Partial Study of Yam Tuber (<em>Dioscorea</em> spp.) Parts during the Growth Period

Abstract

Growing gradient into longitudinal axis of yam tuber was study through starch properties and nutritional composition of tuber parts (proximal, median and distal) during the tuberization. Two varieties of the complex D. cayenensis-rotundata (kangba and kponan) were used. Clarity, swelling and solubility, flow behavior and syneresis of starch and protein content, alcohol-soluble sugars of the flour were studies. The ash assessed by microanalysis. Starch clarity of tuber parts increased during the growth period. The proximal (56±2.06%) and median (54.5±1.09%) parts exhibited high clarity than the distal (48.2±2.56%) one. At earlier stage of tuberization, the viscosity ratio of tuber parts (var. Kponan) was weak. This indicates the possibility to use it as thickening agent in shearing sauce. Water loss decreased during the growth period for the three tuber parts. It was the same behavior for the swelling power. Concerning the nutritional composition of the flour, amount of protein did not influenced by the degree of tuber maturity. Alcohol-soluble sugars were higher at earlier stage of tuberization than at maturity of the tuber. Mineral content was appreciable at maturity than at beginning of the tuberization. The extent mineral according to their amount was: K, P, Mg and S. Starch properties such as clarity, syneresis and swelling were improved at maturity of the tuber. It was more for the proximal and median parts than the distal one. Yam tuber content a appreciable amount of protein and mineral at maturity.

Influence of Technique Cultivation on Some Properties of Two Varieties of Yam (Dioscorea spp) Flour

“…In fact, it varies within the same tuber, especially for the variety bete-bete. The middle part gives a clearer gel than both ends [19].…”