(C6H10O5)n – starch – is a tasteless white powder, insoluble in cold water. When starch is compressed, the friction between its particles produces a characteristic creak. It is a complex carbohydrate made of many glucose units joined by chemical bonds. Starch is the most common carbohydrate in human diets. The main sources of starch are cereals: rice, wheat, corn; various root crops, including potatoes. Papermaking is the largest non-food application for starches globally; starch lends paper its necessary strength. Starch is also used in the pharmaceutical industry as a filler of tablet forms of drugs.