Evaluation of Chemical Properties of Shea Butter Produced by Traditional Methods in Kogi and Niger States

Shea butter produced from the seeds of Vitellaria paradoxa is a significant non-timber forest product of economic and nutritional importance in North Central Nigeria, yet variations in traditional processing methods produce products with differing chemical properties that affect their quality and market value. This study evaluated the chemical properties of shea butter produced by traditional extraction methods in six communities across Kogi and Niger States. Samples were obtained from producers using three different processing methods: wet extraction, dry extraction, and combined wet-dry extraction. Chemical characterisation included determination of free fatty acid content, saponification value, iodine value, peroxide value, unsaponifiable matter, moisture and volatile matter content, refractive index, and fatty acid composition by gas chromatography. Free fatty acid content ranged from 0.8 to 4.6 percent oleic acid equivalent, with dry-extracted samples showing higher values indicating greater oxidative degradation during heat processing. Peroxide values were 2.4 to 14.8 meq O2/kg. Oleic and stearic acids were the dominant fatty acids, comprising 84 to 88 percent of total fatty acids in all samples, consistent with the known composition of West African shea butter. Iodine values (54 to 62 g I2/100g) and saponification values (178 to 192 mg KOH/g) were within the expected range. These findings indicate that processing method significantly affects shea butter quality and suggest that wet extraction methods, combined with improved hygiene and storage practices, produce superior chemical quality products with greater commercial and food-grade potential.

Keywords: shea butter, chemical properties, fatty acid composition, traditional processing, North Central Nigeria