Some engineering properties of peanut and kernel

Some physical properties of peanut fruit and kernel were evaluated as functions of moisture content. At the moisture content of 4.85% d.b. the average length, thickness, width, geometric mean diameter, sphericity, unit mass and volume of peanut fruits were 44.53 mm, 15.71 mm, 16.68 mm, 23.00 mm, 51.60%, 2.16 g and 5.17 cm3, respectively. Corresponding values for kernel at the moisture content of 6.00% d.b. were 20.95 mm, 8.80 mm, 10.44 mm, 12.60 mm, 57.05%, 1.063 g and 1.14 cm3, respectively. Studies on re-wetted peanuts showed that the bulk density decreased from 243 to 184 kg/m3, the true density, projected area, and terminal velocity increased from 424 to 545 kg/m3, 4.88 to 6.85 cm2 and 7.25 to 7.93 m/s, respectively as the moisture content increased from 4.85% to 32.00% d.b.; for the kernel, the corresponding values changed from 581 to 539 kg/m3, 989 to 1088 kg/m3, 1.53 to 2.09 cm2 and 7.48 to 8.06 m/s, respectively as the moisture content increased. The rupture strength of peanut and kernel decreased as moisture content increased. The dynamic coefficient of friction varied from 0.30 to 0.73 for peanut, and from 0.22 to 0.63 for kernel over different structural surface as the moisture content increased from 4.85% to 32.00% d.b.