Chymotrypsin (EC 3.4.21.1) is a digestive serine proteinase secreted by the pancreas as an inactive precursor and activated in the small intestine. It cleaves peptide bonds adjacent to aromatic amino acids such as tyrosine, tryptophan, and phenylalanine, continuing the digestive work that pepsin begins in the stomach. Beyond digestion, food scientists use chymotrypsin to study protein structure and to produce defined protein hydrolysates for specialized nutrition, flavour applications, and hypoallergenic formulas. Its predictable cleavage pattern makes it a precise tool for mapping and modifying food proteins.