Linear regression
confirmed that the degradation of anthocyanin in black
mulberry juice and concentrate followed a first-order
reaction. As the determination coefficient of the equations
obtained from the results for 5 °C is too low, the
results were not used for calculation of kinetic parameters.
The heat dependence of the rate constants of anthocyanin
degradation was represented by Arrhenius equation
on the basis of linear regression analysis of natural
logarithms of rate constant against reciprocal absolute
temperature 1/T in Kelvin (Fig. 4). Activation energies
for anthocyanin degradation in juice samples and concentrate
in the range of 20–40 °C were calculated as
56.48 and 49.75 kJ mol−1, respectively (Table 2)