Anthocyanins Based Indicator Sensor for Intelligent Packaging Application

Natural dyes extracted from the flower of rose and red cabbage were immobilized on filter paper as carrier to prepare a colorimetric sensor for application in intelligent packaging. Indicator sensor was based on natural flavonoids (anthocyanins) extracted from red cabbage and rose whose colour changed from red to green with increase in pH. On characterization of extracts by UV–Vis spectrophotometer, absorption maximum of 530 nm was observed which is ascribed to anthocyanin present in two extracts. The characteristics of sensor including response time, reproducibility, reversibility, stability towards light and the storage stability were also studied. Sensors were also kept in atmosphere of ammonia simulating total volatile basic nitrogen production which changed its colour from red to green with increase in pH. Since pH value of flesh foods concerns their freshness, the indicator sensor is expected to provide a convenient, non-destructive and visual method for flesh food spoilage in storage condition and also for the prediction of shelf life.