Assessment Of Cowpea (Vigna Uncruiculata Walp) Production, Consumption And Nutritional Evaluation Of Cowpea - Fortified Fermented Maize

Abstract

In an effort to evaluate the nutritional value of cowpea - fortified maize-dough, and to assess the availability and utilization of cowpeas in the Ga - district, this study was carried out. The study was designed to ascertain the socioeconomic factors associated with cowpea production, consumption, Post-harvest handling and distribution, as well as the nutritional benefit and efficacy of using cowpea as a fortifying-agent in fermented maize dough, a popular base for both traditional weaning gruel and coastal staple diets in Ghana. Eighty-nine (89) cowpea farming households, drawn from 23 rural communities in the Ga - district of the Greater Accra Region, were involved in the study (interviewed with their consent). Four (4) cowpea fortified fermented maize doughs (CFFMD's), two each of a 60:40 maize : cowpea constitution by weight, were prepared by the traditional and an "improved" method of fermentation, respectively, for the nutritional evaluation; using wistar moll rats. The outcome of the study suggested that Cowpea production in the study area was beset with numerous problems pertaining to cultivation, crop management, storage and marketing. This accounted for the observed low yields and short household cowpea stock durations, in other words, household cowpea availability for consumption, in the farming communities studied. Farmers in the study population regarded, and hence treated cowpea as a secondary crop to maize and cassava which constituted their staple foods. In addition, cowpea consumption rate was high, that is, when available in the population studied. Furthermore, indigestion, diarrhoea and flatulence were identified as the common problems associated with cowpea consumption. The method of fermentation used; traditional or "improved", seemed to have an effect on the resultant protein quality of the cowpea-fortified maize doughs. The observed improvement in protein quality was slightly higher in the maize doughs traditionally fermented. Nonetheless, fortification with dehulled cowpea flour did improve the protein quality of all the maize doughs considerably. Relative to ordinary maize dough, high protein digestibility and utilisation values were obtained for the CFFMD's, though found limiting in lysine and tryptophan. The following range of values were obtained - Essential amino acid total of 289.68 - 314.89 mg/g crude protein; Apparent digestibility .of 83 - 86%; True digestibility of 100 - 103%; Biological value of 82 - 86%; Balance values of 54 59%; and Net Protein Utilization values of 81 - 88%. The range of Chemical Scores of limiting amino acids Lysine and Tryptophan obtained were 57.33 - 63.33% and 58.18 80.36% respectively.