Evaluation of the Chemical, Functional and Sensory Properties of Pre-release White Yam (Dioscorea rotundata) Genotypes in Umudike, Southeast, Nigeria
V. C. Ezeocha *
Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria
I. I. M. Nwankwo
National Root Crops Research Institute, Umudike, Abia State, Nigeria
V. N. Ezebuiro
National Root Crops Research Institute, Umudike, Abia State, Nigeria
*Author to whom correspondence should be addressed.
Abstract
Aims: To assess the chemical, functional and sensory properties of some pre-release white yam (D. rotundata) genotypes.
Methodology: Tubers from ten genotypes of white yam (namely; 99/Amo/03, 99/Amo/XA, 99/Amo/080, 99/Amo/109, 99/Amo/064, 99/Amo/060, 99/Amo/010, 99/Amo/95A, 99/Amo/056 and 99/Amo/144) and two local checks (Adaka and Ameh) obtained from the yam programme experimental field of National Root Crops Research Institute, Umudike were used for this study. The chemical properties (dry matter, ash, starch yield, amylose and amylopectin contents) and functional properties (bulk density, water and oil absorption capacity, swelling capacity and gelatinization temperature) were evaluated using standard methods. Sensory evaluation was conducted on the boiled and pounded yam samples from the different genotypes.
Results: The result indicated that the dry matter content were high in all the genotypes ranging from 30.50% in genotype 99/Amo/010 to 36.78% in genotype 99/Amo/144 and the local check (Adaka). The amylose content of starch of the pre-release white yam genotypes were significantly lower than that of the local check, Ameh (P<0.05), however, they were comparable with the second local check, Adaka. The highest water and oil absorption capacities were observed in genotypes 99/Amo/010 (1.550) and 99/Amo/XA, 99/Amo/03 (1.936) and the local check Adaka respectively. The swelling capacity ranged from 105.26% (in genotype 99/Amo/080) to 142.86% (in genotype 99/Amo/XA). In terms of sensory acceptability, the genotype 99/Amo/95A was disliked by the panellists, however, genotype 99/Amo/144 was the most preferred of all the boiled yam samples. Pounded yam from genotypes 99/Amo/95A, 99/Amo/060, 99/Amo/056 and 99/Amo/010 were not acceptable to the panellists while the other varieties produced pounded yam which were acceptable.
Conclusion: The functional properties of the starches showed that some genotypes such as 99/Amo/144, 99/Amo/03, 99/Amo/010, 99/Amo/060, 99/Amo/109 and 99/Amo/XA may find application in industrial food processing. These genotypes are therefore recommended for release to farmers for commercial production.
Keywords: Yam, genotypes, food quality, functional properties, sensory evaluation