Agriculture Reference
In-Depth Information
1334/2008. These 'traditional food preparation processes' are a new requirement
in this Regulation and are a pre-requisite for calling a material a 'fl avouring
preparation'.
Thaumatin is listed in Table III of the Codex General Standard for Food
Additives (GSFA). This means that it is permitted for use in food in general,
unless otherwise specifi ed, in accordance with GMP.
The JECFA ADI for thaumatin is 'not specifi ed', meaning its use is limited
only by GMP, whereas there are strict maximum concentrations specifi ed for its
use as a sweetener in the EU.
Thaumatin in the US is approved by the FDA as a 'fl avour preparation' under
GRAS rules for about 30 applications. FEMA allows the substance widely at
levels of 0.1-0.5 parts per million (ppm).
3.4
Potential future sweeteners
3.4.1
Monatin
Structure, source
Monatin is an amino acid, closely related to tryptophan, found in the root bark of
the plant
Sclerochiton ilicifolius,
found in the north-western region of South
Africa. The root has long been known for its sweetness, but monatin itself was
fi rst described only in 1988 (Van Wyk and Ackerman 1988). The name monatin
was coined from the Sepedi name 'monate' which translates as 'nice' (Vleggaar
et al.
1992). Because of various naming conventions, monatin is also known by a
number of alternative chemical names, including 2-hydroxy-2-(indol-3-ylmethyl)-
4-aminoglutaric acid, 4-amino-2-hydroxy-2-(lH-indol-3-ylmethyl)-pentanedioic
acid, 4-hydroxy-4-(3- indolylmethyl)glutamic acid and 3-(l -amino- l,3-dicarboxy-
3-hydroxy-but-4-yl)indole.
Monatin's structure is shown in Fig. 3.10, from which it is apparent that the
molecule has two optically active carbon atoms, leading to four possible isomers.
The term monatin has been generally used to describe any and all of the possible
isomers. All four (
S,S, S,R, R,S
and
R,R
) have been characterised and have very
different sweetness potencies. That of
S,S
is 50-200, while
R,R
is several thousand
times the sweetening power of sucrose (Evans and Goulson 2010). Indeed, it may
Fig. 3.10
Structure of monatin, free acid form, showing two optically active centres
(asterisked).
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