Synthesis of biodegradable semolina starch plastic films reinforced with biogenically synthesized ZnO nanoparticles

Syzgium cumini seed/poly vinyl alcohol based water resistant biodegradable nano-cellulose composite reinforced with zinc oxide and silver oxide nanoparticles for improved mechanical properties

The current work explored a comparative study of biodegradable jamun seed/polyvinyl alcohol (JS) nanocomposites reinforced with varying concentrations of ZnO and Ag2O nano-fillers. The effect of spherical shaped ZnO and Ag2O nanoparticles (NPs) on the on structure, morphology, swelling and solubility, crystallinity and mechanical properties together with biodegradation performance of the composite films was fully studied. SEM results showed uniform distribution of ZnO and Ag2O nanofillers into the JS matrix and dense or compact nanocomposite films were formed. JS-ZnO and JS-Ag2O nanocomposites with 0.5 wt% ZnO and Ag2O content showed maximum crystallinity i.e. 11.3 and 9.58 %, respectively, as determined by XRD. When compared to the virgin JS film (8.41 MPa), the resultant JS-ZnO-0.5 and JS-Ag2O-0.5 nanocomposites showed significantly enhanced tensile strength (35.7 MPa, 29.2 MPa), elongation at break (15.42 %, 14.62 %) and Young's modulus (141 MPa, 126 MPa), respectively. Also, reduced swelling (120.4 % and 116.1 %) and solubility ratio (17.45 % and 18.42 %) was observed for JS-ZnO-0.5 and JS-Ag2O-0.5 nanocomposites, respectively. Biodegradation results showed that maximum degradation (88 %) was achieved for the JS film within 180 days of soil burial whereas JS-ZnO-0.1 and JS-Ag2O-0.1 nanocomposites showed 78 % and 72 % degradation within 180 days, respectively.

Development of basil seed mucilage (a heteropolysaccharide) - Polyvinyl alcohol biopolymers incorporating zinc oxide nanoparticles

The effect of zinc oxide nanoparticles (ZnONPs) on various properties of basil seed mucilage (a heteropolysaccharide)-polyvinyl alcohol (BSM-PVA) films was investigated. Increasing concentration of ZnONPs in BSM-PVA films reduced moisture content (from 24.73 to 17.09 %), water solubility (from 36.36 to 27.65 %), water vapor permeability (from 4.66 × 10-7 to 2.55 × 10-7 g·m/m2·Pa·h), oxygen permeability (from 2.96 to 2.13 cm3 μm/m2 d kPa), and elongation at break (from 40.34 to 29.44 %), and increased ultimate tensile strength (from 16.81 to 21.48 MPa). Color and light transmission were affected by ZnONPs concentrations. The lack of formation of new peaks, along with the displacement of peaks, indicated the formation of hydrogen bonds between ZnONPs and the film matrix. Dynamic mechanical-thermal analysis showed that storage modulus and glass transition temperature increased with the concentration of ZnONPs. Scanning electron microscopy images illustrated that the addition of ZnONPs improved film integrity. X-ray diffraction pattern showed that the crystal shape of nanoparticles was preserved in the film matrix. Films containing ZnONPs showed good antibacterial activity against Staphylococcus aureus (reductions ≥ 3 log CFU/cm2) and Escherichia coli (reductions ≥ 4 log CFU/cm2). Films containing ZnONPs also showed a suitable antifungal activity during the storage of wheat bread.

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.

Functional Properties of Antimicrobial Neem Leaves Extract Based Macroalgae Biofilms for Potential Use as Active Dry Packaging Applications

Antimicrobial irradiated seaweed–neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves’ extracts with 5% w/w concentration were incorporated into the matrix of seaweed biopolymer and the seaweed–neem bio-composite film were irradiated with different dosages of gamma radiation (0.5, 1, 1.5, and 2 kGy). The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem–seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed–neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.