Authentic sweet potato vermicelli is made of sweet potato, which costs a lot and needs to be sold for more than ten yuan a catty. The reason why the supermarket dares to sell two pieces of sweet potato powder is because these vermicelli are produced by big factories. These factories must be made by machines, so it replaces labor, saving a lot of labor costs, but not much money. Because in the process of making sweet potato vermicelli, even if it is made by machine, the crushing process is only omitted in the middle, and other cleaning and drying are still done by hand.
Those vermicelli in the supermarket are not real sweet potato vermicelli at all, but a lot of cheap starch is added and sold very cheaply, so if it is added to sweet potato powder to make vermicelli, the cost is relatively low. Even some factories add some industrial gelatin when making vermicelli. This kind of food is harmful to your health, so people usually see two or three yuan a catty of vermicelli in the supermarket, so it is best not to buy it.
There is actually a way to identify the true and false sweet potato vermicelli. The first is to look at the color. Generally, the color of pure sweet potato vermicelli is yellow or yellowish brown, and some are even translucent, but some bleach will be added to the fake sweet potato vermicelli. Another way is to smell. Generally, even if the sweet potato vermicelli is made into vermicelli, it will still have the taste of sweet potato, but those fake vermicelli will have the taste of dye or other smells.