Agriculture Reference
In-Depth Information
Stability is also an important issue. The dry substance must be able to be
transported and stored at a range of ambient temperatures that can extend from
0 to 40°C (and possibly higher on board ship) without undergoing deleterious
change. Typical storage lives demanded by industry for raw materials range from
two to fi ve years. Then the manufacturer generally has to be able to process the
dissolved sweetener at high temperature without signifi cant loss in pasteurisation
and sterilisation procedures. Once incorporated in a consumer product, a shelf life
of 6-9 months may be suffi cient for soft drinks, while several years' stability
would be demanded of a sweetener in some canned goods.
Finally, the candidate substance has to be capable of being produced at an
attractive price. This requires that the molecule has a high potency in order to
achieve an attractive cost per unit sweetness. In this context it should be noted that
all the synthetic HPS are very much less costly per unit sweetness than bulk
sweeteners like sucrose or the various starch hydrolysates such as glucose syrup
and high-fructose corn syrups. Natural low-calorie sweeteners thus face very
considerable price competition from synthetic types. However, experience shows
that manufacturers are prepared to pay some premium for a natural HPS that
allows them to highlight to consumers the absence of synthetic additives.
Most of the commercially signifi cant sweeteners described below are either
isolated from their plants of origin or are manufactured by an enzymatic route that, in
the US at least, allows for the description 'natural' to be applied legally. The protein
HPS are obviously synthesised in the wild under genetic control, and much progress
has been made in isolating the genes responsible and transferring them to other
organisms more convenient than the original plant. For example, brazzein can now be
prepared fermentatively using yeast and thaumatin has been successfully obtained
from transgenic barley. Both achievements could remove the need to grow and harvest
tropical fruit and offer the promise of larger yields and lower costs, and the advantages
of moving production closer to major markets. Nevertheless, these approaches have
their own drawbacks, ranging from consumer resistance to foods incorporating the
products of genetic engineering to accusations of bio-piracy (e.g. brazzein).
3.1.3 Regulation
The laws controlling food additives are approached differently in almost every
country. The regulatory defi nition of natural, or rather the lack of such defi nition,
is dealt with in Chapter 1. As far as sweeteners are concerned, there are major
differences between the two key markets - Europe and North America - as well
as with the rest of the world. For example, in Europe until recently only the protein
thaumatin was regulated as a permitted, natural HPS. However, in late 2011
steviol glycosides were added to this class, following a positive opinion on their
safety from the European Food Safety Authority (EFSA) and agreement on
maximum concentrations for each permitted use.
Also permitted in Europe is neohesperidin dihydrochalcone (NHDC), but it is
a common misconception that this is natural. It is actually artifi cial, although the
starting point for synthesis is either neohesperidin or naringin, both of which are
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