The incorporation of chitosan nanoparticles enhances the barrier properties and antifungal activity of chitosan-based nanocomposite coating films.

The potential alternative of exploring the development of nanocomposites through a single-molecule approach, such as combining chitosan nanoparticles (ChiNP) with chitosan (Chi), remains to be investigated. To maintain the insolubility of the ChiNP filler in the system, the protonation of weakly basic amino groups necessitates the pH of the coating solution above the pKa (6-6.5). This study aimed to evaluate the biofunctional properties improvements of Chi coatings incorporated with ChiNP as filler agents. The coating film forming solution comprised of 0.8 % Chi combined with varying concentrations (0 %, 0.1 %, 0.5 %, and 1 %) of ChiNP. The morphology of ChiNP was characterized via atomic force spectroscopy (AFM). Incorporating the ChiNP (1 %) significantly enhanced antifungal efficacy, i.e., an 88.28 % reduction in fungal activity compared with the control group, and a 65 % reduction compared with pure Chi against Botrytis cinerea. The incorporation of ChiNP improved the ultraviolet and visible light wavelengths, water vapor permeability, hydrophobicity, and thermal properties. Scanning electron microscopy and AFM were performed to assess the surface and internal microstructures of the coating. The findings of this study suggested that the nanocomposite coatings herein presented is potential for use in active packaging, especially in the context of preserving fresh fruit products.

Improvement of cross-linked films based on chitosan/diepoxy-poly (ethylene glycol) incorporating trans-cinnamaldehyde essential oil: Preparation, properties, and application in banana storage.

In this study, development of bioactive coatings containing 1 % (w/v) chitosan (CS), 0.6 % (w/v) diepoxy-polyethylene glycol (PEG), and trans-cinnamaldehyde (CIN) was achieved. The physicochemical and biological properties of the coatings were investigated. The tensile strength, light transmission, water vapor permeability (WVP), and antibacterial properties were enhanced by the incorporation of CIN. The CIN-containing films appeared compact and rough, as observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the quality attributes of the bananas were evaluated at room temperature for 24 days, and the results showed that the CS/PEG/CIN coating delayed the respiration peak, weight loss, sugar content loss, and maintained firmness, color, total soluble solids (TSS), titratable acid (TA), and the appearance of the bananas. Principal component analysis (PCA) revealed that the bioactive coating significantly affected the respiration rate and weight loss of bananas.

Characterization and bio-functional performance of chitosan/poly (vinyl alcohol)/trans-cinnamaldehyde ternary biopolymeric films.

Bioactive films of chitosan (CS)/polyvinyl alcohol (PVA)/trans-cinnamaldehyde (CIN) were prepared by co-blending, and the impact of varying concentrations (0.5, 1.0 and 1.5 %) of CIN on the physicochemical properties of the ternary films was investigated. The ATR/FT-IR analysis revealed that the bioactive film is modulated by Schiff base (C=N) and hydrogen-bond interactions of CS, PVA, and CIN. Inclusion of CIN into the film improved mechanical properties with tensile strength increased from 0.5 % (68.52 MPa) to 1.5 % (76.95 MPa). The presence of CIN within the CS/PVA film also remarkably affected oxygen permeability and improved light transmittance. Additionally, the water barrier and contact angle properties were improved with increasing CIN content. The morphology of the CIN-containing films appeared non-stratified and dense when observed by SEM and AFM. Moreover, spore germination and in vitro assays confirmed strong antifungal activity of the CIN-containing film against P. italicum (~90 %) and B. cinerea (~85 %). The ternary films also exhibited excellent antioxidant activity, as evidenced by DPPH radical scavenging activity (31.43 %) and ferric reducing power (OD700 nm = 0.172) at the highest CIN concentration tested. Thus, this bioactive CIN films are proposed as a versatile packaging material for the food industry.

Edible film of native jicama starch, agarwood Aetoxylon Bouya essential oil and calcium propionate: Processing, mechanical, thermal properties and structure.

The objective of this study was to determine the properties of natural jicama starch and edible film made from the starch. The film was prepared by adding agarwood aetoxylon bouya essential oil and calcium propionate to investigate its properties as an edible coating for fruit or vegetables. The microstructure of the edible film was observed using scanning electron microscopy. The three main materials mostly had significant effects (P < 0.05) on the properties of the sample films, and starch film incorporating essential oil­calcium propionate showed optimum properties as an edible coating material because it had the highest elongation of 10.81%, the lowest stiffness with a Young's modulus of about 2.53 MPa, the lowest of water vapor transmission rate and permeability of 0.117 g h-1 m-2 and 3.092 g mm h-1 m-2 kPa-1, respectively, and the lowest weight loss of 75.30%. It was also found that the microstructure of starch-essential oil­calcium propionate film had a homogeneous surface and the presence of essential oil droplets was not visible.