Double-interpenetrating nanostructured networks of marine polysaccharides possessing properties comparable to synthetic polymers.

Sustainable circular economy requires materials that possess a property profile comparable to synthetic polymers and, additionally, processing and sourcing of raw materials that have a small environmental footprint. Here, we present a paradigm for processing marine biopolymers into materials that possess both elastic and plastic behavior within a single system involving a double-interpenetrating polymer network comprising the elastic phase of dynamic physical cross-links and stress-dissipating ionically cross-linked domains. As a proof of principle, films possessing more than twofold higher elastic modulus, ultimate tensile strength, and yield stress than those of polylactic acid were realized by blending two water-soluble marine polysaccharides, namely alginic acid (Alg) with physically cross-linkable carboxylated agarose (CA) followed by ionic cross-linking with a divalent cation. Dried CAAlg films showed homogeneous nano-micro-scale domains, with yield stress and size of the domains scaling inversely with calcium concentration. Through surface activation/cross-linking using calcium, CAAlg films could be further processed using wet bonding to yield laminated structures with interfacial failure loads (13.2 ± 0.81 N) similar to the ultimate loads of unlaminated films (10.09 ± 1.47 N). Toward the engineering of wood-marine biopolymer composites, an array of lines of CAAlg were printed on wood veneers (panels), dried, and then bonded following activation with calcium to yield fully bonded wood two-ply laminate. The system presented herein provides a blueprint for the adoption of marine algae-derived polysaccharides in the development of sustainable high-performance materials.

Biomass-derived nanoparticles reinforced chitosan films: as high barrier active packaging for extending the shelf life of highly perishable food.

This study emphasizes the potential of biomass-derived nanoparticles such as nanocellulose (NC), nanohemicellulose (NHC), and nanolignin (NL) as reinforcements in chitosan (C) films to produce a higher barrier active packaging film. The incorporation of NC, NHC, and NL (1.5%) significantly improves the mechanical, water, and UV barrier properties of the chitosan film (P < 0.0001). Additionally, NHC and NL reinforcement significantly enhance antioxidant and antimicrobial activity. The physicochemical, sensory, and microbiological properties of fresh meat packed in chitosan films with 1.5% nanoparticles, as well as a commercial LDPE film, were assessed when stored at 4 °C for up to 18 days. C-NHC and C-NL packaging films preserved the quality of meat until the 18th day, whereas the meat packed in the LDPE film spoiled entirely on the sixth day. In conclusion, chitosan films with biomass-derived nanoparticles could be an excellent packaging material for highly perishable food, such as fresh meat, with an extended shelf life. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05896-9.

Symbiotic Antimicrobial Effects of Cellulose-Based Bio-Nanocomposite for Disease Management of Agricultural Crops.

In the present work, a bionanocomposite for plant crop protection was prepared by non-toxic biocompatible & biodegradable nanomaterials (Cellulose & TiO2 ) to utilize its synergistic effects against antimicrobial pathogens. The commercially available microcrystalline cellulose has been reduced to a nanometric scale regime using acid hydrolysis, while the standard TiO2 nano-powder of particle size ~20 nm has been used to prepare their nanocomposite (NC). The antibacterial studies via agar well diffusion method demonstrated that after 72 h of incubation, parent nanomaterials Ncell and TiO2 were not showing any activity against phytopathogens X. campestris pv. campestris, and Clavibacter while the nanocomposite's NC's were still effective depicting both bacteriostatic and bactericidal actions. However, the bacterial growth of biocontrol P. fluorescence was not affected by Ncell, TiO2 NPs and NC after 72 h of incubation. The antifungal testing results via poison food agar assay method suggest that the nanocomposite, along with Ncell and TiO2 NPs, exhibited strong inhibition of fungal growth of Phytophthora Spp at 0.125 mg/ml concentration while for F. graminearum, similar effect was observed at 0.25 mg/ml concentration. The nanocomposite has proved its potential by exhibiting longer & stronger synergistic effects against plant pathogens as a good antimicrobial agent for protection of agricultural crops.

Electrochemiluminescent immunosensor for detection of carcinoembryonic antigen using luminol-coated silver nanoparticles.

Recently, electrochemiluminescent (ECL) immunosensors have received much attention in the field of biomarker detection. Here, a highly enhanced ECL immunosensing platform was designed for ultrasensitive detection of carcinoembryonic antigen (CEA). The surface of the glassy carbon electrode was enhanced by applying functional nanostructures such as thiolated graphene oxide (S-GO) and streptavidin-coated gold nanoparticles (SA-AuNPs). The selectivity and sensitivity of the designed immunosensor were improved by entrapping CEA biomolecules using a sandwich approach. Luminol/silver nanoparticles (Lu-SNPs) were applied as the main core of the signaling probe, which were then coated with streptavidin to provide overloading of the secondary antibody. The highly ECL signal enhancement was obtained due to the presence of horseradish peroxidase (HRP) in the signaling probe, in which the presence of H2O2 further amplified the intensity of the signals. The engineered immunosensor presented excellent sensitivity for CEA detection, with limit of detection (LOD) and linear detection range (LDR) values of 58 fg mL-1 and 0.1 pg mL-1 to 5 pg mL-1 (R2 = 0.9944), respectively. Besides its sensitivity, the fabricated ECL immunosensor presented outstanding selectivity for the detection of CEA in the presence of various similar agents. Additionally, the developed immunosensor showed an appropriate repeatability (RSD 3.8%) and proper stability (2 weeks). Having indicated a robust performance in the real human serum with stated LOD and LDR, the engineered immunosensor can be considered for the detection and monitoring of CEA in the clinic.

Fabrication and characterization of bio-nanocomposites based on kafirin and polyethylene oxide as auxiliary polymer: process optimization, rheological, morphological and thermal properties.

The aim of this research was to compare the effects of various solvents on producing kafirin/polyethylene oxide (PEO) bio-nanocomposites by the technique of electrospinning. Different concentrations of kafirin (15, 20, 25, 30 and 40% w/v) and PEO (2, 4 and 6% w/v) were electrospun. For the dissolution and electrospinning of these two biopolymers, different solvents were used comparatively, i.e. distilled water, ethanol (70%), acetic acid (40%), 2-Butanol and glacial acetic acid. An evaluation of flow behavior showed that kafirin and PEO had Newtonian and pseudoplastic behaviors, respectively. A mixture of these two polymers demonstrated quasi-Newtonian and shear-independent behaviors in a low shear rate range, which positively affected the electrospinning process. SEM images showed that the best concentrations of kafirin and PEO were 25 and 2%, respectively, for producing nanofibers with uniform structures. Fourier-transform infrared spectroscopy (FTIR) indicated the presence of kafirin and PEO in the bio-nanocomposite after electrospinning. The FTIR proved that these two polymers had no chemical interactions with each other. Overall, the results showed that selecting an appropriate solvent and a suitable auxiliary polymer could have significant roles in producing biodegradable kafirin nanofibers.

A novel, eco-friendly bio-nanocomposite (Alg-Cst/Kal) for the adsorptive removal of crystal violet dye from its aqueous solutions.

Herein, we report the synthesis of a novel bio-nanocomposite (Alg-Cst/Kal) for the effective removal of the dye "Crystal Violet" from its aqueous solutions. In order to observe the surface morphology and functional groups, the bio-nanocomposite was characterized using various techniques such as SEM, EDX, TEM, FTIR, XRD, and TGA. The effect of parameters like contact time, pH, concentration and temperature on the adsorption of the dye over adsorbent has been studied in detail. The dye - adsorbent system has been tested over various isotherm models and found to follow the Freundlich adsorption isotherm model at 303 K. The developed bio-nanocomposite material exhibits an excellent adsorption toward Crystal Violet with a maximum adsorption capacity of 169.49 mg.g-1. The experimental data has been further validated by applying various kinetic models and the pseudo-second order kinetic model was the best suited model. The calculated rate constant values ranged from 0.0046 to 0.0204 g.mg-1.min-1 for different dye concentrations. The positive values of change in enthalpy, ΔH° (9.765 kJ.mol-1) and change in entropy, ΔS° (0.0565 kJ.mol-1.K-1) obtained through thermodynamic studies demonstrate the endothermic nature and spontaneity of the adsorption process, respectively. The adsorption capacity of the adsorbent for the removal of the Crystal Violet dye was also compared with other adsorbents and found maximum. Novelty statement A novel bio-nanocomposite is synthesized by modifying the biopolymer alginate, cysteine and mixing the clay, kaolinite (Kal). The adsorption abilities of the material was tested the on the cationic hazardous dye, Crystal Violet. The material is novel and no attempt has so far been made to examine its batch adsorption abilities to remove hazardous dyes from the wastewater. The results are highly encouraging as out of all the adsorbents tested so far highest adsorption of the dye is observed in the present studies.

Influence of Polymer Processing on the Double Electrical Percolation Threshold in PLA/PCL/GNP Nanocomposites.

For the first time, the double electrical percolation threshold was obtained in polylactide (PLA)/polycaprolactone (PCL)/graphene nanoplatelet (GNP) composite systems, prepared by compression moulding and fused filament fabrication (FFF). Using scanning electron microscopy (SEM) and atomic force microscopy (AFM), the localisation of the GNP, as well as the morphology of PLA and PCL phases, were evaluated and correlated with the electrical conductivity results estimated by the four-point probe method electrical measurements. The solvent extraction method was used to confirm and quantify the co-continuity in these samples. At 10 wt.% of the GNP, compression-moulded samples possessed a wide co-continuity range, varying from PLA55/PCL45 to PLA70/PCL30. The best electrical conductivity results were found for compression-moulded and 3D-printed PLA65/PCL35/GNP that have the fully co-continuous structure, based on the experimental and theoretical findings. This composite owns the highest storage modulus and complex viscosity at low angular frequency range, according to the melt shear rheology. Moreover, it exhibited the highest char formation and polymers degrees of crystallinity after the thermal investigation by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The effect of the GNP content, compression moulding time, and multiple twin-screw extrusion blending steps on the co-continuity were also evaluated. The results showed that increasing the GNP content decreased the continuity of the polymer phases. Therefore, this work concluded that polymer processing methods impact the electrical percolation threshold and that the 3D printing of polymer composites entails higher electrical resistance as compared to compression moulding.

Trends and challenges of biopolymer-based nanocomposites in food packaging.

The ultimate goal of new food packaging technologies, in addition to maintaining the quality and safety of food for the consumer, is to consider environmental concerns and reduce its impacts. In this regard, one of the solutions is to use eco-friendly biopolymers instead of conventional petroleum-based polymers. However, the challenges of using biopolymers in the food packaging industry should be carefully evaluated, and techniques to eliminate or minimize their disadvantages should be investigated. Many studies have been conducted to improve the properties of biopolymer-based packaging materials to produce a favorable product for the food industry. This article reviews the structure of biopolymer-based materials and discusses the trends and challenges of using these materials in food packaging technologies with the focus on nanotechnology and based on recent studies.

Effect of pH on functional, gas sensing and antimicrobial properties of bio-nanocomposite gelatin film for food packaging application.

A bio-nanocomposite film is a polymer blend with nanofiller dispersed in a biopolymer matrix. The aim of this study is to investigate the functional, gas sensing and antimicrobial properties of bio-nanocomposite films incorporated with chicken skin gelatin/ tapioca starch/zinc oxide at different pH levels (pH 4, 6, 7 and 8). Bio-nanocomposite films were prepared using a casting technique followed by the characterization of their functional, gas sensing and antimicrobial properties. Film formulations with pH at different levels showed increased thickness, colour and water vapour permeability (WVP) (p < 0.05). In addition, the increase of pH in films in chicken skin gelatin bio-nanocomposite films increased the tensile strength (TS), while decreasing the elongation at break (EAB). The highest response for ammonia gas in chicken skin gelatin bio-nanocomposite films was obtained at pH 7, with quick response time (τres) within 10 s. The inhibition zone of Staphylococcus aureus in chicken skin gelatin bio-nanocomposite films increased with increasing pH levels. Overall, chicken skin gelatin bio-nanocomposite films with a pH level of 8 were found to have the optimal formulation, with the highest values in thickness, and TS, with the lowest values for WVP and EAB. In conclusion, bio-nanocomposite chicken skin gelatin films with an alkaline pH are a superior packaging material.

Properties and characteristics of nanocomposite films from tilapia skin gelatin incorporated with ethanolic extract from coconut husk.

Impacts of ethanolic extract from coconut husk (EECH) at 0-0.4 % (w/w, on protein basis) on properties of films from tilapia skin gelatin and gelatin/Cloisite Na(+) nanocomposite films were investigated. Young's Modulus, tensile strength and elongation at break of both films decreased with addition of EECH (P < 0.05). The lowest water vapour permeability (WVP) was obtained for gelatin film containing 0.05 % EECH (w/w) (P < 0.05). Nevertheless, the nanocomposite film showed the lowest WVP when incorporated with 0.4 % EECH (w/w) (P < 0.05). Generally, L*- value (lightness) decreased and a*- value (redness) of films increased (P < 0.05) with increasing levels of EECH, regardless of nanoclay incorporation. Transparency of both films generally decreased as the level of EECH increased (P < 0.05). Intercalated or exfoliated structure of nanocomposite films was revealed by wide angle X-ray diffraction (WAXD) analysis. Based on scanning electron microscopic (SEM) analysis, the rougher surface was found when EECH was added. EECH had varying impact on thermal stability of films as revealed by thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. Thus, the incorporation of EECH determined the properties of both gelatin film and nanocomposite film in which the improved water vapour barrier property could be obtained.

Novel chitosan-based smart bio-nanocomposite films incorporating TiO2 nanoparticles for white bread preservation.

Chitosan (CS)-based bio-nanocomposite food packaging films were prepared via solvent-casting method by incorporating a unique combination of additives and fillers, including polyvinyl alcohol (PVA), glycerol, Tween 80, castor oil (CO), and nano titanium dioxide (TiO2) in various proportions to enhance film properties. For a comprehensive analysis of the synthesized films, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile testing, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and UV-vis spectrophotometry were employed. Furthermore, the antimicrobial efficacy of the films against S. aureus, E. coli, and A. niger was examined to assess their potential to preserve food from foodborne pathogens. The results claimed that the inclusion of castor oil and TiO2 nanoparticles considerably improved antimicrobial properties, UV-vis light barrier properties, thermal stability, optical transparency, and mechanical strength of the films, while reducing their water solubility, moisture content, water vapor and oxygen permeability. Based on the overall analysis, CS/PVA/CO/TiO2-0.3 film can be selected as the optimal one for practical applications. Furthermore, the practical application of the optimum film was evaluated using white bread as a model food product. The modified film successfully extended the shelf life of bread to 10 days, surpassing the performance of commercial LDPE packaging (6 days), and showed promising attributes for applications in the food packaging sector. These films exhibit superior antimicrobial properties, improved mechanical strength, and extended shelf life for food products, marking a sustainable and efficient alternative to conventional plastic packaging in both scientific research and industrial applications.

Simultaneous Electrochemical Detection of Dopamine and Tryptophan Using 3D Goethite-Spongin Composites.

In this study, a facile approach for simultaneous determination of dopamine (DA) and tryptophan (TRP) using a 3D goethite-spongin-modified carbon paste electrode is reported. The prepared electrode exhibited excellent electrochemical catalytic activity towards DA and TRP oxidation. The electrochemical sensing of the modified electrode was investigated using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Through differential pulse voltammetry analysis, two well-separated oxidation peaks were observed at 28 and 77 mV, corresponding to the oxidation of DA and TRP at the working electrode, with a large peak separation of up to 490 mV. DA and TRP were determined both individually and simultaneously in their dualistic mixture. As a result, the anodic peak currents and the concentrations of DA and TRP were found to exhibit linearity within the ranges of 4-246 µM for DA and 2 to 150 µM for TRP. The detection limits (S/N = 3) as low as 1.9 µM and 0.37 µM were achieved for DA and TRP, respectively. The proposed sensor was successfully applied to the simultaneous determination of DA and TRP in human urine samples with satisfactory recoveries (101% to 116%).

Adsorption of Metal Ions from Single and Binary Aqueous Systems on Bio-Nanocomposite, Alginate-Clay.

The aim of this work is to characterize and evaluate the retention of Cu2+ and Ni2+ from single and binary systems by alginate-Moroccan clay bio-composite with the utilization of calcium chloride as a cross-linking agent, using the ionotropic gelation method. The bio-nanocomposite was characterized by using a variety of techniques (SEM, EDX, XRD, and pHPZC). The efficiency of the adsorbent was investigated under different experimental conditions by varying parameters such as pH, initial concentration, and contact time. To demonstrate the adsorption kinetics, various kinetic models were tried and assessed, including pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models. The research results show that the adsorption process of Cu2+ and Ni2+ metal ions follows a pseudo-second-order kinetic model, and the corresponding rate constants were identified. To evaluate the parameters related to the adsorption process in both single and binary systems, different mathematical models of isotherms, such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, were investigated. The correlation coefficients obtained showed that the most suitable isotherm for describing this adsorption process is the Langmuir model. The process is considered to be physical and endothermic, as suggested by the positive values of ΔH° and ΔS°, indicating increased randomness at the solid/liquid interface during Cu2+ and Ni2+ adsorption. Furthermore, the spontaneity of the process is confirmed by the negative values of ∆G°. The bio-nanocomposite beads demonstrated a maximum adsorption capacity of 370.37 mg/g for Ni2+ and 454.54 mg/g for Cu2+ in the single system. In the binary system, the maximum adsorption capacities were observed to be 357.14 mg/g for Ni2+ and 370.37 mg/g for Cu2+. There is significant evidence for the use of alginate-Moroccan clay bio-nanocomposite as a cost-effective alternative adsorbent for the efficient removal of metal ions in single and binary systems.

Performance and reaction mechanism of montmorillonite/α-Fe2O3/starch bio-nanocomposite as high-efficiency photocatalytic degradation of acetaminophen: Characterization, feasibility, and pathway.

The worldwide challenge of eliminating pharmaceutical contaminants requires immediate attention. Developing bio-based catalysts that are eco-friendly, reusable, and high-performance, employing starch (ST) and montmorillonite (MMT) as support, holds tremendous promise as a novel biocatalyst for pharmaceutical waste removal. In this study, a montmorillonite/α-Fe2O3/starch (MMT/α-Fe2O3/ST) bio-nanocomposite photocatalyst was successfully synthesized and used for acetaminophen (ACT) degradation under UVA-LED irradiation. The influence of operational factors, such as catalyst, ACT concentrations, and solution pH, on photocatalytic activity was examined in detail; catalyst: 0.75 g/L, pH: 7.1, leading to total ACT (10 mg/L) removal in ∼80 min. MMT/α-Fe2O3/ST showed excellent durability due to negligible Fe leaching. After four successive degradation cycles, ACT and TOC elimination efficiencies remained over 91 and 42.7 %. Compared to other anions studied, carbonate ions suppressed the most ACT degradation. Based on the radical scavenger experiments, hydroxyl and superoxide radicals and holes were involved in the MMT/α-Fe2O3/ST system. LC-MS results were used to propose ACT degradation pathways. This work illuminated the significance of biocatalysts in removing emerging pollutants from wastewater.

Optimization of fenugreek seed mucilage extraction for the synthesis of a novel bio-nano composite for efficient removal of cadmium ions from aqueous environments.

This research investigates the application of an innovative bio-nanocomposite, Fenugreek seed mucilage/silicon carbide (FSM/SiC), as an exceptionally effective adsorbent for eliminating cadmium ions from aqueous solutions. Optimization of fenugreek mucilage extraction involved ultrasonic methods, establishing ideal conditions with a solid-to-solvent ratio of 1:55, 50 °C temperature, 37 kHz frequency, 100 % power, and 30 min processing time. Comprehensive characterization through FTIR spectroscopy, XRD, imaging, DLS, and SEM confirmed the preservation of crucial adsorption-related characteristics. Enhanced adsorption efficiency was achieved by systematically adjusting pH, temperature, adsorbent concentration, pollutant concentration, and contact time, identifying optimal conditions at pH 6, 0.03 g adsorbent dosage, 35 min contact time, and 30 mg/L initial cadmium concentration at 30 °C. Adsorption kinetics followed a pseudo-second-order model, while the Langmuir isotherm fit suggested monolayered adsorption. Thermodynamic analysis indicated exothermic and spontaneous Cd2+ ion adsorption onto FSM/SiC. Remarkably, FSM/SiC demonstrated exceptional regeneration potential, positioning it as a promising solution for water decontamination and environmental remediation. This research showcases FSM/SiC's potential with a maximum adsorption capacity of 41.6 mg/g for cadmium ions, highlighting its significance in addressing cadmium contamination.

Multifunctional bio-nanocomposite films integrated with essential oils@metal-phenolic network nanocapsules for durable fruit preservation.

Food spoilage exacerbates global hunger and poverty, necessitating urgent advancements in food shelf life extension methodologies. However, balancing antibacterial efficacy for food preservation with human and environmental safety remains a significant challenge. Natural essential oils (EOs), known for their potent antibacterial and antioxidant properties, offer eco-friendly alternatives, yet their high volatility and instability limit practical applications. Herein, we conducted the encapsulation of EOs within biocompatible metal phenolic networks (MPNs) to create EOs@MPN nanocapsules. Subsequently, these nanocapsules were integrated into bio-nanocomposite films composed of natural soy protein isolate (SPI) and carboxymethyl cellulose (CMC). The resulting films exhibited robust mechanical properties (Tensile Strength >10 MPa) and significantly enhanced antioxidant activity (7-fold higher than pure films). Importantly, the synergistic combination of EOs and MPNs conferred enhanced antibacterial efficacy. Safety assessments confirmed the bio-nanocomposite films' high biodegradability (> 90 %) and negligible cytotoxicity, ensuring environmental sustainability and human health safety. In practical applications, the bio-nanocomposite films effectively delayed the surface browning of fresh-cut fruits for up to 48 h, demonstrating a pronounced synergistic antioxidative effect against oxidation. Moreover, tomatoes and blueberries packaged with the bio-nanocomposite films still maintained freshness for up to 12 days, offering promising strategies for extending the shelf life of perishable fruits. These findings underscore the potential of EOs@MPN-based bio-nanocomposite films as sustainable solutions for food preservation and highlight their practical viability in mitigating food spoilage and enhancing food security globally.

Fabraction of edible bio-nanocomposite coatings from pectin-containing lignocellulosic nanofibers isolated from apple pomace.

Minimally processed fruits are increasingly demanded in modern society, but the management of perishable waste pomaces (WPs) and the products' short shelf-life are still big issues. Here, a facile approach of reconstruing apple pomace (AP) into edible bio-nanocomposite coatings of fresh-cutting apple slices was successfully developed through alkaline demethylation followed by high-pressure homogenization. The fibrillation of AP fibers is largely improved by -COO- at a concentration of 1.23 mmol g-1, which is released through alkaline demethylation of pectin, instead of relying on intricated or costly cellulose modifications. The average width of AP nanofibers (AP-NFs) downsizes to 18 nm. By casting, AP-NFs fabricate homogeneous films with comparable transparency (56 % at 600 nm), superior mechanical strength (6.4 GPa of Young modulus and 81.7 MPa of strength) and oxygen barrier properties (79 mL µm m-2 day-1 bar-1), and non-toxicity. Moreover, the AP-NF coatings effectively extend shelf life of apple slices by inhibiting browning and respiration, and retain firmness. This research demonstrates a way to valorize WPs as edible coatings for fruit packaging.

Nanoemulsion-integrated gelatin/bacterial cellulose nanofibril-based multifunctional film: Fabrication, characterization, and application.

The current requirements of food safety regulations and the environmental impact stemming from plastic packaging can only be addressed by developing suitable bio-nanocomposite films. Therefore, this study is dedicated to the fabrication of multifunctional film composed of gelatin, bacterial cellulose nanofibrils (BCNF), and black pepper essential oil nanoemulsion (BPEONE) and application for duck meat preservation. BCNF was prepared through ultrasonication of cellulose derived from Komagataeibacter xylinus. BPEONE observed spherical morphology with a diameter ranging from 83.7 to 118 nm. A film matrix containing a higher gelatin proportion than BCNF was more effective in trapping BPEONE. However, increasing the BPEONE fraction showed more surface abrasion and voids in the film morphology. A flexible film with good interaction, crystallinity, and greater thermal stability (421 °C) was developed. Nevertheless, film hydrophobicity (118.89°) declined, resulting in a notable effect on water solubility, swelling, and water vapor permeability. Moreover, the film had improved antibacterial and antioxidant activities, coupled with controlled release characteristics. Consequently, the developed film effectively retarded the lipid oxidation, inhibited microbial growth, and extended the shelf life of duck meat at refrigeration (4 °C) by 3 days, and made the film a promising alternative in the realm of bio-active packaging technology.

Experimental investigations on PVA/chitosan and PVA/chitin films for active food packaging using Oxytenanthera abyssinica lignin nanoparticles and its UV-shielding, antimicrobial, and antiradical effects.

This study investigated the effect of adding lignin nanoparticles (LNPs) derived from Oxytenanthera abyssinica via alkali-acid nanoprecipitation method to polyvinyl alcohol/chitosan (PVA/CI) and polyvinyl alcohol/chitin (PVA/CH) films for the active food packaging applications. Adding LNPs at concentrations of 1 % and 3 % improved the films' thermal stability and mechanical properties. The lowest water solubility and moisture content were observed in PVA/CI/LNPs films. LNPs exhibited effective 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, with the highest values observed in PVA/CH/LNPS and PVA/CI/LNPS films with values of 87.47 and 88.74 % respectively. The addition of LNPs also improved the UV-blocking abilities of the films. PVA/CH/LNP3 and PVA/CI/LNP3 have the smallest percentage transmission values of 3.34 % and 0.86 % in the UV range. The overall migration of dietary stimulants was lower in PVA/CI/LNPS and PVA/CH/LNPS films compared to PVA film. Antibacterial tests demonstrated the inhibitory capacity of the synthesized biofilms against both gram-positive and negative bacterial species, with the highest inhibitory value of 26 mm. The study suggests that PVA/CH/LNPS and PVA/CI/LNPS films have potential applications as active food packaging materials and can be explored in other potential applications such as drug delivery, tissue engineering, wound healing, and slow-release urea fertilizer development.

Investigation study of methyl violet photodegradation over alginate-carboxymethyl cellulose/titanium(IV) oxide/covalent organic frameworks bio-nanocomposite beads under ultraviolet irradiation.

Concerned about water treatment, it is of great importance to present new approaches for improving photocatalytic activity. Since photocatalysis is ubiquitous in almost all chemical manufacturing processes, the development of photocatalytic systems carries significance for our environment. In this regard, three different amounts of covalent organic frameworks decorated with titanium(IV) oxide nanoparticles (TiO2/COF hybrids) in Alginate-Carboxymethyl cellulose (Alg-CMC) blend matrix were prepared under ultrasound irradiation, which Citric acid and Calcium chloride acted as two green cross-linkages. Based on the physio-chemical analyses of these bio-nanocomposite (bio-NC) beads, the Alg-CMC blend polymer appeared to be the best candidate for a disparity of TiO2/COF hybrids. Not only did COF aid to increase the distribution of TiO2 nanoparticles, but it declined the bandgap energies. The resultant Alg-CMC/TiO2/COF (TiO2/COF = 15:6) bio-NC beads demonstrated efficient photodegradation activity towards Methyl violet (MV) under Ultraviolet light. The obtained results of scavenger studies indicated that superoxide radicals and electron agents played a major role in MV degradation. Further investigation confirmed that single oxygen addition and N-de-methylation could be two important pathways for the decomposition of MV by these bio-NC beads.