Amorphous state and delayed ice formation in sucrose solutions

Autor:	Marcus Karel, Yrjö H. Roos
Rok vydání:	2007
Předmět:	Phase transition Annealing (metallurgy) Chemistry Thermodynamics Industrial and Manufacturing Engineering law.invention Amorphous solid Differential scanning calorimetry law Congelation Crystallization Glass transition Water content Food Science
Zdroj:	International Journal of Food Science & Technology. 26:553-566
ISSN:	1365-2621 0950-5423
DOI:	10.1111/j.1365-2621.1991.tb02001.x
Popis:	Summary Phase transitions of amorphous sucrose and sucrose solutions (20–100% sucrose) were studied using differential scanning calorimetry, and related to viscosity and delayed ice formation. Glass transition temperature (Tg) was decreased by increasing water content. Ice formation and concurrent freeze concentration of the unfrozen solution increased apparent Tg. Tg could be predicted weight fractions and Tg values of components. Williams–Landel-Ferry (WLF) relation could be used to characterize temperature dependence of viscosity above Tg. Crystallization of water above Tg was time dependent, and annealing of solutions with less than 80% sucrose at –35°C led to a maximally freeze-concentrated state with onset of glass transition at –46°C, and onset of ice melting at -34°C. The state diagram established with experimental and predicted Tg values is useful for characterization of thermal phenomena and physical state at various water contents.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::ce83a271c7e4d144ba8bddca2e6a194a https://doi.org/10.1111/j.1365-2621.1991.tb02001.x Zobrazit plný text záznamu Plný text