Kinetic study on the color deterioration of crude anthocyanin extract from Schizandra fruit (Schizandra chinensis fructus)

摘要

The effects of temperature and pH on color deterioration of anthocyanin in Schizandra fruit (Schizandra chinensis friictiis) were determined with temperature range of 80~100"C and pH range of 2.0-5.0. Browning index was used as an index of color deterioration of crude anthocyanin extract from Schizandra fruit. As pH of crude anthocyanin extract was increased, color deterioration was accelerated, showing pH-dependency of thermal stability of anthocyanin extract from Schizandra fruit. Anthocyanin degradation could be modeled as a second-order rate reaction, with rates of 3.2 X 10~(-3) h~(-1) (pH 2.0)-4.1 X 10~（-3）3 h~（-1） (pH 5.0) at 100 deg C. Temperature dependence of deterioration was described by the Arrhenius relationship. Activation energies for pH 2.0-5.0 ranged from 24.87-42.54 kJmol~(-1).