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The use of inappropriate equipment to crack bush mango (Irvingia gabonensis) nut to obtain the kernel has adversely affected the processing and utilization of the crop. The manual method of cracking the nut with stone, cutlass or pestle and mortar, is not only slow and risky, but also wasteful. Knowledge of the nut mechanical properties is important in the development of its processing equipment. This study was undertaken to determine some strength or mechanical properties of the nut at different moisture contents under lateral and longitudinal loading orientations, using the Universal Testing Machine (UTM). In the moisture range of 7.52%-20.6% (d.b) under the above loading orientations, results of tests showed that all the strength properties decreased with increase in moisture content. Only the rupture strength increased from 0.0507 to 0.0723 N mm-2 as moisture content increased in the above range, under lateral loading orientation. Loading along the longitudinal axis had higher strength property values than lateral loading. This implies that the nut will be easier to crack when loaded on the lateral axis. These findings will be useful in the development of a cracking equipment for bush mango (Irvingia gabonensis) nut. [ABSTRACT FROM AUTHOR]

The effect of moisture content on some physical properties of bush mango (Irvingia gabonensis) nut was studied at four moisture levels in the range of 7.52%-20.6% (d.b). Results showed that the length, width and thickness of nut increased from 37.84 to 50.16 mm, 30.23 to 42.62 mm and 19.25 to 28.15 mm respectively, as moisture content increased in the above range. Nut sphericity decreased from 76.2% to 69.5% as moisture content increased. One thousand seed weight, bulk density, true density and angle of repose increased from 6.634 to 9.158 kg, 756.7 to 1095 kg m-3, 984.4 to 1265.8 kg m-3 and 25.3 ° to 38.9° respectively, in the above moisture range. Static coefficient of friction on different surfaces increased in the order of fiber glass (0.278 to 0.394), metal sheet (0.478 to 0.499) and plywood (0.577 to 0.602) as moisture content increased. Regression analysis showed that all properties followed a linear trend with moisture content. [ABSTRACT FROM AUTHOR]