Search Results (122)

This work presents a green chemistry route to obtain titanium dioxide TiO₂ nanoparticles with an average size of about 13.25 nm using lemongrass (Cymbopogon citratus) extract. For these assessments, TiO₂ nanoparticles were added to the coating at concentrations of 1% and 5% w/w on fiber-cement sheets. Self-cleaning evaluation was analyzed by the photodegradation of methylene blue (MB) dye at concentrations of 5, 10, and 20 mg/L applied to the coated sheet, and then exposed to simulated sunlight. The coating containing 5 wt% TiO₂ nanoparticles showed the highest photodegradation, reaching 93.3% after 4 h under simulated sunlight exposure at the lowest MB concentration (5 mg/L). Additionally, average contact angles of 80.4°, 92.03°, and 104.25° were determined for coatings containing 0%, 1%, and 5 wt% TiO₂, respectively. Moreover, the modified 5 wt% TiO₂ exhibited up to 30.9% greater hydrophobicity than the control. Antifungal efficacy against Aspergillus niger and Penicillium was evaluated using the Poisoned Food method with nanoparticles at concentrations of 1 and 3 mg/mL showing a moderate growth inhibition. In conclusion, the versatility demonstrated suggests potential applications such as a nano-additive for aqueous acrylic coatings, improving hydrophobicity, self-cleaning and antifungal properties, which could be attractive to the construction industry. Full article

Bisphenol A (BPA) is an endocrine disruptor found in food-contact materials and, even at very low concentrations, poses a serious risk to human health. Therefore, its presence in food should be monitored. Optical fiber sensors are a highly advantageous option for detecting chemical contaminants; however, due to the low concentrations at which these compounds are found, the surface needs to be modified to promote interaction with the target compound. In this work, we present an optical fiber sensor incorporating a microstructured fiber that is sensitive to external media and, therefore, to refractive index variations. To increase sensitivity, the sensor was coated with a chitosan film, a polysaccharide with high biosorbent ability that has been proposed as an effective adsorbent for several contaminants, including BPA. The sensor was then characterized by its response to variations in BPA concentration from 0 to 0.1 mg/mL. The chitosan-coated sensor exhibited a sensitivity over three times higher than that of the uncoated sensor, with a resolution of 9.98 × 10⁻⁴ mg/mL. Washing assays revealed that, although the coating cannot be fully regenerated, the sensor can be reused without requiring a complex or time-consuming procedure. Full article

Advanced technologies, such as antimicrobial coatings on food contact surfaces (FCSs), are critical to prevent the occurrence of food-contaminating bacteria. Titanium dioxide coatings were fabricated by the sol–gel method on stainless steel following an experiment consisting of eight different combinations of these synthetic parameters: type of protocol (method), amount of surfactant, aging time, spinning speed, and sintering temperature. Hardness and elastic modulus values of the eight coating combinations were assessed by nanoindentation, and their values were statistically analyzed to determine which protocol and sintering temperature were significant influencing factors. Additional experimental points were procured to obtain trends relating sintering temperature to hardness and elastic modulus. Within the experimental range studied, hardness monotonically increased with sintering temperature, reaching its maximum value at 595 °C, while elastic modulus attained a maximum value at 640 °C. These maxima’s isotherms were overlapped on the coating’s photocatalytic activity contour plot to explore which combinations of protocol, aging time, and sintering temperature yielded optimal photocatalytic activity, hardness, and elastic modulus. The optimized coating was tested against two representative foodborne pathogens, Escherichia coli O157:H7 and Staphylococcus aureus cells and their biofilms, and was characterized by nanoindentation, scanning electron microscopy, and X-ray diffraction. The properties of the coating, as found in this study, present evidence for its potential FCS applications. Full article

This article presents the results of research on UV-curable epoxy coatings developed with selected plant modifiers such as garlic (Allium sativum), turmeric (Curcuma longa), common nettle (Urtica dioica), and privet (Ligustrum vulgare). This study aimed to evaluate the influence of these natural components on the functional properties of UV-cured coatings and to assess their potential as bio-based modifiers. The coatings were formulated using Epidian^® 5 epoxy resin, a safe and non-toxic material approved for food-contact applications, and cured with a commercial cationic photoinitiator. Their mechanical, surface, optical, and antibacterial properties were investigated. The results showed that all plant-based additives modified both the mechanical and esthetic characteristics of the coatings; however, garlic demonstrated outstanding antibacterial activity, achieving nearly complete inhibition of Staphylococcus aureus growth with a reduction rate of 99.998%. These findings highlight that natural modifiers, especially garlic, can serve as highly effective functional components, while future work should focus on implementing these coatings for surfaces exposed to bacteria, such as public utility items and shop, hospital, sports, and rehabilitation equipment. Full article

Edible coatings are widely used to modulate oil uptake and moisture in fried foods. In this study, we evaluated a microfluid-assisted flow-blurring spray against conventional application by dipping/spraying, focusing on the coating efficiency and preliminary implications for sustainable process. This study combines benchtop experiments with a near-nozzle numerical analysis where the gas–liquid interface and primary breakup are modeled using the Volume of Fluid (VOF) approach implemented in OpenFOAM, configured for a flow-blurring geometry to generate whey protein isolate (WPI) coatings. Viscosity, density, solid content, and contact angle were validated experimentally and used in the simulation setup. An image-based droplet pipeline quantified spray characteristics, yielding a volumetric median diameter D₅₀ = 83.69 µm and confirming process uniformity. Contact angles showed marked substrate dependence: hydrophilic surfaces, 68°–85°; hydrophobic surfaces, 95°–110°. For turkey sausages, sessile-drop contact angles were not determinable (N.D.) due to wicking/roughness; wettability was therefore assessed on smooth surrogates and via performance metrics. Fit-for-purpose simulation procedures are outlined. Microfluidic application (WPI-McF) lowered oil uptake versus uncoated controls. Together, robust modeling, targeted image analytics, and high-precision microfluidics enable rational tuning of coating microstructure and barrier performance, offering a scalable pathway to reduce lipid content and enhance fried food quality. Full article

In recent years, the use of silver nanoparticles (AgNPs) in various fields has been investigated due to their highly potent properties. One of these areas is the adaptation of AgNPs to food packaging/preservation technologies. The primary reasons for the use of AgNPs in food preservation studies are their high levels of antibacterial, antioxidant, and antifungal activities. In particular, the slow and controlled release of silver provides a sustained protective effect throughout the contact period of AgNP-integrated packaging with food and reduces microbial load by preventing biofilm formation. Furthermore, high thermal stability of AgNPs provides high protection to foods under various conditions. Their high surface-area-to-volume ratio, making them effective even at low concentrations, further supports AgNPs as a promising alternative in food preservation technologies. Moreover, their ease of surface modification facilitates the integration of these nanoparticles (NPs) into polymer matrices, biodegradable films, and coatings. Additionally, some AgNP-based films are also used in smart packaging applications, providing a color change indicator of degradation. Their broad pH tolerance enhances their applicability to a variety of food types, from dairy to meat products. For all these reasons, AgNPs are considered as one of the essential components of innovative food packaging to slow down food spoilage, prevent microbial contamination, and provide safer, longer-lasting products to the consumer, and studies on them are ongoing. Full article

Tetramethyl bisphenol F (TMBPF) is being increasingly used as a Bisphenol A (BPA) substitute, particularly as a coating material for food and beverage cans. Unlike BPA, TMBPF is considered safe because of the lack of reported estrogenic effects, and it is often marketed under the “BPA-free” label. Initial cell-based assays and rat toxicity studies indicated much lower systemic and sex hormone-related toxicity of TMBPF compared with BPA, which has facilitated its substitution and significant market expansion. Since 2021, however, a growing body of research has reported various adverse effects of TMBPF across multiple biological systems. These include cytotoxicity associated with apoptosis and endocrine-disrupting effects on the thyroid axis, skeletal system, neurodevelopment, and reproductive function. Although the effects on the estrogen and androgen systems, as well as obesogenic potential, show variability across studies, several studies have indicated significant biological impacts. Of particular concern is the potential neurodevelopmental toxicity, which may manifest only after long-term exposure and is often irreversible. Even if current leaching levels from food contact materials are minimal, environmental accumulation and biomagnification over time may pose significant risks. Therefore, comprehensive toxicological profiling of TMBPF is essential. This review summarizes the current toxicological findings on TMBPF and discusses the implications for future research and regulatory considerations, highlighting the importance of early attention to potential public health impacts. Strengthening the toxicological evidence base will help inform regulatory frameworks and support proactive measures to safeguard consumer safety as the use of TMBPF expands. Full article

This study investigates the potential of acetylated xylan as a functional component in coatings for biodegradable paper-based food packaging. Acetylated xylan was synthesized in the laboratory via the reaction of native beechwood xylan with acetic anhydride. Multilayer coatings composed of acetylated xylan, chitosan, and zinc oxide nanoparticles (ZnO NPs) were applied to paper substrates as single and double layers (approximately 5 g/m²) to enhance their barrier and antimicrobial properties. The coated papers were evaluated for mechanical properties, resistance to water, oil, and grease, antimicrobial activity against pathogenic bacteria, and biodegradability in soil. The combination of xylan derivatives with chitosan significantly improved surface hydrophobicity (contact angle ~87°) and achieved complete inhibition (100%) of Staphylococcus aureus and Salmonella spp., without compromising biodegradability. Incorporation of ZnO NPs further enhanced both the barrier properties and antimicrobial efficacy, particularly against S. aureus. A high biodegradation rate (~92%) was recorded after 42 days of soil burial. These results demonstrate the suitability of xylan-based multilayer coatings as sustainable alternatives for food packaging applications. Full article

Superhydrophobic surfaces, characterized by water contact angles greater than 150°, have attracted widespread interest due to their exceptional water repellency and multifunctional applications. However, traditional fabrication methods often rely on fluorinated compounds and petroleum-based polymers, raising environmental and health concerns. In response to growing environmental and health problems, recent research has increasingly focused on developing green superhydrophobic surfaces, employing eco-friendly materials, energy-efficient processes, and non-toxic modifiers. This review systematically summarizes recent progress in the development of green superhydrophobic materials, focusing on the use of natural substrates such as cellulose, chitosan, starch, lignin, and silk fibroin. Sustainable fabrication techniques, including spray coating, dip coating, sol–gel processing, electrospinning, laser texturing, and self-assembly, are critically discussed with regards to their environmental compatibility, scalability, and integration with biodegradable components. Furthermore, the functional performance of these coatings is explored in diverse application fields, including self-cleaning, oil–water separation, anti-corrosion, anti-icing, food packaging, and biomedical devices. Key challenges such as mechanical durability, substrate adhesion, and large-scale processing are addressed, alongside emerging strategies that combine green chemistry with surface engineering. This review provides a comprehensive perspective on the design and deployment of eco-friendly superhydrophobic surfaces, aiming to accelerate their practical implementation across sustainable technologies. Full article

Agricultural and food by-products offer valuable opportunities for circular and bio-based innovation across sectors. In the textile industry, replacing fossil-based coatings with sustainable alternatives is increasingly urgent. This study evaluates the performance of a textile coating based on coffee silverskin (CS)—an abundant by-product of coffee roasting—applied to four natural fibre substrates: cotton, lyocell, wool, and silk. A formulation combining 60% CS sludge (8% solids), treated by wet ball milling, with an aliphatic polyester-polyurethane dispersion was applied via knife coating. Standardised tests assessed mechanical resistance, air permeability, colour fastness, moisture management, and water repellency, including contact angle and drop absorption analyses. Results revealed that all substrates were compatible with the CS-based coating, which reduced air permeability and increased hydrophobicity. Notably, silk showed the most significant functional enhancement, transitioning from hydrophilic to waterproof with increased durability—indicating strong potential for technical applications such as outerwear and performance textiles. Given the renewable origin of both the substrate and coating, this study highlights the feasibility of valorising agri-food waste in high-performance, bio-based textile systems. These findings demonstrate the potential of CS as a bio-based coating for technical textiles, supporting the development of high-performance and sustainable materials within the textile industry. Full article

This study determined the feasibility of using zinc oxide nanoparticles of various origins as an active compound for biopolymer packaging films. The study focused on the effects of green synthesis using passion fruit or tomato extracts and commercial zinc oxide nanoparticles on the physicochemical properties of pectin films, including thickness, microstructure, water content, optical properties, water vapour permeability, water contact angle, sorption properties, and thermal stability. Zinc oxide nanoparticles resulted in lower lightness, higher absorbance, especially in the UV light range, and increased transparency, from 1.55 to 2.18 a.u./mm. Films containing zinc oxide nanoparticles showed reduced water vapour adsorption but increased water vapour permeability, from 6.35 to 12.07 × 10⁻¹⁰ g/m·s·Pa. The initial water contact angles were in a similar range, from 57.3° to 59.2°, but a decrease in contact angle values was observed over 60 s. All films containing nanoparticles exhibited better thermal stability, particularly during the third stage of degradation above 200 °C. Developed composite active films, prepared from apple pectin and zinc oxide nanoparticles of different origins, showed their potential for practical use as UV-VIS light barrier packaging films or protective coatings for food applications. Full article

Microbial contamination and biofilm formation on food contact materials (FCMs) represent critical challenges within the food supply chain, compromising food safety and quality while increasing the risk of foodborne illnesses. Traditional materials often lack sufficient microbial resistance to contamination, creating a high demand for innovative antimicrobial surfaces. This study assessed the effectiveness of a nanosized deposited SiO_xC_yH_z coating approved for food contact on 3D-printed polyamide 12 (PA12) disk substrates, aiming at providing antimicrobial and anti-biofilm functionality to mechanical components and packaging material in the food supply chain. The coating was applied using plasma-enhanced chemical vapor deposition (PECVD) and characterized through Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and contact angle measurements. Coated PA12 samples exhibited significantly enhanced hydrophobicity, with an average water contact angle of 112.9°, thus improving antibacterial performance by markedly reducing bacterial adhesion. Microbiological assays revealed a significant (p < 0.001) bactericidal activity (up to 4 logarithms after 4 h, ≥99.99%) against Gram-positive and Gram-negative bacteria, including notable foodborne pathogens such as L. monocytogenes, S. aureus, E. coli, and S. typhimurium. SiO_xC_yH_z-coated PA12 surfaces exhibited strong antibacterial activity, representing a promising approach for coating additive-manufactured components and equipment for packaging production in the food and pharmaceutical supply chain able to enhance safety, extend product shelf life, and reduce reliance on chemical sanitizers. Full article

Cellulose-based paper products derived from agro-industrial waste have attracted considerable interest due to their potential in sustainable material development. In this study, bacterial cellulose (BC) residue from the food and beverage industry was employed as a reinforcing agent to fabricate high-performance paper composites by blending with eucalyptus pulp (EP) at various ratios and basis weights. These papers were coated with a cationic modified starch solution (MS) using a rod coater, followed by hot pressing. Mechanical strengths (TAPPI Standard), water resistance (Cobb test and water contact angle), and air permeability (ASTM D737) were evaluated to assess material performance. The results showed that incorporating 50 wt% BC produced paper with outstanding mechanical performance, characterized by a high tensile index and excellent tear resistance. The application of the MS coating significantly boosted water resistance and air barrier performance, underscoring the effectiveness of this approach in creating high-performance paper materials. The resulting coated composites demonstrated excellent mechanical strength and barrier properties, positioning them as promising candidates for filtration applications such as personal protective face mask membranes. Full article

To mitigate the serious environmental impact caused by the persistent accumulation of plastics, replacing conventional plastics with paper-based alternatives has emerged as a promising trend. In response to the environmental and health concerns associated with petrochemical-based plastic meal boxes and fluorinated water- and oil-repellent agents, this study proposes a sustainable, fluorine-free coating technology based on chitosan to enhance the water and oil resistance of molded-paper pulp meal boxes. By adjusting the degree of deacetylation and the solution concentration of chitosan, coated meal boxes were fabricated via a spraying method. The results demonstrate that coatings prepared with highly deacetylated (>95%) and concentrated (4% w/v) chitosan significantly improve barrier properties, achieving a water contact angle of 114.9° ± 3°, the highest oil-resistance rating (12/12) according to TAPPI standards, and stable resistance to 95 °C hot oil for up to 30 min without leakage. In addition, the coated samples exhibit enhanced mechanical strength (21.26 MPa) and excellent biodegradability. This work provides a cost-efficient and eco-friendly disposable food packaging solution, facilitating the sustainable substitution of petrochemical-based plastics. Full article

Food security is one of the main problems in several countries. In food processing the cutting operation is very important as the operation is basic to food preparation. Due to cutting tools being exposed to a high-demand environment that includes high contact pressure, a corrosive atmosphere, and a high-speed process, they are subject to high mechanical and corrosive wear that reduces their lifetime and efficiency. Tribocorrosion is one of the main phenomena that reduces the lifetime and efficiency of cutting tools. This work presents electrochemical and tribocorrosion studies of D2 steel surfaces coated with TiN, TiCN, and TiCrN films. The samples were coated by a commercial source, using the PVD-cathodic arc technique. The crystalline structure of TiN and TiCN films presented a TiN and Ti phase, while the crystalline structure of TiCrN showed CrN and Cr phases. The films exhibited good adhesion, but the surfaces coated with TiN and TiCN films presented lower hardness. Although the TiN, TiCN, and TiCrN films showed better wear and corrosion resistance than the D2 steel surfaces, the inclusion of C and Cr in the TiN films decreased the TiN wear and electrochemical resistance in 3.5% (w/w) of NaCl solution. Full article