Production, physicochemical and sensory characterization of cocoyam mixed flours and pastes (achu)

Abstract

Colocasia esculenta L. Schott and Xanthosoma sagittifolium L. Schott are two tropical tubers species commonly referred as cocoyams. Colocasia esculenta tuber is usually used for the preparation of achu (smooth paste food), but not always available. This work is aimed at evaluating the effect of mixing two cocoyam flours on the physicochemical and sensory characteristics of precooked composite flours and achu. In this respect, a factorial design was realized. This factorial design was 2 varieties of Xanthosoma sagittifolium (white-flesh and red-flesh) coded as WX and RX and 5 levels of substitutions (0, 25, 50, 75 and 100%) in the Colocasia esculenta (Ibo coco) coded as IC. Precooked flours showed significant (p < 0.05) differences in the contents of ash (2.09 ± 0.33 to 4.21 ± 0.03%), fiber (1.33 ± 0.04 to 1.57 ± 0.43%), total sugar (71.12 ± 0.85 to 74.02 ± 1.42%), starch (47.26 ± 0.95 to 66.59 ± 1.09%), proteins (3.20 ± 0.14 to 4.35 ± 0.07%) and total oxalate (0.41 ± 0.16 to 0.82 ± 0.11%). The water absorption capacity and water solubility index also shown a significant difference (p < 0.05). The highest gelatinization temperature, final viscosity, setback, and consistency during the heating time were recorded for Xanthosoma sagittifolium flours, meanwhile the peak viscosity and breakdown indexes were higher in Colocasia esculenta flour. It was also observed that there was least difference (p < 0.05) in the overall acceptability (4.54 ± 1.96 to 5.74 ± 1.40) of the sensory attributes of reconstituted achu by the participants. Elsewhere, the results revealed that more than 35% of the participants like very much the achu made from cocoyam flour mixtures while 44.65% of them just like it. These results indicate the potential of Xanthosoma sagittifolium precooked flours for substituting Colocasia esculenta flour at varying proportions in achu making.