KEEPING UP APPEARANCES
The thickening agent in jam is pectin (E440).
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EMULSIFIERS
We all love smooth foods and they get that way through the use of Emulsifiers.
ANTICAKING AGENTS
The substances that keep food flowing
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Texture, important both for the feel of
food and for digestion, is maintained by thickening and stabilising agents Thickening
and stabilising agents are gums that assist emulsifiers in maintaining texture and in
modulating the texture of many water-based foods. Technically, gums are not quite what the
term usually implies in everyday use: they are thick and viscous but they are not usually
tacky.
Very many foods require thickening and gelling agents. The most familiar example is
jam, in which fruit juices are thickened with pectin (E440). A more modern requirement
would be the need to bind the soya proteins in veggieburgers. Gums come from a range of
sources: many are substances exuded from plants, e.g. gum arabic (E414), locust bean gum
(E410), guar gum (E412); others are derived from seaweeds, carageenan (E407)and alginates
(E400-4), and many more are derived from cellulose by chemical modification, e.g. sodium
carboxymethyl cellulose (E466). Yet another category is produced by microbiological
fermentation, the principal product being xanthan gum (E415).
All gums are polysaccharides, that is they are related to sugars but with many sugar
units making up a large molecule. Starch (E1414-1451), the classic polysaccharide, also
furnishes thickening agents, as in its traditional role in making roux-based sauces. The
large, cage-like structure of polysaccharides is responsible for the thickness of gums
when mixed with water. The molecules have groups with affinity for water but the large
lattice structure prevents the total solution that occurs with simple sugars.
Gums are famously bland, they are generally odourless and tasteless and most have no
energy value. They do though have a nutritional function besides their mechanical and
cosmetic ones: in digestion they function as fibre, easing bowel function, and some are
used as bulk laxatives. |
