Color degradation kinetics of pineapple puree during thermal processing

Improvement of color, as a quality attribute of processed pineapple puree, has been made possible by the increase in knowledge of kinetic of color change. The kinetics of color degradation of pineapple puree were investigated during heat treatment at 70-110 degrees C in order to cover the temperature range that used in preheat and sterilization of commercial aseptic pineapple puree. Color changes associated with heat-treated puree were monitored using Hunter colorimeter (L, a, b, total color difference-Delta E) and Browning index (A(420)). The changes in L and b values fitted well to the first-order kinetic model while Delta E, a value, and Browning index followed the zero-order kinetic. The dependence of the rate constant on temperature was represented by an Arrhenius equation. The results suggested that Delta E and lightness, based on activation energy, were the most sensitive measures of color change at temperature range 70-90 and 95-110 degrees C, respectively. (c) 2005 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.