Production and Evaluation of Soap from Shea Butter Residue and Caustic Soda in Nasarawa State

Shea butter processing in Nasarawa State, North Central Nigeria, generates substantial fatty acid residues currently discarded or burned, representing a lost raw material resource for local soap production. This study formulates and evaluates laundry and toilet soap from shea butter residue obtained from processing cooperatives in Lafia Local Government Area using a cold process saponification method. Residue samples were characterised for fatty acid profile, free fatty acid content, and peroxide value. Soap formulations were developed at fixed sodium hydroxide concentrations with partial substitution of shea butter residue for purified shea butter at ratios of 0%, 25%, 50%, and 75% residue content. Saponification was confirmed by pH measurement and the spot test. Soap bars were evaluated for total fatty matter, free caustic alkali, moisture content, lathering capacity, pH, hardness, cleansing performance, and dermal safety. Results showed that formulations with up to 50% shea butter residue produced soap meeting the Nigerian Industrial Standards for bar soap across all evaluated parameters. Lathering capacity and cleansing performance were not significantly different from the 0% residue control at the 0.05 significance level. Dermal safety testing revealed no irritation at 25% and 50% residue levels. The study demonstrates that shea butter processing waste can be converted into commercially acceptable soap, providing rural cooperatives in Nasarawa State with a value-added enterprise opportunity. Keywords: shea butter residue, soap production, saponification, Nasarawa State, agro-waste