In fact it is believed that it has been man's insistence on selecting and growing grain varieties with every increasing volumes of gluten (and binding properties) that may have lead to the increase in celiac disease in the first place, but I digress. But before we discover the value of xanthan and guar gum it is valuable to understand what part of the gluten molecule is actually the problem for celiacs.
Surprisingly, gluten is actually not the real issue for celiac and gluten intolerant people (up to 20% of the population) - it is the 'prolamin' portion of the molecules in the grains mentioned above. That is, it is "the toxic component of the gluten molecule lies in the prolamin portion. In wheat this portion is called gliadin. It comprises approximately 40 - 50% of the protein. In rye this portion is called secalin. It comprises approximately 30 - 40% of the protein. In barley this portion is called hordein. It comprises approximately 35 - 45% of the protein. In oats this portion is called avenin. It comprises approximately 10 - 15% of the protein. There are prolamins in rice, corn and other foods but these do not contain the toxic tetrapeptide(s) which are reportedly responsible for the villous damage and rash experienced by celiacs and people with 'gluten' sensitivities.
THE DRAWBACKS OF GLUTEN Upon entering the digestive tract, gluten breaks down into peptide chains in a similar fashion to other protein sources, however the resulting g-related peptide chain length is considerably longer than for other proteins. These longer peptides are part of the reason that immune response triggers occur and cause celiac disease. However celiac are not the only people who chose to avoid gluten. Some of the disease that also benefit from a gf diet are: irritable bowel syndrome, Crohn's disease, dermatitis herpetiformis (autism) and those with ulcerative colitis. For people who are new to a g-free diet it is worth noting that there are an increasing number of 'health food' products on our supermarket shelves listed as wheat free, but still containing gluten - read your ingredients carefully! There are many 'natural' products used as jellying agents in foods. Some of these can replace the cooking properties of 'gluten' in some foods however the main focus of this article is on those products that replace the function of it in flours. The two main products discussed at the end of this section are xanthan gum and guar gum.
Gelling agent descriptions (from wikipedia)
The following substances are only a few of those with gelling properties that used in the food industry.
Pectin: is found in apples, quince, plums, gooseberries, oranges and other citrus fruits. The main use for pectin is as a gelling agent, thickening agent and stabilizer in food. The standard application is giving the jelly-like consistency to jams or marmalades. People with fructose intolerance and fructose mal-absorption however avoid pectin like a celiac avoids gliadin!
Alginate is a viscous gum that is abundant in the cell walls of brown algae. It ranges from white to yellowish-brown, and takes filamentous, granular and powdered forms. Alginate absorbs water quickly, which makes it useful as an additive in dehydrated products such as slimming aids, and in the manufacture of paper and textiles. It is also used for waterproofing and fireproofing fabrics, as a gelling agent, for thickening drinks, ice cream and cosmetics, and as a detoxifier that can absorb poisonous metals from the blood.
Carrageenans or carrageenins are a family of linear sulphated polysaccharides extracted from red seaweeds. The name is derived from a type of seaweed that is abundant along the Irish coastline. Gelatinous extracts of the Chondrus crispus seaweed have been used as food additives for hundreds of years. Some of the many uses of carageenins are:
· Desserts, ice cream, milk shakes, sweetened condensed milks,
· sauces: gel to increase viscosity ·
. Beer: clarifier to remove haze-causing proteins
· Pâtés and processed meat: Substitute fat to increase water retention and increase volume
· Toothpaste: stabilizer to prevent constituents separating
· Fire fighting foam: thickener to cause foam to become sticky
· Shampoo and cosmetic creams: thickener
· Air freshener gels
· Shoe polish: gel to increase viscosity
Agar or agar agar is a gelatinous substance derived from seaweed. Historically and in a modern context, it is chiefly used as an ingredient in desserts throughout Japan. White and semi-translucent, it is sold in packages as washed and dried strips or in powdered form. It can be used to make jellies, puddings and custards.
WHAT ARE THE 'G' RELACEMENT OPTIONS?
While the above products have many jelling uses, they don't have the combined properties of: texture, taste, binding, stabilizing and rising properties required to act as a standard flour replacement. Hence the use of xanthan and guar gum.
XANTHAN GUM Xanthan gum is used as a substitute for wheat gluten in GF breads, pastas and other flour-based food products. Xanthan gum comes from a strain of bacteria (Xanthomonas campestris) that is used during the fermentation process. This is the same bacteria that is the cause of black rot on broccoli and cauliflower. It is the slimy substance formed by the bacteria during the fermentation process that acts as a natural stabilizer or thickener and gluten replacement. Xanthan it is a long chain of three different forms of sugar. What's important to know is that all three of these natural sugars are present in corn sugar, a derivative of the corn syrup. The Xanthomonas campestris bacteria literally eat the corn sugar under controlled conditions, and the digestion process converts the individual sugars into a single substance with properties like cornstarch. Xanthan gum is used in dairy products and salad dressings as a thickening agent and stabilizer.
Surprisingly Xanthan is also used as a stabilization and binding component in many cosmetic products. The value of xanthan gum its binding property is highly concentrated, meaning that only a small amount needs to be used in any application, thus keeping the costs down. cosmetic manufacturers use very small amounts to cream-based products to stop individual ingredients from separating. Even more remarkable (the next time you eat xanthan gum) is knowing it is used in the oil industry. Natural thickeners like guar gum or xanthan gum are often blended with water to increase waters viscosity, or thickness for lubrication purposes. Celiacs should be aware that unlike the Botox causing bacteria (Clostridium botulinum) the bacteria used to create xanthan is typically not considered harmful to human skin or digestive systems, though some individuals may find they are allergic to it. The difference between Xanthan and Guar gum (discussed below) is that some people avoid Xanthan due to its derivation from corn, soy or other plant products.
GUAR GUM Often where you find xanthan gum you will find guar gum being used. The guar plant, also known as a cluster plant, grows mainly in Pakistan and the northern regions of India. Guar gum is a natural food thickener, similar to locust bean gum, tapioca flour or cornstarch. The popularity of guar gum is for the same reason that xanthan is used: it is highly concentrated regarding its gel-like properties thus reducing the amount and cost required in breads, puddings and ice creams etc. Guar gum is a thickening agent, binder and plasticizer.
Processed foods with creamy textures are usually bound by binders such as guar gum. This high gelling property has also seen guar gum used in non-prescription diet pills as it can create the sense of 'fullness' but its use as an ingredient in non-prescription diet aids was officially banned in the early 1990s by the FDA (in America). It was found that the mass of swollen guar gum had the potential to cause harmful intestinal and duodenal blockages. The typical amount of guar gum ingested in regular foods is not considered harmful although another unwanted side effect of guar gum is that when used in excess it can have a strong laxative effect. This is why some people who are celiac and still suffer from very sensitive bowels or even IBS need to be aware of this potential problem.
HOW Xanthan and Guar gum are used
Xanthan gum (E415) is a stabilizer, thickener, and emulsifier used with water, and often blended with guar gum (E412). When it gets wet, it turns rubbery so when added to flour it works in a very similar way to gluten i.e. it traps the gas from the yeast thus causing the dough to rise. When added to gluten free wheat flour (about a heaped teaspoon to 1lb. flour), the flour starts to perform in a similar way to a strong white flour. Xanthan gum and guar gum are often already included in g-free flour replacements however some people prefer to make up their own blends. Because some celiacs wish to reduce their intake of corn and others are concerned about guar gums potential laxative effects they are often combined to reduce the reliance on either specific gum. That said, you will find many forum articles suggest that Xanthan gum and guar gum are the absolutely essential ingredients (gluten replacement) for gluten free baking. If you are after the holy grail of gluten free flour recipes to replace white wheat flour in baked goods this is it: 'Wendy Wark's gluten-free flour mix recipe' was originally published in the book 'Living Healthy with Celiac Disease' (now out of print). It calls for the following mix:
- 2-1/4 cup brown rice flour
- 3/4 cup sweet rice flour
- 2/3 cup tapioca starch flour
- 1/4 cup potato starch flour
- 1/3 cup cornstarch
- 2 tsp xanthan or guar gum
Use 1 cup of this flour for 1cup of regular flour in recipes. When using this mix as a flour substitute in baked goods, xanthan gum must be added to the batter in the following proportions:
- bread: add 3/4 tsp xanthan gum per cup of flour mix
- cake: add 1/4 tsp xanthan gum per cup of flour mix
- cookies: no additional xanthan gum needed, if flour mix contains it already.
What substitutes for Xanthan? People with corn / soy allergies sometimes try:
- agar agar, and caragenen as discussed above.
- milled flax seed with coconut for its binding properties.
- glucomannan flour - yam based.
- unflavoured Gelatine - an animal based product
- methyl cellulose and hydroxypropyl methyl cellulose are used to create thermoreversible gels - that means they gel when heated.
CONCLUSION There are many jelling agents derived from natural resources. While many have 'interesting' origins it appears that xanthan and guar gum still remain the most popular g-free substitute ingredients in flours. So the next time you eat either additive, you will now be aware of their great versatility.
No comments:
Post a Comment