Indicating film based on blueberry anthocyanin and preparation method thereof

The invention discloses a freshness indicating film based on blueberry anthocyanin and a preparation method of the freshness indicating film. The blueberry anthocyanin-based freshness indicating film disclosed by the invention takes blueberry anthocyanin, carboxymethyl cellulose, gelatin and polyvinyl alcohol as main film forming materials, and is prepared by the following specific steps: firstly, respectively adding deionized water into the carboxymethyl cellulose, the gelatin and the polyvinyl alcohol, stirring in an oil bath pan until the carboxymethyl cellulose, the gelatin and the polyvinyl alcohol are completely dissolved, and then mixing the three solutions; adding a plasticizer, and uniformly stirring to obtain a mixed solution; and finally, adding the blueberry anthocyanin powder, stirring to obtain a mixed solution, coating a polytetrafluoroethylene plate with the mixed solution, and drying to obtain the blueberry anthocyanin indicating film. The prepared freshness indicating film based on the blueb