Starch is a storage polysaccharide stored in cells in the form of starch granules during plant growth, and is made from corn, sorghum, wheat and other grains and potato, sweet potato, cassava and other crops as raw materials, by soaking, grinding, and non-starch substances such as protein, fat, cellulose and other non-starch substances are separated and removed. Starch is also the most common carbohydrate in the human diet, widely found in staple foods such as potatoes, wheat, corn, rice and cassava.

It is composed of two parts: straight-chain starch (starch granules) and branched-chain starch (starch cortex). Their proportion of starch varies with the type of plant.

Straight-chain starch is a chain-like compound composed of glucose bound by alpha-1,4-glycosidic bonds that can be hydrolyzed to maltose by amylase. The content in starch is about 10~30%. Soluble in hot water but not paste. It shows blue color when it meets iodine.

Branched-chain starch glucose molecules in addition to α-1,4-glycosidic bonds, there are α-1,6-glycosidic bonds connected. So with branching, about 20 glucose units have a branch, only the peripheral branch chain can be hydrolyzed by amylase to maltose. It is insoluble in cold water and swells to a paste with hot water. It is purple or reddish purple when exposed to iodine.

Use of starch:

Starch is processed in the food industry to produce a variety of sugars, and plays a great role in various types of food processing. Foods that utilize starch as an ingredient or main ingredient include: various kinds of vermicelli, tripe, cold noodles, jiongzi, vermicelli, vermicelli, ham, Luo Han tripe, etc.

Starch is dissolved in warm water to produce dextrin, which can be used as a thickener, and hardened as a bonding agent. The most widespread use of starch in the non-food industry is as a binder in the papermaking process.