Evaluation of Physico-Chemical Properties of starches from Disocorea Rotundata species

Abstract

Three species of starches from dioscorearotundata:Giwa, Lagos, Sule and Kwasi were investigated and characterized by X-ray diffraction, EDX/XRF/PIXE/SEM with Proximate composition determined.Yams tarches were found in all the D.R. species.XRD peaks of highest intensity are at~17.02,17.12 and 17.26ι2ߠ with relative crystallinities (%) ~ 18.25േ1.25, 22.25േ5.75, and 18.75േ0.75Ψ, respectively.A distinctive characteristic is that all the species contain elements Ru(18.37 to 27.71) and K (11.48 to 21 w/w%)in major concentrations. Their microstructure has grain sizes of 3.59, 3.54 and 3.19 µm, respectively, forGiwa, LagosandSule. The grains are generally uniform/oval in shape and mixtures of B and C-crystal types.The crystallite sizes are ~2.5, 3.0 and 2.4 nm, for Giwa, LagosandSule, respectively.Whole profile fitting of the patterns with subsequent refinement using GSAS II suite of programs, together with instrumental resolution curve fitting and peak profile analysis show agreement factors (Rwp) of 1.49, 2.66 and 1.75%, and were all indexed as orthorhombic cells.It is concluded that the starches can be stored safely due to their low moisture content, the possibility of some mineral deposits in the soil and that they have physico-chemical properties that may be suitable for application in the starch industry, particularly when modified.