Melting and Crystallization of Sugars in High-Solids Systems
| Autor: | Yrjö H. Roos, Harry Levine, Theodore P. Labuza, Evgenyi Shalaev, David S. Reid, Mohamed Mathlouthi, Marcus Karel, Louise Slade |
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| Rok vydání: | 2013 |
| Předmět: |
Supersaturation
Materials science Carbohydrates Temperature General Chemistry Crystal structure Decomposition law.invention Crystallography Chemical engineering Impurity law Thermodynamics Crystallization General Agricultural and Biological Sciences Dissolution Melting-point depression Chemical decomposition |
| Zdroj: | Journal of Agricultural and Food Chemistry. 61:3167-3178 |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf305419y |
| Popis: | Crystalline structures of sugars, particularly that of sucrose, depend on crystallization conditions and the presence of impurities. Sugar crystals show melting that often occurs at low temperatures with time- and temperature-dependent characteristics. Melting at low temperatures can be accounted for by the presence of impurties and defects. Sugar crystals also contain noncrystalline regions that may undergo decomposition and subsequent dissolution at the decomposition interface and acceleration of decomposition reactions. Such processes with melting establish a supersaturated condition for the remaining crystals, leading to a time-dependent melting point depression and subsequent melting of the remaining crystals. Decomposition of sugars, as well as dissolution and melting of sugar crystals, are separate phenomena, although they are commonly found to coincide. Decomposition of sugars requires the presence and mobility of molecules for reactions outside the crystal lattice; that is, the molecular mobility of amorphous or melted regions is a prerequisite for decomposition, whereas melting of sugar crystals occurs as a separate thermodynamic process with no chemical change of the molecules. |
| Databáze: | OpenAIRE |
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