EDI), non-carcinogenic risks were evaluated by the target hazard quotient (THQ) and Hazard Index (HI), and carcinogenic risks were evaluated by target cancer risk (TCR). The EDI values of all the metals were found to be below the maximum tolerable daily intake (MTDI). The highest EDI value for Mn, Zn, Hg, Cr, Cd, and Pb was noted in spinach. THQ values for Cd, Co, and As were higher than 1 in most of the vegetable species analyzed, indicating non-carcinogenic health effects to consumers. HI results also posed a non-carcinogenic health risk associated with the intake of these vegetables. Mean TCR values of Cr, Ni, As, and Cd indicated carcinogenic risk for consumers. This study showed that there are potential health risks with consumption of these vegetables. Lastly, regular monitoring of metal levels in vegetables is suggested/recommended to minimize health risks and support pollution control efforts. Full article

The aim of this study is to establish a rapid and convenient microwave-assisted digestion method for sample pretreatment to evaluate amino acids in Chebulae fructus (CF). The microwave digestion method was optimized to extract amino acids from CF, and the differences in amino acids in CF from different origins and different processing states were analyzed and evaluated. The influences of digestion temperature, digestion time, and liquid–material ratio on extraction effect were investigated by sing factor test and response surface method (RSM), and the extraction conditions were optimized. The contents of 17 amino acids were determined by an automatic amino acid analyzer. The optimal digestion conditions were a digestion temperature of 150 °C, a digestion time of 18 min, and a liquid–material ratio of 65:1 (mL:g). Under these conditions, the total amino acid content of CF could reach 19.72 mg/g. CF from Lincang city of Yunnan province and unprocessed CF were considered to have higher nutritional value. The results of chemometric analysis showed that there were significant differences in the amino acid content in CF between Guangxi province, Dehong prefecture of Yunnan province, and Lincang city of Yunnan province, and six differential amino acids between the three origins were screened out. This study can provide references for the quality evaluation of the producing area, the extraction, and content research of amino acids of CF. Full article

As the focus on green chemistry intensifies, researchers are progressively looking to incorporate biodegradable and environmentally friendly solvents. Given the prevalent use of inorganic solvents in conventional methods for detecting selenium content, this study utilized a mixture design approach to create four deep eutectic solvents (DESs). The elements of the DESs consisted of six different compounds: guanidine hydrochloride, fructose, glycerol, citric acid, proline, and choline chloride. The synthesized deep eutectic solvents (DESs) exhibited a uniform and transparent appearance. The ideal ratios for each DES were established based on their density and viscosity measurements, leading to the formulations of DES1 (34% guanidine hydrochloride, 21% fructose, 45% water), DES2 (23% guanidine hydrochloride, 32% glycerol, 45% water), DES3 (27.5% citric acid, 27.5% proline, 45% water), and DES4 (30% choline chloride, 25% citric acid, 45% water). The characterization of the deep eutectic solvents (DESs) was performed using nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy, which confirmed the molecular formation of each DES. Following this, the DESs were applied as extraction solvents in a process involving ultrasonic-assisted microextraction (UAE) combined with inductively coupled plasma mass spectrometry (ICP-MS) to assess the selenium levels in selenium-rich rice. The results were benchmarked against traditional microwave-assisted acid digestion (TM-AD), revealing selenium recovery rates ranging from 85.5% to 106.7%. These results indicate that UAE is an effective method for extracting selenium from selenium-rich rice, thereby establishing a solid data foundation for the environmentally friendly analysis of selenium content in rice. Full article

Background: This study aimed to validate a method for characterizing and quantifying the multi-elemental profiles of different insect flours to enable their distinction, identification, and quality assessment. The focus was on three insect species: cricket (Acheta domesticus), buffalo worm (Alphitobius diaperinus), and mealworm (Tenebrio molitor). Methods: Mealworms were powdered in the laboratory through mechanical processing. Sample analysis involved acid digestion using a microwave digester, followed by profiling with Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This technique enabled rapid, multi-elemental analysis at trace levels. Chemometric methods, including Principal Component Analysis (PCA) for exploratory analysis, Covariance Selection-Linear Discriminant Analysis (CovSel-LDA), alongside forward stepwise LDA classification methods, were applied and compared. Results: ICP-MS accurately detected elements at micro trace levels. Both classification models, based on different variable selection methods and externally validated on a test set comprising 45% of the available samples, proved effective in classifying samples based on slightly different pools of trace elements. CovSel-LDA selected Mg and Se, whereas the stepwise-LDA focused on Mg, K, and Mn. Conclusions: the validated methods demonstrated high accuracy and generalizability, supporting their potential use in food industry applications. This model could assist in quality control, facilitating the introduction of insect-based flour into European and international markets as novel foods. Full article

An environmentally compatible and less costly (greener) analytical method for the digestion of bone meal samples using microwave-assisted dilute nitric acid (HNO₃) was developed and optimized. The method, employing a mixture of 1 mL concentrated HNO₃ and 4 mL of deionized water, offered a comparable performance to the conventional method using 5 mL of concentrated HNO₃. The accuracy of the method was validated by using certified reference material NIST 1486 (Bone Meal); percentage recoveries were within ±15% for all eight certified elements. Statistical analysis revealed no significant differences (p > 0.05) in percentage recoveries between the green and conventional methods for all elements except calcium. The greenness of the developed method was evaluated by using the analytical Eco-Scale, achieving a score of 87, categorizing it as an “excellent green analysis” method. This research highlights the potential for adopting greener practices in trace element analysis that reduce the environmental impact and safety risks associated with concentrated acids. Full article

This paper introduces a new methodology for a routine metal analysis of plastic waste (PW) and PW blended with petroleum feedstock such as vacuum gas oil and VGO (PW/VGO). For such purposes, recycled polyethylene and polypropylene plastic were selected to mimic the potential feeds to be integrated at the Fluid Catalytic Cracking unit (FCC) to produce valuable products. Elements such as P, Ca, Al, Mg, Na, Zn, B, Fe, Ti, and Si were included in the method development. Different sample preparation methods were evaluated, such as microwave-assisted acid digestion (MWAD) and dry/wet ashing, followed by a fusion of the ash with lithium borate flux. Some PW homogenization pretreatments, such as cryogenic grinding and hot press molding, were also covered. The finding of this work suggests that MWAD with HNO₃ and H₂O₂ is adequate for both types of samples and is the quickest sample preparation; however, the sample needed to be homogenized, and recoveries for Si and Ti may be biased for PW due to the limited solubilities of these elements in the nitric acid media. Carbon removal is required before fusion sample preparation and analysis due to the amount of carbon in PW samples. The sample needed to be homogenized for wet ash fusion but not for the pre-ash (dry) method. A benefit to the damp ash pretreatment is that the ash for the sample was created in the same crucible used for fusion digestion, avoiding material loss during sample management. Fusion from wet ash or carbon removal allowed for better acid solubility for Si and Ti in PW. The results of the PW samples evaluated matched well with those of both sample preparation methodologies. For most elements, precision was <10% regardless of the sample preparation; however, Fe and P had some variation using wet ash fusion, possibly due to contamination in an open digestion system or variation due to being close to the method limit of quantification (LOQ). The methodology reported here is robust enough to be implemented as routine analysis in any laboratory facility. Full article