Title: Alternative Sweeteners

482 Fry and Hoek
achieved in 1995, when Fry and Van Soolingen (2) invented such a process and
used it to produce a range of intense sweetener salts, including the first, unique
crystals of aspartame-acesulfame. Patent applications on the Fry-Van Soolingen
method have been filed widely, including in Europe (2) and the United States
(3). Also the subject of patents is the aspartame-acesulfame compound itself.
From all the possible sweetener-sweetener salts, this latter has become the leading
candidate for full commercial production, and its introduction is being carried
out by Holland Sweetener Company under their trademark Twinsweet.
The reasons for marketing this particular salt are clear. First, there are the
well-known advantages of blending aspartame with acesulfame-K. For example,
in the case of liquid products, these two sweeteners together offer greater sweetness
stability and longer shelf-life compared with aspartame alone. In addition,
aspartame and acesulfame-K exhibit quantitative synergy, which means that,
when used jointly, they are a more potent sweetener than would have been expected
based on their properties used independently. Furthermore, the quality of
sweetness is improved by blending the two. The best features of the sweetness
profiles of each come to the fore when they are combined, and a favored blend
to achieve this is 60:40 by weight of aspartame and acesulfame-K, respectively.
This ratio happens to be equimolar (equal numbers of molecules of each) and is
exactly the ratio in which the sweeteners appear in the aspartame-acesulfame
salt.
These quantitative and qualitative synergies between this pair of sweeteners
have fostered an enormous growth in their joint use, as well as a general acceptance
that blended sweetener systems can often offer the consumer a better taste
than single sweeteners alone, however ‘‘sugarlike’’ the latter are claimed to be.
Yet mechanical blends of aspartame and acesulfame-K are not without technological
problems (4, 5). There are issues of dissolution time, hygroscopicity, and
the homogeneity of powder mixes, all of which bear on the ease of use of physical
mixtures of these sweeteners and the quality of consumer products made with
them. In the creation of the novel crystalline form of Twinsweet, where aspartame
and acesulfame are combined at the molecular level, these issues have been
largely resolved.
The way aspartame and acesulfame are combined in the salt gives rise to
yet more advantages. For example, the molecular arrangement in such that, in
the solid, access to the free amino group of the aspartyl moiety is hindered. The
availability of this group is critical to the (in)stability of aspartame when used
conventionally as a separate sweetener in certain low-moisture applications, such
as sugar-free confectionery, especially chewing gum. Where these products include
flavors high in aldehyde content, there is a risk that aspartame is degraded
through reaction with the flavor. This can shorten the shelf-life unacceptably
because there is simultaneous loss of both flavor and sweetness. The hindered
structure of the solid aspartame-acesulfame salt, however, is less susceptible to