The Components and Characteristics of Xanthan Gum

Xanthan gum, commonly known as corn syrup gum, is a compound polysaccharide produced by fermentation of sugars (glucose, sucrose, lactose) by Xanthomonas campestris.

Ⅰ. What is xanthan um made of?

Xanthan gum is usually manufactured from corn starch. After Xanthomonas brassicae black rot uses carbohydrates as the main raw material, through aerobic fermentation bioengineering technology, the 1,6-glycosidic bond is cut and the branched chain is opened. By pressing 1,4-bonds, an extracellular acidic heteropolysaccharide composed of linear chains is synthesized.

Ⅱ. The characteristics of xanthan gum

1. Xanthan gum is a white or light yellow powder with excellent thickening, suspending, emulsifying and water solubility, and good thermal and acid-base stability, so it is widely used in various foods.

2. Xanthan gum can quickly dissolve in water, and xanthan gum water solubility is very good. Especially it can dissolve in cold water, which saves complicated processing and is convenient to use.

However, due to its strong hydrophilicity, if it is directly added to water and the stirring is insufficient, the outer layer will absorb water and expand into a micelle, which will prevent water from entering the inner layer, thereby affecting its function. Therefore, it must be used correctly.

Dry xanthan gum powder or mix it with salt, sugar and other dry powder auxiliary materials and slowly add it to the stirring water to make a solution for use.

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

The xanthan gum aqueous solution has a high viscosity under static or low shear action. Under high shear action, the viscosity drops sharply, but the molecular structure does not change.

The viscosity of the xanthan gum solution will not change greatly with the change of temperature. The viscosity of the xanthan gum solution will hardly change between 10-80℃. Even the low-concentration aqueous solution will still show stable high viscosity within a wide temperature range. When a 1% xanthan gum solution (containing 1% potassium chloride) is heated from 25°C to 120°C, its viscosity is only reduced by 3%.

The stability of xanthan gum solution to acid and alkali is very obvious, and its viscosity is not affected between pH 5-10, and the viscosity changes slightly when the pH is less than 4 and greater than 11. In the range of PH3-11, the difference between the maximum and minimum 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. The nature will not change for several months.

4. 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 persulfuric acid, and the degradation accelerates as the temperature rises.

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 the condition of higher salt concentration, it maintains its solubility even in saturated salt solution without precipitation and flocculation, and its viscosity is almost unaffected.

The stable double helix structure of xanthan gum has strong anti-oxidation and anti-enzymatic ability. Many enzymes such as protease, amylase, cellulase and hemicellulase cannot degrade xanthan gum.

However, during the dissolution process of xanthan gum, due to the rapid swelling of the particle surface to form a viscous glue layer, it is easy to cause agglomeration and reduce the overall dissolution rate, which is limited in some application fields. At present, xanthan gum is mostly used to mix with starch for dry heat treatment to increase the viscosity of starch, inhibit gelatinization, heat stability and other physical and chemical properties, including tapioca starch, corn starch, potato starch, etc. and dry heat treatment with xanthan gum, the hydroxyl of starch molecules It cross-links with the carboxyl group of the xanthan gum molecule to cause changes in physical and chemical properties.