Estimation of the kinetic parameters of anthocyanins degradation at different water activities during treatments at high temperature (100–140 °C) using an unsteady-state 3D model
2020
Jiménez, Nadiarid | Bassama, Joseph | Bohuon, Philippe
A 3D model of a reactor was developed, combining heat transfer and chemical reaction, to identify kinetic parameters under non-isothermal conditions for intermediate-moisture foodstuffs. In particular, the model was used to assess the impact of high-temperature heat treatments (100–140 °C) on anthocyanin degradation in blackberry juice. A quartz-sand system was used at 25 °C, with three different water activities (aw = 0.34, 0.76 and 0.95). Heat transfer resistance and kinetic parameters were identified, using a nonlinear regression method. Estimates of kinetic parameters showed that the constant for the anthocyanin-degradation reaction rate (k₁₂₀°C) increased from 0.9 to 4.1 × 10⁻³ s⁻¹ with decreasing water activity, with a maximum rate at aw = 0.76. No significant difference (p < 0.05) was found between the corresponding activation energies (Eₐ= 94 ± 7 kJ mol⁻¹). Reduced water activity therefore negatively affects anthocyanin stability at high temperatures.
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