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.
