Developmentof pH Indicator Film Composed of Corn Starch-Glycerol and Anthocyanin from Hibiscus Sabdariffa

Food packagingfeaturing colorimetric pHindicatorsis among the most reliable and intelligent packaging system.In the present study,the pHindicator film was madeupofcorn starch and glycerol,with the addition of a natural dye extracted from Rosellecalyxes, Hibiscus sabdariffa. This work emphasizedonthe development of a pH indicator film made of corn starch-glycerol and anthocyanin to detect food spoilage.Corn starch and glycerol actedas polymer and plasticizer,respectively,thus creating a solid matrixto immobilize anthocyanin within the film. Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectraconfirmed the effective incorporation of anthocyanin in the corn starch-glycerol mixture. The film color variation was measured usinga chromameterafter immersingthe film in acidic and basic solutionsofdifferent pHvalues. In order to evaluate the applicability and reliability of the proposed pH indicator film, a test on real samples,i.e. milk and meat,was conducted. The indicator film turned pink and greenwhen in contact with spoiledmilk and meat,respectively,which provedthe acidic and basicfeatures of spoiledfood.Therefore, it showsthat this pHindicator film canbe used as a sensor inorderto notifythe quality of food.