Engineering Properties of Rice-bean Varieties from North-East India

Rice-bean (Vignaumbellata) is a non-conventional, under utilized and multipurpose crop of South and South-East Asia. Eleven rice-bean varieties were studied for their colour, bean area, bean volume, sphericity, bulk density, true density, porosity, angle of repose, static coefficient of friction, and thermal transitions. Beans of variety JCR-08-10 had dark (L: 20.96±1.00), trifling red (a: 0.42±0.1) and minute blue (b: -0.69 ± 0.13) in colour. The length, width and thickness of all varieties ranged from 6.52–8.44 mm, 3.87–5.28 mm and 3.14–4.35 mm, respectively. The sphericity, bean volume and bean surface area of these varieties were between 63.02–69.9%, 30.94–70.92 mm³, and 51.09–87.73 mm², respectively. The thousand-bean mass, bulk density, true density, porosity, angle of repose of rice-bean varieties were 57.64–118.72 g, 820–877 kg.m⁻³, 1138.40–1388.79 kg.m⁻³, 26.47–40.57%, 9.57–21.40º, respectively. The varieties JCR-08-8, JCR-08-12, JCR-08-15 had comparatively higher bulk density than other varieties. The static coefficients of friction for glass, stainless steel and aluminium were 0.29–0.37, 0.38–0.45, and 0.35–0.55, respectively. Differential scanning calorimetry thermograms revealed that JCR-08-8, JCR-08-12 and JCR-50 had highest melting temperature ranging between 121.73°C and 155.45°C.