Effect of processing on the physico‐chemical properties of African yambean, Sphenostylis stenocarpa (Hochst ex A. Rich) Harms

Soaked and heat‐trated yambean seeds were studied for some of their chemical and physical characteristics. An increase of between 2.9 and 29.4% in the ash contents reflected mineral pick‐up by seeds pre‐soaked in salt solutions. Subsequently, remarkable losses of Ca. K. and Na resulted when seeds pre‐soaked in salt solutions were cooked. Roasting also caused a substantial loss of Ca. A phytic acid loss by 4.5 to 36.7% was obtained by soaking and heat treatment of yambeans. Trypsin inhibitor activity (TIA), although decreased substantially with cooking, slightly increased during the pre‐soaking step. Alkali and alkali‐brine soaked seed flours, with a water‐oil‐absorption index of about 2.0, exhibited the best hydrophilic‐lipophilic balance.