Conception et caractérisation d’un bio matériau fonctionnel

Abstract

This study focuses on the development and optimization of biodegradable composite films based on natural biopolymers, aimed at innovative applications in ecological and intelligent food packaging. Two types of polymeric matrices were studied: cassava starch and polylactic acid (PLA), enhanced by the incorporation of functional fillers such as onion peel powder (OPP) and zinc oxide nanoparticles (ZnO NPs) derived from agricultural waste. Initially, cassava starch-based films were formulated with onion peel powder, rich in phenolic compounds, to improve the mechanical properties, moisture resistance, and functionality of the films. The OPP confers a dark color and opacity suitable for protecting light-sensitive foods, while also providing pH sensitivity that can be used as a visual indicator of food freshness, particularly for ground beef. Optimization of the formulations using a response surface methodology made it possible to obtain biodegradable films exhibiting significant degradation within 30 days. Furthermore, nanocomposite films based on cassava starch and ZnO nanoparticles, synthesized from date palm pits, were developed. These films exhibit a reduction in moisture content and excellent UV-blocking capability, although the addition of ZnO leads to a slight decrease in mechanical strength and an increase in water vapor permeability. The nanoparticles also confer effective antimicrobial activity against certain pathogenic bacteria (Bacillus cereus, Staphylococcus aureus), thus enhancing food safety. Finally, PLA-based composite films were produced by simultaneous incorporation of ZnO NPs and a deep eutectic solvent (DES), improving mechanical strength while maintaining good dispersion of the additives. These PLA/DES/ZnO films demonstrate increased water vapor permeability and enhanced opacity, as well as significant antibacterial activity against S. aureus and Escherichia coli, making them particularly suitable for multifunctional active food packaging. In summary, this multidisciplinary research highlights the potential of biodegradable composite films based on cassava starch and PLA, enriched with natural and nanostructured fillers, to offer sustainable, functional, and intelligent solutions in food packaging, combining mechanical performance, antimicrobial protection, freshness indicators, and environmental friendliness.