Last week, we asked
you to tell us why it is that some foods, like
eggs, get hard when you cook them - while other
foods, like chocolate, get softer.Thanks to
everyone who took the time to write in. And now,
without further ado... the explanation, as sent in
by listener Gretchen Kolsrud!
Foods that get harder
when heated contain lots of animal protein and they
get harder because the heat denatures the protein,
thus changing the linkages among amino acids. Note
that it isn't just eggs, but other proteinaceous
substances, such as chicken and steak, and scallops
and lobster, that are also harder when they are
cooked. Substances containing low amounts of
protein, or containing vegetable protein, and
especially substances with substantial amounts of
fat, get softer when heated because the heat just
excites the component molecules, making them
"slippier" so to speak.
