Effect of carbohydrate crystallization on stability of dehydrated foods and ingredient formulations

Sugars are important components of the amorphous regions of dehydrated foods, and their structure may define product performance. The objective of present work was to analyze the impact of sugar crystallization on product quality, and to discuss some strategies to avoid sugar crystallization. Chemical changes, (non-enzymatic browning, lipid oxidation and enzymatic activity) were accelerated upon crystallization of the sugar matrix. Oxidation of encapsulated pigments was not prevented in the glassy state but it was delayed by crystallization inhibition of the encapsulating sugar. At a kinetic level, sugars promote the formation of glassy matrices delaying deteriorative reactions. At a specific-interaction level, dehydroprotectants interact with proteins and membranes and stabilize them by hydrogen bonding. Both aspects are related, since specific interactions cannot be manifested if the sugar is in the crystalline state and vitrification is the property which ensures inhibition of crystallization. The study of delay/inhibition of sugar crystallization in supercooled liquids may increase the range of applications of sugars for specific purposes. (C) 2004 Elsevier Ltd. All rights reserved.