Effects of Extraction Method and Geographical Location on the Physico-chemical Properties of Shea (Vitellaria paradoxa) Butter

Aim: To determine the effects of extraction technology and geographical location on the quality of shea butter.

Study Design: Data for physico-chemical characteristics were entered into Micro soft Excel spread sheet and summarized into mean and standard deviations. Analysis of Variance (ANOVA) was carried out to assess the variation between the parameters. All analyses were carried out in triplicates. Duncan’s Multiple Range Test was used to compare mean variance. Significance was accepted at 5% level of probability.

Place and Duration of Study: The study took place in selected villages in the Upper East, Upper West and the Northern regions of Ghana between August, 2015 and February, 2016.

Methodology: Oil samples from the chemical (C), mechanical (M) and the traditional (T) extraction methods (EM) and those from different shea butter extraction villages across the north of Ghana were evaluated to determine their effects on the physicochemical properties of shea butter. All analyses were carried out in triplicates and Duncan’s Multiple Range Test used to compare mean difference. Significance was accepted at 5% level of probability.

Results: The mean oil yield, saponification, iodine, acid, free fatty acid values were (50.04±3.35%; 40.21±7.21%, 39.09±2.46%), (160.79±1.50; 162.15±40, 193±8.58 mgKOH/g), (49.18±2.83; 49.58±1.39, 54.78±12.88 gI2/100g), (9.77±1.75; 12±0.27, 13.765±1.10 mgKOH/g) and (5.42±0.17; 4.69±0.04, 7.61±0.35 mg/KOH/g) for the CEM, MEM and TEM respectively. While the mean specific gravity, refractive index and peroxide values were (0.97±0.00; 0.92±0.02, 0.88±0.01), (1.46±0.00; 1.45±0.01, 1.47±0.00) and (2.25±0.15; 2.80±0.16, 3.55±0.30) respectively. The mean oil yield, saponification, and iodine values were (43.08±2.75%; 45.87±1.25%), (39.62±1.40%; 39.02±1.16%), (53.27±2.40%; 50.26±1.44%), (155.80±9.46; 127.50±5.96 mgKOH/g), (163.63±2.66; 155.45±1.30 mgKOH/g), (201.39±2.78; 193.29±3.59 mgKOH/g), (46.84±2.06; 43.93±1.47 gI2/100g), (39.19±0.99; 53.96±4.87 gI2/100 g), (66.19±1.52; 47.46±0.97 gI2/100g) for oil samples from (Jonga; Kpongo) in the Upper West, (Doba; Pusunamongo) in the Upper East and (Savelugu; Tantuani) in the Northern region of Ghana respectively. The acid value, specific gravity, refractive index and peroxide values were (9.60±1.11; 12.53±1.17 mgKOH/g), (15.46±1.00; 16.47±1.26 mgKOH/g), (12.81±0.90; 11.57±1.02 mgKOH/g), (0.85±0.16; 0.94±0.01), (0.98±0.01; 0.92±0.01), (0.88±0.02; 0.88±0.01), (1.46±0.01; 1.48±0.01), (1.52±0.11; 1.42±0.01), (1.47±0.01; 1.46±0.01), (2.67±0.05; 3.42±0.18 mEqKOH/g), (2.59±0.06; 2.65±0.02 mEqKOH/g) and (2.84±0.06; 2.26±0.02 mEqKOH/g) respectively.

Conclusion: The MEM technology had values almost mid-way between CEM and TEM and therefore yielded butter of superior quality than the other two technologies and should therefore be encouraged even if at a smaller scale. Geographical effect on the quality of shea butter revealed that kernels from the Northern region produced good quality shea butter, followed by those from the Upper West and finally to the Upper East regions. The results showed significant differences in the oil samples extracted by the different extraction methods and from different geographic locations but all fell within the acceptable ranges for edible vegetables oils.