TA and pH are usually chosen as the major quality attributes and fermentation indexes of kimchi because it has the characteristic sourness and carbonated taste.
The changes in TA of kimchi during fermentation at 0°C, 10°C, and 20°C were measured as presented in Fig. 1.
Regardless of temperature, the TA values of kimchi increased gradually at the initial stage and steeply at the middle stage, and remained constant at the final stage of fermentation, which had a sigmoid increase with increase in fermentation period. Mainly lactic acid bacteria produce organic acids such as lactic, citric, and tartaric acid during fermentation, which confers the
peculiar sourness on kimchi
To reach the optimum fermentation period with TA of 0.70 mg/dl,it took about 2.5, 7, and 28 days at 20°C, 10°C, and 0°C,respectively. This result was similar in pattern to the previous reports on the changes of TA of kimchi during fermentation at various temperatures