This research presents an active biodegradable packaging, where papain was incorporated into chitosan films reinforced with cellulose nanofibers (CNF). The objective of this study was to evaluate the properties of chitosan‐film and CNF (0%, 4%, and 8%, w/w) incorporated with papain (0%, 2%, 6%, and 10%, w/w) and their release in the aqueous medium. Films were characterized by thickness, scanning electron microscopy, UV‐Vis light transmission, X‐ray diffraction, proteolytic activity, and kinetics of papain release. The papain impaired the dispersion of the CNF in the polymer matrix and increase crystallinity, however, the films show good transparency. The proteolytic activity of the films increased according to the concentration of papain. The CNF acted to control the release of papain. Films made with 2% papain and 4% CNF presented the lowest diffusion coefficient of the papain and may be used in packaging where the slow release of the active compound is required. Novelty impact statement This research presents an active biodegradable packaging, where papain was incorporated into chitosan films reinforced with cellulose nanofibers (CNF). The films developed showed good transparency and both the addition of CNF and papain resulted in increased crystallinity of chitosan films. The films with CNF presented the lowest diffusion coefficient of the papain and may be used in packaging where the slow release of the active compound is required.

Sulfiting agents are added to crustaceans products to prolong their shelf life. However, depending on the concentration, these agents can be toxic to consumers due to the presence of SO 2 . In this context, a colorimetric indicator label based on starch and iodine was developed to detect SO 2 in shrimp, showing whether the product is safe or not for consumers. The incorporation of iodine into the starch matrix resulted in labels with a smooth and homogeneous surface, and reduced water solubility from 9.26% to around 0.12%. In both in vitro and shrimp paste test, a visual detection response was observed in the label containing 0.02% of iodine when evaluated in the presence of 100 to 160 ppm of SO 2 , with ΔE* values greater than 5 (can be identifiable by the human eye). Therefore, the elaborated label showed potential as an economical and simple method to detect SO 2 concentration in shrimp-based foods.