Yeast is a quite advanced microorganism with differentiated nuclear membrane and nucleolus, and its cell structure is complex. Yeast cells are like a treasure house of nutrition, rich in various nutrients needed by the human body, among which protein is the most abundant, and also contains essential amino acids, I+G and other flavor substances, B vitamins and calcium, magnesium, zinc, iron, selenium and other trace elements. Since the nutrients of yeast cells are surrounded by thick cell walls, they need to be broken down to make full use of the rich nutritional resources in the yeast cells.