Processing Effects on the Nutritional and Anti-Nutritional Contents of African Locust Bean (Parkia biglobosa Benth.) Seed

Abstract

African locust bean (Parkia biglobosa Benth.) seeds with thin layers of pulp material were processed by soaking in water for 12 h, washing to depulp the seeds and boiling in water for 8 h to dehull the seeds. The dehulled seeds were boiled again for 30 min to produce the processed substrate which were fermented for 72 h. Mechanically dehulled bean seeds were obtained from depulped bean seeds with a pair of pliers. Proximate compositions of the samples were determined for crude protein, ether extract, ash and total carbohydrate content. The presence and levels of trypsin inhibitors, tannin and phytic acid were determined. Fermentation gave rise to significant increase in crude protein content. The ether extract was significantly increased by soaking and boiling, this was further increased by fermentation at 72 h. The ash content decreased significantly by soaking and boiling. Also the total carbohydrate content decreased significantly by soaking and boiling, this was further decreased by fermentation at 72 h. In all the anti-nutritional factors evaluated, soaking and boiling significantly reduced the levels of anti-nutritional factors, fermentation at 72 h led to further reduction in the levels of anti-nutritional factors. The reduction in content of trypsin inhibitors activity at 72 h fermentation was greater than the other anti-nutritional factors with a total reduction level of 89.0%.