A pH-sensitive dye-based freshness indicator system was prepared, and visible color changes based on the production of volatile acids and CO<sub>2</sub> during kimchi storage were monitored. During fermentation, the pH of the kimchi, which was initially 5.4, decreased to moderate values of 4.2–4.4, and reached 4.0 at the end of fermentation. Based on pH and acidity, three fermentation stages were identified. Good correlation between the pH and acidity was observed. The tested indicators all showed visible color changes with the fermentation stages of kimchi, and the values were significantly correlated with the CO<sub>2</sub> concentration, pH, and acidity. Results of this study will be useful for developing a freshness indicator and determining the application of freshness indicator formulations and influencing consumer purchasing decisions.

Freshness indicator for monitoring changes in quality of packaged food products during storage

2019 Spring National Meeting

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