Functionality of gums and hydrocolloids ranges widely. Some form gels; others do not. Some are soluble at room temperatures; others require heat. Some are stable at low pH, while others do better under neutral to alkaline conditions, and still others require the presence of potassium or calcium ions to work their magic. Most are thermo-reversible. Typical usage levels come to less than 1%, with most in the range of 0.1 to 0.3%, based on flour.
“The choice of which gum or gum system to use depends completely on what the product is, the outcome the baker has in mind and how hydrocolloids can help solve the problem or set of challenges,” explained Harold Nicoll, marketing manager, TIC Gums, White Marsh, MD.
Applications include breads, cakes and bakery mixes, as well as icings, decorations and fillings. “For example, some baked goods have special requirements for volume, moisture retention and mouthfeel,” he continued, “and there are hydrocolloid systems for that. There are other hydrocolloids that improve structure and mouthfeel. Others act as lubricants in extruded snacks. Some adhere spices or add sheen to baked snacks. Some are a good source of soluble dietary fiber. There are other gums for fillings and icing. So there is no single answer.”
Where do gums come from?
Gums or hydrocolloids, as they are more technically described, get their functionality from long-chain carbohydrate polymers, mostly arabinoxylans, arabinogalactans and galactomannans. All consist of polysaccharides except gelatin, which is derived from animal collagen, a protein.
Gum categories are:
Animal collagens: gelatin
Microbial fermentations: crudlan, gellan and xanthan
Plant extracts: konjac and pectin
Plant exudates: arabic, acacia, ghatti, karaya and tragacanth
Plant celluloses: carboxymethylcellulose, hydroxypropyl cellulose, hydropropopyl methylcellulose, methylcellulose and microcrystalline cellulose
Seaweed extracts: agar, alginate, carrageenan and furcellaran
Seeds: fenugreek, flaxseed, guar, locust bean, psyllium and tara
Many naturally occurring gums come from remote regions of the world, so formulators should explore sourcing of raw materials with their suppliers. Most international trading partners are careful to keep their supplies consistent in quality and reliable in availability.
Sometimes, however, world politics and supply-and-demand economics intervene. For example, Iran grows the most tragacanth, and the largest producers of gum arabic (gum acacia) are Sudan and Senegal. Competing demand from the oil drilling industry causes the tight supply situation in guar. And today’s elevated prices for xanthan result from US antidumping action against certain Chinese and Austrian companies.
Food gums and their bakery applications were discussed in detail by E.J. Pyler and L.A. Gorton in “Baking Science & Technology, 4th ed.” in Volume I, starting on Page 465. Order a copy at http://www.sosland.com/bakingscience/