Molecular mobility and ageing of sugar glasses

• Published in: Food chemistry Vol. 106; no. 4; pp. 1314 - 1317
• Main Authors: Grigera, J. Raúl, Bolzicco, Viviana
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 15.02.2008; Elsevier
• Subjects: aging; Biological and medical sciences; carbohydrates; dielectric properties; Dielectric relaxation; Food industries; Fundamental and applied biological sciences. Psychology; glass transition; Glasses ageing; glucose; molecular conformation; molecular sugar glasses; Sugar glasses; sugars; water stress; Sugar glasses; Glasses ageing; Dielectric relaxation; Molecular mobility; Ageing; Glass; Sugar
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2007.01.078

Carbohydrates play an important role in the stabilization of biological components under water stress and, consequently, in the preservation of foods. Water stress is produced either by freezing or drying producing damage in proteins and tissues mainly due to the generation of large gradients of concentration of salts. Some carbohydrates act as protectors but, although some explanations have been proposed, the mechanism is not yet properly known. We have measured the dielectric relaxation times of aqueous solutions of glucose in the time domain with a custom made device. Some results are presented here for a solution of glucose in water at 88% w/w, in the range of the glass transition temperature, including some data on the rubbery state (above T g). The curves were fitted with a stretched exponential decay (KWW) with relaxation times in the range of 200–500s and stretching parameter ( β) around 0.5.