The objective of this study was to investigate the effect of moisture content, size and loading orientation on mechanical properties such as force, deformation and energy absorbed per unit volume for fracturing Iranian sunflower seed and its kernel (Azargol as a case study) under quasi-static loading. Sunflower seeds and their kernels were quasi-statically loaded in horizontal and vertical orientations with moisture content in three levels: 3%, 7% and 14%, and size category in three levels: small, medium and large. The obtained results showed that rupture force for both sunflower seed and its kernel decreased with increasing moisture content while the absorbed energy and deformation at rupture point increased for all size categories in both horizontal and vertical loading orientations. Also, seeds in the vertical orientation developed hull cracks at a higher level of force than those loaded in the horizontal orientation. However, for the kernels it was the opposite. In addition, the average forces required to cause kernel rupture were lower (11.64-39.9 N) than those required to rupture the seed (30.06-117.46 N) in both orientations. Seeds loaded in a vertical orientation absorbed more energy (87.67 mJ) prior to rupture than those loaded in the horizontal (46.60 mJ) orientation. However, for the kernels it was the opposite.

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