Effect of moisture content on physical properties of barley seeds.

The aim of this study was to assess how they affect different moisture content on some physical properties of the seeds of two varieties of barley. The size, dimensions, volume, bulk and particle densities, empyting and filling angles of repose and friction coefficients against different surfaces were evaluated for two varieties of barley, Esmeralda and Arabella, both supplied by the producers of the southern region of the state of Hidalgo, Mexico, as a function of moisture content in the range of 10.12 to 42.17 (w.b.%). Most physical properties of barley varieties were significantly affected by moisture content variation. The length, width, thickness and unit mass of Esmeralda variety increased from 9.88 to 10.16 mm, 3.37 to 3.89 mm, 2.54 to 2.80 mm and 0.048 to 0.074 g, respectively, as the moisture content increased. The respective values for Arabella varied from 8.37 to 8.87 mm, 3.03 to 3.21 mm, 2.21 to 2.37 mm and 0.037 to 0.043 g, respectively. That is attributed to major content in carbohydrates (mainly alimidón) Esmeralda variety in comparison with Arabela, which declare adsorption capacity of water and declare and granules filling. In Esmeralda variety, sphericity, geometric mean diameter, bulk density, particle density and porosity increased from 44.59 to 47.40%; 4.38 to 4.79 mm; 568.10 to 613.68 kg m-3; 1,099.65 to 1,245.72 kg m-3 and 48.34 to 50.74%, respectively. The coefficient of static friction increased linearly against all the tested surfaces as the moisture content increased. In Arabella variety, sphericity increased from 45.79 to 45.89%; geometric mean diameter increased from 3.82 to 4.06 mm; bulk density increased from 579.68 to 608.58 kg m-3; particle density varied from 1,410.82 to 1,230.61 kg m-3; porosity varied from 58.91 to 50.55% and the coefficient of static friction increased linearly against all the tested surfaces as the moisture content increased, also attributable to substantially more starch content in a variety to the other. The angle of repose for emptying and filling increased linearly as well.