angustifolius, luteus). They’re unusual
because they contain no starch — they’re 30–
40% protein, 5–10% oil, and up to 50%
soluble but indigestible carbohydrates
(soluble fiber, p. 258). Though there are some
“sweet” types that require no special
processing, many varieties contain bitter and
toxic alkaloids and so are soaked in water for
up to several days to leach these substances
out. They’re then boiled until soft, and served
in oil, or toasted and salted. A New World
species, L. mutabilis, grown in the Andes, has
a protein content approaching 50% of the dry
seed weight.
Soybeans and Their
Transformations
Finally, the most versatile legume. Soybeans
were domesticated in northern China more
than 3,000 years ago, and eventually became a
staple food throughout much of Asia; their