Table 4.
Selected studies involving the incorporation of ZnO NPs in biocomposite materials for food packaging applications.
| Polymer Matrix | Concentration/Percentage (%) Weight of ZnO | Notable Properties | References |
|---|---|---|---|
| Carboxymethyl cellulose (CMC)/curcumin/ZnO functional film | 1.0% | 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) value increased to 7.5% and 92.5% upon the introduction of 1% of ZnO NPs and curcumin to the film, respectively. Improved UV barrier and mechanical properties upon the addition of 0.5 wt% of curcumin and 1 wt% of ZnO. CMC film with of 1 wt% ZnO and curcumin (CMC/Cur1.0/ZnO1.0) showed optimal functional films with antibacterial and antioxidant properties. |
[117] |
| Bacteria cellulose (BC) Gluconacetobacter xylinum/ZnO (mediated propolis extract) Functional films | Not indicated | Showed antimicrobial properties with a minimum inhibition concentration (MIC) recorded at 0.438 mg/mL on Escherichia coli, Bacillus subtilis, and Candida albicans upon the addition of ZnO on the bacteria cellulose matrix. | [118] |
| Gelatin/starch/ZnO composite films | 12.5% of ZnO was used in preparing the nanocomposite | Incorporating ZnO enhanced the tensile strength (0.20–0.22 MPa) and reduced the elongation at breaks and film solubility. The bio-nanocomposite films showed antibacterial properties against Staphylococcus aureus and Escherichia coli. |
[69] |
| Starch/polyvinyl alcohol (PVA)/ZnO composite films | 3.12 μg/mL (Minimum inhibitory concentration value was used) | Enhanced water barrier, UV barrier, mechanical and antimicrobial properties. In the antimicrobial study, an inhibition zone of 28 mm was recorded against Salmonella typhimurium. |
[119] |
| Grape seed extract (GSE, 5 wt% of CMC)/ZnO composite films | 3% | The inclusion of GSE enhanced antioxidant activity to the CMC-based films, exhibiting about 95% and 25% scavenging activity against ABTS and DPPH oxidative free radicals. The film exhibited 100% UV protection. Furthermore, upon the addition of ZnO NPs, the composite film showed enhanced mechanical and water vapor barrier properties. Also, the composite film displayed potent antibacterial properties against foodborne pathogens of E. coli and L. monocytogenes. |
[120] |
| Pectin/ZnO composite films | 0.5–1.5% | The UV-light barrier property of the pectin/ZnO films was significantly enhanced as the concentration of ZnO increased. | [121] |