Functional and Pasting Properties of Lesser Known Nigerian Yams as a Function of Blanching Time and Particle Size

P.A. Okorie ； E.C. Okoli ； E.C. Ndie

《Advance Journal of Food Science and Technology》 3卷6期 (2011/12) Pp. 404-409

並列摘要

The Effects of blanching time and particle size on functional and pasting characteristics of some lesser known Nigerian yams were investigated. Two varieties of lesser known yam Ighu and Ona belonging to Dioscorea dometorum species and two varieties of commonly used yams ozibo and okwanankata belonging to the D. rotunda and D. alata sp., respectively. The yams were processed by peeling, cubing, and blanching at 100°C for 5 or 10 min, drying at 50°C and subsequently milled to flours and fractionated to 40, 60, or 80 mesh sizes. Another batch of the tubers were processed similarly, but they were not subjected to a blanching treatment. Swelling capacity, water absorption capacities, bulk density, solubility and pasting characteristics were evaluated. The result showed that the lesser known yam Ighu exhibited significantly higher (p＜0.05) hot and cold paste viscosities, solubility, water absorption and swelling capacities than the common yam varieties. Hot and Cold paste viscosities, solubility, water absorption and swelling capacities of flour generally increased as particle size decreased in all the test samples. While the bulk density was not affected by the blanching treatment, it decreased with decrease in particle size. The yam starches generally showed weak stability, but starch of the lesser known variety Ona suffered the least share thinning. Rate of retrogradation was found to be high in all the yam varieties but more pronounced in the lesser known yams Ighu and Ona. Ighu starch which exhibited the highest cold and hot paste viscosity showed the highest setback and index of gelatinization values. Industrial and culinary applications of the test yam varieties were suggested.

並列關鍵字

Blanching ； functional ； Nigeria ； particle size ； pasting properties ； yams