The effect of extraction methods, and deep-frying process on the Physico-chemical Properties of (shea oil) vitellaria paradoxa ssp

Abstract

The main goals of this research were to study the effect of extraction methods, and deep-frying process on the Physico-chemical Properties of vitellaria paradoxa ssp. nilotica, beside the chemical composition of shea nuts, the sensory evaluation of potato chips fried in shea butter, groundnut, and their blend oil (1:1) and finally the fatty acid profile of shea butter. The samples were collected from Alradoum area Southern Darfour State – Sudan. Samples were well prepared and kept in deep freezer for further analysis. This study was evaluated the effect of both extraction methods (solvent and boiling) on the physical properties of shea butter concerning, their specific gravity, viscosity, refractive index and color intensity. The reported results for solvent extraction method were, (0.9410 at 30˚c (g/cm3), 1.1(CP), 1.47 and 3.57) were the obtained results for boiling extraction method were, (0.8901 at 30˚c (g/cm3), 3.6 (CP), 1.48 and 10.37) respectively. These findings indicated that, there was no significant difference (P<0.05) between the two methods in their specific gravity and refractive index, where the viscosity and color intensity were completely different (P>0.05). On the other hand, the obtained results for the effect of the solvent extraction method on the chemical properties of shea butter that concerning (moisture content, fat content, free fatty, Peroxide, Saponification and iodine value). The results were, (0.05%, 45.80%, 1.50%, 1.07 (meq/Kg), 181.23 (mg KOH/g oil), and 70.63 (I2/100 g oil) respectively. Beside the stated results for boiling method which were, (0.07%, 28.60%, 1.90%, 3.83 (meq/Kg), 178.07 (mg KOH/g oil), and 65.90 (I2/100 g oil) respectively. These results showed a significant difference (P>0.05) among the two methods except for their moisture content and free fatty acid % which were not indicating any significant difference between them (P<0.05) . More over this study also stated the influence of deep–frying process on the physico-chemical properties of shea butter, groundnut, and their blend oil (1:1) that subjected to different thermal treatments (first, second and third frying), beside their control samples, the obtained results showed a significant difference between the samples (P>0.05). The obtained results of the chemical analysis of shea nuts for moisture content, fat, protein, ash, fiber and CHO were, (8.00%, 45.00%, 7.07%, 2.47%, 6.47% and 31.07%) respectively. Also a sensory evaluation was carried out on potato chips fried in groundnut, blended and shea oil to evaluate their color, flavor, texture and overall acceptability. The best ranking score was obtained by groundnut oil followed by blended oil and lastly shea oil. This might be due to the fact that, the groundnut oil was already refined oil (where refining process is usually improving the physical properties of oils), where the Shea butter and their blend oil (1:1), were not refined oils. This confirmed the Sensory analysis conducted by Akingbala et al., (2006). Finally the fatty acid profile of shea butter, showed that, the five major fatty acids, oleic, stearic, linoleic, palmitic, and arachidic, their values in different extraction methods, were all within values reported by Adikini (2002) and Maranz et al., (2004).