Physico-Chemical Characteristics Of Shea Butter ( Vitellaria paradoxa C.F. Gaertn.) Oil From The Shea Districts Of Uganda
Shea oil is a vegetable oil obtained from the seeds of the shea tree ( Vitellaria paradoxa C.F. Gaertn.). It constitutes an important source of fat in food and cosmetics. Although shea oil can be marketed both locally and internationally, increasing demand worldwide for exportable products calls for their certification. Characterization of shea oil is one step towards developing its certification system. In this study, the physico-chemical characteristics of shea oil in different shea zones of Uganda were assessed. Samples of shea fruits were collected between the months of June-August 2007 in the districts of Pader, Lira, Katakwi and Arua representing Acholi, Lango, Teso, and West Nile shea zones, respectively. Seed oil was extracted by Soxhlet apparatus using n-hexane solvent and analysed for colour, refractive index, viscosity, oil content, acid value, peroxide value, saponification value, iodine value, α-tocopherols and fatty acid profile. Shea oil content, colour, refractive index and viscosity ranged from 41-54%, orange to orange–yellow, 1.670-1.690 and 2.4-2.8 cP, respectively. Acid and peroxide values ranged between 2.3-12.59 mgKOH/kg and 2.10 to 2.50 meq/kg, respectively. Saponification, iodine and α- tocopherols values were between 160 mgKOH/g and 192mgKOH/g, 39.21 I2g/100 and 41.37 I2g/100g and 26.3-44.4 mg/100g, respectively. Fatty acid profile for palmitic, stearic, oleic, linoleic and arachidic fatty acids ranged between 6.52-8.12%, 28.65-30.94%, 55.54- 57.63%, 6.18-7.79% and 0.65-0.90%, respectively. Although there was significant variation in the oil yield (P≤0.05), the physico-chemical characteristic and fatty acid profile showed no significant variation in the shea zones of Uganda (P≤0.05). The fact that physico- chemical characteristics of shea oil from the different shea zones of Uganda are comparable to other high value edible vegetable oils indicates its suitability as raw material for food, cosmetic and pharmaceutical products. This characterization is a bench mark for monitoring the quality of shea oil from Uganda and can be used to enhance its local and international trade.