Proteolysis

Proteolysis is the hydrolysis of peptide bonds in proteins, producing shorter polypeptide chains, peptides, and ultimately free amino acids. In culinary contexts it proceeds via two pathways. The first is enzymatic proteolysis: endogenous proteases (calpains, cathepsins) within muscle tissue continue working post-mortem during dry-aging of beef, lamb, or pork, snipping the long myofibrillar proteins that cause rigor mortis into shorter, looser fragments — the mechanistic basis of tenderness in dry-aged beef. The second pathway is microbial or mold-driven proteolysis: externally introduced organisms produce extracellular proteases that attack protein substrates. In cheesemaking, rennet (containing the protease chymosin) cleaves kappa-casein to initiate coagulation, while the mold Penicillium roqueforti in blue cheese and Penicillium camemberti in Brie produce proteases that break casein into peptides responsible for characteristic pungent, complex flavors. In koji (Aspergillus oryzae) fermentation, protease-rich spores produce enzymes that hydrolyze soy, grain, or fish proteins over days to weeks, generating the glutamate-rich peptide spectrum that gives miso, soy sauce, and garum their deep umami. In garum and fish sauce, autolytic proteolysis (the fish's own endogenous enzymes) plus microbial activity degrade fish muscle into a brown, intensely savory liquid. Marinades containing acidic components (citrus, yogurt) induce mild acid-catalyzed proteolysis near the surface of meat. Free amino acids produced by proteolysis are key precursors in the Maillard reaction, browning flavor compounds when heated.

“The 90-day dry age had allowed proteolysis to work deeply into the ribeye, dissolving the connective tissue framework and developing the nutty, mineral complexity the restaurant was known for.”

• TechniqueDry-Aging
• IngredientKoji
• ConceptMaillard Reaction

1. 1.On Food and Cooking — Harold McGee
2. 2.The Noma Guide to Fermentation — René Redzepi & David Zilber
3. 3.Cheese and Fermented Milk Foods — Frank Kosikowski & Vikram Mistry
4. 4.Meat Science — R. A. Lawrie & D. A. Ledward

Confidence: high