Search Results (1,979)

Poly(vinyl alcohol) (PVA)–bentonite composite coatings combine a hydrophilic polymer with a naturally abundant clay mineral, offering potential advantages for modifying the physicochemical and film-forming characteristics of polymer–clay coatings. However, the combined influence of PVA–bentonite composition and total solids content on drying behavior and film evolution remains insufficiently explored. This study investigates the particle size, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), surface morphology, rheology, thixotropy, zeta potential, drying behavior, solvent transport, and film evolution of PVA–bentonite coatings prepared at total solids contents of 5 and 10 wt.% with different PVA to bentonite ratios. The drying profiles exhibited an initial relatively rapid solvent-removal stage followed by a slower stage associated with progressively restricted solvent transport during film consolidation. A lower total solids content (5 wt.%) generally accelerated drying but was associated with greater microcracking, whereas a higher total solids content (10 wt.%) produced more consolidated and comparatively uniform films with reduced solvent mobility. The combined physicochemical, rheological, drying, and morphological results demonstrate that both PVA–bentonite composition and total solids content substantially influence the structural organization and drying behavior of the coatings. Pure PVA formed a relatively uniform film but exhibited prolonged drying, while pure bentonite required the longest drying time (1083 min). Among the investigated formulations, the 50:50 PVA–bentonite coating demonstrated the shortest drying time, reaching equilibrium in approximately 480 min, while also exhibiting comparatively good film uniformity. During drying, its thickness decreased from approximately 1745 to 440 µm, corresponding to a reduction of about 1305 µm. Overall, under the investigated laboratory conditions, the 50:50 PVA–bentonite formulation provided the most favorable balance of drying behavior, film formation, and rheological characteristics among the compositions studied. These findings provide composition–structure–drying relationships that can guide further development of PVA–bentonite coating systems. At the same time, additional evaluation of mechanical, adhesion, barrier, durability, and economic performance is required to establish broader practical applicability. Full article

Developing biodegradable active packaging films that combine mechanical reinforcement, barrier improvement, antibacterial activity, and controlled release of natural antimicrobials remains challenging. Here, TEMPO-oxidized bacterial cellulose (TOBC) was used to stabilize clove essential oil (CEO) Pickering emulsions, which were incorporated into sodium alginate (SA) matrices. The effects of TOBC concentration on emulsion stability and emulsion loading on film-forming solutions, film structure, mechanical performance, barrier properties, antioxidant and antibacterial activities, and CEO release were evaluated. The emulsion stabilized with 0.7 wt% TOBC showed good visual stability after 30 days and was selected for film preparation. Moderate incorporation of the TOBC-stabilized CEO Pickering emulsion improved SA film performance, with SA-E10 showing the best overall balance. SA-E10 reached a tensile strength of 38.56 ± 1.66 MPa and an elongation at break of 10.27%, while the moisture content decreased from 36.48 ± 2.32% to 27.93 ± 0.46%. The films also showed enhanced UV-shielding capacity and lower water vapor permeability. Antioxidant activity increased with emulsion loading, reaching 71.43 ± 2.55% for DPPH and 83.66 ± 1.49% for ABTS. Film-coated paper disks showed visible inhibition zones against Escherichia coli and Staphylococcus aureus. Compared with direct CEO incorporation, the Pickering emulsion system delayed CEO release, indicating potential for sustained-release active packaging. Full article

The artificial lighting demand of buildings is a controllable sustainability lever, whereas metalized food-packaging waste (i.e., multilayer polymer-aluminum films used for barrier protection) is difficult to recycle and routinely landfilled or incinerated, representing an underexplored circular-economy opportunity. This simulation-based feasibility study connected both objectives by investigating whether metalized snack-packaging waste can function as a daylight-redirecting surface on a faceted interior light shelf. Five configurations were simulated in VELUX Daylight Visualizer 3 using Ankara’s EnergyPlus Weather climate file (39.93° N): a no-shelf baseline (S1), white (ρ = 0.80) and metalized (ρ = 0.80–0.88) flat shelves (S2, S3), and faceted equivalents (S4, S5). None of the five scenarios met the EN 17037:2018 sufficiency threshold (DA300 ≥ 50%); the best configuration, S5 (faceted, metalized), reached DA300 = 40.23%. Within this limitation, S5 outperformed all comparators, averaging 3116 lux (9.6× baseline) and achieving a uniformity ratio of 0.823. Faceted geometry increased illuminance by 1.74–1.78× over an equivalent flat metalized shelf; metalized flat shelves outperformed the white ones by 1.44–1.54×, except in September, when high solar altitude caused a 0.83–0.89× reversal, eliminated by faceting. S5 reduced artificial lighting dependency from 78.42% to 59.77% of occupied hours (~101 kWh/yr, first-year estimate) and nearly halved critical daylighting-deficit hours (49%). However, it exceeded the 2000 lux useful-daylight ceiling in ~55% of occupied hours, indicating that glare mitigation is necessary for deployment. These preliminary results warrant further experimental and life-cycle work before the sustainability benefits of the circular economy pathway can be established. A sensitivity analysis confirms that S5’s daylighting advantage persists, though at reduced magnitude, under both a conservative reflectance assumption (ρ = 0.80) and a more energy-representative window-to-wall ratio (47.5%). Full article

Titanium alloys are widely used for implants, yet corrosion, bacterial colonization and incomplete osseointegration remain important causes of interfacial failure. This review critically analyzes major biomedical functional coating fabrication techniques employed to enhance the surface properties of titanium alloys, including micro-arc oxidation, anodic oxidation, magnetron sputtering, electrochemical deposition, electrophoretic deposition, plasma spraying, physical vapor deposition, plasma immersion ion implantation, laser surface treatment, and hybrid (composite) approaches. For each method, key operational principles, structural and functional characteristics, performance advantages and limitations, and representative application domains are critically analyzed. Across these routes, biological performance depends on coating continuity, pore or nanotube geometry, interfacial bonding, phase composition and ion release. Calcium- and phosphorus-rich oxides and hydroxyapatite deposits generally promote cell adhesion, proliferation, alkaline phosphatase activity, mineralization and osteogenic differentiation. Dense oxide, nitride, tantalum and carbon-based films strengthen corrosion barriers, whereas Mn, Zn, Cu and Ag containing surfaces can inhibit bacterial adhesion and biofilm formation. Excessive ion release, however, may compromise cytocompatibility. Reported outcomes also vary with test medium, exposure time, bacterial strain and cell model. Standardized quantitative endpoints and longer-term corrosion, biofilm and osseointegration studies are required to guide clinically reliable multifunctional coatings. Full article

This study developed surface-functionalized polylactic acid (PLA) films by depositing electrospun gelatin/chitosan (GE/CH) nanofibrous coatings formulated with and without bioactive phenolic compounds (curcumin and anthocyanin). Evaluating various polymer blending ratios and operational parameters revealed that a GE:CH ratio of 7:3 (v/v), processed at an applied voltage of 25 kV and a collector speed of 300 rpm, provided the most stable electrospinning behavior among those tested, yielding a uniform nanoscale fibrillar network. The deposition of this selected GE/CH layer onto the PLA substrate significantly improved the composite bilayer film’s tensile strength and oxygen barrier properties, although it increased macroscopic opacity. Furthermore, active coatings containing 0.25% and 0.50% (w/w) curcumin or anthocyanin were successfully processed. This 0.50% level was the maximum concentration quantitatively evaluated in the present study, as preliminary observations suggested poorer processability at higher concentrations, which induced premature gelation and needle clogging. While interactions (mostly non-covalent physical interactions) associated with the phenolic compounds synergistically reinforced the mechanical rigidity and reduced the water vapor permeability of the bilayer films, the macroscopic bioactive functionality was limited. The low loading concentrations, coupled with severe optical masking and restricted aqueous extraction, resulted in moderate antioxidant activity (10.31–30.46% DPPH radical inhibition) and no visually detectable halochromic (pH-responsive) color changes. Overall, these findings highlight a significant functional trade-off in the design of active coatings, where structural and mass transport barrier enhancements are achieved, but macroscopic bioactive functionality is constrained, underscoring the necessity for advanced encapsulation strategies in future developments. Full article

Cholesteric liquid crystals (CLCs) possess the unique ability to selectively reflect incident circularly polarized light, exhibiting tremendous potential in diverse optical applications. In this study, a trilayer composite architecture of polymer-stabilized cholesteric liquid crystals (PSCLCs) was successfully fabricated. Introducing poly(vinyl alcohol) (PVA) as intervening barrier layers enabled the formation of independent and mutually non-interfering broadband reflection bands within each respective layer. Initially, a single-layer system was evaluated to identify the effects of component concentrations and polymerization conditions on the reflection bandwidth. Under optimal conditions, a maximum reflection bandwidth of 890 nm was achieved. Building upon these parameters, the effective concatenation of two independent reflection bands was accomplished by precisely regulating the concentration of the chiral dopant R5011 in the adjacent layers. Subsequently, the trilayer PSCLC film was constructed, ultimately broadening the total reflection bandwidth to 1650 nm. Characterization via polarized optical microscopy (POM) confirmed that the liquid crystal molecules consistently maintained a well-defined planar texture throughout the fabrication process of the multilayer films. Additionally, the film shows good infrared shielding performance. Its ability to regulate ambient light makes it highly promising as an optical filter and thermal management component in LC smart windows and emerging displays. Full article

The extensive use of common petroleum-based plastics in food packaging has raised serious environmental concerns, accelerating the search for biodegradable and functional alternatives. In this study, poly(butylene adipate-co-terephthalate)/curcumin (PBAT/Cur) bioactive composite films with colorimetric sensing properties were successfully prepared via solution casting. A systematic characterization was conducted on the structural, morphological, barrier, antioxidant, antibacterial, and colorimetric properties of the films. The optimal PBAT/Cur1% films exhibited potent antioxidant activity (DPPH scavenging up to 95.6%) and moderate antibacterial activity against E. coli and S. aureus. Additionally, curcumin incorporation not only increased the water contact angle of the PBAT/Cur1% films, indicating enhanced surface hydrophobicity, but also concurrently improved the barrier properties, as evidenced by a reduced water vapor permeability (WVP of 14.58 g·mm/m²·day·kPa) and a lower oxygen transmission rate (OTR of 7.533 × 10⁻³ cm³/m²·day·Pa) compared to the neat PBAT films. Notably, the films displayed a distinct and rapid color change from yellow to reddish-brown upon exposure to ammonia vapor, suggesting their promise for on-package visual freshness indication. These findings highlight PBAT/Cur composite films as a sustainable option for active and intelligent food packaging, with combined antioxidant, antibacterial, and colorimetric properties, making them promising for packaging protein-rich foods (e.g., meat and seafood). Full article

Poly(lactic acid) (PLA) is a renewable and biodegradable polymer that has attracted considerable attention for sustainable packaging applications. However, its inherent brittleness limits its use in flexible films. In this study, PLA/poly(vinyl alcohol) (PVA) blend films were prepared by a single-solvent-casting rout at PLA/PVA weight ratios of 80/20, 70/30, 60/40, and 50/50 to investigate the influence of composition on their thermal, chemical, morphological, mechanical, optical, and water vapor barrier properties. Increasing the PVA content progressively modified the molecular organization of the system, the crystallization ability of the PLA phase and promoting a more homogeneous phase distribution. These structural changes resulted in a transition from a brittle behavior to increasingly ductile films, with the PLA/PVA 50/50 composition exhibiting the most favorable combination of tensile toughness, transparency, and morphological homogeneity, reaching an elongation at break of approximately 60%. In contrast, the increase in the hydrophilic phase led to higher water vapor permeability, highlighting the trade-off between mechanical performance and moisture barrier properties. Overall, the results demonstrate that controlling the PLA/PVA ratio provides an effective strategy for tailoring the morphology and functional properties of solvent-cast PLA/PVA films, contributing to a better understanding of the composition–structure–property relationships in biopolymer blends. Full article

Fresh-peeled garlic cloves are a very convenient ready-to-cook product; however, their high perishability requires packaging systems that maintain the quality of the garlic while addressing the need for more sustainable materials. This study evaluated the quality evolution of peeled garlic cloves during refrigerated storage (5 °C) in microperforated modified atmosphere packaging (MAP) systems consisting of trays sealed with egg white protein (EWP)-based films, either uncoated (EWP-U) or coated with beeswax (EWP-BW). Their performance was compared with commercial polylactic acid (PLA) and oriented polypropylene (OPP) films. The EWP-based packages generated an internal atmosphere of approximately 7% O₂ and 15% CO₂, under which peeled garlic cloves showed delayed fungal decay, reduced yeast and mold growth, and mitigated surface discoloration compared with other packaging systems, whose atmospheres remained closer to air. However, weight loss was promoted in the garlic cloves packaged with EWP-U films. The hydrophobic coating applied in EWP-BW films improved the water vapor barrier properties compared with EWP films, thus reducing the weight loss observed in the garlic cloves, but increasing fungal decay. These results suggest that an optimized packaging system should combine the lower water vapor transmission rate provided by EWP-BW films with the internal gas composition achieved in EWP-U packages. Accordingly, EWP-BW films represent a promising bio-based alternative for preserving the quality of peeled garlic cloves, provided that the effective O₂ and CO₂ transmission rates through the package are appropriately adjusted to generate a more favorable modified atmosphere. Full article

With the rapid development of recycling and secondary utilization of end-of-life battery materials, it is crucial to clarify the impact of full-lifecycle degradation on the thermal safety limits of lithium-ion batteries. This study focuses on a 16 Ah NCM613|graphite pouch battery. First, it analyzes the evolution of capacity decay, thickness expansion, and internal resistance during cycling at room temperature (25 °C) and high temperature (45 °C). Furthermore, an adiabatic accelerated calorimeter (ARC) is employed to investigate the influence of different states of health (SOH) levels (95% and 85%) on the battery’s thermal runaway characteristics. The findings indicate that, macroscopically, batteries in all states follow similar voltage–temperature failure pathways, with mass loss rates confined to a narrow range of approximately 16%, emphasizing the low catastrophic potential of mid-nickel chemistry. However, the microscopic kinetic mechanisms exhibit significant anisotropy: although thickness and internal resistance display no apparent abrupt increase during the late stage of room temperature aging, the capacity exhibits a highly nonlinear plunge behavior. The severe internal lithium plating side reaction triggered by this phenomenon causes the self-heating onset temperature to drop rapidly from 130.0 °C in the fresh state to 79.7 °C. Concurrently, the activation energy of the exothermic side reaction, fitted using a simplified Arrhenius equation, exhibits a non-monotonic variation with aging progress. In the early stages of aging at 95% SOH, due to high temperatures promoting more significant growth of the interfacial film or moderate film formation at room temperature enhancing interfacial thermal stability, the activation energies for both aged batteries increase, and the energy barrier at high temperatures is slightly higher than at room temperature; however, during the deep aging stage at 85% SOH, due to the degradation of active material components and the emergence of lithium plating characteristics, the energy barrier significantly decreases, with high-temperature-aged batteries exhibiting a greater reduction, highlighting the cumulative negative impact of prolonged high-temperature exposure on thermal safety. The research provides a core scientific basis for establishing a battery safety early warning and dynamic health management system covering the entire lifecycle. Full article

The rising health consciousness among Millennials and Generation Z is boosting the demand for non-alcoholic and low-alcohol beers (NABLABs), which offer the sensory appeal of beer with fewer ethanol drawbacks. This study aims to provide a comprehensive overview of this sector, covering market trends, regulatory complexities, and the technical aspects of biological and physical dealcoholisation methods, and offering insights into production costs and environmental impact. The global market for NABLABs is experiencing rapid growth, with a projected compound annual growth rate of approximately 7% (2024–2028) and an estimated market value approaching USD 44 billion by 2034. Market penetration remains geographically heterogeneous, and there is a lack of regulatory harmonisation, particularly within the European Union, where national thresholds for ethanol content classification diverge significantly. From a process engineering perspective, NABLAB production can be achieved using two main technological approaches: (i) biological ethanol limitation strategies, encompassing controlled mashing, arrested fermentation, cold-contact fermentation and the use of maltose-negative or genetically modified yeast strains, and (ii) post-fermentation dealcoholisation, employing thermal separation technologies, such as vacuum distillation, thin-film evaporation and spinning cone columns, or membrane-based processes such as reverse osmosis, nanofiltration, pervaporation, osmotic distillation and dialysis, alongside emerging supercritical CO₂ extraction. A critical technological trade-off persists between the efficiency with which ethanol is removed and the retention of volatile flavour-active compounds, including esters and higher alcohols. It is evident that biological processes are associated with the accumulation of worty aldehydes and the attenuation of antimicrobial barriers, resulting in increased risks to microbiological safety. Empirical evidence has been documented showing that E. coli O157:H7, Salmonella enterica, and Listeria monocytogenes have been found to survive for extended periods in craft NABs exhibiting pH > 4.20 and an alcohol-by-volume (ABV) < 0.5%. This emphasises the importance of validated thermal or sterile filtration treatments, particularly in the craft beer sector. Full article

Freshwater crayfish impact ecosystems and the food industry. The aim of the study was to valorize shells from the invasive crayfish, Faxonius limosus, to extract novel bioactive biopolymers and prepare biodegradable films, thereby contributing to economic and environmental sustainability. Chitin from crayfish shells was isolated and converted into chitosan through a new protocol to retain astaxanthin, with a shorter procedure, reduced use of organic solvent and energy consumption. The resulting biopolymers were used to prepare chitosan-based films. Thermal, spectroscopic, barrier properties, and surface microstructure of the biomaterials were identified. Spectrophotometric and chromatographic techniques were used on crayfish shells and biopolymers to track astaxanthin throughout the extraction and formulation processes. Crayfish chitosan film exhibited higher stiffness, enhanced thermal stability and water vapor barrier properties with respect to commercial chitosan films. 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl antioxidant assays showed that all crayfish biomaterials exhibited antioxidant activity. Astaxanthin greatly enhanced the antioxidant properties of crayfish chitosan, but chemical degradation during film processing limited this effect in the film matrices. Therefore, crayfish-derived biopolymers and films are promising for incorporation into functional foods and active packaging and support shell waste reduction, offering a viable strategy for managing and valorizing invasive species. Full article

Quercetin is a plant-derived flavonol positioned at the interface of metabolic health and food preservation. This review integrates quercetin chemistry, plant biosynthesis and metabolism, production-relevant extraction and microbial synthesis, bioavailability, mechanisms of action, preclinical and clinical evidence in metabolic syndrome (MetS), and applications in clean-label food preservation. Experimental studies indicate that quercetin modulates obesity-associated inflammation, dyslipidemia, hepatic steatosis, insulin resistance, hypertension, endothelial dysfunction, and gut-barrier impairment through interconnected Nrf2/HO-1, NF-κB/NLRP3, AMPK/SIRT1, PI3K/Akt, eNOS/NO, lipid metabolism, and microbiota-related pathways. Human evidence is narrower and heterogeneous: modest reductions in systolic blood pressure constitute the most consistent signal, whereas effects on fasting glucose, lipids, inflammatory markers, endothelial function, liver fat, and body weight vary by population, formulation, dose, and duration. In food systems, quercetin has been investigated as an antioxidant, antimicrobial, antibiofilm agent, and photodynamic photosensitizer. It is incorporated into edible films, coatings, freshness indicators, and controlled-release packaging, although most evidence remains laboratory-scale. Key translational challenges include limited aqueous solubility, variable bioavailability, incomplete long-term safety evidence, matrix-dependent efficacy, sensory constraints, manufacturing scale-up, migration, and regulation. Overall, quercetin is promising, but clinical use and industrial deployment require formulation-specific, adequately powered human studies and validation in clinically relevant populations and under commercially realistic processing conditions. Full article

Fish processing by-products represent an abundant source of valuable biomolecules that can be valorized through sustainable extraction approaches. In this work, cod backbone hydrolysates obtained by subcritical water hydrolysis were incorporated into chitosan-based films for potential food packaging applications. The hydrolysis residue, rich in minerals, particularly hydroxyapatite (HAp residue), was also incorporated into the films to maximize the utilization of all hydrolysis-derived fractions. The effects of hydrolysate and HAp residue incorporation on the properties of the films were evaluated. The hydrolysate incorporation significantly improved the tensile strength of the films (from 11.56 to 24.39 MPa) and reduced water vapor permeability (from 4.93 to 2.89 (×10⁻¹¹) mol.m.m⁻².s⁻¹.Pa⁻¹), suggesting the formation of a denser and cohesive polymer network. However, the films also exhibited increased swelling and solubility (22–29% and 231–561%, respectively). When adding HAp residue, the films showed lower visible light transmittance and higher opacity, demonstrating improved light barrier properties. The addition of HAp residue also reduced swelling capacity but increased water vapor permeability and decreased tensile strength, suggesting the formation of a more heterogeneous film structure. Overall, the results demonstrate that cod backbone hydrolysates can be an alternative additive to chitosan films to tailor their functional properties for food packaging applications. The incorporation of hydroxyapatite-rich residues contributes to the full valorization of fish processing by-products, supporting the development of sustainable and biodegradable functional materials within a circular economy approach. Full article

In this study, quaternary ammonium salts (QAS) with different alkyl chain lengths (C12 and C18) were incorporated into starch/poly(butylene adipate-co-terephthalate) (PBAT) matrices with ethylenediaminetetraacetic acid (EDTA) to prepare blown films. The film with the combination of QAS and EDTA (D18D12E) achieved antibacterial rates of ≥99% against both Staphylococcus aureus and Escherichia coli, while maintaining cytocompatibility with HepG2 cells (viability ≥ 70%) and preliminary tobacco-growth compatibility. Compared with the control, the D18D12E film showed lower tensile strength (7.60 MPa) and higher oxygen (22.42 × 10⁻¹³ cm³·cm·cm⁻²·s⁻¹·Pa⁻¹) and carbon dioxide permeability coefficients (22.10 × 10⁻¹³ cm³·cm·cm⁻²·s⁻¹·Pa⁻¹). Its elongation at break (805.80%) and water vapor permeability (4.03 × 10⁻¹¹ g·m·m⁻²·s⁻¹·Pa⁻¹) remained statistically comparable to those of the control. Furthermore, the D18D12E films delayed the visible deterioration of Chinese steamed bread and strawberries during 4 and 8 days of storage, respectively. These findings show that EDTA-assisted reduction in QAS loading can maintain antibacterial activity, but the associated mechanical and gas-barrier trade-offs require further formulation optimization. Full article