Production and Quality Evaluation of Pounded Yam Flour Substituted with Cowpea Flour

Abstract

The main objective of this study was to produce and evaluate the quality of pounded yam flour substituted with cowpea flour. The yam and cowpea flours were prepared and mixed at the ratio of 90:10, 80:20, 70:30, 60:40 and 50:50 for samples A, B, C, D and E respectively, while 100% yam flour was tagged sample F, and served as control. Physicochemical and functional properties, proximate and mineral compositions of the flours, as well as sensory properties analysis of the stiff dough was determined using standard methods. There was significant difference (p<0.05) in the TTA, pH and gelatinization temperature of the samples which ranged from 0.003-0.004 % lactic acid, 6.32-6.38, and 25.25-42.25℃, respectively. Inclusion of cowpea flour increased (p<0.05) the bulk density (0.661-0.760 g/ml), water absorption capacity (2.36-2.45 g/g) and solubility (5.64-7.95%) of the samples. Proximate composition results showed significant increase (p<0.05) in crude protein, crude fat, ash and crude fibre contents of the flour samples. The carbohydrate content reduced (p<0.05) as inclusion level of cowpea flour increased and ranged from 75.86-86.74%. There was no significant difference (p>0.05) in the odour score of the stiff dough produced, while mouldability (7.40-8.45) and overall acceptability scores (7.54-8.39) showed significant difference (p<0.05), with the cowpea flour mixed sample (sample E) liked best. The four best liked samples from sensory analysis (samples B, D, E and F) were subjected to mineral analysis with magnesium (24.16-27.30 mg/100 g), calcium (2.26-11.38 mg/100 g), iron (4.77-10.73 mg/10 g) and phosphorous (0.01-0.04 mg/100 g) increasing with increase in cowpea flour and showing significant difference (p<0.05) from the control. Inclusion of cowpea flour did not negatively impact the taste, colour, or texture of the stiff dough. In fact, the sample with 50% cowpea flour (Sample E) was rated highest for mouldability, texture, and overall acceptability, even surpassing the 100% yam flour control sample.