Development of sago (Metroxylon sagu)‐based colorimetric indicator incorporated with butterfly pea (Clitoria ternatea) anthocyanin for intelligent food packaging

Abstract Innovation in colorimetric sensors to detect early signs of food spoilage is a growing interest in food safety and quality control. Currently available chemical dyes for sensor applications have concern because of their possible migration into food packaging and food in contact. In this study, a colorimetric indicator was developed using natural butterfly pea ( Clitoria ternatea ) anthocyanin with Sago ( Metroxylon sagu ) as polymeric film. The principle was based on pH shift due to chemical processes produced by microorganism causing anthocyanin color to change. The film was fabricated by solvent casting method and characterized by color change at different pH values, total water solubility, swelling rate, and morphological structure. Trials on chicken breast samples in various conditions exhibited that the film indicator responded well according to pH variation enabling a real‐time monitoring due to spoilage. Thus, our natural pH indicator with visible color variation allows for simple, economic and safe monitoring of perishable foods.