On Food and Cooking

Mollusc Flavor Oysters, clams, and mussels
are prized for their rich, mouth-filling taste,
especially when eaten raw. We owe this
savoriness to their accumulation of internal
taste-active substances as an energy reserve
and to balance the external salinity of their
home waters. For osmotic balance, marine
fish (and squid and octopus) use tasteless
TMAO and relatively small amounts of amino
acids, while most molluscs rely almost
entirely on amino acids: in the bivalves,
especially brothy glutamic acid. And instead
of storing energy in the form of fat, molluscs
accumulate other amino acids — proline,
arginine, alanine, and some combined forms
— as well as glycogen, the animal version of
starch, which is itself tasteless, though it
probably provides a sense of viscosity and
substance, and is slowly transformed to sweet
molecules (sugar phosphates).
Because shellfish use amino acids to
counteract salt concentration, the saltier the