On Food and Cooking

whisking also incorporates air, which lightens
the mixture. If the fish is very fresh, then it
can be enriched and tenderized with cream
and bound simply with salt, which extracts
some myosin protein from the muscle fibers
to help them stick together. With less pristine
fish — weeks in the freezer can cause
premature protein aggregation and a wet,
crumbly puree — egg whites help hold the
particles of fish muscle together, as do
various starchy materials, including bread
crumbs, flour-based béchamel and velouté
sauces, pastry doughs, and mashed rice or
potatoes. The mousseline mixture is firmed by
refrigeration, then shaped into dumpling-like
quenelles, or wrapped inside thin fish fillets
(paupiettes), and gently poached; or it’s put in
ramekins or a pan and cooked in a water bath
to make pâtés and terrines. The target
temperature at the center is 140–150ºF/60–
65ºC; higher temperatures give a harder,
heavier result.