The role of dry yeast is mainly to ferment food, and it also plays a role in improving the nutritional value of fermented foods. However, it is not a medicine and cannot perform the same effect as a medicine. Dry yeast is a kind of leavening agent, which is generally used in daily life, and can be used in the production of bread and cakes. Dry yeast is rich in protein, vitamins and minerals. Generally, every 100g of dry yeast contains 47.6g of protein, 45.5g of carbohydrates, 372kcal of energy, 45.2mg of vitamin B3 (niacin), and 32mg of vitamin B4 (choline), which can be utilized in the fermentation of food to enhance the nutritional value of fermented food. It is recommended to put in the right amount to avoid excessive fermentation of food.