Some Physico-chemical Properties of Dioscorea Starch from Ethiopia

• Published in: Die Stärke Vol. 50; no. 6; pp. 241 - 246
• Main Authors: Gebre-Mariam, T., Schmidt, P. C.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag GmbH 01.06.1998; WILEY‐VCH Verlag GmbH; Wiley-VCH
• Subjects: Biological and medical sciences; Chemical constitution; Food industries; Fundamental and applied biological sciences. Psychology; Plant physiology and development; Starch and starchy product industries; Viscosity; Monocotyledones; Chemical analysis; Swelling; Yam; Starch; Gelatinization; Sol gel transition; Dioscoreaceae; Thermal properties; Starch granule; Particle size distribution; Water sorption; Angiospermae; Water solubility; Tuber; Technological properties; Spermatophyta; Chemical composition; Tuber plant; Physicochemical properties; Rheological properties
• ISSN: 0038-9056; 1521-379X
• DOI: 10.1002/(SICI)1521-379X(199806)50:6<241::AID-STAR241>3.0.CO;2-R

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 (To) of 64.2°C, a peak temperature (Tp) of 68.2°C and an endset temperature (Te) of 74.8°C. The enthalpy of gelatinization (ΔH) was 19.2 mJmg−1.