Biodegradable Chitosan-Based Films as an Alternative to Plastic Packaging

Anthocyanin and thyme oil embedded carrageenan-PVA towards bioactive and pH-sensitive food-packaging materials

Consumer interest in smart food packaging is rapidly growing due to its ability to monitor food quality in real time. These packages not only track changes in the product but also help prevent microbial growth, extending food shelf life and safety. A prime example is anthocyanin-containing packaging, which visually indicates pH changes through color shifts. We herein illustrate this approach by designing biocompatible and biodegradable packaging containing anthocyanin and thyme oil entrapping bio-based carrageenan (CR) blended with polyvinylalcool (PVA) films. Incorporating thyme oil and anthocyanin into carrageenan/polyvinyl alcohol (CR/PVA) films has significantly enhanced the desired mechanical properties of the biodegradable packaging. Specifically, flexibility increased by 20 % compared to the pristine CR/PVA film. Moreover, the physical properties of the films improved, with a reduction in water vapor permeability (WVP) from 1.74 to 1.30 and an increase in the water contact angle (WCA) from 60.5° to 89.5°, indicating enhanced hydrophobicity. Additionally, the resulting films exhibited substantial antimicrobial potential particularly against Escherichia coli and Staphylococcus aureus, along with strong antioxidant properties, surpassing the performance of the original CR/PVA films. The incorporation of anthocyanin endowed the films with high pH sensitivity, enabling effective visual detection of pH changes. Stability tests showed that anthocyanins degrade under temperature and light exposure. However, their incorporation into CR/PVA films significantly improved stability by reducing degradation. This enhancement highlights their potential for smart, protective food packaging.

A life cycle assessment approach to minimize environmental impact for sustainable printed sensors

A printed hybrid sensor tag for applications in disposable healthcare and environmental monitoring optimized toward sustainability is presented. Following a systematic Life Cycle Assessment according to ISO 14040:2006 guidelines, the global warming potential associated with various substrate-, electrode-, and sensing materials, as well as manufacturing and end-of-life strategies, are evaluated. Results show that the utilization of bio-based polyethylene and copper inks can minimize the global warming potential most effectively by up to 39% from 42gCO2eq to 25.7gCO2eq per sensor tag. Among manufacturing methods, screen printing coupled with intense pulse light curing emerges as the most eco-efficient combination. Recycling is the most sustainable end-of-life option, although infrastructure challenges impede its full implementation. The silicon sensor chip needed for data communication has been identified as environmental hotspot. This study offers a comprehensive environmental evaluation of sustainable printed sensors and highlights critical challenges and opportunities for the electronics industry, particularly in relation to material selection, recycling strategies, and system-level considerations.

Biodegradable chitosan-based films decorated with biosynthetic copper oxide nanoparticle for post-harvest tomato preservation

Postharvest fruit decay caused by pathogens is an important factor leading to product waste and economic losses, and fruit coating is considered an effective strategy to solve this problem due to its simple operation and effectiveness. In this study, nano modified chitosan film (CSC) was created by mixing chitosan (CS) and copper oxide nanoparticles (CuO NPs) synthesized using abandoned Ficus carica fruit. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra indicated the formation of intermolecular interactions between CS and CuO NPs in the composite film. Compared with CS film, the water vapor permeability (WVP), oxygen permeability (OP) and carbon dioxide permeability (CDP) of CSC film were decreased by 71.78 %, 38.03 % and 43.12 %, respectively, while the opacity, tensile strength (TS) and elongation at break (EB) of CSC film were improved by 8.42, 3.42 and 1.89 times, respectively. The in vitro antifungal activity of CSC film against Alternaria alternata was improved by 78.27 %, compared with CS film. Furthermore, CSC coating significantly delayed the development of tomato fruit diseases during storage, reduced respiration rate, ethylene production and weight loss. After 24 d of storage, the decay index and the weight loss rates of fruits in the CS and CSC groups decreased by 25.00 % and 48.54 %, 35.72 % and 54.08 % compared to the control, respectively. CSC coating effectively maintained the contents of ascorbic acid, titratable acid, soluble sugars, total phenols and flavonoids, while increasing copper content in the peel of tomato fruits. Complete degradation of CSC film in soil was extended by 56 d compared to CS film. To sum up, CSC coating can be a potential choice for extending the shelf life of tomato fruits, improving their edible quality and commercialization, and having better environmental friendliness.

Synergistic interaction of green-synthesized titanium dioxide nanoparticles and Averrhoa carambola extract in chitosan films

Chitosan-based films incorporated with green-synthesized TiO2 nanoparticles (CT) and Averrhoa carambola extract (CP) at different concentrations were fabricated and optimised based on enhanced tensile, moisture-gas barrier and retention capabilities of antioxidants. Chitosan incorporated with 0.06 % TiO2 NP and those incorporated with 6 % carambola extract exhibited optimal results, and developed films of the above two concentrations of the additives were blended into chitosan (CTP) for further analysis. Biodegradability assays confirmed the ecological sustainability of the films. FT-IR revealed a successful interaction between the additives and the chitosan. The XRD spectra of the control film and film containing carambola extract and TiO2 NP reveal a broad, amorphous nature, with carambola extract altering diffraction peaks. SEM revealed homogenous surfaces in control films, whereas those incorporated with the additives showed granules and microstructures. TGA revealed that the heat stability of chitosan-based films infused with TiO2 NP was boosted compared to those infused with carambola extract. Antimicrobial profiling showed good inhibition against gram-positive bacteria (E. faecalis and S. aureus), gram-negative bacteria (P. aeruginosa and E. coli), and a fungus (C. tropicalis). The developed biodegradable films are potential natural alternative food packaging or edible coating for delaying the maturation of fresh harvests.

Biorefinery of Lignocellulosic and Marine Resources for Obtaining Active PVA/Chitosan/Phenol Films for Application in Intelligent Food Packaging

This study focuses on the extraction of phenolic compounds from the fermentation of Phanerochaete chrysosporium and Gloeophyllum trabeum. The main goal was to synthesize phenol/chitosan microspheres and PVA films and characterized using FTIR, TGA, DSC, SEM, and mechanical tests to evaluate their physical, chemical, and mechanical properties for antimicrobial packaging applications. Homogeneous chitosan microspheres loaded with lignin-derived phenols were obtained, showing controlled release of antimicrobial compounds. The incorporation of phenolic microspheres into PVA/chitosan films resulted in significant improvements in mechanical properties: the films exhibited an elastic modulus of 36.14 ± 3.73 MPa, tensile strength of 12.01 ± 1.14 MPa, and elongation at break of 65.19 ± 5.96%. Thermal tests revealed that chitosan-containing films had enhanced thermal stability, with decomposition temperatures (T10) reaching 116.77 °C, compared to 89.28 °C for pure PVA. In terms of antimicrobial activity, PVA/chitosan/phenol films effectively reduced Lactobacillus growth and milk acidity, maintaining quality for up to 96 h at room temperature, outperforming controls with acetic acid and H2O2. The films also inhibit yeast growth for one week. In conclusion, phenols can be effective antimicrobial agents in dairy, but their use should be monitored. Additionally, PVA/chitosan-phenol films offer biodegradability, antimicrobial properties, and sustainability for diverse applications.

Antifungal Chitosan Nanocomposites-A New Perspective for Extending Food Storage

Chitosan, a biopolymer derived from chitin, exhibits significant antifungal properties, making it a valuable compound for various applications in agriculture food preservation, and biomedicine. The present study aimed to assess the antifungal properties of chitosan-modified films using sol-gel derivatives (CS:ZnO) or graphene-filled chitosan, (CS:GO and CS:rGO) against two strains of fungi that are the most common cause of food spoilage: Aspergillus flavus ATCC 9643 and Penicillium expansum DSM 1282. The results indicate important differences in the antifungal activity of native chitosan films and zinc oxide-modified chitosan films. CS:ZnO nanocomposites (2:1 and 5:1) completely inhibited spore germination of the two tested fungal strains. Furthermore, a decrease in spore viability was observed after exposure to CS:Zn films. Significant differences in the permeability of cell envelopes were observed in the A. flavus. Moreover, the genotoxicity of the materials against two cell lines, human BJ fibroblasts and human KERTr keratinocytes, was investigated. Our studies showed that the tested nanocomposites did not exhibit genotoxicity towards human skin fibroblasts, and significant damage in the DNA of keratinocytes treated with CS:ZnO composites. Nanocomposites based on chitosan may help reduce synthetic fungicides and contribute to sustainable food production and food preservation practices.

Ultra-Pressurized Deposition of Hydrophobic Chitosan Surface Coating on Wood for Fungal Resistance

Fungi (Neolentinus lepideus, Nl, and Trametes versicolor, Tv) impart wood rot, leading to economic and environmental issues. To overcome this issue, toxic chemicals are commonly employed for wood preservation, impacting the environment and human health. Surface coatings based on antimicrobial chitosan (CS) of high molar mass (145 × 105 Da) were tested as wood preservation agents using an innovative strategy involving ultra-pressurizing CS solutions to deposit organic coatings on wood samples. Before coating deposition, the antifungal activity of CS in diluted acetic acid (AcOOH) solutions was evaluated against the rot fungi models Neolentinus lepideus (Nl) and Trametes versicolor (Tv). CS effectively inhibited fungal growth, particularly in solutions with concentrations equal to or higher than 0.125 mg/mL. Wood samples (Eucalyptus sp. and Pinus sp.) were then coated with CS under ultra-pressurization at 70 bar. The polymeric coating deposition on wood was confirmed through X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) images, and water contact angle measurements. Infrared spectroscopy (FTIR) spectra of the uncoated and coated samples suggested that CS does not penetrate the bulk of the wood samples due to its high molar mass but penetrates in the surface pores, leading to its impregnation in wood samples. Coated and uncoated wood samples were exposed to fungi (Tv and Nl) for 12 weeks. In vivo testing revealed that Tv and Nl fungi did not grow on wood samples coated with CS, whereas the fungi proliferated on uncoated samples. CS of high molar mass has film-forming properties, leading to a thin hydrophobic film on the wood surface (water contact angle of 118°). This effect is mainly attributed to the high molar mass of CS and the hydrogen bonding interactions established between CS chains and cellulose. This hydrophobic film prevents water interaction, resulting in a stable coating with insignificant leaching of CS after the stability test. The CS coating can offer a sustainable strategy to prevent wood degradation, overcoming the disadvantages of toxic chemicals often used as wood preservative agents.

Manufacture of Bioplastics Prepared from Chitosan Functionalized with Callistemon citrinus Extract

The exploration of natural resources in bioplastics has advanced the development of bio-based materials. Utilizing the casting, chitosan (CH)-based films were manufactured with different glycerol (GLY) percentages (from 0 to 50% w/w of CH) and anthocyanin-enriched fractions (from 0 to 5% of w/w CH) of acidified ethanol extract of Callistemon citrinus flowers (CCE). Callistemon citrinus is an ornamental plant known for its bioactive compounds endowed with health benefits. The hydrocolloid films showed promising mechanical properties. The 30% GLY + 5% CCE film achieved an elongation at break of 57.4%, comparable to the 50% GLY film while possessing enhanced tensile strength and Young's modulus. The CCE, rich in antioxidants, acted as a plasticizer, improving films' flexibility and manageability. The films exhibit hydrophilic characteristics with moisture content and uptake values reflecting their water-absorbing capacity, while films with 30% GLY and 5% CCE exhibit enhanced hydrophobicity. In addition, CCE characterization reveals significant polyphenol content (734.45 mg GAE/g), highlighting its antioxidant capacity. Moreover, CCE supplies remarkable antioxidant properties to the films. These findings suggest the potential of these bioplastics for industrial applications as a sustainable solution to traditional plastics and in reducing environmental impact while preventing oxidative reactions in packaged products.

Encapsulation of Inositol Hexakisphosphate with Chitosan via Gelation to Facilitate Cellular Delivery and Programmed Cell Death in Human Breast Cancer Cells

Inositol hexakisphosphate (InsP6) is the most abundant inositol polyphosphate both in plant and animal cells. Exogenous InsP6 is known to inhibit cell proliferation and induce apoptosis in cancerous cells. However, cellular entry of exogenous InsP6 is hindered due to the presence of highly negative charge on this molecule. Therefore, to enhance the cellular delivery of InsP6 in cancerous cells, InsP6 was encapsulated by chitosan (CS), a natural polysaccharide, via the ionic gelation method. Our hypothesis is that encapsulated InsP6 will enter the cell more efficiently to trigger its apoptotic effects. The incorporation of InsP6 into CS was optimized by varying the ratios of the two and confirmed by InsP6 analysis via polyacrylamide gel electrophoresis (PAGE) and atomic absorption spectrophotometry (AAS). The complex was further characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) for physicochemical changes. The data indicated morphological changes and changes in the spectral properties of the complex upon encapsulation. The encapsulated InsP6 enters human breast cancer MCF-7 cells more efficiently than free InsP6 and triggers apoptosis via a mechanism involving the production of reactive oxygen species (ROS). This work has potential for developing cancer therapeutic applications utilizing natural compounds that are likely to overcome the severe toxic effects associated with synthetic chemotherapeutic drugs.

Programmable chitosan-based double layer seed coating for biotic and abiotic-stress tolerance in groundnut

In the face of agricultural challenges posed by both abiotic and biotic stressors, phytopathogens emerge as formidable threats to crop productivity. Conventional methods, involving the use of pesticides and microbes, often lead to unintended consequences. In addressing this issue, ICAR -Indian Institute of Oilseeds Research (ICAR-IIOR) has developed a chitosan-based double-layer seed coating. Emphasizing crop input compatibility, entrapment, and characterization, the study has yielded promising results. The double-layer coating on groundnut seeds enhanced germination and seedling vigor. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the structural changes and entrapment of crop inputs. The persistence of T. harzianum (Th4d) and Bradyrhizobium sp. in chitosan blended film in studied soils revealed that viable propogules of Th4d were recorded in double layer treatment combination with 3.54 and 3.50 Log CFUs/g of soil (colony forming units) and Bradyrhizobium sp. with 5.34 and 5.27 Log CFUs/g of soil at 90 days after application (DAA). Root colonization efficacy studies of Th4d and Bradyrhizobium sp. in groundnut crop in studied soils revealed that, maximum viable colonies were observed at 45 days after sowing (DAS). This comprehensive study highlights the potential of chitosan-based double-layer seed coating providing a promising and sustainable strategy for stress management in agriculture.

Chitosan Extracted from the Biomass of Tenebrio molitor Larvae as a Sustainable Packaging Film

Waste from non-degradable packaging materials poses a serious environmental risk and has led to interest in developing sustainable bio-based packaging materials. Sustainable packaging materials have been made from diverse naturally derived materials such as bamboo, sugarcane, and corn starch. In this study, we made a sustainable packaging film using chitosan extracted from the biomass of yellow mealworm (Tenebrio molitor) shell waste. The extracted chitosan was used to create films, cross-linked with citric acid (CA) and with the addition of glycerol to impart flexibility, using the solvent casting method. The successful cross-linking was evaluated using Fourier-Transform Infrared (FTIR) analysis. The CA cross-linked mealworm chitosan (CAMC) films exhibited improved water resistance with moisture content reduced from 19.9 to 14.5%. Improved barrier properties were also noted, with a 28.7% and 10.2% decrease in vapor permeability and vapor transmission rate, respectively. Bananas were selected for food preservation, and significant changes were observed over a duration of 10 days. Compared to the control sample, bananas packaged in CAMC pouches exhibited a lesser loss in weight because of excellent barrier properties against water vapor. Moreover, the quality and texture of bananas packaged in CAMC pouch remained intact over the duration of the experiment. This indicates that adding citric acid and glycerol to the chitosan structure holds promise for effective food wrapping and contributes to the enhancement of banana shelf life. Through this study, we concluded that chitosan film derived from mealworm biomass has potential as a valuable resource for sustainable packaging solutions, promoting the adoption of environmentally friendly practices in the food industry.

Nanocomposite Films of Babassu Coconut Mesocarp and Green ZnO Nanoparticles for Application in Antimicrobial Food Packaging

In this work, novel nanocomposite films based on babassu coconut mesocarp and zinc oxide nanoparticles (ZnO NPs), synthesized by a green route, were produced for application as food packaging films. The films were prepared using the casting method containing different contents of ZnO NPs (0 wt%, 0.1 wt%, 0.5 wt%, and 1.0 wt%). The films were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), instrumental color analysis, and optical properties. The water vapor permeability (WVP) and tensile strength of films were also determined. The antimicrobial activity of the films against cooked turkey ham samples contaminated with Staphylococcus aureus was investigated. The results showed that incorporating ZnO NPs into babassu mesocarp matrices influenced the structure of the biopolymer chains and the color of the films. The BM/ZnO-0.5 film (0.5 wt% ZnO NPs) showed better thermal, mechanical, and WVP properties. Furthermore, the synergistic effect of babassu mesocarp and ZnO NPs in the BM/ZnO-0.5 film improved the antimicrobial properties of the material, reducing the microbial count of S. aureus in cooked turkey ham samples stored under refrigeration for 7 days. Thus, the films produced in this study showed promising antimicrobial packaging materials for processed foods.

Influence of cellulose viscosity on the physical, mechanical, and barrier properties of the chitosan-based films

This research paper presents a comprehensive investigation into developing biodegradable films for food packaging applications using chitosan (CN) in conjunction with three distinct types of cellulose (CE), each characterized by varying viscosities. The primary objective was to assess the influence of cellulose viscosity on the physical, mechanical, and barrier properties of the resulting films. The medium-viscosity cellulose imparted numerous advantageous qualities to the biodegradable films. These films exhibited optimal thickness (31 μm), ensuring versatility in food packaging while maintaining favorable mechanical properties, blending strength, and flexibility. Also, medium-viscosity cellulose significantly improved the films' barrier performance, particularly regarding oxygen permeability [1.80 × 10-6 (g.mm.m-2. s-1)]. Furthermore, the medium-viscosity cellulose contributed to superior moisture-related properties, including reduced water vapor permeability [14.80 × 10-9 (g.mm.m-2. s-1. Pa-1)], moisture content (13.22 %), and water solubility (22.87 %), while maintaining an appropriate degree of swelling (41.88 %). Moreover, the study employed advanced analytical techniques, including FTIR, XRD, and TGA, to provide critical insights into the films' chemical, structural, and thermal aspects. This research underscored the importance of the viscosity of film formulation materials as a crucial element in designing and efficiently producing films for food packaging.

A critical review on plastic waste life cycle assessment and management: Challenges, research gaps, and future perspectives

The global production and consumption of plastics, as well as their deposition in the environment, are experiencing exponential growth. In addition, mismanaged plastic waste (PW) losses into drainage channels are a growing source of microplastic (MP) pollution concern. However, the complete understanding of their environmental implications throughout their life cycle is yet to be fully understood. Determining the potential extent to which MPs contribute to overall ecotoxicity is possible through the monitoring of PW release and MP removal during remediation. Life cycle assessments (LCAs) have been extensively utilized in many comparative analyses, such as comparing petroleum-based plastics with biomass and single-use plastics with multi-use alternatives. These assessments typically yield unexpected or paradoxical results. Nevertheless, there is still a paucity of reliable data and tools for conducting LCAs on plastics. On the other hand, the release and impact of MP have so far not been considered in LCA studies. This is due to the absence of inventory-related data regarding MP releases and the characterization factors necessary to quantify the effects of MP. Therefore, this review paper conducts a comprehensive literature review in order to assess the current state of knowledge and data regarding the environmental impacts that occur throughout the life cycle of plastics, along with strategies for plastic management through LCA.