[Bhatt (India); Glycine max]
Soybeans are probably native to China and have been important to agriculture there since the earliest times - but not as a food crop. The beans were planted as a fallow field rotation crop to fix nitrogen and restore fertility to the fields, then plowed under. The photo specimens include whole fresh pods, fresh beans (edamame), dried white beans, black beans, and our ever present red kidney bean for scale.
Much is made in health food circles of soy's (almost) "complete protein". This claim is true, but it would be a lot more useful if the soybean was actually edible rather than shot through with toxins, mineral blockers, vegetable hormone analogs and the like. The plants developed these specifically to fight animal predation - and we are animals.
In China, during the Chou Dynasty (1132-246 BCE), a method of fermenting soybeans to detox them was developed, resulting in the paste we now know as Miso, and similar products. A little later a method was developed to make a soybean cheese from finely ground soybeans by precipitating solids with a salt - the product we know as tofu. Most, (but not all) of the toxins are discarded with the liquid. Fresh soybeans see limited use as appetizers and soybean sprouts see fair use but not so much as mung bean sprouts.
Contrary to popular belief in the US, Asians eat soy products, including tofu and sprouts, only in moderation and not as a really significant part of their diets. Unprocessed soybeans have only been much eaten in times of famine.
The vast bulk of soybean production is used to produce oil which may be used as cooking oil or for other purposes. This oil is high in polyunsaturates so exposure to heat should be strictly limited. Once the oil has been chemically extracted the solids left are used for animal feed and as the basis for many modern soy products, some of controversial safety.
It has recently been reported that animals fed this mash from GMO
soybeans are showing a significant increase in infertility and
spontaneous abortions. More study is needed - study not financed by
Monsanto or the soybean industry.
Soybean sprouts should be crisp with bright yellow tops and white
stems with no evidence of wilting or discoloration. Refrigerate them in
their plastic bag - rinse just before using. They'll keep a couple of
days at most. Koreans insist any seed skins be removed and that the
thread-like root tail also be removed before use in a recipe. This is
tedious so Korean markets often stock bags of sprouts with the tails
already cut off.
Unfortunately, they are reported to contain the same endocrine
disrupters and anti-nutrients as more mature beans, but in somewhat
lower concentration. These substances easily survive the light cooking
these beans are usually subjected to. On the other hand, eaten just
occasionally and in moderation they are not dangerous - but some people
are overusing them as a "healthy" snack food. Also 90% of soybeans grown
in North America are GMO and sprayed with Glyphosphate. The GMO form
and the Glyphosphate are the real dangers with soy. You can find
Edamame in plastic bags in the frozen foods section of most
supermarkets, and Yuppie targeting markets have piles of them.
Soy Shell Beans - Edamame
Soybean Products - and Other Information
Soybeans are the basis for a great many products, both traditional and modern. Some are generally considered safe and others are suspect of being less than ideal.