Application of in-situ casted ZnO-starch nanocomposite for packaging of strawberries (Fragaria x ananassa)

Heliyon. 2023 Nov 20;9(11):e22556. doi: 10.1016/j.heliyon.2023.e22556. eCollection 2023 Nov.

Abstract

Nanomaterials have recently been used in packaging as antibacterial coatings because of their desirable antibacterial and antifungal properties. In this study, we describe the synthesis of zinc oxide nanoparticles (ZnO NPs) and evaluate potato peel starch based ZnO NPs nanocomposite paper (ZnO-starch NC paper) on microbiological activity, storage, and properties of strawberries (Fragaria x ananassa). The ZnO-starch NC paper was used to package the strawberries and then stored at 4 °C and 27 °C for 10 days, respectively, controls were incubated without the ZnO-starch NC paper. The ZnO NPs were synthesized and characterized, the formation of sizes ranging from 35 to 40 nm were confirmed by SEM and XRD. The SEM showed that the ZnO NPs were successfully embedded in the starch forming the ZnO-starch NC. The antimicrobial and antifungal analysis showed that the ZnO-starch NC paper was effective against the fungi, B. cinerea, gram positive bacteria, B. subtilis and S. aureus but not against the gram negative bacteria, E. coli and P. aeruginosa. Total phenolic compounds and Vitamin C content of both the ZnO-starch NC packaged and controls were found to be in the normal range of recommended quality parameters of strawberries as there was no change in intrinsic factors of the fruits during incubation. Application of the ZnO-starch NC in packaged strawberries resulted in the reduction of weight loss and microbial growth compared to the controls. The overall weight loss showed that the loss of moisture and nutrients was not statistically significant (p > 0.05). We conclude that the ZnO-starch NC packaging is a promising safe alternative to extend storage period and increase the shelf-life of strawberries.

Keywords: Fragaria x ananassa; Nanocomposites; Nanopackaging; Nanoparticles; Starch; Zinc oxide.