Effect of heat processing on the nutritional and anti-nutritional factors of cowpea (Vigna unguiculata)

Nutritionally enhanced cowpea genotypes provide considerable amounts of nutritional composition, which are useful to tackle nutritional deficiency status among rural and urban populations. However, the presence of anti-nutritional factors reduces the availability and absorption of nutrients, particularly of important micronutrients for growth and development. Therefore, the aim of this study was to assess the response of different processing method that allows availability of maximum nutrients in the seeds of test cowpea cultivars. Results showed that soaked cowpea samples had the lowest nutritional content and greatest anti-nutritional content. Boiling allowed for an improved protein content (19-21%) and was the most effective in reducing cyanogenic glycosides (0.18-0.38 mg/100 g), phytic acid (±1.21 mg/100 g), tannins (0 mg/100 g) and trypsin inhibitors (55-155 TIU/g). While, autoclaving was the most effective in reducing the oxalic acid (±2 mg/100 g) content based on the presence of water-insoluble oxalic acid.