Computation of design-related engineering properties and fracture resistance of plum (Prunus domestica) kernels to compressive loading

Abstract

Variations in the moisture content of kernels strongly influence machine performance during post-harvest handling operations. Force and deformation curve of agricultural material must be provided for proper design of harvesting, processing machineries. This study was conducted to determine the effect of controlled moisture treatment (2.64, 4.75, 8.21, 12.56 and 16.85%) on dimensional, gravimetric, frictional, optical and mechanical properties of plum kernels. The total average expansion of 3.63, 3.07 and 5.12% was observed in major, medium and minor axes of plum kernels with increasing moisture content from 2.64 to 16.85%, respectively. The frictional properties indicated better stability and low flowability with an increase in moisture content. A total color difference (ΔE) of 4.55, 4.40, 2.02 and 1.70% in (L∗ a∗ b∗) was recorded among the differently treated samples. The rupture force, deformation at rupture point, hardness, toughness and energy absorbed at rupture point by plum kernels under different compression loading directions decreased significantly with increase in moisture content. At all the moisture levels, transversal direction showed highest rupture force followed by vertical and horizontal directions of plum kernels. The results showed that the changing moisture content of plum kernels is imperative in moisture-based sorting of the plum kernels, energy conservation, and designing of appropriate handling and processing machinery.