Soybeans can be eaten for themselves, as edamame, lightly boiled immature (green) beans, usually served in their inedible pod and then shelled at the table. Raw soybeans are, practically speaking, inedible. They contain lectins and protease inhibitors, which interfere with digestion. Boiling knocks these gastronomic thugs out of contention.
After heating, soybeans come into their own as food. They have the highest protein content of any vegetable (35 percent), and their amino acid balance is very close to that of meat, making them an extremely efficient and valuable nutritional source for vegetarians. Of Asian origin, soybeans are now the leading agricultural product of the U. S., where they are mainly exploited for their abundant oil and as animal feed.
Most of us higher mammals consume soy as tofu or bean curd, a delicate solid that precipitates out of soy milk* in the presence of gypsum or magnesium chloride (sold in a seasoned form as nigari in Asian markets). I have done this at home, starting with water and beans. It is excessively simple, although something of a mess. My tofu was, I thought, brighter tasting than storebought tofu. But I am perfectly content to buy the equally protein-rich tofu omnipresent in markets and then to use it in one of the hundreds of recipes I like from China and Japan.†
*Produced by soaking raw beans in water, grinding them, and straining off the solid residue
†Deep-fried tofu is an elegant dish, in my view. My friend Madeline Lee thinks otherwise. She once called it “deep-fried nothing.”