OPTIMIZATION OF PROCESS VARIABLES TO OBTAIN QUALITY SHEA KERNELS FROM SHEA NUT

Shea butter is a product of Shea kernel obtained from Shea tree. It has wide range of applications in pharmaceuticals, confectionaries, chocolates, and soap industries. The use of Shea butter for these applications is largely dependent upon its Free Fatty Acid (FFA) content. The resultant FFA of Shea butter produced from the Shea kernel depends largely upon the process variables applied to the kernel prior to Shea butter production. Poor and inconsistent qualities usually characterize unprocessed Nigerian Shea kernels. Thus, the need to improve Shea kernel quality in Nigeria becomes necessary. This study investigated the effects of optimizing processing factors, responses, development, and analysis of predictive response models of Shea kernel leading to its optimization. Shea fruits that have fallen to the ground were picked and the pulp removed to expose the Shea nut. Effects of Shea Nut Conditioning Period (SNCP), Shea Nut Boiling Duration (SNBD) and Shea Nut Drying Temperature (SNDT) on the FFA of Shea kernel were investigated. The boundary conditions obtained from earlier experiments were used for the Design of Experiment (DOE) by Box-Bekehn method of response surface methodology. Fresh Shea kernels were then processed according to the experimental design and the responses of free fatty acid, peroxide value and percentage oil content determined. The upper, middle and lower limits obtained for SNCP were 1, 6.5, and 12 day respectively, SNBD were 0, 60, and 120 minutes respectively and SNDT were 30, 70, 110 oC respectively. The optimum conditions of SNCP, SNBD and SNDT obtained after the optimization of Shea kernel were respectively 4.0 day, 120 minutes and 86 oC and the corresponding predicted responses of PV, percentage oil content, FFA and desirability were 2.868 meq/kg, 0.628 %, 53.8 5 % and 0.878 respectively. Keywords: Shea-kernel, Shea Nut Conditioning Period, Shea Nut Boiling Duration, Shea Nut Drying Temperature, and Optimization