Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
As regards the overall gum market, there has been a dramatic shift due to the
introduction of new chemical derivatives of natural polysaccharides and of new
products of microbial synthesis. The market for gums and food additives has been
reviewed in 1987 6 and more recently in 2000. 7 There is a continuing trend for
expansion of the market for new gums, but as the market overall has increased, there
has been no drop in demand for traditional plant and algal products.
The major uses of plant and algal gums are as hydrocolloid texture modifiers
and viscosity enhancers to control the rheology of manufactured food products.
Some gums are also used as stabilizers or emulsifiers. For particular gums, references
are made to rheological properties that are of importance for their food uses, and
the significance of these properties is discussed in more detail in Chapter 11.
Polysaccharide hydrocolloids for the food industry are also available from
another source since the development of the gums of microbial origin, notably
xanthan and gellan. These gums are produced from microbial cultures and are
discussed further in Chapter 10. Gums have provided food producers with new
rheologies and have been rapidly adopted by manufacturers. Table 15.1 gives
the relative contribution of gums from different sources to the hydrocolloid
market.
Gums of both plant and algal origin are generally considered as indigestible and
forming part of the dietary fiber. Most of the polysaccharide linkages found in gums
are resistant to digestion as the human gut lacks the enzymes necessary to break
these bonds. Gums are, however, susceptible to microbial degradation, and breakdown
of gums by intestinal microbes can release absorbable monosaccharides or
other absorbable products of microbial metabolism. The relative contribution of such
sources to human nutrition is a matter of current debate for various gums. In the
case of gum arabic, which is included at relatively high levels in some confectionery,
a significant contribution to energy intake can be presumed. 8
TABLE 15.1
World Markets for Nonstarch Natural Food
Hydrocolloids
Gum % by Volume% % by Value
Algal polysaccharides 36.9 32.7
Reserve polysaccharides 22.7 16.4
Plant exudates 17.0 13.6
Wall polysaccharides 14.2 22.7
Microbial polysaccharides 9.1 14.5
World total 100 100
Source: From Phillips, G.O. and Williams, P.A., Handbook of
Hydrocolloids, CRC Press, Boca Raton, 2000 and Lillford, P.J.,
in Gums and Stabilisers for the Food Industry, Vol.10, Williams,
P.A. and. Phillips, G.O., Eds., RSC Cambridge, 2000, p. 387.