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Some Physico‐chemical Properties of Dioscorea Starch from Ethiopia
Author(s) -
GebreMariam T.,
Schmidt P. C.
Publication year - 1998
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/(sici)1521-379x(199806)50:6<241::aid-star241>3.0.co;2-r
Subject(s) - amylose , starch , dioscorea , dioscoreaceae , granule (geology) , swelling , chemical composition , scanning electron microscope , chemistry , particle size , solubility , food science , botany , materials science , organic chemistry , composite material , biology , medicine , alternative medicine , pathology
The chemical composition, amylose content and physio‐chemical properties of dioscorea starch ( Dioscorea abyssinica , Fam. Dioscoreaceae) from Ethiopia have been investigated. The proximate composition of the starch on dry weight basis was found to be 0.1% ash, 0.5% protein, 1.0% fat and 98.4% starch. The amylose content was 29.7%. Scanning electron microscopy (SEM) showed rounded granules. Particle size analysis revealed granule size distribution with a mean particle size of 29.2 μm. X‐ray diffraction study showed a pattern that is typical of B‐type with a distinctive maximum peak at around 17° 2 T. The moisture sorption pattern, the swelling power and the solubility values were determined and found to be lower than potato starch. Brabender viscosity curves of 6% starch paste showed a peak viscosity of 781 BU. The breakdown and retrogradation of dioscorea starch were 25 and 501 BU, respectively. DSC parameters of starch‐water mixture (1:2) exhibited an onset temperature (T o ) of 64.2°C, a peak temperature (T p ) of 68.2°C and an endset temperature (T e ) of 74.8°C. The enthalpy of gelatinization (ΔH) was 19.2 mJmg −1 .