Low temperature baking is sterilization by microwave low temperature drying. The baking time varies from product to product, and the nutritional components will not be greatly lost. Low-temperature baking is to bake raw products into mature products and pick out impurities and inferior grains. Coarse grains contain more nutrients than flour and rice. Coarse grains refer to other grains except rice and wheat, namely corn, buckwheat, oats, millet, sorghum and potatoes. Some trace elements in miscellaneous grains, such as iron, magnesium, zinc and selenium, are more than those in flour and rice. These trace elements are of great value to human health. The contents of potassium, calcium, vitamin E, folic acid and bioflavonoids in coarse grains are also richer than those in flour and rice.