Xylan is an important component of hemicellulose and is widely found in various plant resources. Xylanase is a hydrolyzing enzyme of xylan, which has a wide range of applications in the food, feed, paper, and other industries.
Xylanase is mainly used in the food industry for the improvement of wheat flour. The non-starch polysaccharide in wheat flour is mainly pentosan (the main component is arabinoxylan, wherein water-soluble arabinoxylan accounts for about 20%-30%, and water-insoluble arabinoxylan is about 70%-80%. ), although it is rarely present in flour (about 2% to 3% of the dry basis of the flour), it has a significant effect on the rheological properties of the dough and the quality of the pasta. It has been reported that the addition of an appropriate amount of xylanase to the production of bread can significantly improve the handling of the dough, increase the volume and specific volume of the bread, and improve the elasticity, hardness, and softness of the core.
The application of xylanase in health care products mainly refers to the enzymatic production of functional xylooligosaccharides. The xylooligosaccharide has a good physiological function, it is difficult to digest in the human body (high residual rate in the intestine), and has an excellent effect of the proliferation of the bifidobacteria. The proliferative effect of bifidobacteria is much lower than that of other oligosaccharides. In addition, the xylooligosaccharide has a sweetness of only 40% of sucrose and has good acid-base stability and thermal stability. It does not cause an increase in blood sugar level after consumption and can replace glucose as a therapeutic food for diabetics.
In the past, people thought that as long as there was a certain pectinase, it could hydrolyze pectin and increase the juice yield, but the results were not satisfactory. Later, it was found that the proper combination of xylanase and cellulase and pectinase can destroy the cell structure of fruits and vegetables and improve the juice yield under mild conditions. At the same time, since the complex enzyme decomposes pectin and hemicellulose in fruits and vegetables, the viscosity of the juice is lowered, thereby accelerating the outflow of the juice, shortening the pressing time and improving the production efficiency of the factory. In addition, some hemicellulose such as xylan is decomposed into a water-soluble substance by the action of an enzyme, which also increases the content of soluble solids in the beverage.
In agriculture, the use of enzymes in the production of feed is important, with an annual production of more than 600 million tons, equivalent to a turnover of more than $5 billion. The xylanases used in animal feed are proteases, glucanases, pectinases, cellulases, amylases, phytases, galactosidase, and lipases. These enzymes are capable of breaking down the arabinose xylan of the feed ingredient and reducing the viscosity of the material (Twomey 2003). Arabinoxylan is found on the cell wall of cereals and has an effect on the nutrient absorption of poultry. If these substances are present in a dissolved state, they may increase the viscosity of the feed, interfere with fluidity and thus affect the absorption of other substances. If xylanase is added to corn and sorghum feed, corn and sorghum are all low-viscosity foods that improve the absorption of nutrients in the digestive tract, resulting in better energy utilization. The combined action of other enzymes can produce more digestive food mixtures. Smaller poultry and pigs produce less endogenous enzymes than adults, so food supplements contain exogenous enzymes that allow them to grow better. In addition, this feed can reduce excess residues in animal manure (such as phosphorus, nitrogen, copper, and zinc), which is also feasible in reducing environmental pollution.
Xylanase and xylan are rarely used in the pharmaceutical industry. Xylanases are sometimes combined with other enzymes to synthesize complex enzymes (hemicellulose enzymes), which can be used as a dietary supplement or to treat indigestion, but few pharmaceutical product formulations can be found.
Xylanase can be used to enzymatically produce functional xylooligosaccharides. The xylooligosaccharide has a good physiological function, is difficult to digest in the human body (high residual rate in the intestinal tract), and has an excellent proliferative effect of bifidobacteria. In addition, xylooligosaccharide has a sweetness of only 40% of sucrose and has good acid-base stability and thermal stability.
Xylan is the main component of wood fiber and non-wood fiber. During the pulp cooking process, the xylan is partially dissolved, denatured and redeposited on the surface of the fiber. If xylanase is used in this process, some of the redeposited xylans can be removed. This increases the porosity of the pulp matrix, frees trapped soluble lignin, and allows the chemical bleach to penetrate into the pulp more efficiently. In general, it increases the bleaching rate of the pulp and thus reduces the amount of chemical bleach used.