Physical and mechanical properties of seeds and kernels of Canavalia of coastal sand dunes

The wild legumes Canavalia cathartica and Canavalia maritima are common inhabitants of the coastal sand dunes of pantropical regions possess agriculturally, nutraceutically and industrially valuable traits. This study projects the physical and mechanical properties of seeds and kernels of Canavalia of coastal sand dunes of Southwest India in view of designing the equipments necessary for harvesting, handling, sorting and processing. Average value of three characteristic dimensions (length, breadth and thickness) was higher for seeds than corresponding kernels. The thickness to breadth ratio was highest in seeds of C. maritima (0.88) followed by seeds of C. cathartica (0.84), kernels of C. maritima (0.69) and kernels C. cathartica (0.66). The bulk density, true density and porosity ranged from 478.9 to 533.9 kg/m³, 834 to 954.9 kg/m3 and 40 to 45% for seeds and 417.4 to 481.1 kg/m³, 1007.6 to 1315.3 kg/m³ and 57 to 58% for kernels, respectively. The seeds showed higher values of sphericity than kernels. The angle of repose was higher for Canavalia kernels (24.8-26.2°) than seeds (21.4-22.9°). Both seeds and kernels showed minimum static coefficient of friction against stainless steel (0.25-0.48) and maximum on glass (0.33-0.85). Rupture force and energy for rupture was significantly higher for seeds than kernels. All the basic and complex geometric parameters except angle of repose were significantly higher in seeds of C. cathartica than C. maritima. In view of importance of Canavalia seeds, impact of moisture, cooking, roasting and germination on the physical and mechanical properties needs further insight.