Chemical and sensory evaluation of germinated cowpeas (Vigna unguiculata) and their products

Cowpeas (Vigna unguiculata), germinated for 24, 48, 72, or 96 h or ungerminated, were dehulled and milled. The resultant flour was analysed for oligosaccharide and anti-nutritional factors and subsequently used to prepare three recipes, viz., akara, moin-moin and cake. The recipes were evaluated by panellists for acceptability based variously on size of product, texture, colour, crust/crumb tenderness and flavour. Trypsin inhibitor was reduced from 12.4±0.15 to 10.2±0.06 TIU/mg; and haemagglutinin from 1:200 to 1:25. Stachyose disappeared from all germinated products and was replaced by sucrose. Apart from the moisture and carbohydrate, which decreased, the proximate composition of the cowpea flour improved with germination. Although recipes prepared from ungerminated and traditionally processed cowpea showed superior organoleptic properties (7.6 acceptability level), the products of the 24-h-germinated cowpea were satisfactory (6.6 acceptability). Therefore, 24-h germination is considered a worthwhile processing because it totally eliminates stachyose, which otherwise would induce flatulence, and reduces anti-nutritional factors to tolerable levels without a significant change in acceptability.