Dried potatoes are processed peeled into sweet potatoes, cut into strips, laid flat on a board, then taken out for drying. Fresh sweet potatoes contain only a lot of water, but also glucose. The water gradually evaporates, the glucose fructose contained in the flesh penetrate into the skin. Although the sweetness of glucose is as sweet as fructose, it is easy to catch the water in the air.

When it penetrates into the dried skin of sweet potatoes, it becomes a layer of white powder, known as hoarfrost. After steaming drying sweet potatoes, they still contain a large amount of water, as well as glucose fructose. When they are dried, the water gradually evaporates, the glucose fructose contained in the flesh penetrate into the skin.

These two types of sugars have different properties. Fructose has a sweet taste is easy to absorb water. When it penetrates the surface of sweet potatoes, it grabs the moisture in the air adheres to the skin, similar to the syrup on the outside of candies. Glucose has a sweeter taste than fructose, but it is easy to catch the moisture in the air. When it penetrates the skin, it becomes a layer of white powder, which happens to wrap the adhered fructose, Make the entire sweet potato dry.

Usually, it is white heart dried sweet potatoes, while yellow heart dried sweet potatoes are usually cooked as mature snacks. Raw yellow heart dried sweet potatoes are only made when a few people like to eat them. Yellow heart dried sweet potatoes can be made into rice together with rice cooked with porridge because yellow heart is sweet, while white heart dried sweet potatoes have no taste when cooked with porridge, making them difficult to eat. Each has its own way of eating. Sweet potatoes nourish the stomach, yellow heart sweet potatoes don't make people fat, so you can eat more if you want to have a good figure, sweet potatoes are also coarse grains.