Alkaline flour is called soda, and its scientific name is sodium carbonate, which is also edible alkali. It is used in traditional flour to neutralize excess acidity and has no fermentation function. Proper consumption of edible alkali can increase the color, fragrance, taste and shape of food and improve people's appetite. Little Suda, whose scientific name is sodium bicarbonate, is a white crystal, which is soluble in water. The aqueous solution is weakly alkaline and easy to decompose when heated. In hot water, carbon dioxide and sodium carbonate can be slowly decomposed, and all of them will be decomposed at the boiling point.