Starch is a polysaccharide made of glucose units that is produced by plants as a form of energy storage. It has been used in various ways throughout history, such as by the Romans in cosmetics and by Egyptians as a glue. Starch consists of amylose and amylopectin and is the main source of carbohydrates in many staple foods. It is insoluble in cold water and alcohol. While flour contains some protein and minerals, starch contains only empty calories and makes for a crispier coating when deep frying. The document provides recipes using starch as a sauce or coating and discusses differences between starch and flour.