Gelatin/Butterfly Pea (Clitoria ternatea) Extract Film as Intelligent Packaging: Effects of Storage Temperature

This study aimed to determine the effect of butterfly pea flower extract (BPFE) concentration (5, 10, and 15% w/w based on gelatin) on the physicochemical properties of gelatin films as a pH-indicating intelligent packaging film. The incorporation of BPFE increased (p < 0.05) the thickness and antioxidant activity of gelatin film. The gelatin/BPFE films exhibited 28% and 100 mg GAE/g film for the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and total phenolic content, respectively. Meanwhile, the water vapour permeability (WVP) showed a decrease of over 71% with the incorporation of BPFE. The film demonstrated an excellent pH response with a colour shift from pink, blue, to green in acidic, neutral, and basic media, respectively. The pH sensitivity of the gelatin/BPFE film at different storage temperatures (− 20 °C, 4 °C, 25 °C, and 40 °C) after 7 days was also investigated. A decrease in pH sensitivity over time was observed, irrespective of the storage temperature, as shown by the absence of colour shift. In summary, the gelatin/BPFE film has great potential as a sustainable food packaging with pH indicator and antioxidant properties.