Abstract
Postharvest loss is a significant global challenge that needs to be urgently addressed to sustain food systems. This study describes a simple microwave-assisted green synthesis method in developing a nanohybrid material combining natural ilmenite (FeTiO3) and graphene oxide (GO) as a promising antimicrobial fruit peel coating to reduce postharvest loss. The natural ilmenite was calcined in an inert environment and was mixed with GO in a microwave reactor to obtain the nanohybrid. The nanohybrid was then incorporated into an alginate biopolymer to form the fruit coating. Microscopic images revealed successful grafting of FeTiO3 nanoparticles onto the GO sheets. Spectroscopic measurements of Raman, X-ray photoemission, and infrared provided insights into the interactions between the two matrices. The optical band gap calculated from Tauc's relation using UV-vis data showed a significant reduction in the band gap of the hybrid compared to that of natural ilmenite. The antimicrobial activity was assessed using Escherichia coli, which showed a substantial decrease in colony counts. Bananas coated with the nanohybrid showed a doubling in the shelf life compared with uncoated fruits. Consistent with this, the electronic nose (E-nose) measurements and freshness indicator tests revealed less deterioration of the physicochemical properties of the coated bananas. Overall, the results show promising applications for the ilmenite-grafted GO nanohybrid as a food coating capable of minimizing food spoilage due to microbial activity.