Propriedades físicas de grãos de feijão caupi durante a secagem

Abstract

The objective of this work was to evaluate the physical properties of cowpea beans in different moisture contents. Samples of cowpea beans manually harvested and threshed with initial moisture content of 0.250 (b.s) were dried in a forced air oven at 40 °C until the final moisture content was 0.13 ± 1 (b.s). Drying was followed by mass difference, with the initial moisture content being known. During drying, the physical properties were determined for predetermined moisture content: repose angle, bulk density, real density, intergranular porosity, mass of thousand grains and shape factors. To determine the shape factors, the main characteristic dimensions of cowpea beans (major, minor and intermediate) were measured, obtained the characteristic dimensions were calculated the sphericity, circularity (repose position), surface-volume ratio and geometric diameter. According to the results obtained, it was observed that moisture content significantly influenced the physical properties and shape factors of the samples of Cowpea beans analyzed. During drying, the bulk density and real density increased, it was also observed an increase in the form factors: sphericity, circularity and surface-volume relation with the reduction of the moisture content. As for the physical properties: mass of a thousand grains, angle of repose and intergranular porosity as well as geometric diameter form factor had a reduction in their values as the moisture content decreased during drying.