An irreversible ripeness indicator to monitor the CO2 concentration in the headspace of packaged kimchi during storage

An irreversible chitosan-based indicator has been developed to monitor the kimchi quality corresponding to the partial pressure of CO2 gas in the packaging headspace. For this, 0.3% (w/v) solutions of chitosan and the Coomassie Brilliant Blue dye (BB) were mixed at volume ratios of 10:1, 10:2, and 10:5 to yield BB-incorporated chitosan-based CO2 indicators. A greater CO2 accumulation was observed for kimchi samples stored at 25A degrees C than those stored at 15A degrees C. Acidity measurements indicated optimal consumer satisfaction at 1 and 3 days (when the transparency measurements for the developed indicators were approximately 20%) for kimchi samples stored at 15 and 25A degrees C, respectively. A Pearson correlation analysis revealed that the indicator transparency correlated well with several parameters used to indicate the kimchi quality.