Characterisation of two newly developed cowpea (Vigna unguiculata) varieties, Padi tuya and Wang kae, and their suitability to produce Tubani, a northern food in Ghanad

Abstract

Cowpea (Vigna unguiculata (L.) Walp.) is a legume crop widely consumed in several parts of the world. Padi tuya and Wang kae are new varieties that were developed by CSIR-Savanna Agricultural Research Institute. In order to exploit the full food potential of these two varieties, this study characterised the compositional and physicochemical properties of the grains, as well as the functional and pasting properties of the flours from these varieties. The study also investigated the suitability of preparing an optimised form of a popular traditional food, Tubani. Standard methods including those by Association of Official Analytical Chemist and American Association of Cereal Chemists were used. An initial survey showed that the critical steps in processing Tubani included water: flour ratio, mixing and steaming time. Moisture, fat and fibre in Padi tuya and Wang kae were significantly different (p<0.05). With cooking characteristics of the grains, the hydration capacities and indices of the two varieties were significantly different (p<0.05). Cooking time was 42 min and 62 min for Padi tuya and Wang kae, respectively. With the flours, the emulsion capacities and stabilities were significantly different (p<0.05). Analysis of the various response surface regression models showed that the models could account for 62.94 - 82.79% of the variations in sensory properties. To assess the consumer acceptability of the optimised Tubani, respondents scored the following: “7= Most Liked” for overall product, “6= Liked” for method of preparing Tubani from the flour and “7=Most Liked” for purchase intent, on a 9-point hedonic scale. This study therefore shows that the two cowpea varieties, Padi tuya and Wang kae, have good compositional and functional properties for making staple foods, especially Tubani