Characterization of Ethyl Lauroyl Arginate‐Enhanced Poly(Vinyl Alcohol)/Chitosan Biodegradable Indicator Films Containing Betalains From White‐Fleshed Dragon Fruit Peels

This study aimed to fabricate and characterize Polyvinyl alcohol/chitosan‐based films containing 30 wt% chitosan (PCs), crude betalain‐rich extract from white‐fleshed dragon fruit (Selenicereus undatus) peels (DPE), and ethyl lauroyl arginate (LAE). DPE was obtained as a lyophilized powder from hot‐water extraction without pH adjustment, with betacyanins as the major pigment components. PCs films containing 10–50 wt% DPE were prepared, and the film with 20 wt% DPE ( β 20@PCs) exhibited the most suitable halo‐ and vapochromic responses to pH buffers and ammonia vapor. LAE was subsequently incorporated into β 20@PCs at 1, 3, 5, 7, or 9 wt% to provide antibacterial functionality. Although β 20@PCs showed significantly lower tensile performance than PCs, most LAE‐enhanced formulations caused only slight and statistically non‐significant further decreases in tensile properties. Increasing DPE content increased water vapor permeability but reduced swelling and water solubility. LAE had no significant effects on these water‐related properties, except at 7–9 wt% LAE. The β 20@PCs film showed no antibacterial activity, whereas LAE‐containing films inhibited E. coli , S. aureus , B. cereus , L. monocytogenes , and S. typhi . Among them, β 20@PCs‐3wt%LAE (E3‐ β 20@PCs) exhibited the highest ammonia‐responsive color changes. Overall, E3‐ β 20@PCs showed promising colorimetric, antibacterial, and mechanical properties for active–intelligent packaging applications.