Why do you put alum and soda ash in fried dough sticks or oil cakes?

Produce carbon dioxide gas, which plays the role of expansion.

Use baking soda. Equation: 2nahco3 = △ = = Na2CO3+H2O+CO2 ↑ =

The generated carbon dioxide enters the fried dough sticks, thus making the fried dough sticks fluffy and delicious.