Put 500g of cut beef in a pot, then mix soy sauce10g, 7.5g of baking soda, 5g of raw chalk and 75g of clear water into a paste, mix them well with beef, and finally cover with 25g of peanut oil.

First, the purpose of beef in baking soda: Most protein is acidic, and some are alkaline. Protein in beef is acidic. When its protein solution is in PI, its solubility is minimum, while the osmotic pressure, viscosity, expansibility and conductivity of the solution are reduced to the lowest values. Therefore, the beef is soaked in a proper amount of baking soda for a while, in order to adjust the PI value and stay away from the isoelectric point, so that the beef with thick and tough meat can fully expand and absorb water and become soft and tender.

Second, the role of adding raw flour: keep the moisture and umami in beef, and more importantly, nutrients. If you don't mix wet powder, the water will be evaporated quickly during cooking, and the umami and nutrients will overflow with the water, so the texture will become old, the umami will decrease and the nutrients will be lost. Therefore, the raw flour (wet flour) is mixed to wrap the beef with a film, so that the moisture, umami flavor and nutrients in the beef are not easy to overflow. So as to keep it fresh, tender, smooth and full.

Third, why peanut oil is only used as the cover and not mixed with beef at the same time: fat can be hydrolyzed under alkaline conditions. Because beef has been mixed with baking soda, if peanut oil and baking soda are stirred together, the free fatty acids generated in water can easily react with alkalinity to generate corresponding fatty acids (also called saponification reaction), which will produce a soap foam and affect the taste of dishes.