Two kinetic approaches and one empirical model for describing the non enzymatic browning of the Granny Smith apple under static conditions

Browning kinetics of Granny Smith apple cubes were studied under static con ditions (constant temperature and relative humidity-RH). The browning measu red by spectrophotometric analysis seemed to be essentially non-enzymatic. The kinetics were modelled, using two kinetic approaches. Increasing RH (fr om 0.11 to 0.75) increased the browning rate, although the activation energ y remained constant. A simple empirical model is proposed for calculating t he browning rate as a function of temperature and RH, in the range of 40-90 degrees C and 0.11-0.84 RH. From the resulting equation the degree of brow ning during storage and drying processes could be predicted.