Effect of Roasting and Germination on Physicochemical Characteristics of Kernels and Oil from seeds of Moringa peregrine

Abstract

The purpose of this study was to examine the effects of roasting and germination processes on the proximate compositions of the kernels and the physicochemical characteristics of the extracted seeds oil from Moringa peregrina. Roasting was carried out at 180⁰C for 25 minutes whereas germination was carried out at ambient conditions in a wet jute bag for five days. The results have shown that the roasting and germination processes have significantly affected the proximate composition of kernels. Roasting has decreased both protein content from 30.16% to 29.72% and fat content from 40.8% to 36.81%. Furthermore, roasting has observably increased moisture content from 2.90% to 3.32%, ash content from 2.6% to 2.97%, and total carbohydrate content from 23.54% to 27.18%. On the other hand, germinating has increased moisture content from 2.90% to 3.90%, ash content from 2.60% to 3.91%, and total carbohydrate content from 23.54% to 24.74% whereas the protein content was decreased from 30.10% to 27.25% and fat content did not show any appreciable changes (40.80 to 40.20%). Moreover, the physical and physicochemical properties of the extracted oil from raw and processed samples were determined. Both roasting and germinating have altered the measured parameters to varying degrees. The density almost remained unchanged as a result of roasting and germination whereas marginal variations in refractive index were seen between raw and processed samples. Furthermore, both roasting and germination have significantly altered the color of the extracted oil from (12.2Y, 0.1R) to (23.2Y, 0.3R) and from (12.2Y, 0.1R) to (32.3Y, 1.3R) respectively. On the other hand, roasting has noticeably decreased the viscosity of the roasted oil while germination has significantly increased it. Peroxide and acid values were both changed observably by processing. In the case of the roasted sample the peroxide value has changed from 0.57 to 0.95 meqO2/Kg oil and the acid value from 0.68 to 0.25 mgKOH/g while for the germinated sample the acid value changed from 0.68 to 20.03 mgKOH/g and there was no detectable peroxide value (PV).