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Tragacanth is a plant product from the Astralgus species of shrub that’s commonly used as a food additive. It’s normally classified as a gum, and it’s made in most cases by drying the sap that comes from the trunk and bark of the plant. Ancient cultures in the Middle East, where the shrub species grows most prolifically, used it as a thickening agent, and the gum is still very commonly used as an emulsifier and jelling component in prepared foods today. Processing and harvesting normally takes a bit of time, but isn’t normally difficult or expensive with the result that the end product is widely accessible around the world. The gum is normally dried into a fine powder that will then dissolve and blend into a variety of food substances, and is both odorless and colorless. As with most food additives there are a few health risks, but in general these are limited to allergic reactions and other rare sensitivities. Health officials generally deem the gum safe for general use, and provided it’s used and consumed only in small doses there aren’t likely to be any issues.
Plants in the Astralgus family are also commonly known as goat's thorn or locoweed. The stems of these plants exude a special, highly sticky sap that dries quickly, and this dried sap is the ultimate source of the gum. The name comes from the Greek words tragos, which means goat, and akantha, which means thorn. Depending on location the gum can also be called gum elect, shiraz gum, or gum dragon.
There are more than 2000 species of Astralgus, but the most common when it comes to use for gum production is the Astralgus gummifer Labillardiere. The gum may also come from the species Astralgus Microcephalus Willd. Iran is generally the largest producer of quality tragacanth gum, particularly the Zagros Mountains region of the country. Other suppliers in West Asia include the countries of Pakistan and Turkey.
The gum is removed from the shrubs by cutting slits or punctures into the stem. Wet sap will ooze through the openings where it can then be collected. It is generally harvested in long ribbons which resemble the goats' horns after which it is named. This gummy sap is a water soluble carbohydrate that is not suitable for the production of chewing gum like chicle, but is suited for altering the composition of foods without changing the taste. It normally needs to be dried, then crushed or ground and packaged for distribution and use.
Tragacanth is a stabilizer, emulsifier, and thickener in many foods. Thickeners, also called thickening agents, are substances which increase the viscosity of foods without affecting their flavor. It also has practical applications in stiffening fabrics, artist's pastels, and leatherworking.
Before the gum is used as a food additive, it is typically dried and ground into a fine powder. The resulting product may be off-white or cream colored. As a food additive, it is nearly odorless, tasteless, and colorless making it an additive that does not generally change the flavor of the food. Some food products which contain this gum include jellies, mayonnaise, sauces, and syrups. Popsicles, ice cream, liqueurs, and candy sometimes contain the additive also. In certain cases it can be found in textiles and pharmaceuticals including lozenges and emulsions as well.
At least compositionally, the gum is pretty simple; in most cases it’s made up primarily of starch, cellulose, and nitrogenous substances, as well as the chemical compounds polyarabinan-trigalaetangeddic acid and bassorin. In small doses the gum is usually considered safe for human consumption. There have been some reported instances of allergic reaction to this gum when used as a food additive, however. Although uncommon, allergic reactions may range from runny nose and watery eyes to breathing problems and anaphylactic shock. The additive also tends to be susceptible to contamination from bacteria, which means that producers and manufacturers need to have firm safety standards in place — and many governments and health ministries have imposed regulations related to safe handling for both the gum’s production and its use.