MECHANICAL AND PHYSICAL PROPERTIES OF BRAZILIAN MACADAMIA NUTS

For the determination of some physical and mechanical properties as a preliminary study to obtain processing and storage equipment design parameters macadamia nuts of different commercial varieties were used.

The nuts (12% moisture content) showed the following characteristics: Specific gravity = 0,582 g.ml^-1; Porosity in soybean oil = 38,15% (25 nuts); Porosity in soybean oil = 26,16% (single nut); Porosity in distilled water = 46,60% (25 nuts); Porosity in distilled water = 26,16% (single nut); Angle of repose = 29,05°; Internal friction coefficient = 0,7017; Surface friction coefficient: 0,3681 for wood, 0,3165 for galvanized steel, and 0,2335 for plywood.

Mechanical properties were determined through compression of the nut between two plane and parallel plates with a constant deformation rate of 3 mm.s^-1. For macadamia variety 660, moisture content of 10,64% and diameters varying from 20 to 23 mm, the following average values were found: Rupture force = 1757,6 N; Deformation at rupture = 1,44 mm; Total deformation necessary to separate kernel and shell = 3,18 mm.

International Symposium on Tropical Fruits

P.C. Neves, S.L. Honório, A.C.O. Ferraz

https://doi.org/10.17660/ActaHortic.1995.370.32