Xanthan gum, also known as yellow gum, xanthan gum, and xanthan polysaccharide, is a monospore polysaccharide produced by the fermentation of Pseudomonas. Due to its special macromolecular structure and colloidal properties, it has multiple functions and can be used as an emulsifier, stabilizer, gel thickener, wetting agent, film forming agent, etc., and is widely used in various fields of the national economy. Xanthan gum is known as "industrial MSG" and is currently the world's largest microbial polysaccharide with a wide range of uses.
Features and performance
Xanthan gum is currently the most superior biological gum in the world that integrates thickening, suspension, emulsification and stabilization. The amount of pyruvic acid groups at the end of the molecular side chain of xanthan gum has a great influence on its performance. 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 it exhibits different properties under different conditions.
1. Suspension and emulsification: Xanthan gum has a good suspension effect on insoluble solids and oil droplets. Xanthan gum sol molecules can form super-bonded ribbon-like helical copolymers, forming a fragile mesh structure similar to glue, so they can support the morphology of solid particles, droplets and bubbles, showing a strong emulsification stabilization effect and high suspension ability.
2. Good water solubility: Xanthan gum can dissolve quickly in water and has good water solubility. It can also dissolve in cold water, which can save complicated processing and is easy to use. However, due to its strong hydrophilicity, if a small amount of water is added directly and the stirring is insufficient, the outer layer absorbs water and swells into a floc, which will prevent water from entering the inner layer, thus affecting the effect. Therefore, it must be used correctly. 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 to make a solution for use.
3. Thickening: Xanthan gum solution has the characteristics of high viscosity at low concentration (the viscosity of 1% aqueous solution is equivalent to 100 times that of gelatin), and is an efficient thickener.
4. Pseudoplasticity: Xanthan gum aqueous solution has high viscosity under static or low shear, and shows a sharp drop in viscosity under high shear, but the 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. Xanthan gum has a very prominent pseudoplasticity, which is very effective in stabilizing suspensions and emulsions.
5. Thermal stability: The viscosity of xanthan gum solution does not change much with temperature. The viscosity of general polysaccharides changes due to heating, but the viscosity of xanthan gum aqueous solution hardly changes between 10-80°C. Even low-concentration aqueous solutions still show stable high viscosity over a wide temperature range. When a 1% xanthan gum solution (containing 1% potassium chloride) is heated from 25°C to 120°C, its viscosity only decreases by 3%.
6. Acid-base stability: Xanthan gum solution is very stable to acids and bases. Its viscosity is not affected between pH 5-10, and its viscosity changes slightly when the pH is less than 4 and greater than 11. In the pH range of 3-11, the difference between the larger and smaller values of viscosity is less than 10%. 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 will not change for several months. Xanthan gum can also be dissolved in sodium hydroxide solution and has thickening properties. The resulting solution is very stable at room temperature. Xanthan gum can be degraded by strong oxidants such as perchloric acid and persulfate, and the degradation accelerates with increasing temperature.
7. Stability to 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, it still maintains its solubility without precipitation and flocculation, and its viscosity is almost unaffected.
8. Stability to enzymatic reactions: The stable double helix structure of xanthan gum gives it extremely strong antioxidant and anti-enzymatic capabilities. Many enzymes such as proteases, amylases, cellulases and hemicellulases cannot degrade xanthan gum.
Main uses
In industry, it is used as a stabilizer, thickener and processing aid for various purposes, including canned and bottled foods, bakery foods, dairy products, frozen foods, salad dressings, beverages, brewing, candy, cakes and pastries. When making food, it is easy to flow, easy to pour in and out, easy to pipe, and reduce energy consumption.
Usage method
Xanthan gum is completely soluble in most water-based systems, but because it has strong hydrophilicity, if it is directly added to water and not stirred sufficiently, the outer layer absorbs water and swells into a gelatinous mass, thereby preventing water from entering the inner layer, which in turn affects the effect. Therefore, it must be used correctly: take one part of xanthan gum and mix it with ten or more parts of other dry raw materials, such as sugar, monosodium glutamate, salt, etc. in food production, and then slowly pour it into the stirring water, soak for about two hours, and continue to stir until it is completely dissolved.
Application of xanthan gum in the food industry
Xanthan gum has been accepted by many countries as a food additive. This polysaccharide significantly improves the texture, taste, and appearance of food by controlling the rheological behavior of the product, and improves its commercial value. It has become an important stabilizer, suspending agent, emulsifier, thickener, adhesive, and high-value-added, high-quality processing raw material in the fields of beverages, pastries, jellies, canned foods, seafood, and meat products. It can be summarized as follows.
1. Acid-resistant and salt-resistant thickening stabilizer
Applied to various fruit juice drinks, concentrated juices, and seasonings (such as soy sauce, oyster sauce, and salad dressings). The stabilizing effect of xanthan gum is significantly better than other gums, and it has strong thermal stability. General high-temperature sterilization will not affect it. It can be used in various fruit juice drinks, pulp drinks, plant protein drinks, etc., with a dosage of 0.08% to 0.3%. Xanthan gum's excellent salt resistance, acid and alkali resistance can completely replace traditional thickeners such as starch in soy sauce, overcome the disadvantages of starch precipitation, and make soy sauce delicate and uniform, improve wall adhesion and coloring, and extend shelf life. Jam, bean paste and other flavored sauces use xanthan gum as a thickening stabilizer to make the sauce uniform, good coating and mixing, no caking, easy to fill, and improve the taste.
2. Emulsifier
As an emulsifier, it is used in various protein beverages, milk beverages, etc. to prevent oil-water stratification and improve protein stability and protein precipitation. Its emulsifying ability can also be used as a foaming agent and foam stabilizer, such as in beer manufacturing. After adding 0.02% xanthan gum to the emulsification system based on soy protein, the emulsification is significantly improved, and the mixed system has high shear rate and heat-induced high viscosity characteristics.
3. Filler
As a stable high-viscosity filler, it can be widely used in the processing of various snacks, bread, biscuits, candies and other foods. Without changing the traditional flavor of the food, it can make the food have better shape retention, longer shelf life, and better taste, which is conducive to the diversification and industrial-scale production of these foods. In the production of various frozen foods, xanthan gum has the function of preventing water loss, delaying aging, and extending the shelf life.
4. Emulsifier stabilizer
As an emulsifier stabilizer used in frozen foods, xanthan gum in ice cream and popsicles can adjust the viscosity of the mixture, making it have a uniform and stable composition and smooth and soft texture. Due to the plasticity and shear properties of the viscosity and temperature of xanthan gum, the viscosity decreases during processing operations, and the resistance decreases, which is conducive to the process. In the cooling and aging stage, the viscosity is restored, which is conducive to increasing the expansion rate, preventing the formation of large ice crystals in the ice cream tissue, and making the ice cream taste smooth and delicate. At the same time, the freeze-thaw stability of the product is improved, and the cream and water are evenly mixed during melting, and no slurry separation will occur. The general aging time is 2 to 3 hours. The dosage is 0.2% to 0.4%.
5. Application in noodle products
Xanthan gum is used in noodle products. It is an additive worth promoting. In the production of dried noodles, ramen noodles and instant noodles, adding xanthan gum can enhance the gluten strength of the dough, make the pressed noodles tough, reduce the rate of broken strips during drying, and improve the taste of the product. It is chewy, fresh and smooth. It can also save oil and reduce costs for frying. Adding xanthan gum to quick-frozen dumpling wonton wrappers can improve the taste of the product, reduce rotten skin and mixed soup; adding 0.05% to 0.1% of the total amount of xanthan gum to stuffing products can help retain water in the soup, ensure that the product is cooked thoroughly in boiling water, and the soup is rich in flavor, and can improve and improve the taste. Xanthan gum is an additive ingredient in bread, cakes, etc., which can increase the softness and extend the shelf life of the product.
6. Other applications
In addition to the above uses, xanthan gum is also widely used in the processing of meat products, canned fruits and vegetables, and other foods.
Application of xanthan gum in the oil industry
A large market for xanthan gum is the oil industry. At present, the chemicals used in my country's oil fields are mainly polyacrylamide, CMC, modified starch, etc., which result in high drilling costs and low oil yields. Xanthan gum is much stronger than other polymers in viscosity, thickening, salt resistance, and pollution resistance. Especially in drilling in the ocean, beach, high-salinity layer and permafrost layer, xanthan gum is used in mud treatment, completion fluid and tertiary oil recovery. It has significant effects on accelerating drilling speed, preventing oil well collapse, protecting oil and gas fields, preventing blowouts, and greatly increasing oil recovery. As an ideal additive, this product has very good development prospects.
1. Drilling industry
Drilling fluid is the operating fluid used in the drilling process. It plays an important role in the drilling process. People often compare drilling fluid to "drilling blood". Its functions are: suspending and carrying cuttings, cleaning the bottom of the well; lubricating and cooling the drill bit, increasing the drill bit penetration, impacting the formation through the drill bit water hole, which is conducive to breaking rocks; forming mud cakes and increasing the stability of the well wall; establishing a liquid column pressure that can balance the formation pressure to prevent complex accidents such as sticking, collapse, leakage, and spraying; when using turbodrills, it can be used as a liquid to transmit power. Xanthan gum is one of its main components. Its function is to increase viscosity and shear force and improve the suspension capacity of drilling fluid, which is indispensable for the drilling fluid to perform its functions.
2. Oil production industry
Among the various methods of improving oil recovery, polymer flooding occupies an important position. The role of polymers is to adjust the rheology of water injection, increase the viscosity of the driving fluid, and improve the sweep efficiency of water flooding. Reduce the permeability of the water phase in the formation so that water and oil can flow forward at a uniform speed. This type of polymer must have excellent viscosity-increasing properties under reservoir conditions, and must have a high viscosity retention rate under the action of temperature, pressure and salt. Since xanthan gum solution has good viscosity-increasing properties, rheological properties, water solubility, chemical stability, and strong mechanical resistance to degradation, it can be used as a displacement agent for oil field exploitation.
Compared with general hydrolyzed polyacrylamide, it has stable physical and chemical properties, simple processing technology, good oil displacement effect, and low manufacturing cost. Because it has good resistance to shear degradation, it can flow selectively in the formation and has better oil displacement effect. It has gradually been used in oil field exploitation as a displacement agent to improve oil field recovery or a chemical profile control agent to improve the recovery effect. Physical simulation experiments further show that xanthan gum has the effect of improving oil recovery and is an excellent oil field exploitation displacement agent. After completing the primary and secondary recovery of oil by conventional methods, more than 50% of the oil remains in the rock and cannot be recovered.
Based on economic and energy considerations, people pay more and more attention to improving the recovery rate of oil. The process of injecting water into oil strata is used for secondary oil production, but the relative fluidity of the injection fluid and viscous crude oil leaves a large amount of dead oil remaining in the well. If a polymer with thickening properties is added to the injection fluid, the fluidity of water can be reduced, thereby increasing the oil recovery rate. Many polymers can be used as flow control agents for oil recovery, among which xanthan gum is considered to have great application potential. Xanthan gum has many basic conditions necessary to improve oil recovery.
3. Xanthan gum is also used in fracturing fluid, mainly as a thickener for water-based fracturing fluid, and also has the function of reducing friction.
