Search Results (4,396)

The synthesis of silver nanoparticles (AgNPs) using sustainable and non-toxic methods has become an important research focus due to the limitations of conventional chemical approaches, which often involve hazardous reagents and produce unstable products. In particular, the effects of reaction conditions on the quality and stability of AgNPs obtained via green synthesis remain insufficiently understood. This study addresses this gap by examining the influence of pH and temperature on the synthesis of AgNPs using Rosmarinus officinalis extract as both reducing and stabilizing agents. UV-vis spectroscopy and TEM analysis revealed that optimal conditions for producing uniform, stable, and spherical AgNPs were achieved at pH 8, with a narrow size distribution (~17.5 nm). At extreme pH values (≤3 or ≥13), nanoparticle formation was hindered by aggregation or precipitation, while elevated temperatures mainly accelerated reaction without altering particle morphology. HRTEM and SAED confirmed the crystalline face-centered cubic structure, and colloids synthesized at pH 8 showed excellent stability over 30 days. Overall, the results demonstrate that precise pH control is critical for obtaining high-quality AgNPs via a simple, scalable, and environmentally friendly approach. Their stability and homogeneous size highlight potential applications in biomedicine, food packaging, and sensing, where reproducibility and long-term functionality are essential. Full article

Chitin, one of the most abundant natural polysaccharides, has gained increasing attention for its structural diversity and potential in biomedicine, agriculture, food packaging, and advanced materials. Conventional chitin production from crustacean shell waste faces limitations, including seasonal availability, allergenic protein contamination, heavy metal residues, and environmentally harmful demineralization processes. Chitin from fungi and microalgae provides a sustainable and chemically versatile alternative. Fungal chitin, generally present in the α-polymorph, is embedded in a chitin–glucan–protein matrix that ensures high crystallinity, mechanical stability, and compatibility for biomedical applications. Microalgal β-chitin, particularly from diatoms, is secreted as high-aspect-ratio microrods and nanofibrils with parallel chain packing, providing enhanced reactivity and structural integrity that are highly attractive for functional materials. Recent progress in green extraction technologies, including enzymatic treatments, ionic liquids, and deep eutectic solvents, enables the recovery of chitin with reduced environmental burden while preserving its native morphology. By integrating sustainable sources with environmentally friendly processing methods, fungal and microalgal chitin offer unique structural polymorphs and tunable properties, positioning them as a promising alternative to crustacean-derived chitin. 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

The increasing demand for sustainable alternatives to non-biodegradable plastic packaging is driving the development of active packaging based on biopolymers such as methylcellulose. In this study, innovative methylcellulose nanocomposite films incorporating zein nanoparticles loaded with propolis and curcumin were developed for active packaging applications. The zein nanoparticles revealed excellent physicochemical properties, with a zeta potential above 30 mV, suggesting adequate stability. Transmission electron microscopy confirmed nanoparticles containing curcumin and propolis with uniform sizes ranging from approximately 130 to 140 nm with low polydispersity. Release studies revealed that approximately 25% of the curcumin and 35% of the propolis were released from the nanoparticles within 24 h. The release mechanism was best described by the Korsmeyer–Peppas model, suggesting a sustained release profile. The nanoparticles reduced the hydrophobicity and rigidity of the films, as evidenced by a lower elastic modulus and higher percentage elongation, thereby suggesting greater flexibility. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the incorporation of bioactive compounds in the polymer matrix. Differential scanning calorimetry (DSC) revealed the thermal parameters of the synthesized films. Furthermore, the films exhibited antibacterial and antioxidant activities, making them highly suitable for use as biodegradable active packaging. Full article

As an important technology to enhance nutrient use efficiency and reduce agricultural non-point source pollution, controlled-release fertilizers (CRFs) have been widely applied in modern agriculture. However, during packaging, transportation, and field application, CRF particles are prone to mechanical impacts, which can lead to particle fragmentation and damage to the controlled-release coating. This compromises the release kinetics, increases nutrient loss risk, and ultimately exacerbates environmental issues such as eutrophication. Currently, studies on the impact-induced fragmentation behavior of CRF particles remain limited, and there is an urgent need to investigate their fragmentation susceptibility mechanisms from the perspective of internal stress evolution. In this study, the mechanical properties of CRF particles were first experimentally determined to obtain essential parameters. A two-layer finite element model representing the coating and core structure of the particles was then constructed, and a fragmentation susceptibility index was proposed as the key evaluation criterion. The index, defined as the ratio of fractured volume to peak impact energy, reflects the efficiency of energy conversion at the critical moment of particle rupture (1–5). An explicit dynamic simulation framework incorporating multiple influencing factors—equivalent diameter, sphericity, impact material, velocity, and angle—was developed to analyze fragmentation behavior from the perspective of energy transformation. Based on the observed effects of these variables on fragmentation susceptibility, three regression models were developed using response surface methodology to quantitatively predict fragmentation susceptibility. Comparative analysis between the simulation and experimental results showed a fragmentation rate error range of 0–11.47%. The findings reveal the relationships between particle fragmentation modes and energy responses under various impact conditions. This research provides theoretical insights and technical guidance for optimizing the mechanical stability of CRFs and developing environmentally friendly fertilization strategies. Full article

Surface coating materials have many applications in various sectors, such as aerospace, medical technology, packaging, and construction, due to their unique properties, including self-healing, corrosion resistance, and protection from external factors. Their use not only enhances the durability and lifespan of surfaces but also their functionality and esthetic value. These coatings can be effective barriers against moisture, oxygen, chemicals, and the growth of microorganisms, which makes them indispensable in industries where reliability and safety are paramount. In the aerospace sector, they provide protection at extreme temperatures and limit component wear. Special coatings in biomedicine improve implant compatibility and prevent bacterial adhesion. In packaging, they extend the shelf life of products, while in construction they prevent the degradation of structural elements. This review article examines the major categories of these materials, as well as their advantages and limitations, and demonstrates a comparative evaluation of their use in certain applications. Full article

Optimising spraying operations in coffee cultivation can enhance both application efficiency and effectiveness. However, no studies have specifically assessed droplet deposition on leaves adjacent to the spray application band—fraction of droplet deposition referred to as ‘transfer’ in this study. Therefore, this study aimed to quantify droplet deposition and transfer resulting from different application rates and nozzle types in coffee trees. The experiment was conducted in a factorial design including three application rates (200, 400, and 600 L ha⁻¹) and two nozzle types (hollow cone and flat fan), with four replicates. Deposition was quantified at multiple positions: two application sides (left and right), three sections of the plant (upper, middle, and lower), and two branch positions (inner and outer). Thus, all measurements across sides, plant sections, and branch positions were nested, resulting in correlated data that were analysed using linear mixed-effects models (lme4 package), with parameters estimated using the restricted maximum likelihood method. The flat fan nozzle achieved the highest reference deposition, particularly on outer canopy thirds, while spray transfer (~29% of total deposition) was mainly driven by operational factors. Hollow cone nozzles at 200 L ha⁻¹ minimized transfer while maintaining adequate deposition. Optimizing applications requires maximizing reference deposition and minimizing transfer, which can be achieved through operational adjustments, airflow management, and complementary strategies such as adjuvants, electrostatic spraying, or tunnel sprayers. Full article

Corona treatment is commonly used in industry to enhance the surface-free energy of plastic films. However, corona treatment may cause some undesirable effects affecting further processing, such as sealing. In this paper, we deeply analyze the corona treatment effect on selected properties of various polymer films commonly used in packaging applications. The films were treated at two power levels (100 W and 300 W), and the experimental design included surface characterization and mechanical testing to assess changes in wettability, chemical structure, and seal strength. The Owens–Wendt approach confirmed the corona treatment effect by static contact angle measurement and surface free energy calculation. Next, their seal strength was evaluated in relation to surface energy and chemical structure changes. FTIR spectroscopy was used to identify functional groups potentially affected by corona treatment. The results indicate that the impact of corona treatment is material-dependent. In general, corona treatment at a lower level increases the seal strength, while corona treatment at a higher power level is related to a decrease in seal strength. The study highlights the importance of optimizing corona treatment parameters for specific materials to enhance seal performance without compromising surface integrity. Full article

The aim of this study was to develop biodegradable pectin films enriched with anthocyanin-rich fruit juices and evaluate their functional properties. Films were prepared with bilberry and blackcurrant juices, and their color response to pH, mechanical performance, thermal stability, and water vapor permeability were analyzed. The incorporation of juices significantly affected the films’ color, with ΔE values ranging from 8.41 to 39.24 for blackcurrant and 36.60 to 59.59 for wild bilberry juice, showing clear visual differences. Increasing juice concentration from 5% to 10% enhanced color intensity and opacity, with the highest opacity (12.90 a.u./mm) observed for films containing 2% pectin and 10% bilberry juice. Mechanical testing indicated reduced tensile strength after juice addition, with the lowest elongation (11.90%) noted for films with 2% pectin and 5% blackcurrant juice. The lowest water vapor permeability (7.43·10⁻¹¹ g/m·s·Pa) was recorded for films with 2% pectin. Thermal analysis revealed greater mass loss in juice-enriched films (40–44.5%) compared to controls (37.6%), reflecting the presence of volatile compounds. pH testing confirmed the films’ indicator function, with red coloration at pH 2 and shifts toward blue-grey (bilberry) or orange-green (blackcurrant) at pH 8. These findings demonstrate that pectin films enriched with dark red fruit juices exhibit promising potential for smart food packaging applications. Full article

This study reports the development and characterization of novel active edible films based on apple pectin and honey (80:20, w/w), incorporating raw propolis powder at 0.1%, 0.2%, and 0.3% (w/w, relative to honey) as a natural source of bioactive compounds for sustainable packaging of soluble coffee and matcha powders. The study aims to provide sustainable and functional packaging solutions capable of maintaining the stability and quality of these powdered beverages. The effects of honey and propolis incorporation on the physicochemical, mechanical, optical, and microbiological properties of the films were systematically evaluated. Propolis addition resulted in decreased tensile strength, elastic modulus, and elongation at break, but did not significantly alter the thermal stability of the films, as evidenced by differential scanning calorimetry and thermogravimetric analysis. Increasing propolis concentrations led to higher total phenolic content and significantly improved antioxidant activity, with the 0.3% formulation exhibiting the most pronounced effect. Application tests demonstrated that the honey–propolis-enriched pectin films effectively preserved the sensory attributes and physicochemical quality of soluble coffee and matcha powders. Overall, these results highlight the potential of pectin–honey–propolis films as bioactive carriers and functional materials for active packaging of powdered beverages. Full article

In this article, we present density functional theory (DFT) calculations for $Z{n}_{(1-x)}{M}_{x}O$, where M represents one of the following substitutional metallic impurities: Ga, Cd, Cu, Pd, Ag, In, or Sn. Our study is based on the wurtzite structure of pristine ZnO. We employ the Quantum Espresso package, using a fully unconstrained implementation of the generalized gradient approximation (GGA) with an additional U correction for exchange and correlation effects. We analyze the density of states, energy gaps, and absorption spectra for these doped systems, considering the limitations of a finite-size cell approximation. Rather than focusing on precise numerical values, we highlight the following two key aspects: the location of impurity-induced electronic states and the overall trends in optical properties across the eight systems, including pristine ZnO. Our results indicate that certain dopants introduce electronic levels within the band gap, which enhance optical absorption in the visible, near-infrared, and near-ultraviolet regions. For instance, Sn-doped ZnO shows a pronounced absorption peak at ∼2.5 eV, which is in the middle of the visible spectrum. In the case of Ag and Pd impurities, they lead to increased electromagnetic radiation absorption at the near ultra-violet spectrum. This represents a promising performance for efficient solar radiation absorption, both at the Earth’s surface and in outer space. Furthermore, Ga- and In-doped ZnO present bandgaps of ∼0.9 eV, promising an interesting performance in the near infrared region. These findings suggest potential applications in solar energy harvesting and selective sensors. Full article

The increasing complexity of modern food production demands advanced solutions for quality control (QC), safety monitoring, and process optimization. This review systematically explores recent advancements in machine learning (ML) for QC across six domains: Food Quality Applications; Defect Detection and Visual Inspection Systems; Ingredient Optimization and Nutritional Assessment; Packaging—Sensors and Predictive QC; Supply Chain—Traceability and Transparency and Food Industry Efficiency; and Industry 4.0 Models. Following a PRISMA-based methodology, a structured search of the Scopus database using thematic Boolean keywords identified 124 peer-reviewed publications (2005–2025), from which 25 studies were selected based on predefined inclusion and exclusion criteria, methodological rigor, and innovation. Neural networks dominated the reviewed approaches, with ensemble learning as a secondary method, and supervised learning prevailing across tasks. Emerging trends include hyperspectral imaging, sensor fusion, explainable AI, and blockchain-enabled traceability. Limitations in current research include domain coverage biases, data scarcity, and underexplored unsupervised and hybrid methods. Real-world implementation challenges involve integration with legacy systems, regulatory compliance, scalability, and cost–benefit trade-offs. The novelty of this review lies in combining a transparent PRISMA approach, a six-domain thematic framework, and Industry 4.0/5.0 integration, providing cross-domain insights and a roadmap for robust, transparent, and adaptive QC systems in the food industry. Full article

This study valorizes onion peel, an agro-industrial by-product rich in phenolic compounds and structural carbohydrates, for the development of cassava starch-based biodegradable films. The films were prepared using the solution casting method; a cassava starch matrix was mixed with a 2.5% glycerol solution and heated to 85 °C for 30 min. A separate solution of onion peel powder (OPP) in distilled water was prepared at 25 °C. The two solutions were then combined and stirred for an additional 2 min before 25 mL of the final mixture was cast to form the films. Onion peel powder (OPP) incorporation produced darker and more opaque films, suitable for packaging light-sensitive foods. Film thickness increased with OPP content (0.138–0.218 mm), while moisture content (19.2–32.6%) and solubility (24.0–25.2%) decreased. Conversely, water vapor permeability (WVP) significantly increased (1.69 × 10⁻⁹–2.77 × 10⁻⁹ g·m⁻¹·s⁻¹·Pa⁻¹; p < 0.0001), reflecting the hydrophilic nature of OPP. Thermal analysis (TGA/DSC) indicated stability up to 245 °C, supporting applications as food coatings. Morphological analysis (SEM) revealed OPP microparticles embedded in the starch matrix, with FTIR and XRD suggesting electrostatic and hydrogen–bond interactions. Mechanically, tensile strength improved (up to 2.71 MPa) while elongation decreased (14.1%), indicating stronger but less flexible films. Biodegradability assays showed slightly reduced degradation (29.0–31.8%) compared with the control (38.4%), likely due to antimicrobial phenolics inhibiting soil microbiota. Overall, OPP and cassava starch represent low-cost, abundant raw materials for the formulation of functional biopolymer films with potential in sustainable food packaging. Full article

Dielectric covers are generally used to provide external protection to antenna systems by providing electromagnetic transparency. They are utilized in ground applications as well as for protecting airborne, Sat Com, terrestrial and underwater antenna installations. This paper presents a unique and universal design of dielectric sandwich-layered cover that can effectively protect antennas operating in a large frequency band from 1 GHz to 28 GHz, including millimeter-wave and microwave ranges, with minimum insertion loss for various incident angles. The proposed single dielectric cover may give sufficient protection for an entire tower or chimney housing multiple antennas, ranging from first-generation to fifth-generation microwave base-station antennas, as well as other wireless/broadcast antennas in millimeter or lower frequency ranges. In the first step, optimum dielectric constant and thickness of the dielectric cover are calculated numerically through a MATLAB (R2015a) code. In the second step, a floquet port analysis is performed to observe the insertion loss through the transmission coefficient against various frequency band-spectrums in microwave and millimeter-wave ranges for validation of the proposed synthesis. The ANSYS 18.2 HFSS tool is used for the purpose. In the third step, fabrication of the dielectric-layered structure is completed with the optimum design parameters. In the final step, the dielectric package is tested under various fabricated antennas in different frequency ranges. Full article

A novel bio-gelatin fiber-reinforced composite (BFRC) was first developed by incorporating industrial bone glue/gelatin as the matrix, magnesium oxide (MgO) as an additive, and natural or synthetic fibers as reinforcement. Systematic tests evaluated mechanical, impact, and thermal performance, alongside microstructural mechanisms. Results showed that polyethylene (PE) fiber-reinforced composites achieved a tensile strength of 3.40 MPa and tensile strain of 10.77%, with notable improvements in compressive and flexural strength. PE-based composites also showed excellent impact energy absorption, while bamboo fiber-reinforced composites exhibited higher thermal conductivity. Microstructural analysis revealed that coordination between Mg²⁺ ions and amino acids in gelatin formed a stable cross-linked network, densifying the matrix and improving structural integrity. A multi-criteria evaluation using the TOPSIS model identified the BC-PE formulation as the most balanced system, combining strength, toughness, and thermal regulation. These findings demonstrate that ionic coordination and fiber reinforcement can overcome inherent weaknesses of gelatin matrices, offering a sustainable pathway for building insulation and cushioning packaging applications. Full article