Oat Threshing Damage and Its Effect on Nutritional Components

Mechanical threshing can cause damage to oats, and the nutritional quality of the damaged kernels easily changes during storage. The current research on oats with regard to threshing damage and nutritional quality falls into two separate research areas, but they are inextricably linked. It is necessary to combine these two types of studies. In order to explore the damage mechanism of oat threshing and its effect on the nutritional components, a three-dimensional model of oat–nail-tooth impact was established, and a finite element analysis of the dynamic impact process was performed using LS-DYNA. The changes in the von Mises stress, contact force, energy, critical velocity, and damage characteristics during impact on different surfaces of the kernel were analyzed. A threshing test was carried out, and the kernels were classified according to their different damage types. The differences in the nutrient compositions and contents of oats with different damage types were analyzed by means of near-infrared spectroscopy and physicochemical testing. The results showed that the von Mises stress and contact force tended to first increase and then decrease during impact. When the impact velocity was 12 m/s, for the top, bottom, front, back, and left sides of the oat impacted by the nail tooth, the maximum von Mises stresses were 10.05, 10.46, 8.60, 9.28, and 8.49 MPa, respectively. The maximum contact forces were 25.09, 18.57, 34.29, 38.37, and 35.19 N, respectively. The critical velocities of impact damage were 13.38, 13.10, 13.40, 14.64, and 16.00 m/s, respectively. The threshing damage could be divided into four typical types: transverse fracture, bottom breakage, side fracture, and back crack. The chemical compositions of oat kernels with different damage types were basically the same, but their nutrient contents were different. These results provide a theoretical basis for optimizing oat threshing devices, reducing threshing damage, and improving oat quality.