Agriculture Reference
In-Depth Information
obtained from citrus fruit. The European Union (EU) allows the bulk, low-calorie
polyol, erythritol, but does not recognise its preparation by fermentation using
osmophilic yeasts or fungi as meriting the description 'natural'. In another twist,
the natural HPS glycyrrhizin is permitted as a fl avouring but not as a sweetener.
To compound these diffi culties, the sugar tagatose is accepted as a novel food
in the EU, but not as natural (it is produced enzymatically from lactose). Again, at
the time of writing, tagatose in the EU is compelled to bear the statutory standard
calorie content for sugars of 4 kcal/g. While EFSA has been asked to review this,
the US stance is that the sugar is both natural and low-calorie, with an energy
content of only 1.5 kcal/g. Thus, the EU's current view means that tagatose, being
neither natural nor low-calorie, has no place in this chapter, while the US position
is emphatically the opposite.
The US also differs from the EU on almost every other natural sweetener. The
only natural HPS permitted as sweeteners in the US are the steviol glycosides.
Two members of this group, namely rebaudiosides A and C, are deemed GRAS
(Generally Recognised As Safe) fl avour enhancers by the US Flavor and Extract
Manufacturers Association (FEMA) too. Lo han guo (monk fruit) extract is
allowed as a fruit concentrate for use as a sweetener or fl avour enhancer, but there
is no specifi c permission to use the HPS mogroside V, contained in that concentrate,
as a sweetener. In addition, as far as the US is concerned, thaumatin, glycyrrhizin
and NHDC are fl avour enhancers and erythritol is natural.
All the above-named substances except NHDC, together with a number of
others, are reviewed below regardless of national regulatory differences. However,
the key natural sweeteners from industry's point of view are the steviol glycosides,
erythritol, lo han guo/mogrosides and, in the future, most probably monatin. In
contrast, thaumatin, glycyrrhizin and - if you must include it - NHDC are better
regarded as useful fl avour enhancers than as particularly advantageous sweeteners.
3.1.4 Note on potency
No description of a high-potency sweetener is complete without some estimate of
potency. This expression of the sweetening power of a substance is typically given
on a weight-for-weight comparison with sucrose, though some authors prefer
molar units. The latter look more impressive when dealing with sweet proteins.
The principal drawback of potency fi gures is that they seldom recognise that the
sweetening power of HPS is an inverse function of concentration. Potency is
highest at the threshold of recognition, where the sweet taste can just be identifi ed,
and declines as concentration increases. Ultimately, the curve of sweetness against
concentration of sweetener reaches a plateau at some sweetness value dependent
on the molecule in question (see, for example, Fig. 3.5).
There is usually little point in even approaching the plateau value in food
products because the sweetener is then at its least economical (lowest potency) and
the opportunity is greatest for undesirable side tastes or poor sweetness dynamics to
manifest themselves. For manufacturers, the useful area of potency lies somewhere
between threshold and plateau, and relatively distant from either extreme.
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