On Food and Cooking

both cases, the proteins no longer repel each
other as strongly, and therefore approach each
other and bond together earlier in the cooking
and unfolding process, when they’re still
mostly balled up and can’t intertwine and
bond with each other as tightly. In addition,
coagulation of the yolk proteins and of some
albumen proteins depends on sulfur chemistry
that is suppressed in acidic conditions (see the
discussion of egg foams, p. 103). So eggs end
up more tender when salted, and especially
when acidified.
Cooks have known this for a long time. In
Morocco, Paula Wolfert found that eggs are
often beaten with lemon juice before long
cooking to prevent them from becoming
leathery; and Claudia Roden gives an Arab
recipe for scrambled eggs made unusually
creamy with vinegar (the eggs’ alkalinity
reduces the amount of free, odorous acetic
acid, so the flavor is surprisingly subtle). Eggs
scrambled with tart fruit juices were popular