Multifunctional cassava starch bilayers with basil extract and eco-friendly synthesized silver nanoparticles for scalable and sustainable food packaging

Abstract

Plastic packaging remains essential for food safety; however, improper disposal severely affects ecosystems. Thechallenge lies in developing sustainable packaging that preserves food quality while reducing environmentalharm. This research focused on developing biodegradable bilayer nanocomposites made from two layers ofcassava starch. One-layer incorporated basil extract, while the other varying concentrations (1 %, 2 %, or 3 % w/w) of silver nanoparticles (AgNPs), which were synthesized using basil extract and cassava starch. All films wereproduced through an extrusion-thermoforming process. The bilayer with 3 % w/w AgNPs could not be evaluateddue to early cracking during thermoforming process. The bilayers with 1 % and 2 % w/w nanoparticles exhibitedantimicrobial activity against E. coli and demonstrated enhanced mechanical resistance. The basil extract-infusedlayer offered antioxidant properties, UV protection, and reduced water wettability. The bilayer nanocompositecontaining 1 % w/w AgNPs demonstrated better interlayer compatibility and material integrity when in contactwith water than the 2 % w/w formulation. The starch-based bilayer nanocomposite with 1 % w/w nanoparticlesshows great potential for sustainable functional food packaging, combining antioxidant and antimicrobialproperties, UV protection, improved mechanical strength, and reduced water wettability. However, increasingthe concentration of AgNPs is challenging due to the differences in the thermoforming behavior of the layers.