Propriedades físicas da polpa do pequi.

Abstract

Despite the high economic potential of pequi, there are still few studies related to its physical properties for industrial purposes. This paper aimed at studying the physical properties of the pequi pulp with different moisture contents (55, 60, 65 and 70%): rheology, specific heat, thermal conductivity and diffusivity. The rheometry was performed on a Brookfield viscometer; the specific heat in a mixture calorimeter, the thermal diffusivity by using the Dickerson cylinder method and the thermal conductivity by KD-device 2. The rheological data were fitted by Sisko, Ostwald-de-Waelle, Casson, I lerschcl-Bulkley, Mizrahi-Berk and Vocadlo models with coefficients of determination (R~) greater than 0.90 and average percentage deviations (P) less than 10%. the best fits were performed by Mizrahi-Eierk model. The pequi pulps with moisture contents of 55, 60, 65 and 70% tended to decrease in apparent viscosity with increasing rotational speed behave as non-newtonian fluids with pseudoplastic characteristics. The specific heat tended to increase with increasing temperature and moisture content of the pulp. The thermal diffusivity of the pequi pulp increased with increasing moisture content; also the thermal conductivity of the pulp did not show a definite trend with increasing water content and temperature of the pulps investigated.