Assessment of the Physical and Engineering Properties of Baillonella toxisperma Pierre (Moabi) Nuts

Abstract

Background: Baillonella toxisperma Pierre, commonly known as Moabi, is a valuable timber tree species native to Central Africa, widely distributed in Cameroon and exploited for its hardwood, edible fruits, and medicinal bark. Despite its economic importance, there is a lack of technical information on the physical and engineering properties of Moabi nuts, hindering the design of efficient post-harvest equipment. Aims: The study aimed at determining the physical and engineering properties of nuts and kernels of Baillonella toxisperma Pierre. Methodology: Samples for this study were collected from Malen IV, Malen II and Kabillon, villages in the East region of Cameroon. All methods used for determination of length, width, thickness, swelling capacity, swelling index, hydration capacity, surface area, arithmetic and geometric mean diameter followed standard protocol with the use of a vernier caliper to obtain basic size parameters of length, width and thickness. The angle of repose was measured by the fixed funnel and heap formation technique while the coefficient of friction was measured using an inclined plane with three different surfaces (wood, galvanized sheet and glass). Results: The fresh Moabi nuts have a length ranging from 46.80 to 69.20 mm, width ranging from 30.40 to 46.20 mm, and thickness ranging from 15.10 to 44.60 mm. The fresh kernels have a length ranging from 34.30 to 56.30 mm, width ranging from 21.30 to 38.90 mm, and thickness ranging from 11.80 to 29.10 mm. The dry nuts have length, width and thickness of 46.61 to 69.01, 30.35 to 46.15, 14.03 to 44.53 mm respectively. On the other hand, the dry kernels have length, width and thickness ranging between 40.30 t0 55.10, 18.70 to 33.20, 10.60 to 24.20 mm. Angle of repose for both nuts and kernels in both states were between 27 and 330. Swelling capacity moved from 1.57 in fresh nuts to 4.33 in dry nuts while fresh and dried kernels had values of 1.89 and 6.78 respectively. Conclusion: The nuts and kernels of Moabi are significantly larger than most nuts available in literature. This will require grading before handling with already existing equipment and further design adjustments to accommodate all shapes of the Moabi for both nuts and kernels.