Search Results (614)

Hydrophilic colloids are ideal materials for preparing edible films; however, their intrinsic hydrophilicity leads to poor hydrophobicity in the resulting films. Emulsion-based films can significantly improve the hydrophobicity of films made from hydrophilic colloids, but this approach tends to disrupt intermolecular interactions within the film matrix. Phenolic compounds can compensate for this drawback by promoting crosslinking among film-forming polymers. In this study, hemp seed protein was used as the film-forming matrix, and rose essential oil was incorporated to prepare emulsion-based films. Different amounts of propolis flavonoids were added to investigate their effects on the physicochemical properties of the films. The results show that the addition of propolis flavonoids significantly reduced film whiteness (9%–45%), thickness (6%–37%), light transmittance (9%–60%), water vapor transmission rate (34%–65%), and peroxide value (25%–76%) of oil, while increasing tensile strength (15%–149%), elongation at break (24%–95%), Young’s modulus (26%–140%), surface hydrophobicity, thermal stability, and antioxidant and antimicrobial activities. Furthermore, pork wrapped with flavonoid-containing films exhibited inhibition of microbial growth, lipid oxidation, protein degradation, and maintained firmness. Therefore, propolis flavonoids represent a potential active ingredient for improving the physicochemical properties and preservative performance of emulsion-based films. Full article

Apples (Malus domestica Borkh.) are among the most widely consumed fruits worldwide and represent a significant dietary source of phenolic compounds. Efficient extraction is a critical step for the isolation, characterization, and quantification of phenolic compounds. The extraction yield and composition are strongly influenced by multiple parameters, including solvent type and concentration, temperature, extraction time, solid-to-liquid ratio, and the presence and concentration of acidifying agents. This study aimed to optimize an ultrasound-assisted extraction (UAE) procedure using response surface methodology (RSM) to evaluate the effects of extraction temperature, solvent-to-sample ratio (SSR) and citric acid concentration on total phenolic content (TPC) and total flavonoid content (TFC). Statistical analysis showed that SSR and temperature were the most influential factors affecting phenolic recovery, while citric acid concentration exerted a secondary, interaction-driven effect. Optimization using a desirability function identified the operating conditions that maximized phenolic and flavonoid recovery: 55 °C, 10 mL/g SSR and 0.2% citric acid concentration. Model predictions were validated experimentally, confirming the reliability of the approach for TPC and TFC. Chlorogenic acid and flavan-3-ols, including monomers, such as catechin and epicatechin, and polymers such as procyanidins, were identified. Overall, the proposed approach provides a statistically supported framework for phenolic compound analysis in apples. Full article

Background/Objectives: Seasonal waves of respiratory viruses—including SARS-CoV-2, influenza A virus (IAV), and respiratory syncytial virus (RSV)—continue to pose a global health burden and highlight the need for antiviral agents that are effective, safe, broadly active, affordable, and widely accessible. Current interventions are limited by the need for their early administration, the risk of resistance, their costs, and the restricted availability in large parts of the world. For certain natural products, such as European black elderberry (Sambucus nigra L.) fruit extract (ElderCraft^®; EC) and the seaweed-derived sulfated polymer iota-carrageenan (IC), antiviral activities against respiratory viruses, particularly IAV and SARS-CoV-2, have previously been shown. Here, we assessed the antiviral activity of IC and an anthocyanin-standardized EC extract against SARS-CoV-2, IAV, and RSV, either as monotherapy or in multiple-dose combinations. Methods: MDCKII cells were infected with IAV_PR8, human Calu-3 lung epithelial cells with the SARS-CoV-2 Omicron variant, and HEp-2 cells with RSV (A2 strain). Inhibitors were administered either by pre-incubation of cell-free virions prior to infection or, in separate time-of-addition experiments, during or post-infection. Viral replication was quantified by qRT-PCR or intracellular immunostaining. Cytotoxicity was evaluated using a neutral red uptake assay. Results: Most intriguingly, both EC and IC are able to neutralize virions derived from SARS-CoV-2, IAV, or RSV extracellularly in a dose-dependent manner. Notably, EC and IC alone exhibited strong anti-RSV activity, which was not reported previously. Most importantly, combined treatment with IC and EC caused a pronounced synergistic antiviral effect against the tested viruses, as confirmed by the Bliss independence model, without any detectable impact on cell viability. Finally, solutions prepared from matrix-standardized mono- or combi-lozenges, containing IC and/or EC in high or low doses, reproduced the antiviral and synergistic combination effects observed with the pure compounds. Conclusions: In summary, these findings support further development of EC and IC as a topically accessible, virion-neutralizing combination (e.g., lozenges) to provide additional protection against major respiratory viruses and potentially strengthen pandemic preparedness. Full article

Lignin, a complex and heterogeneous polymer, poses significant challenges for effective thermal valorization due to its broad molecular weight distribution and structural diversity. This study systematically compares the effect of lignin’s molecular weight on product distribution under pyrolysis and Ru/C-catalyzed depolymerization conditions. Fractionated lignin samples with distinct molecular weights were subjected to identical thermal and catalytic conversion pathways. Pyrolysis results indicate that, compared with low-molecular-weight (low-MW) lignin, high-molecular-weight (high-MW) lignin more readily generates phenolic compounds, with the relative content of guaiacol increasing by nearly twofold. In contrast, products derived from low-MW lignin contain a higher abundance of unsaturated structures, such as 4-allyl-2,6-dimethoxyphenol, suggesting that side chain cleavage and rearrangement reactions are more pronounced. In contrast, Ru/C-catalyzed depolymerization exhibits a stronger molecular-weight-dependent selectivity, where low-MW lignin is more readily converted into carboxylic acids due to enhanced accessibility of terminal functional groups and reduced structural condensation. This comparative analysis demonstrates that lignin’s molecular weight plays a process-dependent role in governing product distribution, providing guidance for tailored lignin valorization strategies. Full article

Yerba mate (Ilex paraguariensis) is a widely consumed beverage recognized for its high antioxidant content and bioactive compounds with health-promoting properties. Concentrating yerba mate extracts represents a valuable opportunity for industrial applications, including food packaging. Block freeze-concentration is a promising technology for concentrating food solutions while preserving functional compounds. In this context, the use of biodegradable polymers combined with natural components derived from by-products aligns with circular economy principles. This study aimed to develop an active and intelligent biopolymer film using residues from the block freeze-concentration of yerba mate extract (ice fraction). The film was produced by the casting method. Block freeze-concentration was performed in three stages, and process efficiency was evaluated using ice fraction 3. The films were characterized for physical, mechanical, thermal, antioxidant (total phenolic content, DPPH, and ABTS), and intelligent properties, including pH-responsive color changes, thickness, biodegradability, barrier performance, molecular structure by FTIR spectroscopy, and morphology by scanning electron microscopy (SEM). The main results showed a total phenolic content of 1.01 ± 0.02 mg GAE g⁻¹ of film, 2094 ± 5.00 µmol TE g⁻¹ for DPPH, and 1610.00 ± 8.00 µmol TE g⁻¹ for ABTS. Color changes observed at different pH levels (4, 7, 10, and 12) demonstrated the film’s potential for application in intelligent packaging as a freshness indicator. The film exhibited complete disintegration under soil burial conditions within 45 days. The film presented a water vapor permeability of (1.80 ± 0.01) × 10⁻⁷ g H₂O·m⁻¹·s⁻¹·Pa⁻¹ and an average thickness of 0.26 ± 0.03 mm. As a result, these findings indicate that products derived from block freeze-concentration residues of yerba mate extract can be effectively applied in sustainable food packaging systems, contributing to shelf-life extension through antioxidant preservation and intelligent functionality. Full article

Thermal barrier materials play a crucial role in reducing heat transfer, suppressing thermal runaway (TR) propagation, and mitigating the risk of fire and explosion. Among the various types of thermal barrier materials, polymer-based thermal barrier materials, including polyimide (PI), aramid, epoxy resin (ER), polyurethane (PU), phenolic resin (PR), and silicone, have been widely applied in lithium-ion battery (LIB) safety protection owing to their excellent thermal stability, structural tunability, and favorable processability. This review provides a systematic and comprehensive overview of polymer-based thermal barrier materials for mitigating thermal runaway propagation in LIBs. The propagation pathways of TR in battery systems are first outlined to clarify the functional requirements of thermal barrier materials. Subsequently, representative classes of polymer materials are reviewed with emphasis on their structural characteristics and advantages. Strategies for enhancing thermal insulation, flame retardancy, heat absorption capacity, and mechanical robustness are then summarized in the context of thermal safety protection. Finally, key challenges associated with polymer-based thermal barrier materials are discussed, and future development directions are proposed. Full article

Armoracia rusticana (horseradish) is rich in bioactive compounds such as glucosinolates, phenolic compounds, and vitamin C, highlighting promising potential for innovative food applications, while its use in food packaging materials remains largely unexplored. This study aimed to evaluate how the concentration of horseradish root powder affects the properties of novel bioactive membranes formulated with sodium alginate, glycerol and soy lecithin. The physicochemical, mechanical, barrier and optical properties of the membranes, as well as their specific antioxidant and antimicrobial capacity, were investigated. The structure of the membranes was analyzed in terms of the functional groups and the possible interactions between the polymer matrix components using FT-IR analysis. Alongside microscopic observation of the membrane surfaces at 40× magnification, the roughness of the membranes was investigated, as well as the influence of parameters corresponding to the homogeneity and uniformity of the developed edible food membranes. The results show significant differences in the determined properties, highlighting good barrier capacity against water vapor and UV radiation, as well as high tensile strength and elongation at break values of 17.54 ± 1.18 N and 65.6 ± 9.63%, respectively. Values progressively increase as the content of incorporated plant material rises. The addition of horseradish positively influenced the composition of the membranes, increasing their antioxidant activity values by up to 34.92 ± 0.06%. Full article

A lightweight composite that simultaneously exhibits high strength and excellent thermal insulation is of great interest for thermal protection applications. In this study, dimensionally stable needled quartz fiber felt-reinforced phenolic aerogel composites were prepared using vacuum impregnation, sol–gel, and ambient pressure drying. The composites exhibit a multiscale porous structure formed by interconnected nanometer polymer skeletons and micronscale fibers. By regulating the thermoplastic phenolic resin concentration in the precursor solution, the pore structure of the material was refined; the average particle diameter reduced from 99.76 nm to 38.91 nm, and the average pore diameter decreased from 216.79 nm to 49.53 nm. At a phenolic resin concentration of 25%, the composite exhibits outstanding thermal insulation and mechanical properties: a low thermal conductivity of 0.0646 W·m⁻¹·K⁻¹ at room temperature, with a mere 19.5 °C temperature rise on the sample backside after 1800 s heating at 200 °C, and compressive strengths of 7.70 MPa in the XY-direction and 3.87 MPa in the Z-direction (at 10% strain). X-ray micro-CT characterized the internal structural evolution during loading, revealing a failure mechanism dominated by fiber buckling. Theoretical models and experimental data were used to analyze and quantify the contribution rates of gas and solid heat conduction in NQF/PR aerogel composites, with solid conduction accounting for over 80%. Combined with microstructural evolution, the mechanism for the high thermal insulation efficiency of NQF/PR aerogel composites was elucidated. This study prepared NQF/PR aerogel composites with promising application potential. By systematically evaluating their compressive behavior and quantifying the respective contributions of gas and solid conduction, this work provides a methodological framework to guide the rational design of similar aerogel composites. Full article

Maize bran is an abundant cereal byproduct and a promising source of ferulated arabinoxylan biopolymers (FAXs). In this study, alkaline hydrolysis was optimized for FAX extraction from maize bran using a design-of-experiments approach evaluating alkali concentration, extraction time, and temperature. Purified FAXs were characterized for their chemical composition, phenolic and ferulic acid content, antioxidant activity, microstructure, and functional properties using GC–MS, HPLC, FT-IR, SEM, and standard antioxidant and functional assays. The FAX yields ranged from 14.7 to 18.9%, producing arabinose- and xylose-rich polymers (A/X ratio 0.68–0.74) with a high proportion of bound ferulic acid. Antioxidant assays (FRAP, ABTS, and DPPH) showed that alkaline-extracted and bound phenolic fractions exhibited substantially higher antioxidant capacity (p ≤ 0.05) than free phenolics, highlighting the importance of phenolic association with the arabinoxylan backbone. The FAX 3 extract also showed high activity in both the alkaline-extracted phenolic compounds (905.0 μg/g TE) and fraction II (286.5 μg/g TE), indicating that specific structural features may contribute to its bioactivity. In addition, FAXs demonstrated high water-holding capacity and favorable emulsifying properties. These results support the recovery of maize bran-derived FAXs as functional, antioxidant-active ingredients for food and related applications. Full article

Wine alcoholic fermentation occurs in a dynamic biochemical environment where interactions between the vessel and the product can cause inorganic and organic species to migrate into the fermenting must or wine. At low pH and with rising ethanol levels, fermentation tanks made of stainless steel, concrete or cementitious materials, ceramics, or polymers exhibit material-specific behaviors that may promote the release of toxic trace elements or alter technologically important ions. These changes can affect yeast physiology, fermentation kinetics, and matrix stability, directly impacting wine safety and quality. They may also influence the evolution of key fermentation metabolites and phenolic constituents, thereby affecting process performance, color development, oxidative stability, and other quality-related attributes. This review synthesizes current evidence on migration mechanisms and examines how vessel composition shapes the chemical and microbiological profile of fermentation. It also critically evaluates biosensor technologies—covering both biorecognition elements and signal-transduction strategies—and assesses the transition from laboratory prototypes to in situ or at-line implementations capable of detecting both migration-related events and process-relevant compositional changes with operational value for HACCP-based control. Electrochemical, optical, bienzymatic, and nanozyme-enabled platforms are discussed in terms of selectivity, matrix compatibility, and long-term functional stability under polyphenol and protein interference, CO₂ variability, fouling and biofouling, and calibration drift. Particular attention is given to analytes associated with vessel-derived migrants and to biosensor targets related to fermentation metabolites and phenolic indicators, which support dynamic process monitoring and quality-focused decision making. Considering regulatory compliance requirements across the EU, US, and Asia, we propose a practical pathway for integrating biosensors into HACCP monitoring by treating vessel–product interactions as critical control points, while laboratory reference methods remain essential for verification and compliance documentation. Full article

Waste lignin from the hydrolysis of lignocellulosic materials is an abundant but underused by-product of the pulp and biorefinery industries. Phenolic compounds derived from lignin, rich in aromatic structures, show strong antioxidant potential and can be applied in polymer stabilization, food, and medical fields. This study evaluated the radical-scavenging activity of phenolic fractions obtained from alkaline-treated waste lignin against DPPH● and ABTS•⁺, using Trolox as a reference. Both spectrophotometric and electrochemical techniques were employed, providing deeper insight into the underlying mechanisms. Depending on the assay, the phenolic extracts demonstrated substantial radical-scavenging capacity, in some cases matching or surpassing that of Trolox. This behavior was linked to electron/proton transfer pathways, radical reactivity, and solubility effects. The combined use of multiple antioxidant tests offered a comprehensive characterization of the bioactivity of lignin-derived phenolics and supports their potential as sustainable sources of antioxidant compounds within a circular economy framework. Furthermore, the study examined how toluene-extracted phenolics affect the thermo-oxidative stability of model polyurethane films. Incorporating small amounts (1%, 3%, 5%) into the polymer matrix showed that a 1% loading provides the most effective stabilization. At higher concentrations, however, additional oxidative processes seem to be activated, as indicated by FTIR measurements and thermogravimetric analysis. Full article

A new series of polyamides (PAs) employing two phenolic natural compounds as starting materials, eugenol and chavicol, has been successfully prepared. The synthesis was carried out through a solvent-free protocol using the environmentally friendly organocatalyst 1,5,7-triazabicyclo[4.4.0]dec-3-ene (TBD). The obtained materials have been properly characterized. Moreover, the prepared materials, all of them amorphous, showed a wide range of transition temperatures (T_gs) depending on the structure of the diester counterpart used in the polymerization reaction. In addition, the influence of the methoxy group present in eugenol on the thermal properties of the resulting polyamides was studied. The synthesized polyamides demonstrated excellent thermal stability, high hydrophobicity, and great dimensional integrity. Furthermore, the obtained polymers could be depolymerized under alkaline hydrolysis conditions to yield, with good to excellent recovery ratios, the corresponding starting diamine monomer, which could eventually be used in the synthesis of new polymers. Closed-loop chemical recycling emerges as a sustainable alternative to conventional end-of-life management strategies for discarded polymers, while also constituting a promising pathway to mitigate the accumulation of polyamide (PA) waste. Full article

This study evaluates the environmental footprint of producing a polymer flocculant synthesised from phenol–formaldehyde resin waste (novolak T) at a quarter-technical scale, with electricity supply assumed from photovoltaic (PV) generation. A cradle-to-gate life cycle assessment was performed in SimaPro Developer v9.4 using the Environmental Footprint (EF) 3.0 method and ecoinvent datasets. The functional unit was 100 kg of the sodium salt of the sulfonic derivative of novolak T. The characterization results indicate a climate change impact of 170.1 kg CO₂ eq and an acidification impact of 5.99 mol H⁺ eq per functional unit. Hotspot analysis shows that process chemicals dominate most impact categories: sulphuric acid production drives acidification and several air-emission-related categories, while sodium carbonate is a major contributor to toxicity- and eutrophication-related indicators. In contrast, electricity has a marginal contribution across categories. Recycling of novolak waste provides a strong compensatory credit, leading to net negative results in selected categories, including resource use and fossils (−5.02 × 10³ MJ). Overall, the results indicate that improving the upstream supply chains and the consumption of process reagents are the primary levers for reducing the environmental footprint of this waste-derived flocculant. Full article

This study addresses the challenge of high-temperature gas channeling in injection–production wells of karst-fractured reservoirs by developing a high-temperature-resistant resin–gel plugging system capable of withstanding up to 150 °C. The system employs an AMPS/NVP copolymer (molar ratio 3:1) as the polymer matrix, reinforced with phenolic resin to enhance the crosslinked network. Additionally, a polyamide microcapsule was utilized to encapsulate the gel breaker, enabling controlled release. The optimized formulation consists of 0.5% NEP, 0.5% DEP, 0.6% HMTA, 0.3% catechol, and 25% resin curing agent. Experimental results demonstrate that the system exhibits excellent stability at 150 °C, with a G′ ≥ 125 Pa and compressive strength > 18 MPa. It also displays strong contamination resistance, showing a viscosity reduction of <9.7% and a storage modulus retention rate > 87% after mixing with drilling fluid. Furthermore, the gel-breaking performance is controllable, achieving a gel-breaking rate ≥ 99.7% within 21 days. Under high-temperature and high-pressure conditions (150 °C), the system demonstrates a plugging efficiency > 92% for simulated fractures with widths ranging from 0.1 to 2 mm. This technology effectively suppresses gas channeling in complex high-temperature formations, making it suitable for gas injection wells in karst-fractured reservoirs. It also holds promise for extension to shale gas wells and geothermal reservoir sealing applications. Full article

Background/Objectives: Alginate-based rafts are typically used for antacids and provide a floating, gastric-retaining gel in the stomach that acts as a barrier to the entrance of stomach acid into the esophagus. Various technologies have been developed to enhance the sustained release of drugs and bioactive components and overcome challenges associated with gastric retention. Modern methods, such as the alginate raft, not only function as an antacid in gastroesophageal reflux disease but also can serve as a delivery system that extends the drug release time in gastric medium. This study assessed the effects of biocompatible natural polymers, such as Plantago major mucilage (PMM), on raft formation instead of synthetic polymers, such as Carbomer. Methods: PMM was substituted in the raft formulation at concentrations of 0.5% and 1%. The formed rafts were analyzed for their physicochemical, mechanical, and structural properties. To evaluate the sustained release potential of the optimized raft formulation, the aqueous extract of Artemisia annua L. was incorporated into coconut protein nanoparticles and loaded into the optimized raft at three different concentrations of 1%, 2%, and 3%. Results: The rafts formulated with PMM 0.5% revealed excellent stability of the suspension, as well as improved physicochemical properties of the developed rafts compared to the raft that included Carbomer. The results illustrated that the inclusion of PMM in the raft system enhances antacid capacity, swelling percentage, resilience time, strength, and a stiffer gel with a higher G′. Conclusions: The optimized PMM raft was able to prolong the in vitro release of phenolic extracts and reach the cumulative release of less than 30% after 6 h. Full article