The physical properties of three common Iranian varieties of melon seeds have been evaluated as a function of seed moisture content varying from 4.75 to 47.6, from 5.02 to 46.81, and from 4.55 to 45.22% (w.b.) for Ghermez, Kolaleh and Sarakhsi, respectively. Increasing moisture content was found to increase axial dimensions, surface area, emptying angle of repose, bulk and true density, sphericity, geometric and arithmetic mean diameters, and static friction coefficient on five structural surfaces, while decreasing porosity and filling angle of repose. Among the varieties, Ghermez had the highest values of geometrical properties, in all moisture contents studied. An increase of surface area with moisture content was observed. The maximum values of bulk density and true density among the varieties were obtained for Kolaleh seeds. Ghermez melon seed had the highest porosity which decreased with increase in moisture content. The filling angle of repose decreased as the moisture contents increased for all three varieties. The maximum and minimum values for emptying angle of repose were obtained for Sarakhsi and Kolaleh. At all moisture contents, plywood showed the highest friction coefficient, followed by galvanized iron sheet, then fibreglass, and finally glass. The increase in friction coefficient with moisture content was the largest for Ghermez melon seed on fibreglass surface, followed by Sarakhsi and Kolaleh on fibreglass and galvanized iron sheet surface, respectively. Ghermez variety had the highest friction on all frictional surfaces at all moisture levels.

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