What are the applications of xanthan gum in food?

Xanthan gum is a pentasaccharide repeating unit composed of D-glucose, D-mannose, D-glucuronic acid, acetic acid and pyruvic acid. The molar ratio of glucose, mannose and glucuronic acid is 2.8:3.0:2.0. Xanthan gum is made from the fermentation medium containing sugars (such as glucose, sucrose, starch, hydrolyzed starch, etc.), in the presence of suitable nitrogen source, dipotassium hydrogen phosphate and appropriate amount of trace elements, by the action of Xanthomonas campestris strain, fermentation, and then after extraction, drying, crushing and other processes. Xanthan gum is tasteless, odorless, non-toxic, safe for consumption and soluble in water. In the aqueous solution presents polyanion, with unique physical and chemical properties. In industrial production, it is mainly used as a thickener, but also can be used as a suspending agent, emulsifier, stabilizer. So far, xanthan gum is considered to be the most superior performance of the international bio-glue, which is used in a large number of food, juice, beverage, feed, make-up, medicine, ceramics, fire, oil and other industries, and its market growth potential exceeds that of all hydrophilic gums. This paper summarizes the structure, properties and production of xanthan gum, and describes the application of xanthan gum in the food industry.
Structure
Xanthan gum is off-white or light beige powder, composed of five sugar unit repeats, its main chain is the same as cellulose, that is, by the β-1,4 glycosidic bond connected to glucose, three connected monosaccharides to form its side chain: mannose a glucose a mannose. The mannose linked to the main chain is usually modified by an acetyl group, the mannose at the end of the side chain is modified by acetal reaction with pyruvic acid, and the glucose in the middle is oxidized to glucuronic acid.
In addition to its regular primary structure, xanthan gum also has a secondary structure. As determined by X-ray diffraction and electron microscopy, xanthan gum molecules form a regular helical structure by hydrogen bonding. Between the double helix structure rely on the weak force and the formation of a net-like three-dimensional structure, which is the tertiary structure of xanthan gum, which exists in the form of liquid crystals in aqueous solution.
Properties
Xanthan gum is known as “industrial monosodium glutamate”, is currently the world’s largest production scale and the most widely used microbial polysaccharide. It has the following properties.
(1) Xanthan gum is tasteless, odorless, strong safety, high viscosity, 1% aqueous solution viscosity is equivalent to 100 times that of gelatin, so it can be used as a good thickening and stabilizing agent.
(2)Unique rheological properties, under the action of shear, the viscosity of the solution will fall rapidly, once the action of shear lifted, the viscosity of the solution will be immediately restored, this characteristic gives food such as ice cream, ham sausage, fruit juices and plant protein-based beverages, baked goods to a good taste. This property also makes xanthan gum widely used in oil drilling and mining.
(2) Good thermal stability, in a wide range of temperatures (a 18-130 ℃) to maintain the unique function, is the production of frozen food and baked goods, a good auxiliary material.
(4)Acid and alkali stability, its viscosity is basically unaffected by acid and alkali, and it can maintain its original characteristics in the range of PH value 1-12, thus making it have a wide range of applications.
(5)Extremely strong antioxidant and anti-enzymatic effect, even in the presence of hypochlorite, hydrogen peroxide, biologically active enzymes can still play a role in the conditions.
(6)Wide range of compatibility. With guar gum, locust bean gum mixture can produce beneficial synergistic effect. This structural gum can produce gelation under certain conditions.
(7)When coexisting with high concentrations of salts and sugars, it still maintains a stable thickening system.
(8)Good suspension of insoluble solid particles and oil droplets.
(9)Microwave stability. The stabilized system has been formed, even in the microwave oven in the freezing a thawing will not have an effect on its performance.
(10)Good compatibility with salts, acids and bases, good reactivity with galacto-monomannan.
Production
Production of xanthan gum strains: xanthan gum production strains for several species of Xanthomonas genus, the current industrialized production of strains is mainly black rot of kale Xanthomonas, in addition to the soybean Xanthomonas, mallow Xanthomonas and carrot Xanthomonas can also be used as a fermentation strain.
The figure below is a sketch of the xanthan gum production process, the production of xanthan gum is affected by the composition of the medium, medium conditions (temperature, PH value, dissolved oxygen, etc.), reactor type, operation mode (continuous or intermittent) and other factors. The strain can grow at 25 ℃ ~ 30 ℃, the optimal fermentation temperature of 28 ℃, there have been researchers to propose a specific temperature and growth rate of the relationship between the equation. Xanthan gum extraction: In comparison, the cost of recovering the product from the fermentation broth is high. Generally, the components in the final fermentation broth are: xanthan gum: 10-30 L, cells: 1-10 g/L, residual nutrients 3-10 L, and other metabolites. Due to the presence of high concentrations of xanthan gum, the solution concentration is very large, thus increasing the difficulty of the extraction operation, therefore, it is advisable to do the dilution process first. The main steps of extraction include precipitation of the cells, precipitation of xanthan gum, dehydration, drying, and grinding.
Application in food
Xanthan gum has been accepted as a food additive in many countries. In the beverage, pastry, jelly, canned food, seafood, meat processing and other fields to become an important stabilizer, suspending agent, emulsifier, thickening agent, adhesive and with high value-added, high-quality processing materials. Specifically can be summarized as follows.
(1) acid-resistant, salt-resistant food thickening stabilizer used in a variety of juice drinks, fruit juice concentrate, seasonings (such as soy sauce, oyster sauce, salad dressing) in food. The stabilizing effect of xanthan gum is significantly better than other gums, has a strong thermal stability, general high temperature sterilization will not have an impact on it, can be used in a variety of fruit juice drinks, fruit drinks, plant protein drinks, etc., the amount of 0.08 to 0.3.
Xanthan gum excellent salt, acid and alkali resistance can completely replace the traditional thickeners in soy sauce starch, etc., can overcome the shortcomings of starch precipitation, and can make the soy sauce delicate and uniform, improve wall hanging and coloring, and extend the shelf life. Jam, soy sauce and other flavor modification sauce, with xanthan gum as a thickening stabilizer, so that the sauce body uniformity, good coated, non-caking, easy to fill, and improve the taste.
(2) food emulsifier as an emulsifier for a variety of protein drinks, milk beverages, to prevent oil and water stratification and improve the stability of proteins, to prevent protein precipitation, but also its emulsification capacity as a foaming agent and foam stabilizer, such as for the manufacture of beer and so on. After adding 0.02% of xanthan gum in the emulsification system dominated by legume protein, the emulsification is significantly improved, and the mixed system has a high shear rate and heat-induced high viscosity characteristics.
(3) Food filler as a stable high viscosity filler, can be widely used in all kinds of snacks, bread, cookies, candy and other food processing, without changing the traditional flavor of the food under the premise of the food has a superior shape retention, longer shelf life, better taste, and is conducive to the diversification of these food products and industrial scale production. In a variety of frozen food production, xanthan gum has the role of preventing its water loss, delay aging, and extend shelf life.
(4) food emulsion stabilizer as an emulsion stabilizer applied to frozen food, in ice cream, ice cream xanthan gum can adjust the viscosity of the mixture, is to make it have a uniform and stable composition, smooth and soft tissue, due to the viscosity and temperature of xanthan gum viscosity and shear properties of the relationship between the plasticity and shear properties, so in the processing operation when the viscosity decreases, the resistance decreases, is conducive to the process, and in the cooling stage of aging, the viscosity restoration, is conducive to improve the Expansion rate, to prevent the formation of large ice crystals in the ice cream organization, so that the ice cream taste lubricated and delicate.
At the same time improve the freeze-thaw stability of the product, and in the melting of the cream and water mixed evenly, will not produce slurry separation phenomenon. General aging time 2 ~ 3h. dosage of 0.2% ~ 0.4%.
(5) food adhesive xanthan gum can be some water-soluble powder substances, such as sodium fucoidan, casein, methyl cellulose and polyethylene glycol cellulose sodium salt crosslinked to make an adhesive. This adhesive for food processing, can play a role in improving the texture to increase the role of film. By utilizing this property of xanthan gum, granular pastes can be manufactured. Compared with the traditional paste, made with xanthan gum paste dispersion is small, uniformity and high solubility, fluidity and filling performance is good, because it does not have cohesive solid preservation is excellent.
(6) xanthan gum in the application of specific food processing ① xanthan gum on the quality of noodles (1) xanthan gum on the formation of gluten is now the first to strengthen the tendency of weakening, which affects the water retention rate will affect the gluten of other indicators. (2)Xanthan gum has a better effect on the improvement of flour properties, and has a weakening effect on the tensile properties. (3)Xanthan gum has little effect on the swelling potential of starch, and has a regular decrease in the onset pasting temperature of flour, with the maximum peak viscosity at a colloid addition of 0.2. (4) Xanthan gum has a good improvement on the cooking characteristics, with the increase of the proportion of colloid, the cooking characteristics of the indicators decreased. (5) The addition of colloids increased the hardness, adhesion and chewiness of the noodle texture, and the adhesion and elasticity, bonding, and recovery decreased compared with the blank.
② Improvement of beef quality xanthan gum to improve the water retention of beef is mainly based on two aspects, one is the xanthan gum itself is a hydrophilic colloid, infiltration of beef tissues can improve the water-holding capacity of the muscle; the second is that the water retention of meat can be expressed through the gelatinous structure of proteins and static electricity, which muscle structural proteins in the myosin has a decisive role in its water retention.
The pH value is an important parameter to measure the quality of beef, which not only affects the palatability, tenderness, cooking loss and shelf life of beef, but also significantly correlates with the water retention force, meat color and flavor of beef. Muscle pH is close to its protein isoelectric point (5.0 ~ 5.5), the mechanical strength of the meat is the largest, the tenderness is poor, and the system of water force is also lower. Production usually requires that the pH of the meat deviates from its isoelectric point. Soaking beef in xanthan gum solution increases the pH of its muscle; therefore, the addition of xanthan gum will be beneficial in improving the water retention and textural qualities of beef.
The maximum shear force of beef can reflect the tenderness of beef, the smaller the shear force the better the tenderness. Therefore, 0.5% xanthan gum soaking solution can improve the tenderness of beef. The reason may be: xanthan gum can chelate Ca2+, which may induce the Ca2+ in myocytes to be transferred to the sarcoplasm, thereby activating the calcium-activating enzyme in the sarcoplasm and promoting the hydrolysis of muscle proteins, resulting in the disintegration of z-lines in the structure of muscle fibers until they disappeared, as well as making the muscle joints broken and myofibrils fragmented, thus rejuvenating the muscles.
Summarize
The aqueous solution of xanthan gum has unique rheological properties – shear thinning, with the increase in shear rate, the apparent viscosity of the solution decreases significantly; viscosity, in lower concentrations that is, a larger viscosity; good water solubility, thermal and acid-base stability, and a variety of salts have good compatibility. These many characteristics make it through the control of the rheological behavior of the product and significantly improve the texture, taste, appearance quality of food, and improve its commercial value, so the prospects for application in food is very broad.