Amino acid composition protein quality and water-soluble vitamin content of germinated cowpeas (Vigna unguiculata)

Amino acid composition, protein digestibility, calculated protein efficiency ratio (C-PER and DC-PER), chemical scores and water-soluble vitamin content of cowpea seeds germinated at 25°C or 30°C for 24h were determined. Also, the effect of processing steps (heated-air drying, decortication and cooking) on these parameters were examined. Germination had little effect on amino acid profile of cowpeas. In vitro protein digestibility was not improved significantly by germination nor by decortication but was improved by cooking. C-PER and DC-PER ranged from 1.95 to 2.21 and from 1.63 to 1.82, respectively. DC-PER compared well withreported rat PER of cowpea products and seemed more sensitive than C-PER. Based on whole egg values, chemical scores ranged from 37.7 to 45.8% (mean±SD; 42.2±2.4%). Germination increased the contents of niacin, thiamin and riboflavin significantly. Decortication resulted in up to 30% loss in niacin while thiamin content was reduced 41% by cooking.