Cyclodextrin

Cyclodextrin, also known as amylopectin, is an oligosaccharide produced by the action of glucosyltransferase on starch. It is a compound in which 6 to 8 molecules of D-glucose are cyclically linked by α-1,4 bonds. . It is called α-cyclodextrin (α-CD) composed of 6 molecules of glucose, β-cyclodextrin (β-CD) is composed of 7 molecules, and γ-cyclodextrin is composed of 8 molecules. (γ-CD). There are also 9 to 10 glucose molecules. The cyclodextrin is a crystal having a cylindrical structure, and the -OH group is bonded to the upper portion (the wide mouth side) of the cylindrical shape, and the -CH2OH group is bonded to the lower portion of the cylinder (the slit side). The cyclodextrin molecule is hydrophilic as a whole and is soluble in water. Correspondingly, it is hydrophobic inside the cyclodextrin (inside the cylinder). Since it is ring-shaped, it does not have a reducing end. It has a certain stability to acid, and it is difficult to hydrolyze it by ordinary amylase. Various cyclodextrins react differently with iodine. The specific optical rotation and solubility are also different. Among them, β-cyclodextrin has the smallest solubility, is most easily crystallized, and is the easiest to separate. Because there is a hollow cavity in the molecule, the inner diameter is between 7 and 10 A, and some gas, liquid or solid molecules can enter the cavity due to the attraction of the intermolecular van der Waals force to form a clathrate. Therefore, when forming a clathrate with a traditional Chinese medicine molecule, it can improve the properties of the drug, improve the stability of the drug, reduce toxic side effects, and increase bioavailability. For example, borneol and mint in the brain clearing tablets are used in a large amount, and mutual eutectic is formed into a viscous liquid, so that the tablet is unqualified. There is no eutectic phenomenon after the inclusion of β-CYD, so that the quality of the tablet meets the requirements. Cyclodextrin is also a surfactant that can be used in foods as a stabilizer to eliminate and mask special odors; to improve and improve food structure; to reduce and remove bitter taste; to resist oxidation; to envelop food flavors It is not volatile, makes the fragrance lasting; envelops food coloring, makes it stable; enhances the foaming effect of protein; can be used in aquatic products, animal products, ice cream, sauces, dairy products. Depending on the size of the cyclodextrin cavity, it is possible to complex cations with equivalent ionic radii, which can be used as phase transfer catalysts, analytical reagents and pharmaceuticals. The inclusion of cyclodextrin is also used in pesticides to reduce the decomposition of pesticides and improve the efficacy. Used as an emulsifier, deodorant and preservative for cosmetics, defoamer for washing powder, and has certain medical effects on acne.