Gums
Also Known as Hydrocolloids
What are Gums?
Gums, or hydrocolloids, are hydrophilic, non-starchy carbohydrate polymers. They are used in food and bakery products as viscosity enhancers and gelling agents and to impart desirable textural and sensory properties.
They can serve as dietary fiber ingredients, as well as extend shelf life due to their:
- Water holding capacity
- Gelling ability and stabilization of foams
- Emulsions and dispersions
Origin
A wide range of sources can be used to produce gums including:
- Plant (cellulose, hemicellulose, pectins, exudates, mucilage and fructans)
- Seaweed (alginates, carrageenans, agar)
- Microbial (xanthan, pullulan, gellan)
- Insects and shells of crustaceans (chitin and chitosan)
Function
Functionality of these ingredients is dictated mainly by their monosaccharide composition, chain linkage and degree of polymerization among others. They are typically used at less than 1%.
- Gum Arabic is used to stabilize glazes while gum tragacanth stabilizes emulsions, such as bakery fillings containing suspended fruits.2
- Sodium alginate, kappa-carrageenan, xanthan gum, hydroxypropylmethyl cellulose are used to improve wheat dough stability in proofing.
- Carboxymethyl cellulose and guar gum are effective in gluten-free breads
- Xanthan and kappa-carrageenans combinations can form thermally-reversible gels.
Controlling moisture migration in frozen/thawed baked goods, icings and fillings is one of the key functionalities of gums. Xanthan, for example, is used to impart stability in a freeze-thaw cycles due to its ability to control ice crystal growth and size.1 They can also contribute to moisture stabilization in snack cakes, energy bars, and in maintaining soft texture in most breads. They are effective in stabilizing food systems against temperature fluctuations encountered during shipping and storage.
Gums alone or in combination with sugar solutions can be used as edible glue. When added to bread-based coatings, they help crumbs adhere to meat pieces or vegetable strips in commercial production. When combined with spices and water and/or egg white solids, they help salt and spices adhere to nuts in roasting.2
Gums have attracted additional attention in gluten-free and vegan products via stabilizing volume in gluten-free breads and act as emulsifiers and strengtheners for egg-less baked products.3 Synergistic effects can be used to improve functionality of gums.
The following table describes source and function of gums most commonly used in baking:
| Gum | Source | Function |
| Acacia gum or Gum Arabic | Two species of the acacia tree | Emulsifying, stabilizing |
| Agar | Red seaweed | Stabilizing |
| Alginates | Brown seaweed | Thickening, emulsifying |
| Arabinoxylans | Grass bran | Altering water binding, dough rheology, gas retention |
| Carrageenan | Red seaweed | Thickening, suspension, gelling, casein stabilizing |
| Carboxymethyl cellulose (CMC) | Cellulose | Controlling viscosity without gelling |
| Cellulose | Plants, wood pulp | Retaining water, anticaking, emulsifying and thickening |
| Methylcellulose | Cellulose | Gluten substitute |
| Guar gum or guaran | Guar bean | Thickening, stabilizing, emulsifying |
| Pectin | Fruits and vegetables | Gelling, thickening, binding water, stabilizing, replacing fat and/or sugar |
| Xanthan | Synthetic via aerobic fermentation | Controlling viscosity, emulsifying, stabilizing |
Application
Xanthan gum can be used in dough production to prevent lumps from forming when it is kneaded; it also improves consistency and final product volume.
For gluten-free products, the addition of as little as 0.5 percent has reported improved quality. They are also commonly used to create low-fat, low-calorie products. They can be used to retain qualities such as texture and stability in the absence of fat and help with taste when alternative sweeteners are used. Some gums can, however, introduce negative sensory attributes such as astringency.1 However, processes such as encapsulation can help protect flavorings and nutritional supplements added to foods.1
FDA regulation
Regulations for gum used as ingredients in commercial food products varies widely. The United States Food and Drug Administration offers specific guidance on each ingredient.4
Some hydrocolloids are certified organic and most are non-GMO.
References
- Nussinovitch, A., and M. Hirashima. Cooking Innovations: Using Hydrocolloids for Thickening, Gelling, and Emulsification. Taylor & Francis/CRC Press, 2014. pp. 1-5, 8-9, 55, 74, 264.
- Nussinovitch, A. Plant Gum Exudates of the World Sources, Distribution, Properties, and Applications. CRC Press/Taylor & Francis, 2010. pp. 263, 269.
- Ziobro, R., et al. “Non-Gluten Proteins as Structure Forming Agents in Gluten Free Bread.” Journal of Food Science and Technology, vol. 53, no. 1, 25 Sept. 2015, pp. 571–580., doi: https://doi.org/10.1007/s13197-015-2043-5.
- Center for Food Safety and Applied Nutrition. “Food Additives & Ingredients – Food Additive Status List.” U S Food and Drug Administration Home Page, Center for Drug Evaluation and Research, www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm091048.htm#ftnG. Last accessed 26 November 2018.
