Stability of protein digestibility and composition of cowpea (Vigna unguiculata L. Walp.) during sealed storage at different temperatures

Whole grains and flours of two cultivars of cowpea ( Vigna unguiculata ) were stored sealed at steady temperatures of 0, 20 and 55°C, and 11–13% moisture for 7 months. The pH, soluble sugars, free amino nitrogen, titratable acidity, and protein digestibility decreased at 55°C. The changes varied with cultivar and between the flours and the grains stored at 0 and 20°C. All changes, except titratable acidity in white cowpea flour, were strongly correlated with increasing storage temperature.