Glass Transition sugars

The reported effect of konjac GaM on the glass transition of high-sugar/polysaccharide mixtures [242] can be utilized in sugar, hard-boiled and frozen confectionery products and might replace gelatin, which is refused by some consumers due to diet and health problems. 

Roos, Y. and Karel, M. 1993. Effects of glass transitions on dynamic phenomena in sugar containing food systems. In Glassy State in Foods (J.M.V. Blanshard and P.J. Lillford, eds), pp. 207-222. Nottingham Univ. Press, Loughborough, UK. 

S. M. Lievonen, T. J. Laaksonen, and Y. H. Roos, Nonenzymatic browning in food models in the vicinity of the glass transition effects of fructose, glucose, and xylose as reducing sugar, J. Agric. Food Chem., 2002, 50, 7034-7041. 

The transition temperatures of carbohydrates and proteins are significantly affected by water. It is often reported that an increase in water content results in a substantial decrease in transition temperatures (Slade and Levine 1995). For example, the glass transition of dehydrated food solids decreases as a result of water sorption (i.e., water uptake from its surroundings) and their properties may change from those of the glassy solid to viscous liquids or syrup (e.g., sugar systems) or leathery material (e.g., protein systems) in an isothermal process. 

Figure 7.6. Effect of molecular weight on the glass transition temperature of maltodextrins (Reprinted with permission from Roos and Karel, Phase transitions of mixtures of amorphous polysaccharides and sugars, Biotechnol. Progr. 7, pp. 49-53. Copyright (1991) American Chemical Society.)...

Truong, V., Bhandari, B.R., and Howes, T. (2005). Optimization of cocurrent spray-drying process for sugar-rich foods. Part II. Optimization of spray-drying process based on glass transition concept. J. Food Eng. 71,66-72. 

Both this melt temperature and the glass transition of the resultant material are highly susceptible to the presence of plasticizers. The dominant species is water, but small sugars and salts may also have an influence (see Chapter 5). Nonetheless, it is clear that whereas the processes in the extruder barrel should be related to the effect of plasticizers on gelatinisation or melting, their effect on final product properties should be related to the glass transition of the amorphous molten extrudate. 

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