Natural pH Indicator from Potato Starch Films Incorporated with Curcumin

Abstract

In this work, we developed a potato starch film incorporated with curcumin to be used as a pH-sensitive smart polymeric material, which could be applied as a pH probe in food industry. The Beer-Lambert law was used to characterize curcumin which was purchased from the pharmacy of alternative medicine in the city of Benghazi. As a control experiment, the visual colour changes of curcumin powder dissolved in buffered aqueous solution were examined at the pH rage of 5-11. It was found that the colour of the solution altered from yellow to reddish-brown, as the pH of the curcumin solution changed from 7 to 8. Curcuminwas also incorporated into the starch extracted from potato before being formed into an edible film using a solution casting method. The pH-sensitivity of film was investigated at varied pH values (pH 5-11), the visual colour variations of tapioca starch-curcumin film was noted. The colour of edible film changed from pale yellow to dark orange colour by increasing the pH.But, the addition curcumin to the potato starch film did not alter mechanical properties of starch. As a result of an alteration in film colours, the potato starch-curcumin film could be applied as a natural pH indicator for monitoring food spoilage based on the acidity changes. Likewise, an environmentally friendly indicator film was too accomplished