Agriculture Reference
In-Depth Information
sweetening, HPS are used in amounts that are a tiny fraction of the weight of sucrose
needed to achieve the same sweetness. Some HPS are not metabolised for energy
and contribute no calories at all, but even those that are fully metabolised are used
in such minute quantities that their energy contribution is entirely negligible.
3.1.2 Natural sweeteners
Excluding the simple sugars and polyols, there are 100 or so sweet compounds found
in nature. They fall into three main classes (terpenoids, fl avonoids and proteins) and
all bar one group have been found in green plants rather than any other form of life
(Kinghorn and Compadre 2001). The exceptions are lysozymes from eggs (qv):
those from several species are sweet. However, the majority of these natural
sweeteners are of academic interest only. They have little prospect of becoming
commercial ingredients because they fail to meet one or more of the key criteria for
commercial success, discussed further below. Accordingly, this chapter concentrates
on the small number of natural low-calorie sweeteners that either are, or are likely to
become, commercially successful. These are compounds that meet criteria including:
•
good taste
•
safety
•
solubility
•
stability
•
acceptable cost-in-use.
It surprises many that hardly any two sweet compounds taste the same. There are
subtle variations in quality, including fullness and roundness of sweetness, as well
as signifi cant differences in dynamics, such as onset, time of peak sweetness and
linger. In addition, there are sometimes not-so-subtle side tastes of an objectionable
nature, often described as bitter, metallic and liquorice, to contend with. The
degree to which these qualities are acceptable or can be disguised in product
formulation dictates the candidate molecules for commercialisation.
Whereas it might be possible to compromise to some extent on achieving a
completely sucrose-like taste, no compromise on safety is acceptable. Like any
proposed food additive, natural sweeteners have to be shown to be safe for human
consumption to the satisfaction of independent toxicological authorities. A more
lenient view of natural compounds is taken by some countries such as Japan, but
those in the West apply the same rigorous standards to natural materials as artifi cial
ones. The requirements are demanding, the provision of the data required is costly,
and the process is not undertaken lightly. Accordingly, any potential new natural
sweetener has to show considerable promise before the necessary investment is
likely to be made.
Part of that promise is its suitability for use as an industrial ingredient. This
covers the properties of solubility, stability and cost. Adequate solubility in water
is a prerequisite for a useful sweetener. Manufacturers have to be able to dissolve
enough of the material to provide the desired level of sweetness and do so both
completely and reasonably quickly.
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