Some physical properties of almond nut and kernel and modeling dimensional properties

Abstract

Three main dimensions of nut and kernel of almonds were measured.  Then some dimensional properties of nut and kernel were calculated.  Effect of the moisture content on bulk density, true density, porosity and coefficient of friction of kernels and nuts were studied.  Angle of repose on iron, plywood and galvanized sheet were measured.  Also in order to examine the correlation between two dimensions of kernels and nuts and correlation between one dimension of nuts and similar dimension of kernels, linear and quadratic regression were used.  Length, width and thickness distributions of nuts and kernels were modeled using normal, log normal, Weibull and Generalized Extreme Value distributions.  For modeling other dimensional properties, only Generalized Extreme Value was used.  The estimated parameters of the PDF for three main dimensions of nuts and kernels indicated that G.E.V was best fit.  With increasing moisture content of the kernels from 4.20% to 29.64% (w.b.), true density and porosity were increased from 939.629 to 1,077.428 kg m^-3 and 37.704% to 57.088%, respectively; and bulk density was decreased from 585.350 kg m^-3 to 462.343 kg m^-3.  When the moisture content of the nuts increased from 4.03% to 28.13% (w.b.), true density and porosity were increased from 1,025.124 kg m^-3 to 1,149.700 kg m^-3 and 38.562% to 56.55%, respectively, and bulk density was decreased from 629.81 kg m^-3 to 499.532 kg m^-3.  Values of coefficient of friction on all surfaces were increased with increasing moisture content.

Keywords: gravimetric properties, regression, log likelihood, normal distribution, Weibull distribution,generalized extreme value distribution, almond nut