Contração volumétrica e propriedades físicas de grãos de soja : influência varietal

Abstract

The aim of this work was to evaluate the volumetric shrinkage of soybeans and aplly different mathematical models to experimental values obtained according to the moisture content. In addition, it sought to determine some physical properties of soybeans (bulk density, equivalent diameter, sphericity, roundness and surface-volume ratio) due to the reduction of moisture content. To determine the shrinkage, soybeans were dried in an oven with forced air flow at some regulated temperatures of 40, 50 and 60 ° C. To physical properties evaluation due to the moisture content, it was considered the drying at a temperature of 50 °C. The set of mathematical models of shrinkage was done by linear and non-linear regression analysis through Gauss Newton method, whereas the experimental data of physical properties undergone a variance analysis followed by regression. The Bala and Woods adapted and Polynomial models for the NS7901RR variety, and Correa, Exponencial, Linear, Lozano, Mayor and Polynomial models for the TMG132RR variety showed the best fit to the observed data of volumetric shrinkage from apparent to unit in the different drying air temperatures used. All analyzed physical properties presented a direct relationship to moisture content. With the exception of equivalent diameter,and they all the physical properties increased linearly with the reduction of moisture content. The physical varietal differences were maintained for all analyzed properties, but the variation during the drying took place in different ratios.