An active and pH-responsive film developed by sodium carboxymethyl cellulose/polyvinyl alcohol doped with rose anthocyanin extracts

Many anthocyanins were used in active and pH-responsive packaging. The purpose of the study was to prepare an active and pH-responsive sensitive film based on sodium carboxymethyl cellulose/polyvinyl alcohol (CPVA) by a casting process, which contained rose anthocyanin extracts (RAEs) to monitor the freshness of pork. The concentration of RAEs had an important influence on the physicochemical property of RAEs-CPVA films, especially excellent anti-oxidation and light barrier properties. Importantly, the 160-RAEs-CPVA film had a strong response to pH, showing different color at different pHs. Furthermore, when monitoring the freshness of pork stored at 25 °C, the light green color of the 160-RAEs-CPVA film indicated that the freshness of the pork was higher, while the dark green and orange appearance indicated that the pork was spoiled. Therefore, 160-RAEs-CPVA film can be used as a smart indicator for freshness monitoring of pork.