Xanthan Gum: Our Chemical Chum

Xanthan Gum is a common additive found in everything from eye drops to concrete.

As a thickener, it’s used in chewing gum, yogurt, and soup. As an emulsifier, it prevents the formation of crystals in ice cream. In salad dressings, it blends oil and water, suspends spices and herbs, and provides tantalizing coverage and flavor for greens. It binds water to fruit fillings, leaving pastry crust crispy and firm. A mainstay of gluten-free cooking, it lends stickiness to wheat-free doughs. Whether as stabilizing, suspending, or viscosity agent, this miracle chemical has vastly impacted our lives since it first received FDA approval in 1969.

A polysaccharide synthesized by the bacteria Xanthomonas campestris, it’s responsible for the black rot found on broccoli, cauliflower, and leafy greens grown in the garden. Cheap to manufacture and extraordinarily versatile, this pale, odorless, free-flowing powder is soluble in warm or cold water and is stable in the presence of enzymes, salts, acids and bases. First synthesized in quantity during the 1960s, it’s used for a host of consumer, industrial, cosmetic, and pharmaceutical preparations.

How it came to occupy its place in the panoply of culinary additives is a story of history, chemistry, and the struggle for a place at the table—both literal and figurative.

Xanthan gum is one of two well-known breakthroughs from a less well-known female chemist called Allene Rosalind Jeanes (b. July 19th, 1906, d. December 1, 1995) who lived and worked quietly in service of humankind.  A grande dame of science, her life lacked the heady scandals and wider notoriety of Marie Curie, whom I wrote about this time last year.

A summa cum laude graduate of Baylor University (1928), she received her MA in Organic Chemistry at UC Berkeley (1929). For five years, she taught science at Athens College before enrolling at the University of Illinois where she later received her Ph.D. (1938).

It took time for this talented chemist to find work in her field due in part to Depression-era thinking, when such jobs were more often reserved for men. Eventually, she found work at the National Institutes of Health (NIH) before joining the Northern Regional Research Lab (NRRL), a branch of the U.S. Department of Agriculture, where she remained for the rest of her working life. When she joined NRRL in 1941 at its Peoria, Illinois, location, the lab was already famous for its groundbreaking work in deep-tank fermentation and large-scale production of life-saving Penicillin.

At NRRL, Jeanes focused on polysaccharides, complex carbohydrates made up of long chains of polymers (large molecules made up of smaller molecules of repeated types). A simple example of a polysaccharide is starch.

While at the Department of Agriculture’s labs, a chance encounter with a sample of root beer led to scientific breakthrough. Faced with an unexpected viscous sludge and a soda manufacturer’s search for an explanation, she discovered the root beer was contaminated with a bacteria useful in producing Dextran, a polysaccharide commonly found in wheat, corn, rice, and potatoes. Dr. Jeanes and her team isolated the microbe and were considering its uses when researchers in England and Sweden proposed using Dextran as a plasma extender to stabilize  trauma patients en route to blood transfusion. Dextran was widely used in the Korean War before its introduction for civilian use. (Source: Chemical Heritage Foundation)

 

 

 

Similarly, Xanthan gum is another polysaccharide derived from bacteria. Inexpensive to make, effective in quantities as small as 0.1% to 1% of a solution, it can be used in conjunction with Guar gum and/or Locust Bean gum to cumulative effect.  In contrast to the use of lab chemicals, pressure, and high temperature, Dr. Jeanes used fermentation to produce the Xanthan Gum in large quantities. (Source: Chemical Heritage Foundation) To understand better how Xanthan gum is produced, click here for a useful infographic.

 

 

 

During the course of a lifetime of service, Dr. Jeanes received 10 patents and wrote in at least 60 publications. She was recognized in her lifetime for her exemplary work, and received the U.S. Department of Agriculture’s Distinguished Service Medal (1953), the Garvan Medal (1956) (an Award for American female scientists), and the Federal Women’s Service Award (1962).

She retired in 1976 but continued to work and collaborate for another decade, despite physical frailties, and died in 1995 at the age of 89. She was the first woman inducted into the ARS (Agricultural Research Service) Hall of Fame in 1999.