Dextrin is a technical term used to measure the cooking process of raw materials. When starch is decomposed and hydrolyzed by heating, acid or amylase, the macromolecular starch is first converted into a small molecular intermediate substance. At this time, the intermediate small molecule substance is called dextrin. Dextrin is usually divided into three categories: maltodextrin, resistant dextrin, and cyclodextrin.

Maltodextrin is a low-degree hydrolysis product of starch by enzymatic process, with a DE value of less than 20%. The main components of maltodextrin are dextrin and polysaccharides with different polymerization degrees. In the final analysis, maltodextrin belongs to starch polysaccharides and can be digested and absorbed by the human body. Maltodextrin has the characteristics of good thickening effect, high solubility, stable carrier, not easy to absorb moisture, and outstanding water holding capacity after water absorption. At the same time, the amount of maltodextrin is not limited and can be widely used in various foods. For example, maltodextrin can be used in powdered products such as milk powder and soy powder to improve solubility, can act as a carrier in solid beverages, and has a good thickening effect in meat products and canned foods.

Resistant dextrin is a water-soluble dietary fiber made from edible starch through dextrinization under acidic conditions. This fiber is difficult to be decomposed by human digestive enzymes and is not absorbed in the digestive tract and directly enters the intestine, thereby playing the role of dietary fiber in improving intestinal function. Foreign countries have studied and applied resistant dextrin earlier. In 2012, it was approved as a food raw material in China. The development momentum is rapid, and the number of products with resistant dextrin as a selling point is gradually increasing. 
Resistant dextrin is applied in the food industry based on function, and can be applied to the following scenarios. 
1. Diabetic food. Water-soluble dietary fiber can delay gastric emptying, reduce the digestion rate of food, and inhibit blood sugar increase. Studies have shown that daily intake of a certain amount of resistant dextrin is beneficial to relieve diabetic symptoms. 
2. Intestinal health food, resistant dextrin can promote the growth of beneficial intestinal bacteria, maintain the intestinal environment, and reduce the occurrence of intestinal diseases.
3. Dairy products, in addition to playing the role of "prebiotics", resistant dextrin can also play an emulsifying role, making the taste of dairy products better. Adding it to products such as ice cream and yogurt can significantly reduce the caloric value of the product without affecting the original flavor of the product.
4. Resistant dextrin can form a complex with protein under a heated environment to form a good spatial structure and enhance the taste. At the same time, resistant dextrin can play a flavor-attaching role to retain the aroma of the product. This feature makes it play an important role in protein systems such as pasta and meat products.

Cyclodextrin is a general term for a series of cyclic oligosaccharides generated by amylose under the action of cyclodextrin glucosyltransferase produced by Bacillus, respectively called α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin. It is hydrophilic on the outside and hydrophobic on the inside, which is easy to form inclusion complexes with hydrophobic guest molecules, so that the physical and chemical properties of the guest molecules, especially water solubility, are improved. Cyclodextrin has low hygroscopicity, strong water retention, uniform and pure properties, and is widely used in the food, pharmaceutical and nutrition industries. Cyclodextrin is mainly used in the food industry for molecular analysis of flavor substances and other sensitive components.
Due to the special structure of cyclodextrin, cyclodextrin inclusion complexes and functional "empty" cyclodextrin (unencapsulated guest) effectively improve the solubility of insoluble or insoluble substances in water, reduce the volatility of volatile components, and increase the chemical stability of guest substances in materials, etc., and are widely used in food. At the same time, dextrin, as a natural degradation product of starch, provides a new option for the preparation of water-in-oil emulsions. It can embed fatty acids to stabilize the emulsion. In addition, emulsions of different viscosities can be made, and the taste can be adjusted as needed. It can form inclusion complexes with starch lipids and inhibit the retrogradation of amylose.
Regulations on the use of cyclodextrin as a food additive in food: The U.S. Food and Drug Administration (FDA) lists α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin as food additives on its safe list (GRAS), and also lists HP-β-cyclodextrin in the inactive drug ingredient list. Regarding food additive labeling, the FAO/WHO expert committee recommends that the amount of β-cyclodextrin added to food is 5 mg/kg per day. Due to their toxicological properties, there is no definition of their daily allowable intake. my country's "GB2760-2014" food additive use standard stipulates that α-cyclodextrin and γ-cyclodextrin can be used as stabilizers and thickeners in various foods according to production needs. The use of β-cyclodextrin as a thickener in gum candies is 20.0g/kg.
In recent years, cyclodextrin polymers, complexes and their derivatives have received more and more attention and research in food processing, and more valuable applications will be found in the food industry in the future. Functional foods and packaging related to cyclodextrin will also be a truly emerging field.