To peptonise is to digest protein with enzymes, breaking long polypeptide chains into shorter peptides and peptones. The term comes from peptone, the historical name for these partial digestion products, and it describes both the body’s own digestive action and industrial processes that mimic it. Food manufacturers peptonise proteins deliberately: enzymatic hydrolysis of milk, soy, or fish proteins produces hydrolysates used in sports drinks for rapid amino acid delivery, in hypoallergenic infant formulas where extensively broken-down protein reduces allergenicity, and in flavourings where peptides contribute savoury, umami notes. The degree of hydrolysis is controlled precisely, since under-hydrolysed protein retains allergenic epitopes while over-hydrolysed protein tastes bitter from exposed hydrophobic amino acids. Peptonisation is digestion outsourced to the factory.