It is called yacon, which originated in the Andes of South America. Yacon, commonly known as "underground fruit", is a rare and precious food. It looks like a sweet potato. The pulp, such as Sydney, is thin and juicy, crystal clear, sweet and crisp, and belongs to low-calorie carbon hydrate. Yacon is rich in fructooligosaccharides and 20 essential amino acids. It also contains trace elements and rich minerals, such as potassium, calcium, magnesium, zinc, selenium and iron. Yacon, an original wild plant, has the functions of cooling and annealing, clearing away heat and toxic materials, can be eaten raw without skin, can eliminate acne, constipation, diminish inflammation and diuresis, clear away liver-heat and toxic materials, soften blood vessels and lower blood pressure, and has obvious health care effect on cardiovascular and cerebrovascular diseases of the elderly, so it is suitable for diabetics and dieters.