gum Substances that can disperse in water to form a viscous mucilaginous mass. Used in food processing to stabilize emulsions (such as salad dressings and processed cheese), as a thickening agent, and in sugar confectionery.

The substances may be extracted from seeds (guar gum, locust (carob), quince, psyllium), plant sap or exudates (gum arabic, karaya or sterculia, tragacanth, ghatti, bassora or hog gum, shiraz, mesquite, anguo), and seaweeds (agar, kelp, alginate, Irish moss), or they may be made from starch or cellulose. Most (apart from dextrins) are not digested and have no food value, although they contribute to the intake of non‐starch polysaccharides. See also fibre, soluble.

guar gum Cyamopsis gum; from the cluster bean, Cyamopsis tetragonoloba; a water‐soluble galactomannan; used in ‘slimming’ preparations, since it is not digested by digestive enzymes, and experimentally in the treatment of diabetes, since it slows the absorption of nutrients, and so prevents a rapid rise in blood sugar after a meal.