Development of Cake from Composite Blends of Wheat (Titricum aestivum) and Purple Yam (Dioscorea alata) Flour

Abstract

This study investigates the potentiality of incorporating purple yam flour as a wheat flour substitute to formulate cake with the objectives of encouraging the use of underutilized purple yam, reducing the dependency on wheat flour, adding variety to cake flavors and increasing the nutritional value. The effect of substituting purple yam flour with wheat flour on the composition, texture, sensory, and flour qualities of the resulting cakes were evaluated. The following ratios of wheat flour to purple yam flour were used for cake preparation: 100:0 (A - control), 80:20 (B), 60:40 (C), 50:50 (D), and 40:60 (E). The texture parameters (hardness, adhesiveness, cohesiveness, resilience, gumminess, springiness, and chewiness) were analyzed in all cake formulations. According to the results of sensory evaluation (hedonic ranking test, 30 untrained panelists), the cake formulated with composite C was selected as the most consumer acceptable sample. The proximate composition of the selected cake formula (C) and the control sample (A) were compared and the results showed as moisture (24.15±0.67, 22.20±0.80%), crude fat (19.26±0.05, 23.91±0.04%), total ash (2.36±0.01, 2.30± 0.10%), and crude fiber (0.71±0.16, 0.64±0.10%) respectively. The flour properties (bulk density, water and oil absorption capability, swelling capacity, water activity and color) of purple yam flour were significantly different (p<0.05) from wheat flour. The texture profile results showed a significant difference of hardness in sample D and E compared with other samples. However, the other texture parameters (cohesiveness, springiness, chewiness and gumminess) were not significantly (p<0.05) varied between cake formulations. The study found that the purple yam flour can be substituted for wheat flour up to 40%, to produce cake with good consumer acceptability.