Biosynthesize of ZnO nanoparticle from orange fruit peel biomass and its PVA-based composite packaging material: a greener material for suitable packaging

The utilization of biosynthesized ZnO nanoparticles derived from orange fruit peel in the development of polyvinyl alcohol (PVA) composite packaging materials has been investigated. This study explores the multifaceted impact of incorporating these nanoparticles on the mechanical, thermal, and antimicrobial properties of the resulting composite material. Incorporating orange fruit peel ZnO nanoparticles substantially improved PVA composite mechanical properties. PV3 exhibited maximum tensile strength (55.61 MPa) and tear strength (33.51 N/mm), with reduced elongation (121.6%). PV4 achieved high shore-D hardness (39), attributed to nanoparticle reinforcement in the polymer matrix. Incorporating ZnO particles improved thermal stability. The composite PV4 started decomposing at a high 260 °C temperature, indicating resilience during packaging and storage. Moreover, composite PV4 demonstrates strong antimicrobial activity, evident in inhibition zones of 14.5 mm and 15.4 mm against Staphylococcus aureus and Escherichia coli. This potent antimicrobial effect is credited to ZnO nanoparticles, releasing Zn²⁺ ions and generating ROS when exposed to the environment, effectively inhibiting the growth of pathogenic microorganisms like S. aureus and E. coli. In summary, the incorporation of biosynthesized orange fruit peel ZnO nanoparticles into PVA composite packaging material results in a significant improvement in mechanical strength, thermal stability, and antimicrobial performance. Additionally, PV4 stands out with a water contact angle of 63° and a thermal conductivity of 0.7 W/mK, highlighting its superior surface hydrophobicity and thermal insulating properties. These findings suggest the potential of this environmentally friendly composite for various packaging applications, offering both mechanical integrity and enhanced protection against microbial contamination.