Search Results (436)

Developing innovative, low-cost halochromic materials for diagnosing microbial contamination in wounds and burns can effectively facilitate tissue regeneration. Here, we combine the pH-sensing capability of highly colorful red cabbage anthocyanins (RCAs) with their healing potential within a unique cellulose polymer film that mimics the skin matrix. Biological activities of RCA extract in bacterial cellulose (BC) showed no cytotoxicity and skin-sensitizing potential to human cells at concentrations of RCAs similar to those released from BC/RCA dressings (4.0–40.0 µg/mL). A decrease in cell viability and apoptosis was observed in human cancer cells with RCAs. The invisible eye detection of the early color change signal from RCAs in response to pH alteration by bacteria was recorded with a smartphone application. The incorporation of RCAs into BC polymer has altered the morphology of its matrix, resulting in a denser cellulose microfibril network. The complete coincidence of the vibrational modes detected in the absorption spectra of the cellulose/RCA composite with the modes in RCAs most likely indicates that RCAs retain their structure in the BC matrix. Affordable, sensitive halochromic BC/RCA hydrogels can be recommended for online monitoring of microbial contamination, making them accessible to patients. Full article

Microbial contamination is a global concern with impacts on a variety of industries ranging from marine to biomedical applications. Recent research on hydrophilic polymer-based coatings is focused on combining antifouling polymers with nanomaterials to enhance mechanical, optical, and stimuli-responsive properties, yielding colour changing, self-healing, and super hydrophilic materials. This study combines the hydrophilic and antifouling properties of vitamin B5 analogous methacrylamide (B5AMA)-based polymers with stimuli-responsive anthocyanin-dye-loaded cellulose nanocrystals (CNCs) to develop antifouling materials with colour changing capabilities upon bacterial contamination. Poly(B5AMA)-grafted CNCs were prepared through surface-initiated photoiniferter reversible addition fragmentation chain transfer (SP-RAFT) polymerization and characterized through proton nuclear magnetic resonance (¹H-NMR), transmission electron microscopy (SEM/TEM), and X-ray photon spectroscopy (XPS) to confirm the formation of surface-grafted polymer chains. The bare CNCs and poly(B5AMA)-grafted CNCs were loaded with anthocyanin dye and evaluated for pH-dependent colour changing capabilities. Interestingly, anthocyanin-loaded CNCs demonstrated vibrant colour changes in both solution and dried film form upon bacterial contamination; however, limited colour changing capabilities of the composites, specifically in dried film form, were attributed to the enhanced dispersibility and antifouling capabilities of the polymer-coated CNCs. Full article

This study addresses the challenge of chitosan (CS) being difficult to dissolve in water due to its highly ordered crystalline structure. Chitosan is modified with chloroacetic acid to reduce its crystallinity and enhance its water solubility. Through single-factor experiments, the optimal conditions for preparing carboxymethyl chitosan film (CMCS) were determined: under conditions of 50 °C, a cellulose substrate (CS) concentration of 18.75 g/L, a NaOH concentration of 112.5 g/L, and a chloroacetic acid concentration of 18.75 g/L, the reaction proceeded for 5 h. Under these conditions, the resulting carboxymethyl chitosan film exhibited the best flocculation effect, forming chitosan films in water that had flocculation activity toward mung bean starch protein wastewater. The successful introduction of carboxyl groups at the N and O positions of the chitosan molecular chain, which reduced the crystallinity of chitosan and enhanced its water solubility, was confirmed through analysis using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The prepared carboxymethyl chitosan film (CMCS) was applied in the flocculation recovery of protein. Through single-factor and response surface experiments, the optimal process conditions for flocculating and recovering protein with CMCS were determined: a CMCS dosage of 1.1 g/L, a reaction time of 39.6 min, a reaction temperature of 42.7 °C, and a pH of 5.2. Under these conditions, the protein recovery rate reached 56.97%. The composition and amino acid profile of the flocculated product were analyzed, revealing that the mung bean protein flocculated product contained 62.33% crude protein. The total essential amino acids (EAAs) accounted for 52.91%, non-essential amino acids (NEAAs) for 47.09%, hydrophobic amino acids for 39.56%, and hydrophilic amino acids for 12.67%. The ratio of aromatic to branched-chain amino acids was 0.31, and the ratio of basic to acidic amino acids was 1.68. These findings indicate that the recovered product has high surface activity and good protein stability, foaming ability, and emulsifying properties. Full article

This study investigates the combined use of electron beam irradiation (EBI) and nanotechnology to develop improved food packaging films. EBI, commonly applied for sterilization, can alter polymer microstructure, while irradiated cellulose nanocrystals (CNCs) offer enhanced functionality when incorporated into biopolymer matrices. Here, CNCs were irradiated with doses up to 50 kGy, leading to the formation of carboxyl and aldehyde groups, confirmed by FTIR analysis, as a consequence of the initial formation of free radicals and peroxides that may subsist in that original form or be converted into various carbonyl groups. Flexible films were obtained by incorporating pristine and EB-irradiated CNCs in an internal mixer, using minute amounts of poly(ethylene oxide) (PEO) to facilitate the dispersion of the filler within the polymer matrix. The resulting PLA/PEO/CNC films were evaluated for their mechanical, thermal, barrier, and antioxidant properties. The results showed that structural modifications of CNCs led to significant enhancements in the performance of the composite films, including a 30% improvement in water barrier properties and a 50% increase in antioxidant activity. These findings underscore the potential of irradiated CNCs as effective additives in biopolymer-based active packaging, offering a sustainable approach to reduce dependence on synthetic preservatives and potentially extend the shelf life of food products. Full article

This study investigates the development of corn starch-based biocomposites reinforced with pistachio shell powder, focusing on improving their mechanical and thermal performance. Composite films were prepared by solution casting with pistachio shell contents ranging from 2 wt% to 8 wt% by weight. The materials were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and tensile testing. The incorporation of pistachio shell particles led to a progressive improvement in tensile strength and elastic modulus, with the highest values observed in the formulation with 8% reinforcement (SP08). The TGA results indicated a shift in degradation temperatures for the sample with the highest percentage, reflecting a higher thermal stability that is attributed to the interactions between the starch, plasticizer, and cellulosic components of the pistachio shell. The FITR spectra shows very similar structures between starch and pistachio. An XRD analysis shows the alpha-type structure for starch and the cellulose type 1 structure for pistachio. Overall, the results suggest that pistachio shell powder can serve as an effective natural reinforcement, improving the functional properties of starch matrices and promoting the development of environmentally friendly materials derived from agro-industrial waste. Full article

With the increasing demand for food quality and the need for green and sustainable development of food packaging materials in the environment, the preparation and optimization of multifunctional natural and renewable antibacterial packaging materials have become an important trend. This article aims to explore the development of chitosan–cellulose composite materials with good antibacterial properties and promote the widespread application of chitosan and cellulose in food packaging materials. Combining various natural polysaccharide polymers, we discuss the application of chitosan cellulose in meat, dairy products, fruits and vegetables, and fishery products. Meanwhile, we explore their antibacterial and antioxidant behaviors during their use as food packaging materials. This provides a reference for effectively improving the performance of modified chitosan and cellulose food packaging materials in the future. Based on the above explanation, we analyzed the advantages and disadvantages of modified chitosan and cellulose and looked forward to the future development trends of chitosan and cellulose blend films in food preservation. Chitosan–cellulose blends not only have important prospects in food packaging and preservation applications, but can also be combined with intelligent manufacturing to enhance their food preservation performance. The aim of this review is to provide valuable references for basic research on the antimicrobial properties of these composites and their practical application in smart food packaging. Full article

As the global plastic pollution problem intensifies and the environmental hazards of traditional petroleum-based plastics become increasingly significant, the development of sustainable alternative materials has become an urgent need. This paper systematically reviews the research progress, application status and future trends of new generation bioplastics in the field of food packaging. Bioplastics are categorized into three main groups according to their sources and degradability: biobased biodegradable materials (e.g., polylactic acid PLA, polyhydroxy fatty acid ester PHA, chitosan, and cellulose-based materials); biobased non-biodegradable materials (e.g., Bio-PE, Bio-PET); and non-biobased biodegradable materials (e.g., PBAT, PCL, PBS). Different processing technologies, such as thermoforming, injection molding, extrusion molding and coating technologies, can optimize the mechanical properties, barrier properties and freshness retention of bioplastics and promote their application in scenarios such as food containers, films and smart packaging. Although bioplastics still face challenges in terms of cost, degradation conditions and industrial support, promising future directions are found in the development of the large-scale utilization of non-food raw materials (e.g., agricultural waste, algae), nano-composite technology to enhance the performance, and the development of intelligent packaging functions. Through technological innovation and industry chain integration, bioplastics are expected to transform from an environmentally friendly alternative to a mainstream packaging material, helping to realize the goal of global carbon neutrality. Full article

Herein, all components of corncob residues were acetylated to synthesize an acetone-soluble resin material. Moreover, titanium oxysulfate (TiOSO₄), a low-cost intermediate for the industrial production of TiO₂, was first used as an acetylation reagent. Through optimizing reagent dosages and reaction times, above 90% of hydroxyl groups in the corncob residue can be substituted by acetyl groups. During the acetylation reaction, TiOSO₄ was transformed into TiO₂ and uniformly distributed within the acetylated corncob residue. The resulting product, owing to its solubility in acetone, can be employed to fabricate a composite film with excellent mechanical properties, achieving an increase of 85% in tensile strength and 90% in strain rate compared to commercial cellulose acetate film. By this preparation technique, the industrial-grade corncob residue as raw material can be converted to acetylated composite films. Further analysis indicates that the coexistence of acetylated lignin and TiO₂ plays a pivotal role in enhancing the mechanical properties of acetylated corncob residue composite film. Additionally, this material exhibits substantial degradation within 28 days under natural environmental conditions, whereas commercial cellulose acetate shows no significant changes even after 60 days. The present achievements are a significant breakthrough in the high-value technologies for the conversion of corncob residues. Full article

Biodegradable mulch films were developed over the last decades to replace polyethylene, but their short durability and higher costs still limit their diffusion. This work aimed to test an innovative composite mulching film constituted by a mixture of carboxylmethyl cellulose, chitosan and sodium alginate, enriched or not with an inorganic N- and P-source to help the microbial breakdown in soil. The trial was carried out using outdoor mesocosms cultivated with lettuce plants with high-density planting. Commercial Mater-Bi^® and a polyethylene film were taken as control treatments. Air temperature and humidity monitored daily during the 51 d cropping cycle remained within the ideal range for lettuce growth with no mildew or fungi infection. Visible mechanical degradation of the experimental biopolymers occurred after 3 weeks; however, Mater-Bi^® and polyethylene remained unaltered until harvest. Chemical soil variables (TOC, TN, CEC, EC) remained unchanged in all theses, whereas the pH varied. The yield, pigments, total phenols, flavonoids and ROS scavenging activity of lettuce were similar among treatments. Despite their shorter life service (~3 weeks), polysaccharide-based mulching films showed their potential to protect lettuce plants at an early stage and provide yield and nutraceutical values similar to conventionally mulched plants, while allowing a reduced environmental impact and disposal operations. Full article

This study presents the development and analysis of hybrid polyurea composite materials. Neat polyurea was reinforced with cellulose nanocrystals (CNCs) and isocyanate-modified CNCs (CNC-ISOs) via a two-step prepolymer process. Introducing CNC considerably increased the mechanical strength and stiffness of the polyurea matrix. The tensile strength increased by up to 16.4%, and the Young modulus improved by approximately 29% compared to the pure polyurea. When CNC was functionalized with isocyanate, the interfacial bonding was further improved, and superior dispersion and load transfer were achieved. At 1.5% CNC-ISO loading, the modulus increased by approximately 128% compared to the unmodified matrix. Comprehensive analyses using FT-IR, XPS, DSC, TGA, DMA, tensile testing, and SEM showed that CNC-ISO films not only achieved higher tensile strength and better thermal stability but also formed a denser polymer network as evidenced by the increased crosslinking density. These findings highlight the importance of tailored nanofiller modification to create advanced polyurea composites with enhanced performance suitable for demanding protective and structural applications. Full article

The multifactorial modification of the structure and properties of alginate matrix was conducted using partially acetylated cellulose nanocrystals. Fourier-transform infrared spectroscopy and thermogravimetric analysis indicated the absence of chemical interactions between the polymer matrix and the filler. The surface texture was examined using optical microscopy and scanning electron microscopy, along with a reconstruction of its 3D model. With an increase in the content of nanoparticles in the composite, the following was revealed. Firstly, the roughness and density of the arrangement of surface elements increased, while their size decreased. Secondly, at pH values < 7, the puncture resistance increased, whereas the swelling coefficient of the films decreased. In Hanks solutions, the low solubility of the films was established, as well as a higher swelling coefficient at pH > 7. Thirdly, the contribution of donor centers to the free surface energy, cytocompatibility of composite films, and adhesion of fibroblasts to the surface increased. The hematological tests of the composites showed a procoagulant effect. Summarizing the data, we propose a model that explains the influence of nanocrystals and their concentration on the formation of the observed composites’ structure and their physicochemical and biological properties. The main driving forces of structurization are the factor of the excluded volume and interactions in a heterogeneous colloidal system. Full article

Chitosan (CS)-based films have demonstrated significant potential as biodegradable packaging materials, but their suboptimal barrier and mechanical properties limit practical applications. In this study, CS/carboxymethyl cellulose (CMC) composite films were prepared using a NaOH/urea-based alkaline system. Optimal ratios (1.5% CS, 2% CMC, 2.5% NaOH, and 4% urea) were determined through an L₁₆(4⁴) orthogonal array design. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirmed the formation of stable physical crosslinks between CS and CMC via hydrogen bonding. These interactions significantly enhanced mechanical properties (tensile strength: 46.08 MPa; elongation at break: 68%), improved thermal stability (maximum decomposition temperature: 304 °C), and superior barrier properties (water vapor transmission rate: 0.26 × 10⁻⁵ g/(m²·h·Pa); oxygen transmission rate: 1.12 × 10⁻⁴ g/(m²·s)). NaOH concentration exhibited the most pronounced influence on film performance. The composite film combines inherent biodegradability with excellent functional properties, offering a sustainable alternative to conventional petroleum-based packaging materials. Full article

A new active composite film intended for bread packaging is described here. The active film has the aim of prolonging bread’s shelf life while avoiding the use of nanoparticles that, with very few exceptions, are a type of material not allowed by regulatory agencies like EFSA (European Food Safety Agency) and FDA (US Food and Drug Administration) in food contact materials. Moreover, the increasing consumer demand for natural and wholesome products, possibly “clean label”, and packaged in natural, non-petroleum-based materials has been taken into consideration. Accordingly, precursor materials from renewable sources were used to prepare the active film: pectin from citrus peel (PEC) and carboxymethyl cellulose (CMC) were used as the matrix, with oleic acid (OA) as plasticizer. Moreover, the bread preservative calcium propionate (CaP) was used as the crosslinker, and also zeolite microparticles loaded with silver ions (AgZ) were added to the films as an additional antimold agent. This strategy allows us to avoid the addition to bread of the now commonly used preservatives ethanol and calcium propionate, moving the latter to the packaging. Permeance measurements revealed excellent barrier properties against O₂ and CO₂, while the typical high water vapor permeance of polysaccharide films was mitigated by the non-hydrophilic OA plasticizer. Moreover, the quantities of Ag⁺ and CaP released in bread are low and below the limits imposed by regulatory agencies. The antimold activity of the films is excellent, with Aspergillus niger, Penicillium janthinellum, and wild-type Penicillim molds reduction on bread in the 99.20–99.95% range for the films containing only CaP and in the 99.97–99.998% range for the films containing both CaP and AgZ. Finally, the rheological properties of the film-forming solutions were investigated, demonstrating their potential application as coatings on natural packaging materials for bread, such as paper. Full article

Food packaging plays a crucial role in preserving freshness and prolonging shelf life worldwide. However, traditional packaging primarily acts as a passive barrier, providing limited protection against spoilage. Packaged food often deteriorates due to oxidation and microbial growth, reducing its quality over time. Moreover, the majority of commercial packaging relies on petroleum-derived polymers, which add to environmental pollution since they are not biodegradable. Growing concerns over sustainability have driven research into eco-friendly alternatives, particularly natural-based active packaging solutions. Among the various biopolymers, cellulose is the most abundant natural polysaccharide and has gained attention for its biodegradability, non-toxicity, and compatibility with biological systems. These qualities make it a strong candidate for developing sustainable packaging materials. However, pure cellulose films have limitations, as they lack antimicrobial and antioxidant properties, reducing their ability to actively preserve food. To tackle this issue, researchers have created cellulose-based active packaging films by integrating bioactive agents with antimicrobial and antioxidant properties. Recent innovations emphasize improving these films through the incorporation of natural extracts, polyphenols, nanoparticles, and microparticles. These enhancements strengthen their protective functions, leading to more effective food preservation. The films are generally classified into two types: (i) blend films, where soluble antimicrobial and antioxidant substances like plant extracts and polyphenols are incorporated into the cellulose solution, and (ii) composite films, which embed nano- or micro-sized bioactive fillers within the cellulose structure. The addition of these functional components enhances the antimicrobial and antioxidant efficiency of the films while also affecting properties like water resistance, vapor permeability, and mechanical strength. The continuous progress in cellulose-based active packaging highlights its potential as a viable alternative to conventional materials. These innovative films not only extend food shelf life but also contribute to environmental sustainability by reducing reliance on synthetic polymers. This review deals with the development of functional biopolymer films with antimicrobial and antioxidant properties towards sustainable food packaging. Full article

Bacterial cellulose (BC) is a polysaccharide produced by Gram-positive and Gram-negative bacteria with a strictly aerobic metabolism, having a huge number of significant applications in the biomedical field. This study investigates the development of bacterial cellulose (BC)-based composite systems that incorporate cerium dioxide nanoparticles (CeO₂ NPs) used as antibacterial agents to enhance wound healing, particularly for burn treatments. The innovation of this study resides in the integration of CeO₂ NPs synthesized by using a precipitation method using both chemical and green reducing agents, ammonium hydroxide (NH₄OH) and turmeric extract (TE), in BC membranes composed of ultrathin nanofibers interwoven into a three-dimensional network appearing as a hydrogel mass. Characterization by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR) confirmed the effective deposition of this agent onto the BC matrix. Antibacterial activity tests against E. coli and B. subtilis indicated strong inhibition for the composites synthesized following these routes, particularly for the BC-CeO₂-TE-OH sample, processed by employing both precipitating agents. Cytotoxicity evaluations showed no inhibition of cell activity. Additionally, loading the composites with dexamethasone endowed them with analgesic release over 4 h, as observed through ultraviolet–visible spectroscopy (UV-Vis), while the FTIR spectra revealed a sustained drug presence post-release. These findings highlight BC-based films as promising candidates for advanced wound care and tissue engineering applications. Full article