Table 2.

Some examples of natural biopolymers with different metal-based nanoparticles and their role in the design of some active food packaging materials. Adapted and modified from [58], with permission from Enviro Research Publishers.

Metal-Based Nanoparticles Enmeshed in Some Natural Biopolymers	Observed Properties Due to the Metal-Based Nanoparticles
Carboxymethyl cellulose/ZnO, CuO, and Ag	Enhanced rate of UV absorption. Decreased water vapor permeability (WVP). Improvement of Young’s modulus (YM), tensile strength (TS), and elongation at break (EB). [66]
Starch/Ag-ZnO-CuO	Decreased water solubility (WS), water vapor permeability (WVP), and elongation at break (EB). Increase of TS and YM. Optimum UV and visible absorbance. [67]
Fish skin gelatin/Ag-Cu	Enhanced thickness, TS, a* (red/green) and b* (yellow/blue) in value, total colour difference (ΔE), transparency, and thermal degradation temperature (TDT). Decreased EB and lightness (L*) value. Darker colour. [68]
Gelatin-starch/ZnO	Enhanced thickness, TS, and melting temperature. Decreased EB, WVP, and WS. [69]
Soy protein/ZnO	Decreased L* value, whiteness index, and OTR (oxygen transmission rate). Enhanced a* and b* value, transparency, ΔE, EB, and TS. Showed good barrier properties against UV and visible light. WVP isolate. [70]
Gelatin-PVA/TiO2-ZnO	Decreased oxygen permeability (OP), transparency, WVP, and EB. Enhanced YM, TS, and thickness. [71]
CMC-chitosan/ZnO	Decreased a*, b*, and L* value, YM, and TS. Enhanced b* value, chroma value, ∆E, EB, and contact angle reduction. [72]
Galactomannan/ZnO	Enhanced contact angle, TS, TDT, YM, UVA, and UVB absorption. Decreased OP and WVP. [73]
Nanolignin-PLLA/Ag, Ag2O, TiO2, WO3, Fe2O3 and ZnFe2O	Enhanced a* and b* value, TS, thickness, ∆E, and YM. Decreased EB, WVP, and L* value. [74]
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/ZnO	Decreased a*, b*, and L* value and EB. Enhanced TS, TDT, transparency, and toughness. [75]

UVA and UVB: types of UV radiation.