Effect of ‘Kanwa’ treatment of cowpea (vigna unguiculata) seed flour on protein quality as measured by growth rate assays in rats

The growth performance of weanling Sprague‐Dawley rats fed test diets based on cowpea seed flour prepared using ‘Kanwa’ (an alkaline rocksalt) was studied. In addition, the protein quality (NPR & PER), feed efficiency and organ weights were determined at the end of the 21‐day growth assay. A 10% casein protein diet and a protein free diet were fed as positive and negative controls respectively. Growth, feed utilization, protein efficiency ratio (PER) net protein ratio (NPR) and relative net protein ratio (RNPR) were significantly (P < 0.05) reduced for rats fed Kanwa treated cowpea diets. Kanwa treatment did not however affect the relative organ weights. The results show that Kanwa treatment used in this study did affect the protein quality of the cooked cowpeas leading to a reduction in NPR and PER. The level of kanwa used in cooking cowpeas for infant foods should be minimized in order to prevent reduction in protein quality while saving cooking fuel.

Key words:

• cowpeas
• kanwa processing
• fuel economy
• cooking time
• flavour
• protein quality and growth

Notes

Present address: Department of Biochemistry, University of Port Harcourt, Choba, Port Harcourt, Nigeria.