Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 46: 3086 - 3092. Published October 28, 2011.
Effect of processing on the nutritional contents of yam and cocoyam tubers
Adegunwa MO1, *Alamu EO2 and Omitogun LA3
1Department of Food Services and Tourism. University of Agriculture, Abeokuta, Nigeria; 2International Institute of Tropical Agriculture, Ibadan, Nigeria (IITA); 3Department of Home Economics and Hotel Management, Tai Solarin University of Education, Ijebu-Ode, Nigeria.
*Corresponding author email: oalamu@cgiar.org
ABSTRACT
Objective: To evaluate the effect of processing on the nutrient content of yam and cocoyam (Colocasia esculentum) tubers.
Methodology and results: Two species of water yam (Dioscorea alata) and white yam (Dioscorea rotundata) were subjected to various processing methods, i.e. boiling, sun-drying and roasting. The proximate, chemical and pasting properties of the processed yams were determined. The results showed that the moisture content (flour) ranged from 5.01 to 15.71%; ash content from 1.88 to 5.50%; fat content d from 0.24 to 0.75%; protein content from 0.03 to 5.02%; amylose from 23.35 to 33.28%; sugar content 2.13 to 7. 59% and starch content from 62.94 to 93.67%. The Tannin content ranged from 0 to 1.10%, swelling power from 5.63 to 9.95%; soluble content from 4.10 to 11.30% and trough set point from 18.75 to 189.71oC. The break down set point ranged from 4.63oC to 97.46oC ; final viscosity from 47.79 to 366.38 RVU; set back from 24.33 to 213.96 RVU; peak time from 4.6 to 7 min and the pasting temperature from 61.84 to 62.40oC. There exists significant difference (P < 0.005) among the samples analyzed.
Conclusion: Apart from establishing the nutritional contents of these commonly consumed yams that are semi-perishable, the effects of the common traditional methods of processing on the nutrient contents are established.It was found that fresh- oven-dried and fresh -sun dried were better processing methods.
Key words: Yam, Cocoyam, processing, proximate analysis, boiling, roasting.
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