Now as we chew our food we're basically mechanically digesting that food. Mechanical digestion refers to the process by which we break down large food particles into smaller food particles. And what this does is this increases the surface area on which the enzymes, the proteolytic digestive enzymes can actually act on. So inside the oral cavity we have mechanical digestion but we also have chemical digestion as well. Chemical digestion refers to the process by which our digestive proteolytic enzymes actually act on the macromolecule food molecules and break them down into their constituents. They cleave the bonds via the process of hydrolysis.