On-Package Color Indicator for Ripeness Monitoring of tape ketan Packaging

Abstract

A color indicator for tape ketan (TK) (Indonesian fermented steamed glutinous rice product) packaging was developed to monitor the fermentation stage of TK during storage and distribution. Tape ketan was packed in a tray of polypropylene (PP) with a lid of nylon/cast polypropylene (Ny/CPP). A color indicator film consisting of Nafion® and crystal violet (CV) was attached to the lid as an on-package indicator and change its color as water vapor or relative humidity changes. During fermentation at ambient temperature (28±1°C), the TK quality was assessed for pH, titratable acidity (TA), ethanol content and sensory evaluation (aroma, taste, and color), in correlation with the color change of the indicator. In conclusion, the color values of the indicator correlated well with sensory values as a degree for fermentation stage of TK along with other parameters, such as pH, TA, and ethanol, and could be detected clearly with yellow for unripe, blue for ripe, and finally pale blue for overripe.