Effect of Dry Heat Pre-Treatment (Toasting) on the Cooking Time of Cowpeas (Vigna unguiculata L. Walp)

Abstract

Four cowpea varieties (Brown beans, Oloka beans, IAR48 and IT89KD-288) were toasted at 105oC, and used to study the effect of dry heat treatment on the cooking time and nutrient composition of cowpea seeds and also its effect on the functional properties of resultant flour of the cowpea seed varieties. Toasting reduced the cooking time for brown and oloka cowpea varieties from 55.00 – 31.00 and 70.67 – 51.67 min, respectively. The cooking time for IAR48 and IT89KD-288 cowpea varieties increased from 104.67 to 106.00 and 88.00 to 88.67 min, respectively. The results indicate that the cooking time of cowpea seeds can be reduced significantly on toasting, while maintaining their potential as functional agents in the food industry for nutrition and utilisation. Correlation between the amount of water imbibed by cowpea seeds and their cooking time was -0.74, but was not significant at p ≤ 0.05, suggesting that there is no significant relationship between the amount of water imbibed by cowpea seeds and their cooking time.

Keywords: Cowpeas, toasting, cooking time, nutrient composition, functional properties.