The impact of onion (Allium cepa L.) addition on the softening characteristics of seeds of cowpeas (Vigna unguiculata L. Warp)

Cowpeas (Vigna unguiculata L. Warp) are a nutrient-rich legume widely consumed in many regions and often require prolonged cooking times. This study examines a traditional Ghanaian belief that adding onion (Allium cepa L.) during the cooking of cowpeas enhances their softening characteristics and impacts sensory properties. Three methods were tested: cowpeas cooked with; iodised salt, iodised salt plus baking soda, and iodised salt plus onion. Sensory evaluation using a 5-point hedonic scale was conducted by a panellists (n = 21) to assess odour, colour, consistency, and flavour. Results showed that incorporating baking soda samples exhibited significantly softer texture compared to the other samples. There was no significant differences between the control and samples with onions added, challenging the anecdotal belief. No significant differences were observed at p < 0.05 in odour, flavour, and colour among the samples, except for samples with iodised salt plus onion for which there was a darker appearance attributed to baking soda.