Xylan, a kind of hemicellulose, is a kind of poly five carbon sugar, which widely exists in plant cell wall. It is a carbohydrate with content second only to cellulose in nature. The structural unit of xylan is xylose. The long chain of xylose connected by xyloside bond becomes the main chain, and some groups on the main chain are replaced by side chain groups. These side chain groups include acetyl group, arabinosyl group, galactosyl group, glucuronic acid group, coumaric acid group, ferulic acid group, etc. xylan is then connected with other components of plants such as cellulose, lignin and pectin through side chain groups to form a dense structure, Together, they form the supporting skeleton of plants.
Xylans are used in the following industries:
1. Food industry: it is used for flour processing and improvement to produce special flour. It can also be used for the terminal to improve the quality of baking and cooking products. For effect, suggestions and fungi а- Amylase, lipase or glucose oxidase are used together. The recommended dosage is 1.0-3.0g/100 kg flour (10-30ppm).
2. Beer brewing industry: decompose xylan or pentosan to reduce the viscosity of wort. Solve the turbidity caused by carbohydrates such as xylan or pentosan. It is especially suitable for the saccharification process of wheat beer chemicalbook or beer with wheat as auxiliary material and the cleaning of filter membrane. Recommended dosage: 100-300g / ton malt.
3. Feed industry: effectively degrade the anti nutritional factor xylan in plant feed, promote the digestion and absorption of nutrients, and improve feed utilization. Promote the growth of beneficial bacteria in the intestinal tract, inhibit the reproduction of harmful bacteria, and improve animal immunity, survival rate and production performance. Recommended dosage: Based on 10000u/g enzyme activity, it is recommended to add 100-300g to each ton of formula feed, and add concentrated material and premix in proportion.
Its name is xylanase. It is quite common for xylanase to be used in bread processing. Generally, we first mix an appropriate amount of xylanase with the raw and auxiliary materials for making bread, and then prepare the dough, wake up, cut and round it, wake up in the middle, shape and dish it, bake it, and then reach the finished product. With the help of xylanase, the processed bread is not only full of color, flavor, but also more tenacious.
Xylan synthesis, with the help of high-speed crushing treatment method to separate starch from bran, and then use colloidal mill and cellulase treatment and alkali soaking treatment to recover protein. Finally, through optimization, determine the best process of oligosaccharide. The test results show that the crushing time is 2 min, and the particle size range of the test raw materials is >125 μ m. The yield of starch was 72.43 percent ; The optimum technological conditions of cellulase and alkali treatment are as follows: the amount of enzyme added is 1.0 ml/hg, the alkali treatment temperature is 60 degree , the alkali treatment pH is 9.5. Under these conditions, the mass fraction of xylan is 35.5 percent , the extraction rate of protein is 74.9 percent , and the optimum washing times of water washing is 4 times. At this time, the mass fraction of xylan is 36.5 percent .
In the process of bread making, xylanase will first convert water-insoluble pentosan into water-soluble pentosan, and then hydrolyze water-soluble pentosan into xylose, xylobiose and other substances, which is conducive to the formation of gluten network structure. At the same time, small molecular sugars can provide energy for yeast fermentation, enhance the gas production capacity of dough, and shorten the wake-up time of dough.
During this period, the content of water-soluble pentosan increases due to the degradation of water-insoluble pentosan, which will make the water-soluble pentosan with higher viscosity wrap around the liquid film of CO bubble, which greatly improves the strength and extensibility of gluten starch film and optimizes the gluten network structure. Make the bread softer.
At the same time, the toughness of the small air chamber is enhanced, so that its rapid expansion into the furnace is also enhanced, thereby increasing the volume of bread. In addition, the optimization of gluten network structure can enhance the water holding capacity of bread cores, effectively slow down the evaporation of water from the bread epidermis, and achieve the effect of delaying the aging of bread and extending the shelf life of products.
Even so, do not add too much xylanase, otherwise it will backfire, which will lead to the decline of bread quality, which is not conducive to production operations. We should know that xylanase can degrade pentosan and release the water it absorbs. Therefore, excessive addition will lead to sticky dough, affect the processing and operating performance of products, hinder dough fermentation, and reduce the volume of bread.