Uv-Crosslinked Gelatin/Chitosan Films Containing Echium Amoenum Anthocyanins: A High-Performance Smart Packaging System for Food Spoilage Monitoring Publisher



Zahedi Y ; Alighadri T ; Alizadehsani M ; Shaddel R ; Jekle M ; Yousefi A
Source: Carbohydrate Polymer Technologies and Applications Published:2026

Abstract

Gelatin (G)/chitosan (Cs) composite films were synthesized and crosslinked under UV treatment for 15, 30, or 45 min, either in the absence or presence of Echium amoenum anthocyanins (EAA, 10% v/v) as natural pH-responsive colorimetric indicators. The films were assessed for their physicochemical properties and functionality in monitoring the freshness of packaged foods. According to the findings, EAA incorporation coupled with UV treatment decreased water solubility by 46–80%, altered the color coordinates (L*: 84.16 to 38.22–40.51; a*: −0.20 to 46.38–50.17; b*: 3.90 to 27.47–28.52), increased thermal stability, and reduced transparency by about 53–63%, thereby providing effective UV shieldability (P ≤ 0.05). In addition, the tensile strength of these films ranged from 6.06 to 10.45 MPa, close to that of the neat film, while elongation at break increased from 33.45% to 91.04–96.95%. Interestingly, highest antioxidant capacity (86%) was observed for the G/Cs/EAA/UV 15 min film in comparison to G/Cs/EAA/UV 30 min (77%) and G/Cs/EAA/UV 45 min (51%) films. SEM indicated that the surface of G/Cs/EAA/UV 15 min film was smoother than untreated films. G/Cs/EAA/UV films exhibited distinct color changes in response to pH variations and ammonia vapor, and lower UV exposure times resulted in more pronounced colorimetric effects over a wide pH range (2–10). Application tests revealed that during model food (chicken fillet) spoilage, the pH increased from 5.6 to 8.5, while simultaneously the smart indicator transitioned from red to pale pink. Altogether, promising physical property along with functional property and smart-indicator capability was observed by G/Cs/EAA/UV 15 min film, thus suggesting possible use in active packaging for monitoring the freshness of perishable foods. © 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/