[Mung Bean: Thua Ngok (Thai); Tauge (Chinese Hokkien); Tao Nge (Thai Hokkien); Tua Ngok (Laos); Sukjunamul (Korea)]
[Soy Bean: Kongnamul (Korea)]
Various kinds of beans are sprouted before being served or cooked in recipes. Sprouted beans cook quickly and are more nutritious than the dried seeds. One study of sprouted soybeans showed Vitamin B levels stayed the same, while Vitamin A increased 300% and Vitamin C increased between 500% and 600%. There was also a wider range of amino acids. Soybean sprouts have also proven effective in regulating blood sugar levels. What beans are sprouted and to what extent they are sprouted varies from region to region.
As with all legumes, bean sprouts do contain some anti-nutrients, so consumption of raw bean sprouts should be moderate. Phytic acid, a primary anti-nutrient which blocks mineral absorbtion, is reduced by the many rinsings the beans go through during sprouting, but there is still a fair amount remaining, particularly in soybean sprouts. Anti-nutrients are further reduced by cooking.
Sprouting beans at home is very easy, but do not expect to produce the straight plump stems of the sprouts shown to the left. This takes special equipment to accomplish, including keeping the sprouting beans under weights. See the section below on Sprouting Beans, Peas and Lentles.
More on Products made from Beans.
East Asia & Southeast Asia
In this region, long sprouts of Mung Beans (Vigna radiata) predominate, with sprouts of Soybean (Glycine max) used to a much lesser extent, except in Korea. These sprouts are shown in the photo above, with Soy Sprouts at the top and Mung Bean Sprouts below. Soybean sprouts sold in North America are usually around 3 inches, not including the root, but are grown as long as 11 inches in Korea. Mung bean sprouts are very well known in North America, but Soybean sprouts are mostly available from Korean markets.
While Soybean sprouts are the most used kind in Korea, they are used to a much lesser extent in China, and are hardly used at all in Japan. I attribute this to the relative robustness of Korean recipes, where a durable sprout with a more robust flavor is appropriate. They are also used in Southeast Asia, to about the same extent as in China.
Buying: Fresh Mung Bean sprouts are available in markets everywhere in North America. Soybean Sprouts are available in Korean markets. Sprouts should be crisp, with no sign of softening or decay.
Storing: Refrigerated in a plastic bag, with no free water, Mung Bean Sprouts will last three days or so, Soybean Sprouts about 2 days longer.
Prep: Bean sprouts should be rinsed. In China and Korea, the thread like root end will always be pinched off (it's jobs like this children are for), but we Barbarians often skip this tedious step. It takes about 45 minutes to pinch the roots off 12 ounces of bean sprouts. In Korea, some recipes call for the yellow bean to be removed, but for most recipes it is left on. Some Korean markets carry bags of Soybean Sprouts with the root ends cut off.
Cooking: Keep it short. For some recipes, as little as 10 seconds in boiling water for Mung Bean Sprouts, 30 seconds for Soybean Sprouts. For soups and stews, the bean sprouts go in in the last minutes of cooking. In some Southeast Asian soups, raw mung bean sprouts are simply sprinkled on top of the soup at serving.
South Asia - India
In India, both Mung Beans and Soybeans are are sprouted, and many other beans as well, but much differently than in East and Southeast Asia. The photo to the left shows a close up of mung beans sprouted properly for Indian recipes. Most of the nutritional advantages of sprouted beans are already realized when the tails are just 1/2 inch or so long. You will not be able to find sprouts like these in markets in North America, and will have to sprout your own.
Cooking: Sprouts in this form can stand more cooking
than than the East Asian style sprouts. Most beans should be cooked to
reduce the natural toxins they contain. Generally, beans that didn't
sprout are cooked right along with the sprouted ones. Some beans,
like Black Beans, have a low germination rate (as little as 50%).
In India, many different beans are used sprouted. The beans shown in the
photo to the left are Kodava Val, a rather small variety of Lablab
beans from southern India. This one has a very tough skin, so is usually
sprouted, then the skin is removed. That's a rather tedious job (again,
this is the sort of job children are for), but the flavor of the beans
is very good.
A rig like the one in the photo to the left is all you need to successfully sprout beans, peas, lentles. Of course, there are many much more complex sprouters available on the Internet, but this one does fine for beans, peas and lentils, especially when sprouting them for Indian recipes. If you want to sprout grassy things you mow for your salad, that's another matter entirely. The mung beans in the pictured sprouter were started 2 days ago, and will be ready in another day or so.
Don't expect to produce sprouts with straight plump stems like the commercial ones in the photo at top of page - this takes special equipment and techniques. Sproutable Mung Beans are very widely available in North America, but soybeans for sprouting are usually special small varieties, though these can probably be found in Korean markets. Many other beans, peas and lentles can be sprouted, and are sprouted, particularly in India.
Always take care with sanitation, as sprouts can host E.coli and
Salmonella. This is usually a problem with commercial sprouts, which
will spend a fair amount of time between sprouter and salad.