Montmorillonite-Reinforced Starch Films for Sustainable, Active and Intelligent Food Packaging: Structure, Performance and Food Preservation Applications

Abstract

The increasing demand for sustainable food packaging has promoted the development of biodegradable alternatives to petroleum-based plastics. Starch-based films are renewable, low-cost and compostable, but their practical application remains limited by poor mechanical strength, high water sensitivity and insufficient barrier performance. This review discusses recent advances in Montmorillonite (MMT)-reinforced starch films, with emphasis on the relationship between nanocomposite structure, processing conditions, functional properties and food preservation performance. The reinforcing role of MMT is analyzed through intercalation, exfoliation and network formation mechanisms, which improve polymer-clay interactions and contribute to enhanced mechanical, thermal and barrier properties. The review also highlights the influence of starch source, plasticizer content, MMT modification and processing strategies on film morphology and final performance. Special attention is given to food packaging applications, where MMT-starch films have shown potential to extend shelf life by reducing moisture loss, microbial spoilage, oxidative degradation and quality deterioration in perishable products such as strawberries, paneer, chicken, cottage cheese, tomato and litchi. In addition, intelligent packaging applications based on pH-sensitive color changes are briefly discussed as promising tools for monitoring food freshness. Comparative tables summarize reported improvements in mechanical and thermal behavior as well as relevant formulation effects. Finally, the main challenges related to nanoparticle dispersion, large-scale processing, cost-efficiency, food safety and compostability are addressed. Overall, MMT-reinforced starch films represent a promising platform for sustainable, active and intelligent food packaging, provided that future studies continue optimizing formulation, processing and functional performance under real food storage conditions.