Purple potatoes, also known as black potatoes, have purple to dark purple flesh. It is rich in selenium and anthocyanins in addition to the nutrients of ordinary sweet potatoes. Purple potato is one of the main raw materials for anthocyanins. Purple is the purple potato in the presence of anthocyanins, anthocyanins molecular weight: 287.246, molecular formula: C15H11O6 This is nature is widely present in the plant water-soluble natural pigments, belongs to the flavonoid compounds. It is also the main color presenting substance in plant petals. Anthocyanin exists in the vesicles of plant cells and can be transformed from chlorophyll. Low temperature, lack of oxygen and phosphorus and other adverse environment will also promote the formation and accumulation of anthocyanins.

In recent years, people began to pay attention to food nutrition, found that the purple sweet potato nutritional value is very high, all over the agricultural research units to breed a lot of high yield, good quality of purple sweet potato new varieties, the market purple sweet potato on more, and the price is higher than the general varieties. Many foods contain anthocyanin, in many purple food, purple potato not only high yield, low cost; and anthocyanin content is also high, so doubly favored. Recently, research papers on purple sweet potato have been published continuously, such as Modern Food Science and Technology, which published "Research on the spectral characteristics and antioxidant properties of purple sweet potato anthocyanins" in 2009, which showed that purple sweet potato anthocyanins have strong antioxidant effects.

Fan Zhihong, an associate professor at the Department of Nutrition and Food Safety in the College of Food Science at China Agricultural University, pointed out, "In fact, natural plants are supposed to come in a variety of shapes. The same kind of thing, big and small, colorful. People only see products of one size and one color simply because humans commonly grow this variety. For example, by crossing various tomato varieties with each other, you can breed tomatoes of different colors such as crimson, pink, yellow, and green, as well as different sizes. These are very normal things, and not related to genetic modification at all. It is just as if there are different ethnic groups in the human race, and when different races intermarry, they will give birth to mixed-race children with changes in nose height, mouth shape, eye and hair color, height and height, and so on. On the contrary, some genetically modified products tend to look normal, so it is not possible to judge whether they are genetically modified by their color or size."

Authoritative answer from Professor He, a researcher at the Institute of Nutrition and Food Safety at the Chinese Center for Disease Control and Prevention: "Focusing on answering the question that people often ask: According to information released by the Ministry of Agriculture's Agricultural Genetically Modified Organisms (GMOs) Safety Administration Office on April 27, 2013, as of that time, China*** had issued Agricultural Genetically Modified Organisms (GMOs) Safety for seven types of GMO plants certificates: storage-tolerant tomato, insect-resistant cotton flower, altered flower color petunia, disease-resistant chili pepper, disease-resistant papaya, insect-resistant rice, and transphytase corn." Purple potatoes are not included in this, which gives us a very authoritative answer that purple potatoes are not genetically modified food, it is a natural food.