The indicator response X when plotted against time gives straight lines (Fig. 5) if we
define F(X)=X=kt as the response function. In the MR type indicator, however, TCD values were normalized to X=TCD=15 to be used as the variable. Plotting the indicator response X vs time undoubtedly showed a square curve (data not shown). If the response function F(X)=X4=kt is assumed, F(X) as plotted against time can give straight lines (Fig. 5). Similarly to the case of TA,small deviation of the last one or two points can be observed so that they may be omitted to obtain the exact kinetic data for the indicators.
The values of the response rate constant (k) and the determination coeffcient (r2) for the BP and MR type indicators at three constant temperatures are also listed in Table 1. Plotting lnk vs reciprocal of temperature gave a good linear fit (r2 = 0.975 for BP, r2 =0.953 for MR, P < 0:05), following closely Arrhenius behavior (data not shown). The kinetic parameters of the indicators were derived from the Arrhenius plot. The frequency factor (k1) and activation energy (Ea) for the BP type indicator are 2.98x1013 /day and 79.6 kJ/mol, while those for the MR type are 1.18x1012 /day and 71.4 kJ/mol. The activation energy values for the indicators can cover that for TA of kimchi.