Thursday, January 7, 2010

Studing about black beans and what i found

Black beans Black beans

Both dried and canned black beans are available throughout the year. Dried beans are generally available in prepackaged containers as well as in bulk bins.

Black beans could not be more succinctly and descriptively named. They are commonly referred to as turtle beans, probably in reference to their shiny, dark, shell-like appearance. With a rich flavor that has been compared to mushrooms, black beans have a velvety texture while holding their shape well during cooking.

Food Chart
This chart graphically details the %DV that a serving of Black beans provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Black beans can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Black beans, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

* Health Benefits
* Description
* History
* How to Select and Store
* How to Enjoy
* Individual Concerns
* Nutritional Profile
* References

Health Benefits

Black beans are a very good source of cholesterol-lowering fiber, as are most other legumes. In addition to lowering cholesterol, black beans' high fiber content prevents blood sugar levels from rising too rapidly after a meal, making these beans an especially good choice for individuals with diabetes, insulin resistance or hypoglycemia. When combined with whole grains such as brown rice, black beans provide virtually fat-free high quality protein. You may already be familiar with beans' fiber and protein, but this is far from all black beans have to offer.

Sensitive to Sulfites? Black Beans May Help

Black beans are an excellent source of the trace mineral, molybdenum, an integral component of the enzyme sulfite oxidase, which is responsible for detoxifying sulfites. Sulfites are a type of preservative commonly added to prepared foods like delicatessen salads and salad bars. Persons who are sensitive to sulfites in these foods may experience rapid heartbeat, headache or disorientation if sulfites are unwittingly consumed. If you have ever reacted to sulfites, it may be because your molybdenum stores are insufficient to detoxify them. A cup of black beans will give you 172.0% of the daily value for this helpful trace mineral.

A Fiber All Star

Check a chart of the fiber content in foods; you'll see legumes leading the pack. Black beans, like other beans, are rich in dietary fiber. For this reason, black beans and other beans are useful foods for people with irregular glucose metabolism, such as diabetics and those with hypoglycemia, because beans have a low glycemic index rating. This means that blood glucose (blood sugar) does not rise as high after eating beans as it does when compared to white bread. This beneficial effect is probably due to two factors: the presence of higher amounts of absorption-slowing protein in the beans, and their high soluble fiber content. Soluble fiber absorbs water in the stomach forming a gel that slows down the metabolism of the bean's carbohydrates. The presence of fiber is also the primary factor in the cholesterol-lowering power of beans. Fiber binds with the bile acids that are used to make cholesterol. Fiber isn't absorbed, so when it exits the body in the feces, it takes the bile acids with it. As a result, the body may end up with less cholesterol. Black beans also contain insoluble fiber, which research studies have shown not only helps to increase stool bulk and prevent constipation, but also helps prevent digestive disorders like irritable bowel syndrome and diverticulosis.
Loaded with Antioxidants

Research published in the Journal of Agriculture and Food Chemistry indicates that black beans are as rich in antioxidant compounds called anthocyanins as grapes and cranberries, fruits long considered antioxidant superstars.

When researchers analyzed different types of beans, they found that, the darker the bean's seed coat, the higher its level of antioxidant activity. Gram for gram, black beans were found to have the most antioxidant activity, followed in descending order by red, brown, yellow, and white beans.

Overall, the level of antioxidants found in black beans in this study is approximately 10 times that found in an equivalent amount of oranges, and comparable to that found in an equivalent amount of grapes or cranberries.
Promote Optimal Health
A study published in Food Chemistry and Toxicology suggests not only that black beans may help protect against cancer, but that whole foods naturally contain an array of compounds that work together for our benefit. When researchers fed laboratory animals a 20% black bean diet to see if it would cause any mutagenic or genotoxic activity, not only did black beans not promote cancer, but a clear reduction in the number of pre-cancerous cells was seen, even in animals who were simultaneously given an agent known to promote cancer, the mutagen, cyclophosphamide. In an attempt to identify the bean components responsible for this protective effect, the researchers tested a single commercial anthocyanin, but instead of being protective on its own, the flavonoid, at the highest dose administered (50 mg per kg of bodyweight), actually induced DNA damage. The moral we draw from this tale: the synergy of compounds brought together by Mother Nature in the creation of whole foods is highly likely to be of greater benefit than a single extracted compound.

Lower Your Heart Attack Risk

In a study that examined food intake patterns and risk of death from coronary heart disease, researchers followed more than 16,000 middle-aged men in the U.S., Finland, The Netherlands, Italy, former Yugoslavia, Greece and Japan for 25 years. Typical food patterns were: higher consumption of dairy products in Northern Europe; higher consumption of meat in the U.S.; higher consumption of vegetables, legumes, fish, and wine in Southern Europe; and higher consumption of cereals, soy products, and fish in Japan. When researchers analyzed this data in relation to the risk of death from heart disease, they found that higher consumption of legumes was associated with a whopping 82% reduction in risk!
A study published in the Archives of Internal Medicine confirms that eating high fiber foods, such as black beans, helps prevent heart disease. Almost 10,000 American adults participated in this study and were followed for 19 years. People eating the most fiber, 21 grams per day, had 12% less coronary heart disease (CHD) and 11% less cardiovascular disease (CVD) compared to those eating the least, 5 grams daily. Those eating the most water-soluble dietary fiber fared even better with a 15% reduction in risk of CHD and a 10% risk reduction in CVD.

Black beans' contribution to heart health lies not just in their fiber, but in the significant amounts of folate and magnesium these beans supply. Folate helps lower levels of homocysteine, an amino acid that is an intermediate product in an important metabolic process called the methylation cycle. Elevated blood levels of homocysteine are an independent risk factor for heart attack, stroke, or peripheral vascular disease, and are found in between 20-40% of patients with heart disease. It has been estimated that consumption of 100% of the daily value (DV) of folate would, by itself, reduce the number of heart attacks suffered by Americans each year by 10%. Just one cup of cooked black beans provides 64% of the DV for folate.

Black beans' good supply of magnesium puts yet another plus in the column of its beneficial cardiovascular effects. Magnesium is Nature's own calcium channel blocker. When enough magnesium is around, veins and arteries breathe a sigh of relief and relax, which lessens resistance and improves the flow of blood, oxygen and nutrients throughout the body. Studies show that a deficiency of magnesium is not only associated with heart attack but that immediately following a heart attack, lack of sufficient magnesium promotes free radical injury to the heart. Want to literally keep your heart happy? Eat black beans. A cup of black beans will provide you with 30.1% of the DV for magnesium.

Black beans also contain compounds called polyphenols that are useful for those with elevated cholesterol because they act as antioxidants in the bloodstream, preventing cholesterol from oxidation by free radicals. Only after cholesterol has been damaged by free radicals does it form plaques on blood vessel walls, initiating the development of atherosclerosis. The polyphenols in black beans also have some potentially negative effects. Some of the polyphenols are tannins that can bind to some of the protein and iron these beans supply, preventing absorption of these nutrients. But don't let this concern you if you have a varied diet that provides you with protein and iron from a range of sources; if so, you can easily offset any negative consequences of the nutrient-binding tannins found in black beans.

Black Beans Give You Energy to Burn While Stabilizing Blood Sugar

In addition to its beneficial effects on the digestive system and the heart, black beans' soluble fiber helps stabilize blood sugar levels. If you have insulin resistance, hypoglycemia or diabetes, black beans can really help you balance blood sugar levels while providing steady, slow-burning energy. Studies of high fiber diets and blood sugar levels have shown the dramatic benefits provided by these high fiber foods. Researchers compared two groups of people with Type 2 diabetes who were fed different amounts of high fiber foods. One group ate the standard American Diabetic diet, which contained 24 grams of fiber/day, while the other group ate a diet containing 50 grams of fiber/day. Those who ate the diet higher in fiber had lower levels of both plasma glucose (blood sugar) and insulin (the hormone that helps blood sugar get into cells). The high fiber group also reduced their total cholesterol by nearly 7%, their triglyceride levels by 10.2% and their VLDL (Very Low Density Lipoprotein--the most dangerous form of cholesterol) levels by 12.5%.

Iron for Energy

In addition to providing slow burning complex carbohydrates, black beans can increase your energy by helping to replenish your iron stores. Although the tannins in black beans may block absorption of some of the iron they contain, a cup of black beans contains so much iron--20.1% of the daily value for this important mineral--that you will still benefit. Particularly for menstruating women, who are more at risk for iron deficiency, adding to their iron stores with black beans is a good idea--especially because, unlike red meat, another source of iron, black beans are low in calories and virtually fat-free. Iron is an integral component of hemoglobin, which transports oxygen from the lungs to all body cells, and is also part of key enzyme systems for energy production and metabolism. And remember: If you're pregnant or lactating, your needs for iron increase. Growing children and adolescents also have increased needs for iron.

Manganese for Energy Production and Antioxidant Defense

Black beans are a good source of the trace mineral manganese, which is an essential cofactor in a number of enzymes important in energy production and antioxidant defenses. For example, the key oxidative enzyme superoxide dismutase, which disarms free radicals produced within the mitochondria (the energy production factories within our cells), requires manganese. Just one cup of black beans supplies 38.0% of the daily value for this very important trace mineral.

Protein Power Plus

If you're wondering how to replace red meat in your menus, enjoy the rich taste of black beans. These smoky flavored beans are a good source of protein, and when combined with a whole grain such as whole wheat pasta or brown rice, provide protein comparable to that of meat or dairy foods without the high calories or saturated fat found in these foods. And, when you get your protein from black beans, you also get the blood sugar stabilizing and heart health benefits of the soluble fiber provided by these versatile legumes. A cup of black beans will provide you with 15.2 grams of protein (that's 30.5% of the daily value for protein), plus 74.8% of the daily value for fiber. All this for a cost of only 227 calories with virtually no fat.

Description

Black beans could not be more succinctly or descriptively named. They are just what they say they are, beans that are black. They are commonly referred to as turtle beans, probably in reference to their shiny, dark, shell-like appearance. Along with a rich smoky flavor that has been compared to mushrooms, black beans have a velvety texture, yet hold their shape well during cooking.

History

Black beans and other beans such as pinto beans, navy beans and kidney beans are all known scientifically as Phaselous vulgaris. (This scientific name refers to the genus and species of the plant; navy, kidney, pinto, etc. are different varieties of beans, all found within the species vulgaris). These varieties are all referred to as "common beans," probably owing to the fact that they all derived from a common bean ancestor that originated in Peru. From there, they were spread throughout South and Central America by migrating Indian tribes.

Beans were introduced into Europe in the 15th century by Spanish explorers returning from their voyages to the New World and were subsequently spread to Africa and Asia by Spanish and Portuguese traders. As beans are a very inexpensive form of good protein, they have become popular in many cultures throughout the world. Black beans are an important staple in the cuisines of Mexico, Brazil, Cuba, Guatemala and the Dominican Republic. Today, the largest commercial producers of dried common beans are India, China, Indonesia, Brazil and the United States.

How to Select and Store

Dried black beans are generally available in prepackaged containers as well as bulk bins. Just as with any other food that you may purchase in the bulk section, make sure that the bins containing the black beans are covered and that the store has a good product turnover to ensure the beans' maximal freshness. Whether purchasing black beans in bulk or in packaged containers, make sure that there is no evidence of moisture or insect damage and that they are whole and not cracked.

Canned black beans can be found in most markets. Unlike canned vegetables, which have lost much of their nutritional value, there is little difference in the nutritional value of canned black beans and those you cook yourself. Canning lowers vegetables' nutritional value since they are best lightly cooked for a short period of time, while their canning process requires a long cooking time at high temperatures. On the other hand, beans require a long time to cook whether they are canned or you cook them yourself. Therefore, if enjoying canned beans is more convenient for you, by all means go ahead and enjoy them. We would suggest looking for those that do not contain extra salt or additives. (One concern about canned foods is the potential for the can to include a liner made from bisphenol A/BPA. To learn more about reducing your exposure to this compound, please read our write-up on the subject).

Store dried black beans in an airtight container in a cool, dry and dark place where they will keep up to 12 months. If you purchase black beans at different times, store them separately since they may feature varying stages of dryness and therefore will require different cooking times. Cooked black beans will keep fresh in the refrigerator for about three days if placed in a covered container.

How to Enjoy

For some of our favorite recipes, click Recipes.

Tips for Preparing Black Beans:

Before washing black beans, spread them out on a light colored plate or cooking surface to check for, and remove, small stones, debris or damaged beans. After this process, place the beans in a strainer, rinsing them thoroughly under cool running water.

To shorten their cooking time and make them easier to digest, black beans should be presoaked (presoaking has been found to reduce the raffinose-type oligosaccharides, sugars associated with causing flatulence.) There are two basic methods for presoaking. For each you should start by placing the beans in a saucepan and adding two to three cups of water per cup of beans.

The first method is to boil the beans for two minutes, take the pan off the heat, cover and allow to stand for two hours. The alternative method is to simply soak the beans in water for eight hours or overnight, placing the pan in the refrigerator so that the beans will not ferment. Before cooking the beans, regardless of method, drain the soaking liquid and rinse the beans with clean water.

To cook the beans, you can either cook them on the stovetop or use a pressure cooker. For the stovetop method, add three cups of fresh water or broth for each cup of dried beans. The liquid should be about one to two inches above the top of the beans. Bring the beans to a boil and then reduce to a simmer, partially covering the pot. If any foam develops, you can skim it off during the simmering process. Black beans generally take about one and one-half hours to become tender using this method. They can also be cooked in a pressure cooker where they take about one-half hour to prepare.

Regardless of cooking method, do not add any seasonings that are salty or acidic until after the beans have been cooked since adding them earlier will make the beans tough and greatly increase the cooking time.

If you are running short on time, you can always use canned beans in your recipes. If the black beans have been packaged with salt or other additives, simply rinse them after opening the can to remove these unnecessary additions. Canned beans need to only be heated briefly for hot recipes while they can be used as is for salads or prepared cold dishes like black bean salad.

A Few Quick Serving Ideas:

Include black beans with your other favorite toppings next time you make a stuffed baked potato.

Black bean soup or chili is certain to warm you up on cold winter days or anytime of the year you want to enjoy its nurturing essence.

For a "mucho bueno" twist on traditional burritos, use black beans in place of refried pinto beans.

Blend cooked black beans with tomatoes, onions and your favorite spices to create a delicious bean soup.

For a simple yet delicious lunch or dinner entrée, serve a Cuban inspired meal of black beans and rice.

In a serving bowl, layer black beans, guacamole, chopped tomatoes, diced onions and cilantro to make a delicious layered dip.

Individual Concerns

Black Beans and Purines
Black beans contain purines. Purines are naturally-occurring substances found in plants, animals, and humans. In some individuals who are susceptible to purine-related problems, excessive intake of these substances can cause health problems. Since purines can be broken down to form uric acid, excess accumulation of purines in the body can lead to excess accumulation of uric acid. The health condition called "gout" and the formation of kidney stones from uric acid are two examples of uric acid-related problems that can be related to excessive intake of purine-containing foods. Yet, recent research has suggested that purines from meat and fish increase risk of gout, while purines from plant foods fail to change the risk. For more on this subject, please see "What are purines and in which foods are they found?"

Nutritional Profile

Black beans emerged from our food ranking system as an excellent source of the mineral molybdenum. in addition, they are a very good source of dietary fiber and folate. In the case of folate, for example, a one cup serving of black beans provided about 2/3 of the DV for folate.

Our food ranking system also qualified black beans as a good source of manganese, protein, magnesium, thiamin (vitamin B1), phosphorus and iron. In the case of protein, for example, a one cup serving of cooked black beans provided about one third of a day's protein requirement.

For an in-depth nutritional profile click here: Black beans.

In-Depth Nutritional Profile
In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Black beans is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

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