Nutrient retention of dehulled cowpea (Vigna unguiculata) at varying temperatures and time in soaking water

The residual total solids, carbohydrate, and protein contents of dehulled cowpea were determined after soaking at varied combinations of temperature and time; 32°C, 45°C, 60°C, 75°C, 90°C and 30 min, 60 min, 120 min. The loss of total solids was more dependent on time rather than temperature. Optimum retention of total solids (62.5%) was at 60°C/60 min, 90°C/60 min, for protein (69.6%) and 45°C/60 min, for carbohydrate (21.4% as sucrose) 60°C/60 min. However, the 1.5% and 0.6% losses of protein and carbohydrate, respectively, at 60°C/60 min, were considered insignificant. Hence, 60°C/60 min was recommended for processing cowpea, during which period enzymes are inactivated and gelatinization delayed.