The difference between flour and starch is in the materials used to make them and their appearance. Flour is a powder that is milled directly from wheat or other grains after they have been peeled, while starch is a polysaccharide powder that is extracted from plants such as groundnuts or potatoes or wheat after the proteins and other substances have been separated. Starch is somewhat whiter than flour, which looks yellowish.

Flour is a powder made from ground wheat. According to the amount of protein in the flour, it can be categorized as high-gluten flour, medium-gluten flour, low-gluten flour and gluten-free flour.

Flour is the staple food in most parts of northern China, and there are many varieties of food made from flour, with many different patterns and flavors.

Starch is a polymerization of glucose molecules, and it is the most common form of carbohydrate storage in cells. Starch is also known as gravy in the restaurant industry. There are two types of starch, straight chain starch and branched chain starch. The former has an unbranched helical structure, while the latter is made of 24-30 glucose residues linked head to tail by α-1,4-glycosidic bonds, with α-1,6-glycosidic bonds at the branched chains.

Starch can be regarded as a homopolymer of glucose. In addition to food, starch is used industrially in the manufacture of dextrin, maltose, glucose, alcohol, etc. It is also used in the preparation of printing paste, sizing of textiles, gluing of paper, and pressing of pharmaceutical tablets. It can be extracted from starch-containing substances such as corn, sweet potato, wild acorn and kudzu.