Author(s):
Chaves, M.A. 
; Baptista, F.J. ; Silva, J.N. ; Rodrigues, L. ; Viana, A.D.
Date: 2013
Persistent ID: http://hdl.handle.net/10174/9857
Origin: Repositório Científico da Universidade de Évora
Subject(s): viscosity; shear stress
Description
This work was made aiming at studying the best model for the rheological properties of Cupuassu (Theobroma
grandiflorum, Schum) pulps with 14 (in nature), 17, 19, 23 and 25°Brix of total soluble solids (TSS) which were me asured
at 20, 30, 40, 50 and 60°C temperature using a conc entric cylinder rheometer. The results were adjusted to the following
nine models: Ostwald-de-Waele (power law), Bingham, Casson, Generalized Casson, Heinz–Casson, Herschel–Bulkley,
Mizrahi–Berk, Schulmann–Haroske–Reher and Windhab. The parameters of the best model were correlated with pulp
temperature and TSS by polynomial regression analysis and were kept in the regression equation only those parameters
that contributed more than 1% to the variation of the independent variable. The results indicate that the rheological
behavior of Cupuassu pulp in different concentrations and temperatures can be modeled by the Windhab model, although
other models can be used in a narrower band of shear stress.
