EFFECT OF SOAKING, DEHULLING AND FERMENTATION ON THE OLIGOSACCHARIDES AND NUTRIENT CONTENT OF COWPEAS (VIGNA-UNGUICULATA)

Two cultivars of cowpea (Vigna unguiculata) seeds were fermented for 24 h or soaked for 4 h or dehulled and samples obtained to determine changes in oligosaccharides as well as energy, protein, ascorbic acid, niacin, thiamin, calcium, magnesium, iron, zinc, potassium and phosphorus. The results showed that fermentation caused a 79.7% decrease in the level of verbascose and a 5.9% decrease in stachyose but raffinose increased by 12.8%. Increases in the levels of sucrose (8.1%), fructose (105%) glucose and galactose (56.4%) were observed. Four hour soaking of cowpea seeds in water led to a 49.4% decrease in verbascose, 29.8% in stachyose and 1.0% in raffinose; sucrose increased by 41.9% and fructose by 43% but glucose and galactose levels decreased by 55%. Dehulling of the beans led to a decrease of 76.4% in verbascose, 16.9% in stachyose, 56% in raffinose, 63.6% in glucose and galactose and a 45.9% increase in sucrose. Fermentation led to a significant increase in the levels of thiamin, niacin, phosphorus, energy and protein. Thus, fermentation soaking and dehulling are acceptable methods for decreasing the flatulence properties of cowpeas and increasing acceptability among consumers.