Yam meat purple to dark purple. It is rich in protein, starch, pectin, cellulose, ammonia acids vitamins and a variety of minerals, but also rich in selenium element and anthocyanins. Purple yam nutrient-rich special health functions, including protein, amino acid are easy to digest and absorb by human body. Which are rich in vitamin A can improve eyesight and skin mucosa epithelial cells, vitamin C can make normal for collagen protein synthesis, the prevention and treatment of scurvy, anthocyanins are natural potent free radical scavenger.