Xanthan gum is currently the most superior biological glue in the world, which integrates thickening, suspension, emulsification and stability. The number of Pyruvic acid groups at the end of the molecular side chain of Xanthan gum has a great influence on its properties. Xanthan gum has the general properties of long chain polymers, but it contains more functional groups than general polymers, and will show unique properties under specific conditions. Its conformation in aqueous solution is diverse and exhibits different characteristics under different conditions. 1. Suspension and emulsification properties Xanthan gum has good suspension effect on insoluble solids and oil droplets. Xanthan gum sol molecules can form super combined ribbon helical copolymers, forming a fragile gel like network structure, so it can support the morphology of solid particles, droplets and bubbles, showing strong emulsification stability and high suspension capacity. 2. Good water solubility Xanthan gum can be quickly dissolved in water and has good water solubility. It can also dissolve in cold water, eliminating the complicated processing process and making it convenient to use. However, due to its strong hydrophilicity, if water is directly added without sufficient stirring, the outer layer will absorb water and expand into micelles, which will prevent water from entering the inner layer and affect its effectiveness. Therefore, it is necessary to pay attention to correct use. Xanthan gum dry powder or dry powder auxiliary materials such as salt and sugar are mixed well and then slowly added to the stirring water for feeding to make a solution for use. 3. Thickening properties Xanthan gum solution has the characteristics of low concentration and high viscosity (the viscosity of 1% aqueous solution is 100 times that of gelatin), and it is an efficient thickener. 4. Pseudoplasticity Xanthan gum aqueous solution has high viscosity under static or low shear action, but its viscosity drops sharply under high shear action, but its molecular structure remains unchanged. When the shear force is eliminated, the original viscosity is immediately restored. The relationship between shear force and viscosity is completely plastic. The pseudoplasticity of Xanthan gum is very prominent, which is very effective for stabilizing suspensions and Emulsion. 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 Xanthan gum aqueous solution almost does not change at 10-80 ℃. Even low concentration aqueous solution still shows stable high viscosity in a wide temperature range. The 1% Xanthan gum solution (containing 1% Potassium chloride) was heated from 25 ℃ to 120 ℃, and its viscosity only decreased by 3%. 6. Stability to acidity and alkalinity Xanthan gum solution is very stable to acids and bases, and its viscosity will not be affected when the PH is 5-10. The viscosity will change slightly when the PH is less than 4 and more than 11. Within the range of PH3-11, the maximum viscosity is within 10% of the minimum value. Xanthan gum can be dissolved in a variety of acid solutions, such as 5% sulfuric acid, 5% nitric acid, 5% acetic acid, 10% hydrochloric acid and 25% phosphoric acid, and these Xanthan gum acid solutions are quite stable at room temperature, and the quality of the parts will not change for several months. Xanthan gum is also soluble in sodium hydroxide solution and has thickening property. The solution formed is very stable at room temperature. Xanthan gum can be degraded by strong oxidants such as perchloric acid and persulfuric acid, and the degradation will accelerate with the increase of temperature. 7. Stability of salt Xanthan gum solution can be miscible with many salt solutions (potassium salt, sodium salt, calcium salt, magnesium salt, etc.), and the viscosity is not affected. Under high salt concentration conditions, even in saturated salt solutions, its solubility is maintained without precipitation and flocculation, and its viscosity is almost unaffected. 8. Stability of enzymatic hydrolysis reaction The stable double helix structure of Xanthan gum makes it have strong antioxidant and anti enzymolysis capabilities. Many enzymes, such as protease, Amylase, cellulase and hemicellulase, cannot degrade Xanthan gum.
Post time: 2023/7/5 15:08:25