الخواص الفيزيائية والكيميائية لزبدة الشيا المستخلصة من انوية اشجار الشيا

Abstract

Abstract: Shea butter is an edible oil derived from shea trees(Vitellaria paradoxa),member of the Sapotacea family . Due to increasing demand of Shea butter in both local and worldwide market , characterization of the constituent of the of the oil is extremely important . This study is contribution to the valorization of shea kernels as non-conventional oil resource in Chad. Here phytochemical screening, physicochemical characteristics, and antioxidant activity of shea extracts were assayed. screening revealed the presence of sterols steroids, glycosides, flavonoids, triterpens, tannins and saponins, while alkaloids were not detected . total lipids were : 55±1.11% at 4.9±1.08%moisture . Shea butter was extracted by solvent extraction water , ethanol and n-hexane physicochemical characteristics of shea butter extracts were varying due to differences in extraction methods . Some characteristic values of n-hexanic, aqueous and ethanolic extract as fallow were ; oil yield (55±1.11, 28±1.35 and 44±1.03)% respectively; refractive index (1.466 , 1.467 and 1.469) respectively; acid value (4.7±0.25, 6.9±0.98 and 4.3±0.6)mgKOH/g oil respectively , peroxide value(6.7±0.12 , 10±1.20 & 6±1.12) mg/g oil respectively, unsaponification matter (4.5±0.3, 4.2±0.22 & 4.8±0.15)% respectively , free fatty acid (3.35±0.12, 6±1.21 & 3±0.3)% respectively. Analysis of fatty acid profile has been carried out by using GC-MS. The fatty acid profile revealed that the predominant fatty acids in Shea kernels oil for n-hexanic and aqueous extracts were respectably : Hexadecanoic acid (0.5665% and 0.1473%, respectively) , Linoleic acid (1.1000% and 0.1179%, respectively) 9-Octadecenoic acid (58.280% and 54.69 %, respectively) ,Stearic acid (40.000% and 45.05 %, respectively) and Eicosanoic acid (0.0567% and 0.0%,respectively). The scavenging ability of different extracts on 2,2-diphenyl-1-picrylhydrazyl (DPPH)free radical, were effective in the following order: aqueous > ethanolic > n-hexanic and were found to be : 17±0.7 , 14±0.03 and 06±0.03 respectively.