Baking soda (sodium bicarbonate) raises the surface pH of meat. That change loosens some of the muscle proteins, so they don’t contract as aggressively when heated. The result is better water retention and a meatier, juicier bite. You’ll also notice faster and more even browning because a higher pH speeds the Maillard reaction.
The effect is greatest where the baking soda contacts the meat surface or small pieces of meat, so it’s ideal for burgers, mince, and thin slices. It isn’t a tenderizer that breaks fibers the way enzymes do. Use it sparingly: too much creates a metallic or soapy flavor and an odd texture. Think of baking soda as a precision tool for brief surface or short-contact applications.