Colour changes in concentrated fruit pulp during heating at high temperatures

The colour change in concentrated apple, peach and plum pulp due to extended heat treatment was investigated. Colour differences (Delta E) and Hunter L parameters were used to estimate the severity of damage during heating of the fruit pulp at 56, 66, 80 and 94 degrees C for 700 min. The results indicate apparent first-order kinetics. Hunter a and b and CIE x and y parameters provided information on changes in chromatic attributes after severe heat treatment. The analysis of darn concerning the rate of colour deterioration in concentrated fruit pulps as a function of temperature suggests that more that one mechanism is involved. (C) 1997 Elsevier Science Limited.