Physical and Chemical Structural Analysis of Pistachio Shells

Pistachio shells were examined to determine structure and chemical composition. Structural analysis was completed using a differential scanning calorimeter (DSC), polarized light microscopy (PLM) and environmental scanning microscopy (ESEM). Chemical composition was quantified with Fourier transmission infrared spectroscopy (FT-IR) for organic components and electron dispersive spectroscopy (EDS) analysis for inorganic matter. The shells were found to have a layered, porous structure. Triglyceride fat and cellulose sugar accounted for most of the natural polymers present. The amount of fats increased inversely to the proportion of sugar closer to the outside surface of the shell, possibly accounting for the transport of nutrients into the shell as opposed to the strength needed from cellulose on the inside edge. Understanding the structure and its elemental derivatives will help in the future quantification of physical and mechanical properties.