Baking Powder leavening agent that is a mixture of sodium bicarbonate and other acids, used widely in cakes. It increases the volume and lightens the texture of goods baked. A very common ingredient around the kitchen, it is used a raising agent in cakes, breads and biscuits.Since its a combination of an acid and alkaline, recipes with acid making baking powder more effective. Baking powder is always added to dry ingredients for better aeration. Baking powder is also used a substitute for yeast in bread.