Fracture Resistances of Okra (Abelmoschus esculentus) Seeds Necessary for Processing Machine Design

Abstract

The fracture resistances of okra (Abelmoschus esculentus, cv. Kirikou) seeds were evaluated in this study. Okra pods were harvested at five maturity stages, and their seeds extracted. The five maturity stages at which the okra pods were harvested were; 12 days after peak anthesis (DAPA), 19 DAPA, 26 DAPA, 33 DAPA, and 40 DAPA. These mechanical parameters (fracture force, fracture energy and deformation at fracture point) of the seeds were measured by using the Universal Testing machine, in accordance with ASTM procedures. The results revealed that fracture properties of okra seeds exhibited a strong dependence on the degree of maturation of the seeds. The fracture force and fracture energy of the okra seeds increased linearly as the okra seeds matured from 12 DAPA (maturity stage 1) to 40 DAPA (maturity stage 5). The okra seeds fracture force increased linearly from 19.04 N to 84.147 N; while the fracture energy increased from 0.021 Nm to 0.088 Nm. However, the relative deformation of the okra seeds at the fracture point decreased linearly as the seeds matured from the 1^st stage to the 5^th stage. These results will be useful to mechanical engineers during the design and construction of okra seeds shelling, crushing, and milling machines.