Putting the Polish on those Humble Beans
Katherine Czapp
Wednesday, 28 February 2007
Legumes comprise a family of some 13,000 species characterized by their ability to absorb nitrogen from the air and convert it into protein within the plants' seeds. They also return nitrogen to the soil for the benefit of nearby plants, and legume cover crops are plowed into the soil as valuable green fertilizer around the world.
High Quality Nourishment
The high protein content of legume seeds, such as in beans, peas and lentils, make them a potential source of high quality nourishment, enhanced by impressive stores of minerals, including magnesium, potassium, phosphorus, iron and molybdenum, as well as B vitamins such as folate and thiamine. All legumes contain both omega-3 and omega-6 fatty acids, with kidney and pinto beans particularly high in omega-3.
Many nutrition information sources tout the fairly high content of both soluble and insoluble fiber in legumes as a foil against heart disease, surmising that the fiber lowers serum cholesterol by binding with cholesterol-containing bile in the intestine and removing it from the body.
Arguably much more important to cardiovascular health is legumes' contribution of potassium and magnesium to the diet--minerals chronically deficient in the standard American diet, and vital for the normal functioning of the heart and circulatory system, helping to regulate blood pressure as well as electrical impulses of nerves and muscle (including heart) contraction. Further, legumes, and especially lentils, contain high amounts of folic acid, a B vitamin which, along with vitamins B6 and B12, convert homocysteine in the bloodstream to innocuous forms. Homocysteine is a byproduct of protein metabolism; it can damage arterial walls and is a marker of heart disease with much more predictive value than serum cholesterol levels.
At Wise Traditions 2006, the seventh annual conference of the Weston A. Price Foundation, Dr. Ross Welch spoke of the decline in legume consumption that has accompanied the huge increase in grain production and consumption during the last twenty years. As grains tend to be lower in nutrients than legumes, and are mostly consumed in refined form, this change in cultivation pattern represents a huge loss of nutrients, especially in Third World countries.
The Digestive Challenge
Legumes prepared in meals with whole grains and some animal protein and fat can comprise a healthy, inexpensive nourishing diet, and in fact have been favored in cuisines the world over for thousands of years. However, some detractors of "modern" innovations in the diet occurring over the last 10,000 years or so argue that our relatively recent use of grains and legumes is not healthy or appropriate fare for humans and our digestive systems.
It is certainly true that legumes have their own agenda, which is to germinate, grow and perpetuate their genetic inheritance, rather than go softly into your cassoulet. These seeds are well-armed with anti-nutrients such as phytates and trypsin inhibitors, and some have specialized complex sugars that can wreak painful revenge upon the mammalian gut that consumes them without proper disarming. But long ago clever humans devised ways to coax these sometimes headstrong legumes into many safe, savory and nutritious transformations.
Legumes were used as food, along with the early grains, at least beginning with the Bronze Age. Early Egyptians built and dedicated temples to the life-supporting attributes of legumes, and later the ancient Greeks and Romans favored beans and lentils in their pantheistic festivals. In fact, four of the most prestigious families of Rome were named for highly valued legumes: Fabius (fava beans), Lentulus (lentils), Piso (peas) and Cicero (chickpeas).
Preparation of some of the softer legumes, such as lentils and peas, is accomplished with relative ease. The legumes are soaked for several hours before cooking gently until soft. The soaking helps denature phytic acid, and gentle cooking makes the vegetable protein digestible, especially if served with digestion-enhancing spices (typical of Indian cuisine, for example), pickles, chutneys or fermented dairy products such as yogurt or sour cream.
The harder beans, such as kidney beans, black beans or navy beans, require more careful treatment, as they contain certain oligosaccharides (large, complex sugars) that can completely confound digestion. Mammals do not produce the enzyme alpha-galactosidase in their digestive tracts, which is necessary to break down these sugars. When consumed, these oligosaccharides reach the lower intestine largely intact, and in the presence of anaerobic bacteria ferment and produce carbon dioxide and methane gases, as well as a good deal of discomfort, not to mention embarrassment in polite society. The solution has been to prepare the beans in a way to neutralize or otherwise get rid of these sugars in the resulting cooked beans, but as most of us know from experience, results can vary widely.
Innovations of the "brave new world" type at the Food Technology Division of Bhabha Atomic Research Center in Mumbai, India show that low-dose gamma irradiation successfully degrades raffinose oligosaccharides in mung beans, while increasing their content of glucose, fructose and galactose. This dose of radiation does not inhibit germination, so the irradiated beans can also be used as sprouted food. The authors claim that "gamma irradiation at insect disinfestation dose levels improved the digestibility and nutrition quality of mung beans by reducing the content of oligosaccharides responsible for intestinal gas production" (_http://www3.interscience.wiley.com/cgi-bin/abstract/68000109/ABSTRACT). One of course worries about the other unmeasured effects of gamma radiation on a commonly consumed food item. A healthy dose of skepticism is in order.
The Science of Bean Preparation
By contrast, in May of 2001, the US Patent Office granted a patent to a small team of researchers who devised a way to remove flatulence-causing oligosaccharides in legumes for the commercial bean canning industry(http://www.patentstorm.us/patents/6238725-fulltext.html). Their paper is long, detailed and almost numbingly precise, but contains important insights into the process of "perfect beans, every time." These bean technicians describe a process gleaned from careful observation, and precise measurement, and without special effects or secret ingredients, which makes use of just water, heat and time.
Hallmarks of their research, which can greatly aid the home cook, include first of all choosing your beans with great care. Beans that are more than 13 months old after harvest will have declining nutrient levels, will be harder to rehydrate and therefore more difficult to cook completely. The result will be largely indigestible and not worth your effort. The best age for "fresh" dried beans is from harvest to four months old. Since it's almost impossible to know how long beans have been sitting in storage at the store or when and under what conditions they were harvested, look for lighter colored beans, no matter what type. Older beans will be darker in color. Also, younger beans will have fewer cracked skins and less splitting overall. Store beans at home in glass or earthenware jars in a dry, cool place; when dried beans either absorb moisture or dry out excessively, nutrition and cooking qualities will suffer.
The key to this "flatulence-free" method of bean preparation is to utilize maximally two actions. One is the leaching out of oligosaccharides into a warm, slightly basic soak water, and the other is to initiate the activity of endogenous oligosaccharide-reducing enzymes to digest the sugars inside the bean.
In Step 1, beans are covered with four times their weight in water which has been warmed to about 120°F. This was the optimal temperature for rehydrating navy beans. Different bean varieties rehydrate best at slightly different temperatures, but the range is from 90°F to 130°F and represents the optimal temperature for rehydrating beans to between 50 and 95 percent of their fresh weight.
The water used in this stage should be soft; specifically with a calcium carbonate content less than 90ppm (parts per million), with a pH between 6.5 and 9.0, in other words, just slightly acid to alkaline. These last two particulars may seem inconsequential, but exert invisible important effects. Cookbooks from the 19th century often noted the type of water to be used in recipes, with references to river water, pond water and well water. Well water was often the least favored choice for cooking, as it was likely to be high in minerals, and therefore very hard. Hard water, or water with 200 ppm or more of calcium, will hinder the rehydrating and other processing effects of the warm water on beans.
The time it takes to rehydrate the beans will vary, but can range from one to four hours or so. A well-rehydrated bean has tissues that will allow migration of the endogenous enzymes throughout the entire bean to digest the sugars in Step 2.
After draining the beans, soft, neutral to slightly alkaline water is again added to the beans at a ratio of 4 parts water to one part beans by weight. This time the water is heated to a temperature that the authors have determined to be optimal for maximum activity of the endogenous enzyme, which is 147°F. The enzymes are inactivated and destroyed at 150°F, so this is a bit tricky for the home cook to monitor. The water during Step 2 is changed two or three times to allow for continuous diffusing of the sugars into the water. If the water were not changed, and equilibrium between beans and soak water reached, the sugar might start diffusing back into the beans. The authors note soaking times for Step 2 that range from 2 to 6 hours or so, depending on the type of beans used. At the end of Step 2 the beans were tested and shown to have no oligosaccharides present, at which point the beans were then briefly blanched (to firm their protein) and then proceeded to the canning process.
Traditions
These industrial techniques can shed some light on small scale bean preparation in the home kitchen. Lacking the temperature-controlled vats of commercial operations, we unfortunately also no longer have the traditional hearth for heating and cooking that would provide a similar slow, even heat that so many dishes benefit from. Edda Servi Machlin, in her fascinating book, The Classic Cuisine of the Italian Jews, describes home bean preparation: "When the hearth was not only a source of heat, but also the only way to cook meals, a pignatto was used to cook beans. A pignatto was a tall earthenware pot with a very small bottom, a large belly, and a small opening on the top. It had only one handle. Beans were placed inside the pot with hot water; then the pot was placed at the edge of the hearth with a few red coals very close, under the belly, on the side opposite the handle. The beans cooked to a gentle, even simmering."
The preparation of cholent, a traditional Sabbath dish of Ashkenazi Jews, involved a very slow cooking--often for as long as 24 hours--of a stew containing beans, vegetables and meat that was meant to provide warm and quite substantial nourishment on a day when lighting fires for cooking was proscribed. In the shtetls of Eastern Europe, the family's cholent cooked gently in the community baker's cooling wood-fired oven after the bread had been baked. Modern-day cholent is most often prepared using a slow-cooker, and this device can also be one of the best ways to prepare beans in general. It is important to avoid boiling beans since this will coagulate their vegetable protein and result in permanently hard, unpalatable beans.
Another trick to cooking beans and minimizing those troublesome oligosaccharides is to add a 4-to-6-inch strip of the sea vegetable kombu (Laminaria of various species, a member of the kelp family) to the bean pot during the warmed soak period. Kombu helps alkalinize the water, and also contains alpha-galactosidase, the enzyme needed for digesting these complex sugars, and therefore enhances that process in the pot. I like to add even more kombu during the slow cooking period, as it lends a delicious, meaty flavor to the beans (not at all fishy) and is mineral-rich, with additional B vitamins and trace elements, as well as a digestion-soothing gel that literally melts into the bean sauce.
Phytates
The high phytate content of legumes creates nutritional problems, especially for populations that rely on them--along with cereal foods--as major protein sources. While legumes are generally high in minerals such as magnesium, calcium and iron, they are also high in phytic acid, which can be a potent inhibitor of mineral absorption, especially of iron and zinc. Deficiencies of both these nutrients are common in the developing world, and particularly in the case of infants, deficiencies of iron can cause developmental problems that persist throughout life. Neutralizing phytic acid thus becomes a crucial necessity for vegetarians and for populations that must subsist primarily on legumes and grains without adequate food from animal sources.
Absorption of minerals from legumes also depends to a large extent on the total composition of the meal. Balancing legume consumption with animal products as well as with foods containing vitamin D and ascorbic acid (such as fresh and fermented vegetables) can enhance mineral absorption and prevent deficiencies.
Soaking legumes before cooking is a very useful step in promoting the release of phytase, the enzyme responsible for phytate degradation. It is interesting to note that different varieties of legumes have different optimal levels of acidity or alkalinity to maximize this process. (Germination also effectively converts phytic acid, as does fermentation via yeast or other fungal agents.) While most cereal grains require a pH between a fairly small range of about 4.0 and 6.0, in other words, of slight acidity (7.0 is neutral), legumes span the scale from 4.0 to 7.5; that is, from acidity to slight alkalinity. Phytate degradation will certainly occur at many ranges of pH, but the table below shows various legumes and the best pH levels for each to achieve the greatest breakdown of phytic acid. Tests have shown that the optimal functioning temperature for phytase activity in all legumes measured is 113° F (British Journal of Nutrition (2002), 88, Suppl. 3, S281-S285).
Cooking Those Beans
How does all this science translate into perfect beans? Soak legumes in plenty of water that has been brought to a simmer and poured over the beans; add about 1/4 cup of something acidic (lemon juice, vingear or whey) to black beans, lentils and fava beans but soak other types of beans (white beans, brown beans and dried peas) in plain water--preferably soft water or water with a pinch of baking soda added. You don't need to worry about having the optimal pH if your diet contains animal foods and if the soaking is followed by a long slow cooking. Use the table below to determine approximate soaking times. For beans that require a long soaking time, you may wish to drain, rinse and add more water at least once during the process.
After soaking, drain the beans and rinse well, then add to a pot with more water and bring to a simmer. If digestibility is a problem for you, kombu added to the pot should take care of any pesky oligosaccharides still lurking. Cook those beans gently until completely tender.
The following recipes will transform the humble legume into a delectable, body-and-soul-satisfying dish of epicurean proportion. And very much worthy of polite society.
Cholent
Cholent may be one of the most ancient and best-preserved of all traditional Jewish foods. For at least two thousand years, this slow-cooked dish was served on the Sabbath, when lighting of fires for cooking was proscribed by the Torah. The cholent cooked very, very slowly over Friday night to be served warm the next day. There are dozens of recipes in existence, reflecting the influences of many different cuisines from various corners of the globe, but they all contain beans, a grain and usually meat. As an interesting note, the Pilgrims who later sailed to the New World had spent time with the Jews in Holland--long a haven for religious dissenters and minorities--and recreated cholent with ingredients they found here, in a version we now call Boston Baked Beans.
1 1/4 cups brown or white beans
2 tablespoons olive oil
1 large onion, coarsely chopped
3-6 cloves garlic, minced
1 1/2 tablespoons Hungarian paprika
1 1/2 teaspoons salt
11/2 teaspoon pepper
3/4 cup barley soaked for 6-8 hours in water plus 2 tablespoons lemon juice, vinegar or whey, and then drained
1 1/2 pounds potatoes (such as Yukon gold or similar waxy type),
cut into large chunks
1 pound beef brisket
1 smoked beef bone or marrow bone
6 raw eggs in the shell, washed
Rinse beans and place in a bowl or pot. Add about 6 cups simmering water and soak for 18-24 hours. For best results, drain a couple of times during the soaking process, rinse the beans and add more simmering water.
Heat oil in a large heavy skillet over medium heat and sauté onion until transparent. Add garlic, stir for several minutes then add paprika, salt and pepper, and continue to cook for a minute. Remove from heat. Combine beans, onion mixture, barley or buckwheat, brisket and bone in a large baking dish or Dutch oven with a tightly-fitting lid. Carefully slip in raw eggs in their shells and bury them under cholent mix. Add water to cover mixture.
Place tightly covered pot in oven (seal lid with aluminum foil if not absolutely tight) and bake at 200° F overnight or up to 18 hours (if baking for the longer time, you might want to reduce heat to 180° F). Check liquid level occasionally to prevent cholent from drying out and replenish if needed.
When ready to serve, dig out eggs, shell them and serve in quarters as the first course with fresh raw vegetables. These eggs will have absorbed the flavors and colors of the cholent, and acquired a most delicious taste. Remove the brisket and slice. Serve the brisket and beans family style on a large serving dish.
The best accompaniment for cholent is an assortment of good lacto-fermented pickles and sauerkraut. Yields 6 to 7 generous servings. (Recipe adopted from _www.jewishmag.com/43mag/cholent/cholent.htm.)
Black Bean Soup
2 cups black turtle beans
2 tablespoons or more lemon juice, vinegar or whey
several 6-inch strips of kombu (optional)
6-8 cloves garlic, mashed
2-3 bay leaves and several sprigs fresh thyme, tied together
3-4 tablespoons olive oil or lard
1-2 medium onions, diced
3-4 sticks celery, diced
1 sweet red pepper, diced
2-3 jalapeno peppers, seeded and diced
1 large can tomatoes or 4 or 5 medium-sized fresh tomatoes
1 quart chicken or beef stock
2 teaspoons (or more, to taste) ground cumin seed
black pepper and sea salt to taste
cilantro and sour cream or crème fraiche for garnish
Place beans in a bowl or pot and pour about 8 cups simmering water over the beans. Add lemon juice, vinegar or whey and soak 18-24 hours. For best results, drain a couple of times during the soaking process, rinse the beans and add more simmering water plus lemon juice, vinegar or whey. Drain beans, rinse and place in a large soup pot with water to cover by a couple of inches.
Bring to boil, skim off any foam that appears, then immediately lower to simmer, adding the mashed garlic cloves, bay leaf and thyme, and optional strips of kombu. Cook gently until beans are soft and just starting to fall apart--one hour or more depending on beans. Meanwhile sauté the onions, celery, red pepper and jalapeno pepper in a large skillet in olive oil or lard. Stir in the groudn cumin seed and cook together for about 15 minutes, or until onions are translucent. Add the sautéed vegetables to the beans, along with the beef or chicken stock, tomatoes and salt. Continue to simmer another half hour. The kombu will have melted into the broth by now. Remove bayleaf and thyme, and season to taste with sea salt and pepper. Garnish with minced cilantro and sour cream or crème fraiche. Makes 6-8 servings.
Lobio Tkemali
(Georgian red beans with sour plum sauce)
Georgian cuisine is typical of others of the Caucasus, featuring spices and exotic fruits and nuts in combinations often unexpected to most western tastes. Georgians often utilize beans in their menus, where they usually play the role of accompaniment to meat or fish entrées, but they are never boring! There are many variations of lobio recipes, some with walnut sauce and some with mixed, piquant herbal dressings. The plum sauce traditionally used in Georgia would have been made from an unsweetened paste of wild plum. This paste is rarely available in the US, but tamarind paste will approximate the flavor quite well in this recipe.
1 1/3 cup kidney beans
1 medium onion, peeled
1 medium carrot, peeled
3 celery sticks
6-inch piece of kombu (optional)
5 large dried prunes
1/4 cup balsamic vinegar
2 teaspoons tamarind paste (available in
Indian or Middle Eastern food stores)
1 clove garlic, pounded to paste
1/3 cup extra virgin olive oil
3/4 teaspoon ground coriander seed
1/4 teaspoon ground fenugreek seed
sea salt to taste
1/2 cup finely chopped cilantro
red onion rings
Rinse beans and place in a bowl or pot. Add about 5 cups simmering water and soak for 18-24 hours. For best results, drain a couple of times during the soaking process, rinse the beans and add more simmering water.
Drain the beans, rinse and combine with onion, carrot, celery and optional kombu in a soup pot. Add enough water to cover the beans by 3 inches and bring to a boil. Add the salt, then immediately reduce the heat to low, cover and cook the beans until tender but not mushy--about an hour or more, depending on the beans.
Meanwhile combine the prunes and the balsamic vinegar in a saucepan and simmer for about 15 minutes. Remove the prunes with a slotted spoon and reserve the vinegar. Finely chop the prunes (removing pits if they are unpitted). Add the tamarind paste to the vinegar and let stand until dissolved, about 10 minutes. Stir well and set aside. Drain the beans and discard the onion, carrot, celery and optional kombu. Place the beans in a serving dish and allow to cool. In a small bowl, whisk together the diluted tamarind mixture, garlic paste, and the olive oil, blending well. Add the chopped prunes, ground coriander and fenugreek, again blending well. Toss the beans with the tamarind mixture. Taste and correct the seasoning, and stir in the 1/4 cup cilantro leaves. Refrigerate, covered, for at least 2 hours before serving to allow flavors to develop. Garnish with remaining cilantro and the red onion rings. Serves 6. Recipe courtesy _www.recipeland.com/recipe/13829/.
Sidebar
Neutralizing Phytic Acid
Legume variety Optimal water pH Soaking time Best Soaking Medium
Black beans 5.5 18-24 hours Water with lemon juice, vinegar or whey added
Lentils 5.0 10 hours Water with lemon juice, vinegar or whey added
Fava beans 4.0 10 hours Water with lemon juice, vinegar or whey added
Dried and split peas 7.0 to 7.5 10 hours Plain soft water with pinch of baking soda
Brown, white & kidney beans 7.0 18-24 hours Plain soft water
This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Winter 2006.
