Rheological characteristics and kinetics of colour degradation of green chilli puree

Rheological characteristics as a function of particle size at 25 degrees C and the effects of pre-treatment and temperature on colour degradation kine tics of green chilli puree were investigated. Green chilli puree behaved as a shear-thinning fluid and the power law described well the shear stress-s hear rate behaviour. The consistency index (K) decreased while the flow beh aviour index (n) increased as the particle size of the puree decreased. The results indicated that colour degradation during thermal processing of chi lli puree followed a first-order reaction kinetics. The combination L x a x b closely described the colour degradation behaviour. Dependence of the ra te constant during thermal processing of chilli puree obeyed the Arrhenius relationship. The activation energy values for water-blanched and lye-treat ed chilli puree were 11.4 and 16.0 kJ/g mol, respectively. Lye treatment re sulted in retarding the colour degradation rate. (C) 2000 Elsevier Science Ltd. All rights reserved.