Title: Alternative Sweeteners

492 Fry and Hoek
are rapid dissolution, essential to meet consumer expectations of an instant product,
and the homogeneity of the mix, which is essential to deliver reproducible
product performance. In addition, there are factors that affect the manufacturer,
such as ease of mixing of the ingredients and low dust content.
Unfortunately, aspartame and acesulfame-K crystallize in different forms.
Aspartame has needlelike crystals, whereas those of acesulfame-K are more cubic.
This means it is technologically difficult to create and maintain mixtures of
these sweeteners that are homogeneous and stay so throughout the manufacturing
and retail chains. There is evidence that this difficulty influences the quality of
powder products. Not only is there a tendency for the two conventional sweeteners
to separate from each other, they can also redistribute themselves unevenly
with respect to the other components of the mixture. For example, Hoek et al. (5)
have shown that, in segregation tests of aspartame and acesulfame-K contained in
a typical instant beverage powder, the sweeteners can separate to a degree that
could be perceptible to consumers as differences in sweetness. In the aspartameacesulfame
salt, however, the two sweeteners are combined at the molecular level
and cannot be separated from each other until the moment they are dissolved.
Moreover, the rapid dissolution of the salt (see Section V) means there is greater
freedom to choose a particle size range that gives a mechanically stable, homogeneous
mix. This is an advantage in comparison with aspartame, which dissolves
relatively slowly, a factor that may drive the powder mix manufacturer to use
very finely ground material to increase dissolution speed. Such fine powders bring
other difficulties, however. These include a tendency to cohere, which means
that finely-milled aspartame does not flow easily and can clump. Perversely, such
clumps can act as very large particles and take an extended time to dissolve. The
tendency to form clumps is made worse by the uptake of moisture, a process
encouraged by the sweetener’s hygroscopicity. In contrast, the complete absence
of significant hygroscopicity in the salt has already been noted.
Comparative trials have been made of Twinsweet with an equisweet, equimolar
physical blend of aspartame with acesulfame-K in a typical instant beverage
mix (5). Under standardized mixing conditions, and in both tumbling and
convective mixers, the sweetener-sweetener salt produced a more homogeneous
mix, with coefficients of variation for the concentration of both sweetener components
half those found with the blend. The mixture based on the salt was also
much more resistant to segregation. In tests, columns of powder were deliberately
vibrated to induce segregation and subsequently sectioned horizontally and analyzed.
The spread of sweetness after this test is shown in Fig. 6, from which
it can be seen that the sweetness of the product with Twinsweet is much more
narrowly distributed than that using the blend. More particularly, the variation in
concentration of the blend is likely to be perceptible to a proportion of consumers,
whereas that of the aspartame-acesulfame salt is unlikely to be so detected.
Naturally, although Twinsweet may be used in a powder mix solely because
of its advantageous powder flow properties, its rapid dissolution is also of obvious