What Is Xanthan Gum?

Xanthan gum, also known as xanthan gum, is a widely used extracellular microorganism produced by Xanthomnas campestris with carbohydrates as the main raw material (such as corn starch) through fermentation Polysaccharide. It has unique rheology, good water solubility, stability to heat, acid and alkali, and good compatibility with various salts. As a thickener, suspending agent, emulsifier, stabilizer, it can be widely used. It is used in more than 20 industries such as food, petroleum, medicine, etc. It is currently the world's largest and most widely used microbial polysaccharide. ^[1]

Chinese name: Xanthan Gum
Foreign name: Xanthan gum
Nickname 1: Yellow gum

Nickname 2: Xanthan
Application direction: Thickener, suspending agent, etc.
Application Industry: Food, petroleum, medicine, etc.

Xanthan gum structure

Xanthan gum, also known as xanthan gum and xanthan gum, is an extracellular acidic heteropolysaccharide produced by Xanthomonas fermentation. It is a polysaccharide polymer compound composed of D-glucose, D-mannose and D-glucuronic acid in a ratio of 2: 2: 1, with a relative molecular weight of more than 1 million. The secondary structure of xanthan gum is that the side chain is reversely wound around the backbone of the main chain, and the rod-shaped double helix structure is formed by hydrogen bonding. ^[1]

Xanthan gum properties

Xanthan gum is a light yellow to white flowable powder with a slight odor. Easily soluble in cold and hot water, neutral solution, resistant to freezing and thawing, insoluble in ethanol. It will disperse and emulsify in water to become a stable hydrophilic viscous colloid. ^[2]

Xanthan gum performance characteristics

Xanthan gum is currently the world's most advanced bio-gum that integrates thickening, suspension, emulsification and stability. The amount of pyruvate groups at the ends of the molecular side chains of xanthan gum greatly affects its performance. Xanthan gum has the general properties of long-chain polymers, but it contains more functional groups than ordinary polymers, and will show unique properties under certain conditions. Its conformation in aqueous solution is diverse, showing different characteristics under different conditions.

1. Suspended and emulsified

Xanthan gum has a good suspension effect on insoluble solids and oil droplets. Xanthan colloid molecules can form super-bound band-shaped spiral copolymers, forming a fragile gel-like network structure, so they can support the shape of solid particles, droplets and bubbles, showing strong emulsification stabilization and high suspension ability.

2.Good water solubility

Xanthan gum dissolves quickly in water and has good water solubility. It can dissolve in cold water, which can save complicated processing and is easy to use. However, because it is extremely hydrophilic, if the water is directly added and the stirring is insufficient, the outer layer absorbs water and swells into a micelle, which prevents the water from entering the inner layer and affects the function. Therefore, it must be used properly. Xanthan gum dry powder or dry powder auxiliary materials such as salt and sugar are mixed well and then slowly added into the water to be fed to make a solution for use.

3.Thickness

Xanthan gum solution has the characteristics of low concentration and high viscosity (the viscosity of 1% aqueous solution is equivalent to 100 times of gelatin), and it is an efficient thickener.

4, pseudoplastic

The xanthan gum aqueous solution has high viscosity under static or low shear action, and shows a sharp decrease in viscosity under high shear action, but the molecular structure does not change. When the shearing force is eliminated, the original viscosity is immediately restored. The relationship between shear force and viscosity is completely plastic. Xanthan gum is very pseudo-plastic, which is very effective for stabilizing suspensions and emulsions.

5.Stability to heat

The viscosity of xanthan gum solution will not change greatly with the change of temperature. Generally, the viscosity of polysaccharides will change due to heating, but the viscosity of the xanthan gum aqueous solution is almost unchanged between 10-80 , even at low concentrations. The aqueous solution still shows stable high viscosity over a wide temperature range. The 1% xanthan gum solution (containing 1% potassium chloride) was heated from 25 ° C to 120 ° C. Its viscosity is only reduced by 3%.

6.Stability to acids and bases

Xanthan gum solution is very stable to acids and bases, and its viscosity is not affected between pH 5-10. There is a slight change in viscosity when the pH is less than 4 and greater than 11. In the PH3-11 range, the maximum and minimum viscosities differ by less than 10%. Xanthan gum can be dissolved in various acid solutions, such as 5% sulfuric acid, 5% nitric acid, 5% acetic acid, 10% hydrochloric acid, and 25% phosphoric acid, and these xanthan gum solutions are quite stable at room temperature. The quality has not changed for months. Xanthan gum is also soluble in sodium hydroxide solution and has thickening properties. The resulting solution was quite stable at room temperature. Xanthan gum can be degraded by strong oxidants, such as perchloric acid and persulfuric acid. As the temperature increases, the degradation accelerates.

7.Stability to salt

Xanthan gum solution is miscible with many salt solutions (potassium, sodium, calcium, magnesium, etc.) and the viscosity is not affected. Under higher salt concentration conditions, its solubility is maintained without precipitation and flocculation even in a saturated salt solution, and its viscosity is hardly affected.

8. Stability to enzymatic hydrolysis

The stable double helix structure of xanthan gum makes it extremely resistant to oxidation and enzymatic hydrolysis. Many enzymes such as proteases, amylases, cellulases and hemicellulases cannot degrade xanthan gum. ^[3]

Xanthan gum main uses

Due to its unique properties, xanthan gum has a wide range of applications in more than a dozen fields such as food, petroleum, medicine, and daily chemicals. Its high degree of commercialization and wide range of applications make any other microbial polysaccharide Nowhere can you reach.

1. Food: Xanthan gum is added to many foods as stabilizer, emulsifier, suspending agent, thickener and processing aid. Xanthan gum can control the rheology, structure, flavor and appearance of the product, and its pseudoplasticity can ensure good taste. Therefore, it is widely used in salad dressing, bread, dairy products, frozen food, beverages, condiments, brewing, Confectionery, pastries, soups and canned food. In recent years, people in more developed countries are often worried that the heat value in food will make them fat. Xanthan gum dispels this concern because it cannot be directly degraded by the human body. In addition, according to a Japanese report in 1985, xanthan gum was the most effective anti-cancer agent among 11 food additives.

2. In daily chemical industry: Xanthan gum contains a large number of hydrophilic groups, is a good surface active substance, and has anti-oxidation and skin aging prevention effects. Therefore, almost most high-end cosmetics have Xanthan gum is used as its main functional ingredient. In addition, xanthan gum can also be used as a component of toothpaste to substantially thicken and shape and reduce tooth surface wear.

3. Medical aspects: Xanthan gum is a functional component in the popular microcapsule drug capsules in the world. It plays an important role in controlling the sustained release of drugs. Due to its strong hydrophilicity and water retention, there are many Applications in specific medical operations, such as forming a dense water film to avoid skin infections, and reducing thirst after radiotherapy for patients. In addition, Li Xin and Xu Lei have written that xanthan gum itself has a significant effect on enhancing humoral immune function in mice.

4. Industrial and agricultural applications: In the petroleum industry, due to its strong pseudoplasticity, low-concentration xanthan gum (0.5%) aqueous solution can maintain the viscosity of the drilling fluid and control its rheological properties, so the drill bit rotates at high speed The viscosity of the part is extremely small, which saves power; while maintaining relatively high viscosity at the relatively static drilling site, the wall of the well is prevented from collapsing. And because of its excellent salt resistance and heat resistance, it is widely used in drilling in special environments such as the ocean and high-salt zones, and can be used as an oil displacement agent to reduce dead oil zones and improve oil recovery.

Status of Xanthan Gum Production and Development in China

Xanthan gum was first developed internationally in the United States, followed by France, Japan and the United Kingdom. At present, about 20,000 tons of edible-grade xanthan gum in the world and 20,000 tons of industrial use. Since the 1980s, the demand for xanthan gum has been increasing at a rate of 10% per year. Its wide application fields and high prices are unmatched by many other microbial polysaccharides.

China's development and research of xanthan gum started in the 1960s. Although it started late, Chinese science and technology workers relied on their wisdom and strength to screen from nature without any information to learn from Xanthan gum production strains were produced, and a high-value-added fermentation product-xanthan gum was developed; it was put into commercial production in the 1980s. In the mid-1990s, domestic xanthan gum manufacturers were scattered, such as Zhongxuan in Shandong, Jinhu in Jiangsu, Xinhe in Hebei, Shunxing in Gansu, and Tianguan in Henan. With the development of the western region and the 10th Five-Year Plan, domestic xanthan gum manufacturers will increase to dozens, and xanthan gum production will become another emerging industry in China's fermentation field.

Since China started late in the field of xanthan gum, especially late in the development of xanthan gum applications, domestic manufacturers cannot produce different specifications of xanthan gum according to user needs. At the same time, its application field is also greatly restricted, which has caused the characteristics of small scale in domestic xanthan gum manufacturers. This small-scale xanthan gum production cannot give play to its huge scale benefits; it can only accelerate the disorderly competition in the xanthan gum market, which is not conducive to the company's own capital accumulation and rolling development. Ignoring the development and application of xanthan gum production and technological innovation, so that the quality of xanthan gum has stagnated in recent years. At present, the domestic xanthan gum production is 3,000 tons / year, and the effective demand is 5,000 tons / year. For this reason, China needs to import 2,000 tons of xanthan gum each year. Despite this, the development prospects of xanthan gum are still very attractive.

Problems in Xanthan Gum Production in China

In the late 1980s, dissolved oxygen and bacteria infection were two major problems that plagued the industrial production of xanthan gum in China. With the invention of the GSM fermentation tank and the solution of the problem of bacteria infection, xanthan gum has also entered the industrialization stage. However, with the expansion of production scale and market expansion, the quality problems of xanthan gum have become increasingly prominent. Of course, there are many issues that affect the quality of xanthan gum products, such as the choice of raw materials, the reasonable mix of raw materials, breeding of bacteria, fermentation process, post-treatment process, and production equipment, etc. will affect its quality. However, the factors that affect the quality of xanthan gum in China are three aspects: strain problem, fermentation process and post-treatment process.

Through laboratory analysis of products at home and abroad and new inspections by relevant departments, it is proved that domestic xanthan gum has six major differences from the products of KELCO in the United States and Phone-Poulen in France: the xanthan gum is darker in color; the finished particles are not uniform enough; The specific gravity varies from batch to batch; the solubility is poor; the viscosity of the finished product is low and the stability of heat resistance and acid and alkali is poor; the ash and nitrogen content of the finished product are slightly higher; the microbial index is higher.

The American KELCO company is a pioneer of xanthan gum producers in the world and represents the development direction of international xanthan gum. Its xanthan gum products have the following obvious advantages: the product feels thick, sandy, easy to disperse in water, and water-soluble Good, light color, high viscosity up to 2500cp, strong thermal stability.

Domestic xanthan gum has its own advantages in terms of color, gum feel, solubility, dispersibility, and viscosity. Shandong Zhongxuan, Gansu Shunxing, Hebei Xinhe, and Jiangsu Jinhu have similar products. Henan Tianguan products have fluid solubility. Better characteristics. ^[4]