Abstract

α-Cyclodextrin (α-CD) is an important cyclic oligosaccharide that has shown wide application prospects in many fields, such as medicine, food, cosmetics, environmental protection, and materials science. This paper reviewed the structural characteristics, physical and chemical properties, preparation methods, and applications of α-cyclodextrin and provided a reference for related research and applications.

introduction

Cyclodextrin (CD) is a class of cyclic oligosaccharides composed of D-glucopyranose units linked by α-1,4-glucoside bonds, mainly including α-, β- and γ- types. Among them, α-cyclodextrin has been widely studied and applied in many fields because of its unique molecular structure and physical and chemical properties. In this paper, the structure, properties, preparation methods, and applications in different fields of α-cyclodextrins are reviewed in detail.

Basic structure

α-Cyclodextrin, also known as α-cyclodextrin, is a cyclic oligosaccharide composed of six D-glucopyranose units linked by an α-1,4-glucoside bond. Its molecular formula is C₃₆H₆₀O₃₀ and its molecular weight is 973.00. Because the glucoside bonds connecting glucose units cannot rotate freely, α-cyclodextrin molecules have a slightly conical ring structure, in which the primary hydroxyl group is surrounded by a conical mouth, and the secondary hydroxyl group is surrounded by a conical mouth.¹

Physicochemical property

α-Cyclodextrin is a white crystal, and the crystals formed in water are needle-like crystals. Its solubility in water increases with the increase in temperature, but it is not hygroscopic, and it is easy to form various stable hydrates, which can absorb up to 6.6 water molecules (water content 11.9%). In the range of 20-95% relative humidity, the hygroscopic isothermal curve is platform-like. In addition, it is insoluble in general organic solvents, but soluble in dimethylformamide (54%).²

Preparation method

The preparation of α-cyclodextrin mainly depends on the conversion of amylose under the action of cyclodextrin glucosyltransferase produced by Bacillus. This reaction connects the glucose units in amylose in a circular form to form α-cyclodextrin. At present, the commonly used preparation methods in industry include enzymatic conversion and chemical synthesis, among which enzymatic conversion is widely used because of its advantages of high efficiency and environmental protection.³

Application field

Pharmaceutical Field

In the field of medicine, α-cyclodextrin is widely used in drug carrier systems because of its non-toxicity and good biocompatibility. Its special molecular structure can form an inner cavity and form clathrates with drug molecules, thereby improving the solubility, stability, and bioavailability of drugs. At the same time, it can also cover the bitter taste and odor of the drug and improve the patient's medication experience. In addition, by controlling the release rate of the inclusion compound, the effects of sustained release and controlled release of the drug can be achieved.⁴

Food Industry

In the food industry, α-cyclodextrin as a food additive is mainly used to improve the taste, stability, and nutritional value of food. Its special molecular structure can wrap odor molecules, and reduce the bad smell of food, thereby improving the taste of food. It can also be used as a carrier to combine with vitamins, minerals, and other nutrients to improve the stability and bioavailability of these ingredients in food. In addition, it also has the effect of preventing food oxidation, which helps to extend the shelf life of food.⁵

Cosmetics Industry

In the cosmetics industry, α-cyclodextrin, as a carrier of spices and active ingredients, can effectively encapsulate spice molecules, reduce the volatilization of spices, and make the aroma of cosmetics more lasting. It can also form clathrates with the active ingredients in cosmetics, improving the stability and permeability of these ingredients, helping to increase the efficacy of the active ingredients and reduce their irritation to the skin.

Conclusion and prospect

In summary, α-cyclodextrin, as an important cyclic oligosaccharide, has shown wide application prospects in food, medicine, cosmetics, agriculture and environment. Its unique structure and excellent functional characteristics make it play an important role in improving product quality, improving product performance and protecting the environment. In the future, with the continuous progress of science and technology and the increasing demand for health and environmental protection, its application fields will be further expanded, and its market potential will continue to be released.

However, it is worth noting that despite the many advantages of α-cyclodextrins, there are still some challenges and problems in their production and application. For example, how to further improve production efficiency and reduce production costs; How to optimize the production process and reduce the generation of by-products; How to better play the functional characteristics of α-cyclodextrin and improve the added value of products. Therefore, it is necessary to strengthen the research and development of it in the future, and promote the industrialization process and the pace of technological innovation. At the same time, it is also necessary to strengthen the evaluation and research on its safety and environmental protection to ensure that it can play a safe, environmentally friendly and efficient role in various fields of application.