Effects of Thermal Processing on Physicochemical Characteristics of Kernels and Extracted Oil from Seeds of Balanites Aegyptiaca

Abstract

The objective of this is study was to examine the effects of thermal processing (roasting and boiling) on the proximate compositions of the kernel seeds and the physicochemical properties of the oils which were extracted from raw and processed samples of Balanites aegyptiaca. Boiling was carried out by immersion of the kernel seeds in a boiling tap water at 100oC for one hour whereas roasting was conducted by heating the kernels in an oven at 180oC for 15 minutes. Proximate compositions of raw, boiled and roasted samples were determined. The results have displayed that thermal processing has significant effects on the proximate composition of the kernels. Roasting has decreased moisture considerably from 3.74 to 2.18% and protein from 42.41 to 38.52% whereas the oil content was increased significantly from 39.98 to 46.23%. On the other hand, boiling has decreased ash content from 2.88 to 2.32% whereas total carbohydrate content was increased from 10.99 to 14.25%. Furthermore, the physical and physicochemical characteristics of the oils extracted from raw and thermally processed samples were determined. Both roasting and boiling have increased viscosity from 63.5 to 66.0 poise for roasting and 63.5 to 67.0 for boiling and alter color significantly from 13.2Y + 0.4R to 20.2Y + 1.5R for roasting and 13.2Y + 0.4R to 20.1Y + 1.2R for boiling. The peroxide value, on the other hand, has shown interesting trend for thermally processed samples. Roasting has drastically decreased the peroxide value from 13.34 to 4.56 meq/kg while boiling considerably increased it from 13.34 to 18.06 meq/kg.