Tyrosine crystals
Hard white clusters of the amino acid tyrosine that form inside very old cheeses.
Also: tyrosine, amino acid crystals
Tyrosine is one of the amino acids that makes up milk protein. During long ageing, enzymes break casein into smaller and smaller pieces, freeing tyrosine. It dissolves poorly in the cheese's limited water, so it collects into small white clusters, sometimes visible as pinpoint dots, sometimes as crunchy granules. They are found mostly inside very old cheeses such as Parmigiano Reggiano, Grana Padano, aged Gouda, Comté, Gruyère and old cheddar, and are a sign of long ageing and proteolysis. They are often called salt crystals, but are not salt, and differ from the calcium lactate crystals that form on the outside of cheddar and Gouda.