Dextrose is a natural sweetener much valued as an ingredient in confectionery applications. It can be easily handled, weighed, mixed, and dissolved. However, dextrose is much more than an ‘alternative’ sweetener, due to its functional properties.
In an arbitrary scale of sweetness where sucrose is given a value of 100, dextrose is rated at 75. It can therefore be used to reduce the sweetness. This, however, is an oversimplification because the flavor, acidity, and the presence of other sugars at total concentration influence the relative sweetness. For example, when used with sugar at up to 40% replacement level in a formulation of high sweetener concentration and low acidity the relative sweetness of dextrose could be as high as 90 as a result of the synergistic effect which occurs when these two sweeteners are blended. This technique of using dextrose in combination with sugar is useful in achieving flexibility of sweetness balance.
Crystallization and solubility
Dextrose is less soluble than sucrose at room temperature and hence is more prone to crystallization (Table 1). However, in a combined sweetener system there is an increase in overall solubility. The total solubility in a given amount of water is greater than the sum of the individual components. Crystallization is therefore inhibited or delayed. As a result, in highly oversaturated systems (e.g. fondant) dextrose has a marked softening effect on the texture.
The heat required to dissolve dextrose (25.2 cal g-1) is much greater than that for sucrose (3.85 cal g-1). In consequence, when eating an item of food containing dextrose in the crystalline state, there is a distinct cooling sensation in the mouth. This significantly increases the product appeal of fillings and icings, for example, particularly those flavoured with peppermint or lemon.
Molecular weight and osmotic pressure
Dextrose is a monosaccharide and has a molecular weight of 180 compared with that of 342 for sucrose which is a disaccharide. This difference affects the properties of the sweetener in the solution. For example, at any given concentration, a dextrose solution contains almost twice as many dissolved molecules as a sucrose solution. As a result, dextrose exerts a greater osmotic pressure, an important consideration where preserving action is being sought.