Flow Behavior of Guava Puree as a Function of Temperature and Concentration

Flow behavior of guava puree was determined with a tube viscometer. The puree samples (9.8‐16.0° Brix) exhibited shear‐thinning behavior. The flow behavior index of the power law model was nearly constant for all the samples over a temperature range of 25‐60°C; its mean value was 0.43 with a standard deviation of 0.031. The apparent viscosity decreased with increase in temperature and the activation energy offlow was found to be 3.7 kcallg mole. The apparent viscosity increased as the concentration of the purees was increased; the increase was proportional to concentration raised to a power of 2.7. The Mizrahi‐Berk model described well the flow data of the purees. The magnitude of the shear rate exponent was about 0.48, indicating that the purees were suspensions in shearthinning media.