Enhancing the UV-Light Barrier, Thermal Stability, Tensile Strength, and Antimicrobial Properties of Rice Starch–Gelatin Composite Films through the Incorporation of Zinc Oxide Nanoparticles

Abstract

The effects of zinc oxide nanoparticles (ZnONPs) on the properties of rice starch–gelatin (RS–G) films were investigated. ZnONPs were synthesized by a green method utilizing Asiatic pennywort (Centella asiatica L.) extract. The ZnONPs were rod-shaped, with sizes ranging from 100–300 nm. An increase in the concentration of ZnONPs significantly (p < 0.05) increased the thickness (0.050–0.070 mm), tensile strength (3.49–4.63 MPa), water vapor permeability (5.52–7.45 × 10−11 g m/m2 s Pa), and thermal stability of the RS–G–ZnONPs nanocomposite films. On the other hand, elongation at break (92.20–37.68%) and film solubility (67.84–30.36%) were significantly lower (p < 0.05) than that of the control RS–G film (0% ZnONPs). Moreover, the addition of ZnONPs strongly affected the film appearance, color, transmission, and transparency. The ZnONPs had a profound effect on the UV-light barrier improvement of the RS–G film. The crystalline structure of the ZnONPs was observed in the fabricated nanocomposite films using X-ray diffraction analysis. Furthermore, the RS–G–ZnONPs nanocomposite films exhibited strong antimicrobial activity against all tested bacterial strains (Staphylococcus aureus TISTR 746, Bacillus cereus TISTR 687, Escherichia coli TISTR 527, Salmonella Typhimurium TISTR 1470) and antifungal activity toward Aspergillus niger. According to these findings, RS–G–ZnONPs nanocomposite film possesses a potential application as an active packaging: antimicrobial or UV protective.

Characterization of banana powder-based film reinforced with CNF and Bio-mediated ZnO nanoparticles for potential food applications

“…However, this phenomenon is true at higher nanoparticle concentrations, regardless of the source (PPW or PSW), where the nanoparticle aggregation led to increased matrix density and reduced porosity, significantly impacting the WVP. Similar effects have been reported in the literature, such as in rice starch-gelatin films and other biopolymer matrices, where the presence of ZnO NPs altered the structural dynamics of the films [46]. These findings suggest the importance of optimizing nanoparticle content to balance the mechanical properties and barrier functions of biopolymer-based packaging films [47].…”

“…Conversely, increasing ZnO NP concentrations to 0.6% ZnO-PPW and 0.6% ZnO-PSW in BP/CNF films led to a significant (p <0.05) reduction in OP to 9.44 ± 0.01 and 10.56 ± 0.02 mg.mm/m 2 .day, respectively. This suggests that higher concentrations of ZnO NPs enhance the films' barrier properties by increasing their compactness and structural integrity [46]. These findings support the hypothesis that ZnO nanoparticles function as crosslinkers within the nanocomposite matrix, contributing to a denser, less permeable film structure.…”

“…Light transmission of BP/CNF/ZnO-PPW and BP/CNF/ZnO-PSW nanocomposite films ranged from 0.00%-6.86% and 0.00%-13.23%, respectively, across the NP concentrations. These findings indicate that incorporating higher concentrations of ZnO NPs into BP/CNF films significantly (p < 0.05) reduced UV-vis transmission, enhancing the film's screening ability due to light scattering by the nanomaterials embedded within the film matrix [46]. This is consistent with [53], where increasing ZnO NP concentrations (0.2%, 0.4%, and 0.8%) in PVA films decreased UV absorbance.…”

Characterization of Biodegradable Films Made from Taro Peel (Colocasia esculenta) Starch

“…Opacity of the film samples were determined following the procedures of Abdillah et al [ 15 ] and Homthawornchoo et al [ 16 ], by using DU 730 UV/Vis spectrophotometer (Beckman-Coulter, Brea, CA, USA) with slight modifications. The opacity values were calculated using Equation (3): where: A 600 is the absorbance of taro starch films at 600 nm.…”

An Edible and Quick-Dissolving Film from Cassia Gum and Ethyl Cellulose with Improved Moisture Barrier for Packaging Dried Vegetables

“…However, its poor mechanical property cannot meet the requirements of dried vegetables packaging. These films exhibit appropriate tensile strength, flexibility, transparency, gas barrier properties, and even antibacterial [ 11 ] and antioxidant activity. However, they are not suitable for packaging dried vegetables.…”