There are many ways to make dough rise, such as using baking soda, sourdough starter, or yeast. The principle behind these methods is the same: a leavening agent produces a large amount of carbon dioxide gas in the dough. During the steaming or baking process, the carbon dioxide expands with heat, making the bread soft and delicious.
However, the first two methods have their drawbacks. Baking soda can severely destroy B vitamins in the flour, and sourdough fermentation can give the dough a sour taste. Only yeast fermentation not only improves the taste of the food but also enhances its nutritional value.
Yeast is available in fresh and dry forms. It is an edible, nutritious single-celled microorganism, which is nutritionally called an "inexhaustible source of nutrients." In addition to protein, carbohydrates, and lipids, yeast is also rich in various vitamins, minerals, and enzymes. Experiments have shown that the protein content in 1 kg of dry yeast is equivalent to that of 5 kg of rice, 2 kg of soybeans, or 2.5 kg of pork. Therefore, the nutrients in steamed buns and bread are 3-4 times higher than in flatbreads and noodles, with protein increasing by nearly 2 times. Fermented yeast is also a powerful antioxidant that can protect the liver and has a certain detoxifying effect. Minerals in yeast, such as selenium and chromium, can fight aging, prevent tumors, prevent arteriosclerosis, and improve the body's immunity. After fermentation, phytic acid in the flour, which affects the absorption of elements like calcium, magnesium, and iron, can be broken down, thereby improving the human body's absorption and utilization of these nutrients.