Starch is a natural organic compound synthesized by plants through photosynthesis and is a renewable resource. With the development of production, starch, as an industrial raw material, puts forward different requirements for its properties, and natural starch suffers from its inherent properties, such as insoluble in cold water, easy aging and dehydration of starch paste, poor film performance, lack of emulsifying power, drug resistance and Due to the limitations of poor mechanical resistance and other deficiencies, it is increasingly unable to meet the new requirements of modern industry. Therefore, various modified starches have emerged as the times require. Modified starch refers to starch whose properties have been changed by physical, chemical or enzymatic means.
Starch modification can not only improve the original properties of starch, but also endow it with new functional properties, so that it can be widely used in many fields such as food. In the food industry, modified starch can be used as a variety of functional additives to improve food quality or develop new varieties, reduce production costs and optimize production processes. my country is a large agricultural country, with abundant resources such as corn, wheat, potatoes, sweet potatoes, and cassava
Rich in resources, with obvious resource advantages, the development and utilization of modified starch has very broad prospects.
1 Classification of modified starch
According to the mechanism of denaturation reaction, the products of starch denaturation can be divided into three categories: starch decomposition products, starch derivatives and cross-linked starch.
Starch decomposition products include various acid hydrolysis, enzymatic hydrolysis, oxidation, high temperature degradation products, such as various dextrins, a-starch and oxidized starch.
Starch derivatives are products obtained after hydroxyl groups in starch molecules are replaced by various functional groups, such as carboxymethyl starch, hydroxymethyl starch, and cationic starch. Ether bonds or di-ester bonds make two or more starch molecules "bridge" together to obtain cross-linked starch, such as distarch phosphate, acetylated distarch phosphate and hydroxypropyl glycerol distarch.
Starch can be divided into the following categories according to different processing methods: (1) Physically modified starch: including pregelatinized starch, oil-modified starch, smoke-modified starch, extrusion-modified starch, metal ion-modified starch, ultra-high pressure radiation-modified starch, etc. . (2) Chemistry
Modified starch: extreme dextrin, acid-modified starch, oxidized starch, esterified starch, etherified starch, cross-linked starch, cationic starch, starch graft copolymer, etc. (3) Enzymatically modified starch: resistant starch, dextrin, etc. (4) Natural modified starch: apply genetic technology and selection technology to cultivate modified starch with special purpose.