Chemistry Reference
In-Depth Information
5.10.6.
Tagatose
Tagatose was listed in 2001 as a GRAS ingredient by the US Food and
Drug Administration. The Food Standards Agency in the UK recognized
tagatose as a novel food ingredient in the EU, and this is expected to be
ratified soon. Also, it has been approved for food use in Brazil, Korea,
Australia and New Zealand, and approval in Mexico, Japan and Canada is
expected shortly.
5.11.
Conclusions
5.11.1.
Future Directions and Challenges
The manufacture of GOSs and the other lactose-derived compounds is
in the process of rapid expansion globally. A major reason for this expansion
in production in recent years has been the general regulatory acceptance of
the addition of GOSs to infant milk formulae and infant foods. More
broadly, the ability to include these ingredients under the heading ''dietary
fibre'' on food labels has enabled some health benefits to be stated. However,
as discussed earlier, there is now some doubt whether oligosaccharides will
remain classified as dietary fibres.
As further clinical and animal studies are conducted, a range of non-
digestible carbohydrates are gaining medical acceptance as prebiotics, which
are able to confer some health benefits. This includes GOSs and lactulose.
The evidence is less well established for lactosucrose and lactitol. Lactobionic
acid and tagatose are not considered to be prebiotics, although unsubstan-
tiated claims have been made for tagatose.
Evidence exists that
-galactosidases obtained from certain microor-
ganisms (e.g., B. bifidum) tend to produce higher proportions of the longer
chain galacto-oligosaccharides. These mixtures tend to be used more specifi-
cally by certain species of Bifidobacterium (Rabiu et al., 2001; Tzortzis et al.,
2005a). This search for prebiotic carbohydrates with greater selectivity by
probiotic bacteria is of high interest to manufacturers, and offers scope for
the development of genuine synbiotic products. The ultimate in synbiotic
combinations will include oligosaccharides that can not only benefit the
proliferation and activity of the specific probiotic strains in the colon, but
also protect those bacteria during manufacture, formulation and storage, and
during gastrointestinal transit.
The efficiency of oligosaccharide synthesis is also being improved by
modifying the
-galactosidase molecule by deletion of amino acid residues in
the protein. This has converted the enzyme to being predominantly a trans-
galactosylation enzyme rather than a hydrolytic enzyme (Jorgensen et al.,
