Alpha cyclodextrin

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α-cyclodextrin (CAS No. 10016-20-3) is a cyclic oligosaccharide composed of six D-pyranose glucose units connected by α-(1,4) glycosidic bonds. It is white crystals in appearance and forms needle-shaped crystals in water. Its solubility increases with increasing temperature. It is non-hygroscopic but easily forms stable hydrates and can absorb up to 6.6 water molecules. α-cyclodextrin has a hydrophobic inner cavity and a hydrophilic outer edge. It can encapsulate various appropriate guest molecules such as organic molecules, inorganic ions and gas molecules to form host-guest inclusion complexes and has molecular recognition function. It is widely used in catalysis, separation, food and medicine, and is particularly suitable for encapsulating small molecules and for occasions requiring high CD solubility.

Solubility

The solubility of α-cyclodextrin in water increases with the increase of temperature. It is not hygroscopic, but it is easy to form various stable hydrates, and can absorb up to 6.6 water molecules (water content 11.9%). In the range of relative humidity of 20-95%, the hygroscopic isotherm curve is a platform. In addition, α-cyclodextrin is insoluble in general organic solvents, but soluble in dimethylformamide (54%).

Molecular structure

The inner diameter of the molecular cavity of α-cyclodextrin is about 4.7~5.3Å, and the height is 7.9Å. Because the glycosidic bonds connecting the glucose units cannot rotate freely, α-cyclodextrin is not a cylindrical molecule but a slightly conical ring.

Chemical properties: The specific rotation of α-cyclodextrin is 150±1°. Its purity is usually ≥99%, the loss on drying is ≤10%, and the residue on ignition is ≤0.05%.

Functional properties

α-cyclodextrin is hydrophilic on the outside and hydrophobic in the inside, so it can provide a hydrophobic binding site, as a host to envelop various appropriate guests (such as organic molecules, inorganic ions and gas molecules, etc.), forming a host-guest inclusion complex. This selective enveloping effect is commonly known as molecular recognition. α-cyclodextrin is the ideal host molecule similar to enzymes discovered so far, and it itself has the characteristics of an enzyme model.

Low viscosity, no other peculiar smell

Dietary fiber often presents several general technical performance issues, including high viscosity, poor stability, and unpopular taste. These problems frequently limit the addition of dietary fiber ingredients. Alpha-cyclodextrin addresses these concerns by providing a colorless, odorless liquid with low viscosity and no peculiar smell.