Bionanocomposite Films Research Articles

Fabrication of Bio-Nanocomposite Packaging Films with PVA, MMt Clay Nanoparticles, CNCs, and Essential Oils for the Postharvest Preservation of Sapota Fruits.

Sapota is an important climacteric fruit with limited shelf life. A special system must be employed to extend the shelf life of sapota fruits. In the present study, polyvinyl alcohol (PVA) and montmorillonite clay (MMt)-based bio-nanocomposite films (BNFs) were integrated at various concentrations (2%, 4%, 6%, and 8%) into cellulose nanocrystals (CNCs), produced from garlic peels (GPs). The BNF loaded with 8% CNC has a better crystallinity index and mechanical properties than the other concentrations of CNC. Therefore, the 8% CNC-incorporated BNF (BNF-8) was selected for further packaging studies. The combined effect of BNF-8 with ajwain essential oil (AO) and oregano essential oil (OO) vapors and BNF-8 with carbendazim (commercial fungicide-CARB) were investigated. In this study, the BNF-based packagings are categorized into five types, viz: BNF+8% CNC (BNF-8), BNF-8+AO, BNF-8+OO, BNF-8+CARB and the non-packaged fruits (control). The shelf-life duration, antioxidant activity, firmness, decay index, and sensory quality were evaluated in order to identify the effectiveness of packaging treatment on sapota fruits. BNF-8+CARB, BNF-8+AO, and BNF-8+OO packaging extended the shelf life of sapota fruits to up to 12 days and maintained the overall physiochemical parameters and sensory qualities of the fruits. Therefore, the BNF-8+AO and BNF-8+OO packaging materials are appropriate alternatives to commercial fungicides for the preservation of sapota during postharvest storage.

Effect of Time on the Properties of Bio-Nanocomposite Films Based on Chitosan with Bio-Based Plasticizer Reinforced with Nanofiber Cellulose.

The deterioration of the performance of polysaccharide-based films over time, particularly their hydrophilicity and mechanical properties, is one of the main problems limiting their applications in the packaging industry. In the present study, we proposed to improve the performance of chitosan-based films through the use of: (1) nanocellulose as an additive to reduce their hydrophilic nature; (2) bio-based plasticizer to improve their mechanical properties; and (3) chestnut extract as an antimicrobial agent. To evaluate their stability over time, the properties of as-formed films (mechanical, hydrophilic, barrier and antibacterial) were studied immediately after preparation and after 7, 14 and 30 days. In addition, the morphological properties of the films were characterized by scanning electron microscopy, their structure by FTIR, their transparency by UV-Vis and their thermal properties by TGA. The films showed a hydrophobic character (contact angle above 100°), barrier properties to oxygen and carbon dioxide and strong antibacterial activity against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Moreover, the use of nanofillers did not deteriorate the elongation at breaks or the thermal properties of the films, but their addition reduced the transparency. In addition, the results showed that the greatest change in film properties occurred within the first 7 days after sample preparation, after which the properties were found to stabilize.

ZnO Nanoparticles-Reinforced Chitosan-Xanthan Gum Blend Novel Film with Enhanced Properties and Degradability for Application in Food Packaging.

Nations all over the world are imposing ban on single-use plastics, which are difficult to recycle and lead to creations of nonsustainable and nondegradable piles. To match the requirement in the market, suitable food packaging alternatives have to be developed that are biodegradable and environment-friendly. The current work is designed for the fabrication of a novel nanocomposite by blending xanthan gum in a chitosan matrix and reinforcing it with ZnO nanoparticles, through a solution casting method. Surface morphology of the film was investigated through field emission scanning electron microscopy, along with energy-dispersive X-ray spectroscopy mapping, and characterized through thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, mechanical testing, and ultraviolet spectroscopy. FTIR spectroscopy analysis corroborated the interaction between the components and the H-bond formation. Polyelectrolyte complex formation materializes between the oppositely charged chitosan and xanthan gum, and further nanoparticle incorporation significantly improves the mechanical properties. The synthesized nanocomposite was found to have increases in the tensile strength and elongation at break of pure chitosan by up to 6.65 and 3.57 times, respectively. The transmittance percentage of the bionanocomposite film was reduced compared to that of the pure chitosan film, which aids in lowering the oxidative damage brought on by UV radiation in packed food products. Moreover, the film also showed an enhanced barrier property against water vapor and oxygen gas. The film was totally biodegradable in soil burial at the end of the second month; it lost almost around 88% of its initial weight. The fabricated film does not pose a threat to the environment and hence has great potential for application in the future sustainable food packaging industry.

Effect of thymol on properties of bionanocomposites from poly (lactic acid)/poly (butylene succinate)/nanofibrillated cellulose for food packaging application

The present study developed the formulation of active bionanocomposites films endowed with the abilities of high biodegradability and antimicrobials for active packaging applications. The aim of this work was to prepare poly (lactic acid)/poly (butylene succinate) (PLA/PBS) blended films reinforced with different concentrations of nanofibrillated cellulose (NFC) and 9 % of thymol essential oil (EO) using the casting method. The active films were further evaluated through Fourier transform infrared spectroscopy (FTIR); as well as mechanical, physical, water vapour permeability (WVP), thermal analysis (TGA), biodegradation, morphological, and antimicrobial (% reduction of bacteria) testing. The tensile strength (TS) of PLA/PBS blend films increased by 12 % with the incorporation of 2 wt% of NFC. The PLA/PBS/NFC with 9 % thymol EO has a good water barrier performance with its tensile strength, elongation at break, and tensile modulus was 13.2 MPa, 13.1 %, and 513 MPa respectively. The presence of NFC promoted the disintegration of PLA/PBS films by 70.5 %. These films promoted the antibacterial activity against S. aureus and E. coli. The study demonstrates that the developed films improved the qualities of chicken fillets and have great potential to be used as active bionanocomposites in food packaging applications.

Reuse of used paper egg carton boxes as a source to produce hybrid AgNPs- carboxyl nanocellulose through bio-synthesis and its application in active food packaging

The proper disposal of disposable synthetic plastic food packaging materials presents a significant challenge for both the environment and the solid waste management community. To address this issue, an antibacterial-based high-strength bio-composite serves as the optimal alternative to conventional packaging materials. This study aims to produce a hybrid material of AgNPs-carboxyl cellulose nanocrystals (AgNPs-CCNCs), obtained from used egg carton boxes (UECBs), through bio acid hydrolysis and an in-situ generation process. Furthermore, AgNPs- carboxyl cellulose nanofibers (AgNPs-CCNFs) will be synthesized through a combination of bio acid hydrolysis and ball milling, followed by an additional in-situ generation step. The AgNPs-carboxyl nanocellulose (AgNPs-CCNCs, and AgNPs-CCNFs) exhibited excellent crystallinity index, morphology, thermal, and antibacterial properties. The morphological analysis was performed by electron microscopy, and the results showed the uniform distribution and spherical form of AgNPs appearing over the carboxyl nanocellulose through the in-situ generation process, which was confirmed through XRD analysis. The study further explores the impact of AgNPs-carboxyl nanocellulose on the mechanical, chemical, antibacterial, and thermal properties of the PVA matrix. The results demonstrate that the bio-nanocomposite film offers opportunities for utilization in active packaging applications.

Development of environmentally friendly composite packaging films from safflower (Carthamus tinctorius L.) plant wastes

Safflower, a widely utilized industrial plant in the production of vegetable oil and biodiesel, generates safflower heads as waste during seed oil extraction, which is known to be rich in cellulose. In this study, the production and characterization of environmentally friendly biocomposite and nano-biocomposite packaging films with a reduction in the utilization of fossil-based materials were focused on. The materials of interest were cellulose (SC) and cellulose nanocrystals (SNC), which were derived from safflower head waste (SAW). The fillers SC and SNC were subjected to analysis to investigate changes in their chemical structure (FTIR), degree of crystallinity (XRD), and surface morphology (SEM and AFM). It was observed that SNC, obtained from SC, exhibited a higher crystallinity level (62%) compared to SC, and displayed mostly spherical morphology with an average diameter of approximately 100 nm. The production of low-density polyethylene (LDPE) based biocomposite and nano-biocomposite packaging films filled with SC (5%–20%) and SNC (0.1%–1.5%) was conducted in two stages: compound production using a twin-screw extruder and blown film extrusion. The incorporation of SC resulted in a 75% decrease in the mechanical properties of LDPE/SC biocomposite material. However, the addition of SNC proved to be relatively effective in maintaining the mechanical properties of LDPE/SC/SNC nano-biocomposite films. Furthermore, the LDPE/SC/SNC nano-biocomposite films exhibited increased crystallinity and gas permeability compared to LDPE, which can be attributed to the effective interaction between LDPE and the fillers (SC and SNC).

Improving properties of Litsea cubeba oil Pickering emulsion-loaded gelatin-based bio-nanocomposite film via optimizing blending ratio: Application for mango preservation

To improve the biological and water-barrier properties of gelatin film, we incorporated the red roselle extract (RRE), ZnO nanoparticles (ZnO), and Litsea cubeba oil Pickering emulsion (LCON) into the GE film. The effect of RRE, ZnO, and LOCN on the properties of GE film was assessed using Box–Behnken response surface design (BBD). The BBD results revealed that these compounds greatly affect the properties of the film, especially the contribution of ZnO/LCON on the mechanical and water barrier properties of the film. The optimal antifungal (80.15%), antibacterial (31.24 mm), antioxidant (73.00%), tensile strength (42.03 MPa), elongation at break (25.50%), water vapor permeability (18.01 g mm·m−2·Kpa−1·h−1), and water contact angle (110.2°) of the film were obtained at 1.10% RRE, 1.51% ZnO and 2.38% LCON. The X-ray diffraction pattern and FTIR spectra results indicated the change of molecular interactions and semi-crystalline structure in the film. The scanning electron microscopy, fluorescence image, and energy dispersive X-ray results revealed that the excellent dispersion of RRE, ZnO, and LCON in the GE matrix led to an even and smooth structure in the film. This structure offers a positive effect on improving the mechanical and barrier properties of the film. The colorful patterns were successfully printed on the film to provide essential product information. Due to its excellent biological, mechanical, and barrier properties, the optimized film was applied for mango preservation. The optimized GE/RRE/ZnO/LCON film significantly controlled the postharvest quality and anthracnose in mango. Thus, the GE/RRE/ZnO/LCON film has great potential for mango preservation in active packaging applications.

Bionanocomposites films applied as active and smart food packaging: A review

AbstractFood packaging is used worldwide and is a common technique for protecting food safety and quality while increasing shelf life. Environmental issues caused by using polymers in packaging derived from petroleum are becoming more significant and more well‐known. Interest in ecofriendly packaging materials made of renewable resources (biopolymers) has steadily increased, particularly for temporary and throw‐away packaging applications. However, biopolymers frequently have poor processability, poor mechanical, and poor barrier characteristics, restricting their industrial application and scalable manufacturing. Researchers have created bionanocomposites with improved packaging qualities like antibacterial function, mechanical toughness, optical clarity, and gas and water barrier properties to overcome these restrictions. This review seeks to inform readers about recent advances in active food packaging that use biopolymers and bionanocomposite materials. The difficulties and possibilities presented by such resources for the food packaging sector have been examined. This review is timely given the recent spike in interest in research projects both in academia and industry seeking to create a new group of materials for packaging based on biopolymer for food with potential uses elsewhere.

Biotransformation of banana peel waste into bacterial nanocellulose and its modification for active antimicrobial packaging using polyvinyl alcohol with in-situ generated silver nanoparticles

The present study explored the banana peel waste extract (E-BPW) as economic BNC production using a static intermittent fed-batch (SIFB) strategy, which supported about 9.24 ± 0.31 g L−1 with HS medium. BNC matrix was further loaded with polyvinyl alcohol (PVOH) and silver nitrate by simple immersion and analyzed for suitable capacity for an antimicrobial active packaging system. Using coconut shell extract as a reducing agent, a green route was exercised for the in-situ generation of AgNPs inside the BNC and PVOH matrix. The parameters’ level and effect were studied statistically using a complete factorial design. PVOH-incorporated BNC matrix improved mechanical behavior while moisture content and WVTR decreased. The BNC/PVOH/AgNPs films exhibited maximum inhibition zone widths of approximately 17 ± 0.5 mm against E. coli and 14 ± 0.0 mm against S. aureus. Investigation of pure BNC, BNC/PVOH/AgNPs bionanocomposite films was done by using advanced analytical techniques. Bionanocomposite films also showed excellent mechanical strength, thermal properties, and sensory evaluation results due to the reinforcing effect of PVOH and AgNPs on the BNC matrix. Overall, the present findings supported the use of EBPW for BNC production and the possibility of PVOH/BNC/AgNPs bionanocomposite films as an active antimicrobial packaging system.

Packaging of Fresh Poultry Meat with Innovative and Sustainable ZnO/Pectin Bionanocomposite Films—A Contribution to the Bio and Circular Economy

The development of innovative/sustainable materials capable of enlarging the shelf-life of food products has lately been a focus of research, aiming to reduce food waste. Due to their good antimicrobial properties, zinc oxide nanoparticles (ZnO NPs) can add activity to food packaging, improving its performance. Furthermore, these nanoparticles are considered GRAS by the Food and Drug Administration (FDA), which represents an advantage in their application. Through an innovative and sustainable approach using tomato and passionfruit extracts, ZnO NPs were produced and incorporated into pectin films. The resulting bionanocomposites were tested for their activity via in situ studies, using fresh poultry meat as a food matrix. Overall, the bionanocomposites presented good antimicrobial activity, with the intrinsic antimicrobial properties of pectin having shown to be enhanced by the incorporated ZnO NPs. When used as primary packaging for the meat, the deterioration rate of the poultry meat, measured through microbiological growth and total volatile basic nitrogen content, was reduced. However, the nanoparticles contributed to the increment of discoloration and meat oxidation processes. Nonetheless, it can be concluded that fresh poultry meat protected with the bionanocomposites presented an extension of its shelf-life time, and it was confirmed that this eco-friendly packaging has potential to be employed by the food industry.

Preparation and Application of Active Bionanocomposite Films Based on Sago Starch Reinforced with a Combination of TiO2 Nanoparticles and Penganum harmala Extract for Preserving Chicken Fillets.

The aim of this study was to develop sago starch-based bionanocomposite films containing TiO2 nanoparticles and Penganum harmala extract (PE) to increase the shelf life of chicken fillets. First, sago starch films containing different levels of TiO2 nanoparticles (1, 3, and 5%) and PE (5, 10, and 15%) were prepared. The barrier properties and antibacterial activity of the films against different bacteria strains were investigated. Then, the produced films were used for the chicken fillets packaging, and the physicochemical and antimicrobial properties of fillets were estimated during 12-day storage at 4 °C. The results showed that the addition of nano TiO2 and PE in the films increased the antibacterial activity against gram-positive (S. aureus) higher than gram-negative (E. coli) bacteria. The water vapor permeability of the films decreased from 2.9 to 1.26 (×10-11 g/m·s·Pa) by incorporating both PE and nano TiO2. Synergistic effects of PE and nano TiO2 significantly decreased the oxygen permeability of the sago starch films from 8.17 to 4.44 (cc.mil/m2·day). Application results of bionanocomposite films for chicken fillet storage at 4 °C for 12 days demonstrated that the films have great potential to increase the shelf life of fillets. The total volatile basic nitrogen (TVB-N) of chicken fillets increased from 7.34 to 35.28 after 12 days, whereas samples coated with bionanocomposite films increased from 7.34 to 16.4. For other physicochemical and microbiological properties of chicken fillets, similar improvement was observed during cold storage. It means that the bionanocomposite films could successfully improve the shelf life of the chicken fillets by at least eight days compared to the control sample.

Antifungal Activity of Nanobiocomposite Films Based on Silver Nanoparticles Obtained Through Green Synthesis.

The high incidence of Candida albicans infections has raised concerns regarding side effects and drug resistance, compounded by a limited number of alternative drugs. Silver nanoparticles (AgNPs) have prominent antimicrobial activity, but effective administration remains a challenge. In this study, AgNPs were synthesized via a green chemistry approach, using glucose as a reducing agent, and incorporated into an agar matrix to form a film (AgFilm). The AgNPs and AgFilm were characterized by Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and atomic force microscopic (AFM). The UV-Vis spectra of the AgNPs and AgFilm showed bands at 415 and 413nm, respectively. The PXRD and UV-Vis data suggest that the growth of AgNPs was effectively inhibited in the AgFilm. The diameter of AgNPs dispersed in AgFilm was 76 ± 42nm, and the thickness of the film and 35 ± 3µm. The antifungal activity of AgFilm was evaluated against 20 strains of C. albicans, demonstrating high antifungal activity with an inhibition zone of 19 ± 2mm. Therefore, AgFilm could be a promising option for the treatment of superficial C. albicans infections.

Insight into effect of pigment removal on leaf protein-based bionanocomposite film properties

Capsicum and alfalfa leaves contain numerous leaf proteins (LP) and cellulose resources, making them excellent raw materials for preparing protein-based bionanocomposites films (PBBFs). However, the pigment in LP leads to PBBFs with low light transmission, which limits their application in food packaging. Bleaching can remove pigments; however, its effect on LP and PBBFs remains unknown. This study investigates the effects of pigment removal on the physicochemical and material properties of PBBFs in three dimensions: raw materials, film-forming liquids (FFLs), and PBBFs. The results showed that pigment removal significantly reduced the lignin content of LP, while altering their amino acid composition and thermal properties. The apparent viscosity and stability of FFLs decreased after pigment removal. The PBBF microstructure also changed. The mechanical properties and water sensitivity of PBBFs decreased slightly after pigment removal. This was related to the strength of the hydrogen bonding interactions between the LP and cellulose nanofibers (CNFs), and also to the conformation of the protein and the degree of amino acid exposure within the PBBFs. Pigment removal significantly improved PBBF chromaticity values and light transmission. PBBFs block UV radiation before and after pigment removal and can be used for photochemically sensitive food packaging.

The effect of different clay types on the barrier properties of PLA/PBAT/clay bio-nanocomposite packaging films

The aim of this study was to develop alternative bio-nanocomposite film to Polyethylene (PE) film from poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends and different clay types for flexible packaging industry. Poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) bio-blend films were prepared by using a chain extender. Bio-nanocomposite films were processed on a twin-screw extrusion and blown film extruder by wt.%3 loading the different montmorillonite (MMT), Sepiolite, and Bentonite types in presence of a polymeric epoxy-based chain extender plasticizer (CE; Joncryl® ADR 4468). All films were characterized in terms of thermal, chemically, physically, optical, mechanical, sealing and barrier properties. In conclusion, all analyzing results showed good agreement with PLA/PBAT in the presence of a polymeric epoxy-based chain extender. The main outcome of adding clay types to PLA/PBAT bio-blends is to obtain eco-friendly, improved barrier properties compared to PE film structure, which has inherently poor oxygen permeability. As a result of all studies, the closest alternative bio-blend recipes to PE film structure with improved barrier properties were obtained with composite of wt.%25 PLA + %75 PBAT in the presence of wt.%1 plasticizer and %3 High Purity Sepiolite clay (HPS).

Allantoin‑zinc layered simple hydroxide biohybrid as antimicrobial active phase in cellulosic bionanocomposites as potential wound dressings

Cellulosic materials loaded with a novel zinc layered simple hydroxide (LSH) with allantoin in its structure (allant-ZnLSH) have been developed for potential application as wound dressings. The allant-ZnLSH biohybrid was synthesized by slow addition of a zinc chloride solution to an aqueous solution of allantoin, while adding a NaOH solution dropwise to maintain a controlled pH. The recovered precipitate was characterized by XRD, FTIR, chemical analysis, and FE-SEM. The allant-ZnLSH material was further incorporated into biopolymeric matrices such as hydroxypropylmethylcellulose (HPMC), carboxymethylcellulose (CMC) and cellulose nanofibers (CNF), because of their biocompatibility and biodegradability. The resulting films presented suitable mechanical properties, with Young's modulus values ranging between 1.3 and 3.9 GPa, as well as appropriate water vapor transmission rates (WVTR) for application in would healing, around 250–630 g/m2 per day. The bionanocomposite films also showed interesting barrier properties against the passage of UV light, while keeping a certain transparency in the visible range that would allow the healing process to be monitored without removing the dressing. Their antibacterial action was evaluated against E. coli and S. aureus in agar plates, showing only antimicrobial activity against the latter. The goal is to develop materials that can exhibit antimicrobial, and skin regenerative properties provided by the presence of zinc ions and allantoin, respectively.

Physico-Mechanical Optimization and Antimicrobial Properties of the Bionanocomposite Films Containing Gallic Acid and Zinc Oxide Nanoparticles.

The mechanical and physical properties of the bionanocomposite films based on κ-carrageenan (KC)-gelatin (Ge) containing zinc oxide nanoparticles (ZnONPs) and gallic acid (GA) were optimized using the response surface method, and the optimum amounts of 11.19 wt% GA and 1.20 wt% ZnONPs were obtained. The results of XRD, SEM, and FT-IR tests showed the uniform distribution of the ZnONPs and GA in the film microstructure, and suitable interactions between biopolymers and these additives, which led to increasing the structural cohesion of the biopolymer matrix and improving the physical and mechanical properties of the KC-Ge-based bionanocomposite. In the films containing gallic acid and ZnONPs, an antimicrobial effect was not observed against E. coli; however, the GA-loaded and optimum films show an antimicrobial effect against S. aureus. The optimum film showed a higher inhibition effect against S. aureus compared to the ampicillin- and gentamicin-loaded discs.

Cross-linked CMC/Gelatin bio-nanocomposite films with organoclay, red cabbage anthocyanins and pistacia leaves extract as active intelligent food packaging: colorimetric pH indication, antimicrobial/antioxidant properties, and shrimp spoilage tests

Multifunctional food packaging films were produced from crosslinked carboxymethyl cellulose/gelatin (CMC/Ge) bio-nanocomposites incorporated with Ge-montmorillonite (OM) nanofiller, anthocyanins (ATH) from red cabbage as colorimetric pH-indicator, and pistacia leaves extract (PE) as active agent. The influence of additives on the structural, physical, and functional properties of the films was investigated. The results showed that ATH and PE caused color alteration and reduced transparency. However, they improved the UV light barrier ability by 98 %, with less impact from OM, despite its well-dispersed state in the matrix. Increasing PE content in the bio-nanocomposite films caused an increase in compactness and surface roughness, reduction in moisture content (15.10–12.33 %), swelling index (354.55–264.58 %), surface wettability (contact angle 80.1–92.49°), water vapor permeability (7.37–5.69 × 1010 g m−1s−1Pa−1), and nano-indentation mechanical parameters, without affecting the thermal stability. ATH-included films demonstrated color pH-sensitivity with improved ATH color stability through the ATH-Al3+ chelates formation. PE-added films exhibited effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, reaching 93 % of inhibition, and antimicrobial properties with biocidal effects for PE-rich film. The shrimp spoilage test showed that the T-1.5PE film offered the strongest active intelligent response. The CMC/Ge-based bio-nanocomposite films endowed with antioxidant/antimicrobial properties and colorimetric pH-sensitivity have promising potential for food packaging application.

Improvements of thermal and mechanical properties of achira starch/chitosan/clay nanocomposite films

Thermoplastic biofilms were developed from achira starch, chitosan and nanoclays using the solvent-casting method. To obtain the filmogenic solutions, different sonication times (0, 10, 20 and 30 min) were considered in order to evaluate the incidence of this parameter on the chemical and physico-mechanical properties of the bionanocomposite films. The chemical analysis using FTIR spectroscopy showed strong intermolecular interactions between the components with increasing sonication times. The results for tensile strength and elongation were satisfactory for films with 20 min of sonication with increases of 154% and 161%, respectively. Morphological analysis showed greater homogeneity, while thermal analysis showed that sonication favoured the plasticization process and thus, the production of homogeneous materials. The water absorption and wettability tests showed less hydrophilic materials allowing these new materials to be considered for use as coatings or packaging for the food sector.

Influence of silylated nano cellulose reinforcement on the mechanical, water resistance, thermal, morphological and antibacterial properties of soy protein isolate (SPI)-based composite films

The aim of this research work is to improve the mechanical and water-resistance properties of soy protein isolate (SPI) biofilm. In this work, 3-aminopropyltriethoxysilane (APTES) coupling-agent modified nanocellulose was introduced into the SPI matrix in the presence of citric acid cross-linker. The presence of amino groups in APTES facilitated the formation of - cross-linked structures with soy protein. The incorporation of a citric acid cross-linker made the cross-linking process more productive, and the surface smoothness of the film was confirmed by a Scanning Electron Microscope (FE-SEM). From the study of the mechanical and thermal properties and water resistance of the film, it was confirmed that the results were highly satisfactory for the modified nanocellulose-incorporated film compared to the non-modified one. Additionally, coating of citral essential oil onto SPI nanocomposite film displayed antimicrobial properties due to the presence of various phenolic groups in the citral oil. The Tensile Strength and Young's Modulus of silane-modified nanocellulose containing film were enhanced by ∼119 % and ∼ 112 %, respectively on incorporation of 1 % APTES-modified nanocellulose. Consequently, this work is expected to offer an effective way for silylated nano-cellulose reinforcing soy protein isolate (SPI)-based bio nanocomposite films for packaging applications. As an example, we have demonstrated one of the applications as wrapping films for packing black grapes.

A hydroxypropyl methylcellulose/hydroxypropyl starch nanocomposite film reinforced with chitosan nanoparticles encapsulating cinnamon essential oil: Preparation and characterization

Active packaging derived from polysaccharides plays an important role in prolonging the shelf life of food. In this study, cinnamon essential oil (CEO)-loaded chitosan nanoparticles (CNs) were prepared and embedded in hydroxypropyl methylcellulose (HPMC)/hydroxypropyl starch (HPS) blends to enhance the physicochemical and biofunctional properties of the formed films. Different concentrations (5, 10, 15, and 20 μL/mL) of CEOs were encapsulated with CNs to form CEO-CNs, as confirmed by Fourier Transform Infrared Spectrometer (FTIR), X-Ray Diffraction (XRD), and scanning electron microscope (SEM) images. The prepared CEO-CNs were incorporated into the HPMC/HPS film-forming matrix to prepare reinforced nanocomposite films. SEM images showed that the CEO-CNs were dispersed in the HPMC/HPS matrix, thus filling the void space in the composite matrix and significantly improving the mechanical and barrier properties of the bio-nanocomposite films. The elongation at break of the reinforced films improved from 8.54 ± 0.53 MPa to 24.81 ± 0.47 MPa, and the water vapor permeability was reduced by nearly 30 %. FTIR and XRD analyses indicated the formation of hydrogen bonds between CEO-CNs and HPMC/HPS polymer molecules. Release studies showed that the nanocomposite film was capable of sustained release of CEO, which imparted antioxidant (radical scavenging activity of 27.66–42.19 %) and antimicrobial properties (inhibition of Escherichia coli and Aspergillus flavus growth). Therefore, these HPMC/HPS nanocomposite films with enhanced properties may have great potential for food preservation.