Title: Alternative Sweeteners

374 White and Osberger
When aspartame received clearance for use in food products in 1981, it
became the task of food scientists to determine precisely how to use this sugar
substitute. Contrary to oft-expressed opinion, aspartame does not exhibit a sweetness
profile exactly identical to that of sucrose. Some subtle organoleptic differences
can be perceived, with the significance of these differences being dependent
on the specific conditions under which the aspartame is used. Hyvonen in Finland
(14) and Johnson in the United States (15) discovered that combinations of aspartame
and crystalline fructose could be used to achieve a synergistic sweetening
effect and to minimize any lingering, nonsweet flavors of aspartame.
Thus, the sweetness synergy between fructose and other sweeteners offers
formulators the choice of accepting finished products with greater sweetness or
reducing sweetener levels and accepting ingredient cost savings. Blending fructose
with reduced levels of high-intensity sweeteners has the added benefit of
eliminating their bitter, metallic, or lingering aftertastes that are disagreeable to
some consumers.
D. Colligative Properties
Fructose is a monosaccharide molecule with very different colligative properties
than dextrose, another monosaccharide, or sucrose, a disaccharide. Colligative
properties are those physical properties that depend solely on the concentration
of particles in the specific system of interest. The concentration of particles, in
turn, depends on the solubility and molecular weight of the particles.
The solubility of fructose, sucrose, and dextrose versus temperature is illustrated
in Fig. 2. Fructose is more soluble at all temperatures than either sucrose
or dextrose. Because it is half the molecular weight of sucrose and possesses
greater solubility, it is easy to understand how the concentration of particles and
concomitant colligative properties are accentuated with fructose.
Osmotic pressure, water activity, and freezing point depression are three
colligative properties that are accentuated with fructose. Fructose creates higher
osmotic pressure and lower water activity than sucrose, dextrose, or higher saccharides,
resulting in greater product microbial stability. Fructose depresses the
freezing point more than sucrose. When used in dairy desserts (both soft-serve
and hard-frozen), the tendency of fructose to depress the freezing point can be
countered with the addition of higher molecular weight corn sweeteners, gums,
or stabilizers. The depressed freezing point is actually an asset when fructose is
substituted for sucrose in frozen juice concentrates.
E. Hygroscopicity and Humectancy
Fructose is quicker to absorb moisture (hygroscopicity) and slower to release it
to the environment (humectancy) than sucrose, dextrose, or other nutritive sweet-