Bioactive cassava starch-chitosan film incorporated with vanillin for active packaging applications

Incorporating natural compounds into starch-based films has been widely explored to enhance their bioactive properties. In this study, an active food packaging approach was developed using starch-based films supplemented with vanillin as an antimicrobial component. Vanillin concentrations of 2 and 4 mg/mL were first identified as the minimum inhibitory concentrations effective against food-contaminating bacteria, and these concentrations were subsequently incorporated into the films. The films were active against Escherichia coli SZMC 0582, Staphylococcus aureus SZMC 0579, Salmonella enterica SZMC 23289, Bacillus subtilis SZMC 0209 and Listeria monocytogenes SZMC 21307, with growth inhibition of 12-44%. Fluorescence microscopy showed reduced adhesion of E. coli and S. aureus cells on films containing vanillin. Chitosan in 5-10 mg/mL concentrations enhanced film hardness and elongation time. The biopolymer films were thermally stable up to 250 °C and the vanillin became amorphous during the casting. Raman spectroscopy confirmed Schiff base formation, while scanning electron microscopy showed that chitosan improved film smoothness. Vanillin- and chitosan-containing films demonstrated increased antioxidant activity, biodegradability in compost, and reduced the bacterial counts on coated and packaged strawberries after 8 and 16 days of storage. The bioactive films show strong potential as functional food packaging materials.