The physical and compressive load properties of sunflower (Helianthus annuus L.) fruit

Abstract

The physical properties and compressive loading of six domestic sunflower hybrids were studied. The mean values of length, width, thickness, geometric diameter, surface area, porosity, single kernel mass, sphericity, bulk and true density, 1000-kernel weight and coefficient of friction were measured at a single level of moisture content. The results for the sunflower seeds showed that the length, width, thickness and geometric diameter dimensions ranged from 9.31-11.52 mm, 4.71-5.92 mm, 2.95-4.87 mm and 5.12-6.31 mm, respectively. The mean sphericity, porosity, static coefficient of friction, bulk and true density ranged from 0.313-0.550, 0.313-0.363, 0.211-0.237, 330.10-449.86 and 502.74-701.21 kg m-3, respectively. The objective of this study was to evaluate and compare the behavior of six domestic sunflower hybrids (Perun, Bačvanin, Krajišnik, NS-H-111, Pobednik and Šumadinac hybrids) during compressive loading considering the seed moisture content. The seeds of NS-H-111, Šumadinac, Pobednik and Krajišnik demonstrated low values of bio yield force ranging from 29.3 N to 45.2 N when seeds had a low moisture content (between 3.7 and 5.9% w.b.). The opposite occurred for the Bačvanin and Perun hybrids (60.6 N and 76.2 N, respectively) within the same seed moisture content. For all the hybrids, the machine head displacement (deformation) increased as the seed moisture content increased. The linear model shows a decreasing trend of bio yield modulus for all hybrids as the moisture content of seeds increased.