SELECTED PHYSICAL AND AERODYNAMIC PROPERTIES OF AFRICAN BREADFRUIT (Treculia africana) SEEDS FROM SOUTH EASTERN NIGERIA.

Abstract

Physical and aerodynamic properties of African breadfruit (Treculia africana) seeds were studied at four moisture levels: 12.50, 15.00, 17.50 and 20.10% dry base (w.b). As moisture content increased from 10.50 to 20.10% (w.b), the average weight, major diameter, minor diameter, intermediate diameter, geometric mean diameter, arithmetic mean diameter of the seeds ranged from 0.35 and plusmn;0.08 to 0.60g and plusmn;0.04g, 8.08 and plusmn;0.90 to 10.05 and plusmn;0.60mm, 4.04 and plusmn;0.53 to 5.00 and plusmn;0.10mm, 2.96 and plusmn;0.43 to 4.60 and plusmn;0.40mm, 4.52 and plusmn;0.45 to 6.03 and plusmn;0.20mm, 5.03 and plusmn;0.45 to 6.55 and plusmn;0.50mm respectively. Also the equivalent diameter, surface area, sphericity, projected area and aspect ratio of the seeds ranged from 4.75 and plusmn;0.42 to 6.03 and plusmn;0.41mm, 64.19 and plusmn;12.64 to 114.25 and plusmn;10.00mm2, 56 and plusmn;8.00 to 60 and plusmn;6.00%, 25.64 and plusmn;5.10 to 39.47 and plusmn; 3.80mm2, and 50 and plusmn;0.08 to 50 and plusmn;0.01mm respectively. The volume ranged from 0.35 and plusmn; 0.014 to 0.73 and plusmn; 0.014cm3, while the true and bulk densities ranged from 1.099 and plusmn; 0.141 to 1.110 and plusmn;0.424g/cm3 and 0.835 and plusmn;0.43 to 0.938 and plusmn;0.21g/cm3. Porosity decreased from 15.01 and plusmn;1.5 to 5.60 and plusmn;0.4% as moisture content increased from 10.50 to 20.10% (w.b). The angle of repose ranged from 39.80 to 60.10o with increase in moisture content. The optimum parboiling time, temperature and moisture content for hulling African breadfruit seeds were determined as 7.5minutes, 57.5oC and 20.10% (w.b) respectively. The terminal velocity of the seeds and kernels ranged from 12.5 to 17.02m/s and 11.40 to 13.36m/s. Drag coefficient and drag force of the hulls ranged from 0.1 to 0.7 and 0.518 and times;10-4 to 0.858 and times;10-4N, while the drag coefficient and drag force of the seeds and kernels ranged from 0.09 to 0.2, 4.50 and times;10-4 to 6.00 and times;10-4N; 0.2 to 0.3 and 4.0 and times;10-4 to 5.10 and times;10-4N respectively. This indicates that optimum separation can be achieved effectively without any loss of the seeds if the results obtained are properly applied in processing of African breadfruit.