Xanthan gum is a common food additive used for its wide variety of purposes including as a dispersing agent, a stabilizer of emulsions and suspensions, and a viscosity control agent. Produced through microbial fermentation, xanthan gum is also widely used in many industries outside of the food industry such as cosmetics, pharmaceuticals, textiles, and even petroleum. Since xanthan gum can be found in many food products, people might wonder what the ingredient is and if whether it is vegan or not.
Produced from the fermentation of sugars using a bacterium called Xanthomonas campestris, xanthan gum is completely vegan since its production does not involve the use of any animal product or derivative. There are some rumors surrounding xanthan gum and its production, but none of them have sufficient evidence for concern.
A natural polysaccharide and an important industrial biopolymer, xanthan gum was discovered back in the 1950s. With its complex structure, xanthan gum is denoted by the chemical formula C35H49O29. However, it is simply listed as “xanthan gum,” or by its E number E415, on the ingredients list (1).
Originally classified as polysaccharide B-1459, xanthan gum is produced by the bacterium Xanthomonas campestris, the causative agent of a variety of plant diseases including black rot in cruciferous vegetables and bacterial wilt of turfgrass.
Structurally, xanthan gum is a heteropolysaccharide as it is primarily composed of repeating pentasaccharide units formed by two glucose units, two mannose units, and one glucuronic acid unit.
Xanthan gum is incredibly functionally diverse as it is utilized in a variety of industries. Due to its specific chemical properties, xanthan gum can be found to be used in petroleum, ceramics, textiles, agrochemicals, cosmetics, and pharmaceuticals. Xanthan gum can also be found heavily utilized in the food industry, namely for its emulsion stabilization, temperature stability, compatibility with food ingredients, and its pseudoplastic rheological properties.
Xanthan gum is a common food additive that is produced from the fermentation of a bacterium called Xanthomonas campestris. Without the involvement of any animal product or derivative in its production, xanthan gum is appropriate for vegan diets and lifestyles.
There are rumors around the internet discussing the possibility that xanthan gum contains egg whites (2). However, a review of the literature has showed that rumor to be baseless and unfounded. As a polymeric carbohydrate, xanthan gum has no need for egg whites or the predominant protein in egg whites, albumin.
The only probable situation where xanthan gum would contain egg whites would be if the equipment used for xanthan gum production was also used in the production of other products that utilized egg whites. However, cross-contamination is highly unlikely and good manufacturing practice would require these companies to thoroughly clean the equipment prior to switching. While instances where cross-contamination have occurred before, it is difficult to trace.
Some might also be worried because the growth medium of Xanthomonas campestris might contain sugar. In the vegan community, sugar is a problematic food product because, although it is produced using plant sources (e.g., sugarcane, etc.), it can involve an animal product in its production – specifically bone char.
The charred skeletal remains of animals, bone char is a common product used for filtration when sugar companies further refine their sugar. However, the sugars used for microbial fermentation are not usually refined as that would be too costly. Usually, raw glucose or sucrose would be utilized. Thus, it is unlikely that the sugars added in the production growth medium contain sugar that has been filtered using bone char.
The production of xanthan gum is almost exclusively through microbial fermentation. The production begins by taking a preserved culture of an effective strain of Xanthomonas campestris and grown to a sufficient inoculum size (3).
Once enough inoculum is produced, it is added to a bioreactor – a large fermentation tank that contains growth medium (i.e., including macronutrients [e.g., carbon and nitrogen] and micronutrients [e.g., potassium, iron, calcium salts]) for the inoculum. Modern bioreactors are usually equipped with numerous sensors to monitor different parameters that affect the microbial growth and fermentation process such as temperature, pH, oxygen, and more.
After the fermentation process has been completed, the bioreactor would contain a heterogenous mixture of xanthan, bacterial cells, and many other chemicals. For xanthan gum production, this mixture has to be purified further. First, the bacterial cells are removed, either by filtration or centrifugation.
Further purification can be done by precipitation (using water-miscible non-solvents such as isopropanol, ethanol, or acetone), the addition of certain salts, and pH adjustments. For FDA-approved food-grade xanthan gum, isopropanol is the required solvent for precipitation.
After precipitation, the resulting product is dewatered and dried. Afterward, the dried product is milled and packed into containers with low permeability to water since xanthan gum is hygroscopic and is prone to hydrolytic degradation.
Xanthan gum is widely used in the food industry as an emulsion stabilizer, suspending agent, dispersant, viscosity stabilizer, and more. Food products that would possibly have xanthan gum include salad dressings, dry mixes, syrups, toppings, relishes, sauces, beverages (fruit and non-fat dry milk), dairy products, baked goods, and frozen food.
Outside of the food industry, xanthan gum is also utilized in pharmaceuticals (creams and suspensions), cosmetics (denture cleaners, shampoos, lotions), agriculture (additive in animal feed and pesticide formulations), textile printing and dyeing, ceramic glazes, slurry explosives, petroleum production, and enhanced oil recovery.
The FDA (Food and Drug Administration) conditionally allows xanthan gum for human consumption as long as production follows good manufacturing practice (4). Essentially considered to be GRAS (“generally recognized as safe”), the FDA permits the use of xanthan gum in the food industry as a stabilizer, emulsifier, thickener, suspending agent, bodying agent, or foam enhancer.
The FDA also notes that the strain of Xanthomonas campestris used for food-grade xanthan gum has to be non-pathogenic and non-toxic to humans and animals. Moreover, the final product has to be free of bacterial cells.
The EFSA (European Food Safety Authority) last re-evaluated xanthan gum as a food additive back in 2017 (5). According to their studies, xanthan gum is unlikely to be absorbed intact and is expected to be fermented by bacteria that reside in the intestines. Numerous genotoxicity and carcinogenicity studies were performed on xanthan gum and the results show no evidence to be concerned with regarding the safety of xanthan gum.
Aside from minimal abdominal discomfort from repeated oral intake, the EFSA concluded that xanthan gum does not need an acceptable daily intake (ADI; the maximum amount of substance that can be taken every day for a year without any adverse health effects) value. While the evaluation states that xanthan gum poses no concern for infants and young children, they also specify that their evaluations are not applicable for infants under the age of 12 weeks.