What does powder or soda do in baking?

Answer 1

When baking soda (which is a base) confronts the lactic acid in buttermilk (buttermilk is frequently used in baking, chiefly when making pancakes or corn muffins or biscuits) a chemical reaction occurs spontaneously in which carbon dioxide is liberated. When this happens the CO2 moves upward as small or large bubbles of gas. The rising of the gas is opposed by the stickiness of the batter which usually is part wheat flour which contains gluten, a wheat protein which makes the batter sticky and elastic. The net result of these two opposing actions is the leavening of the baked product so that the texture is soft and light as in the case of muffins, biscuits or pancakes.

With baking powder carbon dioxide is liberated when a phosphate acid-based salt reacts with sodium bicarbonate in the baking powder. In slow-acting baking powder, heat is required to activate the CO2-liberating reaction so rising doesn't begin until the product is placed in the oven. Fast-acting baking powder, however causes rising as soon as the batter is mixed. Most baking powder sold today is called "double-acting" in that it contains both slow and fast-reacting constituents. It is preferable, from a health standpoint, to use aluminum-free baking powder such as Rumfords which contains sodium phosphate instead of aluminum phosphate.

Answer 2

that helps the food rise