Development of color indicators for Kimchi packaging

Color indicators for kimchi (fermented vegetable product) packaging were developed to monitor the quality of such commercial products during storage and distribution. Kimchi was packed in a polypropylene (PP) tray with nylon/cast polypropylene (Ny/CPP) lid. A color indicator film consisting of PP resin, Ca(OH)2 as a CO2 absorbent and bromocresol purple or methyl red was attached to the lid. During fermentation at 0, 10, and 20 degrees C, kimchi quality was evaluated for pH and titratable acidity (TA), which had been correlated with Hunter color values of the indicators. Regardless of fermentation temperature, the color values correlated well with pH and TA values.