| Autor: |
Rangelov, Antoan, Arnaudov, Luben, Stoyanov, S.D., Spassov, Tony |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
|
| Zdroj: |
Bulgarian Chemical Communications, 49(2), 422-429 |
| ISSN: |
0861-9808 |
| Popis: |
The microstructure and thermal behaviour of industrial starches with different origin were characterized by X-ray diffraction and thermal analyses (DSC, TG). Some of the studied starches revealed crystalline structure (type A and type B), while others were predominantly amorphous, having only about 15 % crystallinity. The moisture content of the pristine starches correlated with their microstructure: starches with a higher amount of amorphous phase showed larger water content. The thermal behaviour of the starches with different amount of additional water was also studied by DSC. In a starch-water paste at higher water content the gelatinization started earlier and gelatinization enthalpy change was greater, than what was observed at lower water content. At certain starch to water ratio two distinguished endothermic peaks denoted the gelatinization and melting processes. The determined enthalpies of gelatinization were in the range of 5-15 J/g and did not correlate with the initial crystallinity of the starches. The activation energies of gelatinization in the range 40-100 kJ/mol, obtained by the Kissinger method, were found not to depend on the initial crystallinity of the starch either. At starch concentrations of 20-35% after the gelatinization endothermic peaks a clear exothermic effect could also be observed, which could be described by the formation of internal hydrogen-bonded associations |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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