Xanthan gum is a polysaccharide that is made up of a repeating 2-to-2-to-1 molar ratio of glucose, mannose and glucuronic acid. Whether lactose, glucose or sucrose is fermented, the subsequent product precipitates from an isopropyl-filled growth medium and is then crushed into a fine powder after being dried. The gum characteristic of Xanthan gum is created only after the final step in which the precipitate is added to a liquid medium. The strain of bacterium responsible for fermenting lactose was developed as a result of the United States Department of Agriculture (USDA) trying to maximize the use of cheese’s by-product, whey. The cabbage-derived Xanthomonas campestris strain (hence the name, xanthan) that specifically grew on lactose had 75% of its yield turn into xanthan gum from the original whey concentration.
During the 60s many biopolymers – macromolecules with repeating units produced by living organisms – were extensively investigated by American chemical researcher, Allene Jeanes, and her USDA team in order to determine their safety and subsequent use. Xanthan gum was one of them and eventually was given the green light in terms of being used as a food additive in 1968. Its variety of uses during the last few decades has broadened.