Highly sensitive zinc oxide nanoparticle composite film with deep learning-assisted mobile technology for enhanced food freshness monitoring

Abstract

Smart packaging has been introduced to change the way that food freshness is managed. In this study, a new pH-sensitive film based on chitosan (CS), methylcellulose (MC), zinc oxide nanoparticles (ZnO-NPs), and black wolfberry (BW) anthocyanins was developed and characterized. The composite film showed high sensitivity to total volatile basic nitrogen (TVB-N), with clear and distinguishable color changes, improving freshness monitoring. The film demonstrated ultraviolet (UV) absorbance with an optimum concentration of ZnO-NPs at 4%, enhancing UV protection. The Visual Encoder Transformer (VET) model, trained on 4000 high-resolution images, predicted seafood freshness with an accuracy of 98.44%, outperforming other models. Additionally, the moisture content of the composite films decreased significantly from 18.64% to 7.35%, and the water contact angle increased to 92.89° with the incorporation of ZnO-NPs. The developed system, integrated with an Intelligent Color Recognition (ICR) mobile application, provides a real-time, non-invasive solution for monitoring food freshness, offering both high accuracy and practical usability in seafood packaging.