Physicochemical properties of Roselle (Hibiscus sabdariffa L.) seeds oil (Elrahad-1) in North Kordofan, Sudan

Abstract

The aim of this study was to clarify the physicochemical property evaluation of Roselle seed oil. Two samples (red and white calyces) of Roselle seeds (Elrahad-1) were obtained from El-obied Agricultural Research Station. The Roselle seed oil was extracted by soxhlet method. The standard procedure of the Association of Official Analytical Chemists (AOAC) was used to determine the physicochemical properties (oil%, specific gravity, refractive index, viscosity, saponification value, acid value, iodine value, peroxide value and fatty acids). The yield of the extracted oil for both red and white was found to be 21.1%. The oil had a refractive index (1.467, 1.466), saponification value (189.7, 189.1), iodine value (119, 119), peroxide value (4.6, 4.7), acid value (3.57, 3.55), viscosity (22.5, 22.5), specific gravity (0.90, 0.90). The main unsaturated fatty acids in the oil are Oleic (47.0555%, 47.8868%), Linoleic (30.5836%, 30.7931%) and Elaideic acid (14.359%, 15.1603%) and the saturated acids are Palmitic acid (3.9494%, 3.9198%) and Myristic acid (1.9609%, 1.9845%). These values were arranged for red and white calyces respectively. Comparing the study results with the standards and guideline of edible oils set by the FAO/WHO and the Sudanese standard and the metrology organization (SSMO) the study recommended that the Roselle seed oil can be an economic source of healthy edible fat and for other food industry applications and suggest further study on the effect of storage time on the physicochemical characteristic of the oil.