Chinese name: Huangyuan gum
Foreign name: Xanthan gum
Other name 1: Huangjiao
Other name 2: Hansheng gum
Uses: Thickener, suspending agent, etc.
Industries: Food, petroleum, medicine, etc.
Xanthan gum is currently the most internationally recognized biogel that combines thickening, suspending, emulsifying, and stabilizing properties in one, with the best overall performance. The number of pyruvate groups at the ends of its molecular side chains greatly affects its properties. Xanthan gum has the general characteristics of long-chain polymers, but it contains more functional groups than typical polymers, which can give it unique properties under certain conditions. Its conformation in aqueous solution is diverse, showing different traits under different conditions.
1. Suspension and Emulsification
Xanthan gum has a good suspension effect on insoluble solids and oil droplets. The molecules in xanthan gum solution can form highly bonded, ribbon-like helical copolymers, creating a delicate gel-like network structure, so it can support the shape of solid particles, liquid droplets, and bubbles, showing strong emulsifying stability and high suspension ability.
2. Good Water Solubility
Xanthan gum dissolves quickly in water and has very good water solubility. It can even dissolve in cold water, saving complicated processing steps and making it easy to use. However, because it is highly hydrophilic, if added directly to water without thorough stirring, the outer layer will swell into a gel lump, preventing water from reaching the inner part and thus affecting its effectiveness. Therefore, proper usage is important. The dry powder of xanthan gum or a mixture with dry ingredients like salt or sugar should be slowly added to water that is being stirred to make a solution.
3. Thickening
Xanthan gum solution has the characteristic of high viscosity at low concentrations (1% solution is about 100 times more viscous than gelatin), making it a highly efficient thickener.
4. Pseudoplasticity
Xanthan gum aqueous solutions have high viscosity under static or low shear conditions, but the viscosity drops sharply under high shear, while the molecular structure remains unchanged. Once the shear force is removed, the viscosity immediately returns to its original level. The relationship between shear force and viscosity is completely plastic. Xanthan gum's pseudoplasticity is very prominent, and this property is extremely effective for stabilizing suspensions and emulsions.
5. Thermal stability
The viscosity of xanthan gum solutions does not change significantly with temperature. Unlike many polysaccharides that change viscosity when heated, xanthan gum solutions show almost no change in viscosity between 10–80°C. Even low-concentration solutions maintain stable high viscosity over a wide temperature range. For example, a 1% xanthan gum solution (containing 1% potassium chloride) heated from 25°C to 120°C sees only a 3% decrease in viscosity.
6. Acid and alkali stability
Xanthan gum solutions are very stable in acidic and basic conditions. Its viscosity is not affected within a pH range of 5–10, and only slightly changes at pH values below 4 or above 11. Within the pH range of 3–11, the difference between maximum and minimum viscosity is less than 10%. Xanthan gum can dissolve in various acid solutions, such as 5% sulfuric acid, 5% nitric acid, 5% acetic acid, 10% hydrochloric acid, and 25% phosphoric acid. These acid solutions are quite stable at room temperature and can remain unchanged for several months. Xanthan gum can also dissolve in sodium hydroxide solutions and shows thickening properties, forming solutions that are stable at room temperature. However, it can be degraded by strong oxidizers, such as perchloric acid and persulfates, with the degradation rate increasing as temperature rises.7. Stability with Salts
Xanthan gum solutions can mix with many salt solutions (potassium, sodium, calcium, magnesium, etc.) without affecting viscosity. Even at higher salt concentrations, and even in saturated salt solutions, it remains soluble without precipitation or flocculation, and its viscosity is hardly affected.
8. Stability against Enzymatic Reactions
The stable double-helix structure of xanthan gum gives it strong resistance to oxidation and enzymatic degradation. Many enzymes, such as proteases, amylases, cellulases, and hemicellulases, cannot break down xanthan gum.
