Saba, A.M., Okafor, J. O., Adeniyi, O.D. and Egwim, E.C. (2017), Preliminary Study of Process Route for Quality Improvement of Traditionally Produced Shea Butter in Nigeria to Meet Export Requirements, Nigerian Journal of Renewable Energy (NJRE), Vol. 17(1&2),151 – 160, ISSN: 1115-0610

Abstract

This preliminary study investigates the various routes for the production of improved quality shea butter to meet export requirements (African Standard for Unrefined Shea Butter) ARSUSB. Fresh shea fruit were collected, de-pulped, boiled and dried using three methods viz-a vis; sun drying, traditional oven drying and manually operated rotary drying (MORD). The fresh shea nuts were subjected to boiling times of 0, 15, 30, 45 and 60 minutes. The drying stage was preceded by cooking, milling, kneading and curd boiling to obtain shea oil. Physicochemical properties of the shea oil for example, yield, iodine value, free fatty acid, peroxide value, percentage impurities, refractive index, moisture content, absorbance, saponification value and unsaponifiable fractions were determined. The results for each of the treatment methods i.e for sun drying,(yield, 20-37%), (density, 0.894-0.980g/cm3), (iodine value, 23-34.6g/100g), (free fatty acid, 3.99-6.91%), (peroxide value, 2.42-5.20mEq/100g),(impurity,1.0-2.00%), (refractive index,1.465-1.468), (saponification value, 178.12-293mgKOH/g), (unsaponifiable fractions, 5.07-9.31g/kg), for traditional oven drying, (yield, 21-42%), (density, 0.896-0.991g/cm3), (iodine value,26.6-40.43g/100g), (free fatty acid,4.62-7.51%), (peroxide value, 2.99-4.95mEq/100g), (impurity,0.69-2.0%), (refractive index,1.465-1.469), (saponification value,173.4-287.4mgKOH/g), (unsaponifiable fraction 4.78-9.2g/kg), and for manually operated rotary dryer, (yield,25-32%), (density, 0.898-0.988g/cm3), (iodine value, 22.01-46.020g/100g), (free fatty acid, 3.05-7.32%), (peroxide value,2.99-5.82mEq/100g), (impurity, 1.05-2.00%),(refractive index,1.4650-1.469), (saponification value,154.1-268.5mgKOH/g), (unsaponifiable fractions, 1.15-8.72g/kg). The results of parameters obtained refractive index (1.465-1.468), density (0.896 g/cm3-0.991g/cm3) and moisture content (0.211-1.264) are comparable with ARSUSB, however some other parameters for example saponification value 178.12 mgKOH/g -293mgKOH/g), free fatty acid, (4.62%-7.51%), Iodine value (26.6 g/100g -40.43g/100g), and peroxide value (2.42 mEq/100g -5.20mEq/100g), were found to be at variance with ARSUSB. The percentage impurity (1.05%-2.00%), was found to be high as compared to ARSUSB of percentage impurity figure of 0.09% - 0.2% necessitating further treatment for good industrial application like biodiesel production.