What are potatoes make of?

Potatoes consist of about 80 percent water and 20 percent solid matter. Starch makes up about 85 percent of this solid mass, and the rest is protein. Potatoes also provide vitamins including niacin, riboflavin, thiamin, and vitamin C. They also contain minerals such as calcium, iron, magnesium, phosphorus, potassium, sodium, and sulfur.