Production of oligosaccharide prebiotics
Preparation route
The production methods of oligosaccharides are roughly classified into the following five types:
Raffinose
① Extracted from natural raw materials, such as extracting raffinose from beet juice or beet waste molasses, extracting stachyose from plant Zelan, extracting soybean oligosaccharides from soybean whey with soybean protein removed, and extracting from carrots It produces bifidogenic factors such as nitrogenous polysaccharides and oligosaccharides. [8]
②It is produced by microbial enzymatic hydrolysis, such as milk or egg white treated with papain or pepsin to obtain peptide bifidus factor.
③Manufactured by the transfer reaction of microbial enzymes, industrially produced oligosaccharides are produced by biological enzymatic hydrolysis or transfer reaction, such as isomaltose, fructooligosaccharides, xylo-oligosaccharides, lactulose, lactose oligosaccharides and chitosan oligosaccharides Glycan etc.
④It is produced by acid hydrolysis or alkali conversion. For example, lactulose is an oligosaccharide produced by alkali conversion in industry; oligosaccharides produced by acid hydrolysis polysaccharide have no specificity due to acid hydrolysis, and the saccharides in the product are complex. It is not easy to obtain specific oligosaccharides.
⑤Manufactured by chemical synthesis method, such as the production of sugar alcohols with bifidogenic factor functions from sugars by pressurized hydrogenation method, such as xylitol and lactitol.
As far as the above-mentioned main ways of preparing oligosaccharides are concerned, it is very difficult to directly extract oligosaccharide products from natural raw materials. Under normal circumstances, the concentration of oligosaccharides in the body is extremely low, and it is colorless and uncharged. The preparation process is very complicated, difficult to control, and the production cost is extremely high. The oligosaccharides produced commercially by this method include raffinose extracted from sugar beet sugar and soybean oligosaccharides extracted from soybean whey. The chemical hydrolysis of natural polysaccharides to prepare oligosaccharides refers to the use of chemical reagents such as acid, hydrogen peroxide, etc. as catalysts. Degradation of natural polysaccharides to obtain oligosaccharides, due to the complexity of the product, the product quality is not easy to ensure, the yield is low, and it is not easy to obtain high-activity oligosaccharides, so it has not been promoted in practical applications. The artificial chemical synthesis method is to obtain oligosaccharides by means of chemical synthesis. The oligosaccharides prepared by this method have high purity and single components, but the complexity of the oligosaccharide molecular structure makes the chemical synthesis process complicated. The process parameters need to be strictly controlled. Therefore, artificial chemical synthesis of oligosaccharides is mainly limited to the research on the physical and chemical properties of oligosaccharides, which is still far from industrial production. From the point of view of the feed industry and animal husbandry and aquaculture industry, the production cost of oligosaccharides must be considered as a large-scale functional feed additive and a substitute for feed antibiotic growth-promoting agents. A more economical and most promising route is to use biotechnology, namely enzymatic hydrolysis of natural polysaccharides and enzymatic catalyzed synthesis to produce various oligosaccharides. With the development of biotechnology and enzyme engineering technology, it is not only possible to produce various oligosaccharides by enzymatic hydrolysis of natural polysaccharides and enzymatic catalytic synthesis, but also the production cost will be greatly reduced, which is beneficial to the application in the feed industry and aquaculture industry. promotion.
Enzymatic synthesis of oligosaccharides is an effective method for synthesizing oligosaccharides. Due to the stereospecificity of the enzyme-catalyzed reaction, there are specific requirements for the reaction substrate, the type and position of the glycosidic bond, so it has great advantages over chemical synthesis. Various highly specific carbohydrases have been tried to synthesize oligosaccharides, but common animal-derived carbohydrases have low content, are difficult to purify, and have poor stability, so microbial enzyme sources are mostly selected. Enzymes used for oligosaccharide synthesis include various glycosyltransferases, glycoside hydrolases and phosphorylases. The raw materials used to synthesize oligosaccharides are mainly starch, sucrose, lactose, etc. These raw materials are abundant, cheap, and can be comprehensively utilized. For example, fructooligosaccharides (sucrose as raw material), isomalt oligosaccharides, Palatin oligosaccharides, galacto-oligosaccharides, etc. can be synthesized by enzymatic methods