On Food and Cooking

Scrambled eggs and omelets kept hot in a
chafing dish or on a steam table will
sometimes develop green patches. This
discoloration results from the same
reaction that turns hard-cooked yolks green
(p. 89), and is encouraged by the persistent
high temperature and the increased
alkalinity of the cooked eggs (the rise is
about half a pH unit). It can be prevented
by including an acidic ingredient in the egg
mixture, around a half teaspoon/2 gm
lemon juice or vinegar per egg; half that
amount will slow the discoloration and
affect the flavor less.
Curdling Insurance: Starch in Custards
and Creams Flour or cornstarch can protect
against curdling in custards and creams, even
if they’re cooked quickly over direct heat and
actually boil. (The same is true for egg-based
sauces like hollandaise; see p. 628.) The key
is the gelation of the solid starch granules in
these materials. When heated to 175ºF/77ºC