Black turtle bean nutrition, glycemic index, calories, and serving size
Complete nutrition and health benefits analysis for Black turtle bean
The black turtle beans are a small, nutritious, and flavorful variety of the common bean, popular in Latin American cuisine. From Latin America, these beans have traveled from West Africa to Southeast Asia and all across the world.
In this article, we will discuss everything you need to know about the black turtle bean.
Black turtle beans are small, black or dark violet, oval or round, and glossy beans with a white spot on one side.
In different cultures, black turtle beans have various names. In Latin America these beans can be called frijoles negros, judía negra, caviar criollo, zaragoza, poronto negro, caraota or habichuela negra. In Portuegese black turtle beans are named feijão preto. In Indian or Tamil cuisine these beans are known as maa ki daal or karuppu kaaramani. In Maharashtrian culture, these beans are called Kala ghevada.
Black turtle beans are also known as black shelling beans or simply as black beans. However, black bean is a name that can be used for several other beans, such as black gram, black adzuki beans, or black soybeans.
Black turtle beans are a variety of common beans, belonging to the Phaseolus vulgaris species, and the Fabaceae family.
The common bean is an annual herb, native to the Americas, also known as the French bean. Black beans share this species with other widely popular beans, such as kidney beans, navy beans, and pinto beans.
The Fabaceae family that the black turtle bean belongs to, is also called the legume, pea, or bean family and includes thousands of various other species, including beans, soybeans, peas, chickpeas, peanuts, and others.
Depending on the variety and cooking method of the black turtle beans the nutritional values of these beans can slightly differ. The nutritional information below will be focusing on mature seeds of black turtle beans, boiled without added salt, while also talking about mature raw and canned black turtle seeds (1, 2, 3).
Macronutrients and Calories
Raw black turtle beans are incredibly dense in nutrients, containing only 11% of water. Black turtle beans can double in size after being cooked. Cooked black turtle beans consist of 65.7% water and 34.3% of nutrients.
Canned black turtle beans, on the other hand, are less dense in nutrients, consisting of 75.6% water.
Boiled black turtle seeds provide 130 calories per 100g serving. This puts black turtle seeds in the high-calorie category of foods.
Raw black turtle beans are naturally much higher in calories, containing 339 calories in every hundred-gram serving. At the same time, the same serving size of canned black turtle beans provides only 91 calories.
The average serving size of these beans per one person is 90g for boiled black turtle beans, 190g for canned beans, and 35g for dry beans. Consequently, one average serving size of boiled black beans provides 117 calories. One average serving size of canned black turtle beans contains 118 calories, while one average serving size of dry beans has 119 calories.
Carbohydrates in Black Turtle Bean
A 100g serving of boiled black turtle beans provides 24.4g of carbohydrates. Of these carbohydrates, 8.3g constitute dietary fiber and only 0.32g are sugars. Other carbohydrates include resistant starch, as beans are considered to be “starchy vegetables” and oligosaccharides.
Naturally, raw black turtle beans are much higher in carbohydrates, being denser in nutrients. The same serving size of raw black turtle beans is 2.5 times higher in carbohydrates, containing 63.25g.
An equal amount of canned black turtle beans provides 16.6g of carbohydrates, of which dietary fiber makes up almost 7g.
Protein in Black Turtle Bean
Black turtle beans are a great source of protein, especially in diets low in meat and dairy.
In a hundred grams of cooked black turtle beans, 8.18g of protein can be found. This protein is considered to be of high quality, as it contains sufficient amounts of all essential amino acids. The only essential amino acid that is relatively low in black turtle beans is methionine.
The same serving size of canned black turtle beans provides 6g of protein, while raw black turtle beans contain 21.25g of protein.
Fats in Black Turtle Bean
Black turtle beans are overall very low in fats. A hundred-gram serving of boiled black turtle beans provides 0.35g of fats. The same serving size of canned black turtle beans contains only 0.29g of fats and raw black turtle beans have 0.9g of fats.
Of these fats, most consist of polyunsaturated fatty acids, followed by saturated fatty acids.
Naturally, as a plant product, the black turtle bean contains no cholesterol.
Black turtle beans are a great source of most B complex vitamins. These beans are particularly high in vitamin B9 or folate, vitamin B1 and vitamin E. Black turtle beans fall in the top 26% of foods as a source of folate and the top 32% of foods as a source of vitamin B1.
Other vitamins that can be found in black turtle beans in sufficient amounts include vitamin K, vitamin A, and vitamins B6, B5, B3, and B2.
Black turtle beans are completely absent in vitamin B12, vitamin C, and vitamin D.
Black turtle beans are incredibly rich in various minerals. These beans fall in the top 15% of foods as a source of potassium, containing more of this mineral than bananas or cucumber.
Black turtle beans are an excellent source of magnesium and iron, falling in the top 22 and 23% of foods respectively, as a source of these minerals.
These beans also contain significant amounts of copper, calcium, and manganese. Moderate levels of phosphorus, zinc, selenium, and choline can be found as well.
Black turtle beans are very low in sodium, containing only around 3mg of it in a hundred-gram serving.
Black turtle beans are rich in a chemical compound called anthocyanin. This compound belongs to a family of molecules called flavonoids. Anthocyanin is the pigment that gives the black turtle bean its distinct dark coloring.
One gram of dry extract of black beans was found to have 32mg of anthocyanins (4).
Anthocyanins are known for their strong antioxidant qualities. Antioxidants help protect cells from damage by inhibiting oxidation from free radicals.
Other antioxidant compounds that have been found in black beans include antioxidant vitamins, such as vitamin A and vitamin E, myricetin, quercetin, and kaempferol (5).
The glycemic index of common black beans, that have been soaked overnight and cooked for 45 minutes, from the Philippines, has been calculated to be 20 (6).
While the specific number has not yet been calculated for the glycemic index value of black turtle beans, it can be assumed to fall in the low category.
Black turtle beans have also been researched to potentially benefit diabetic individuals by ameliorating insulin resistance (7).
The pH value of black beans, in general, has been calculated to fall in the range of 5.78 to 6.02, which makes the black bean an acidic food (8).
Another way of measuring food’s acidity is by looking at its potential renal acid load, which demonstrates how much acid or base the given food produces when already inside the gastrointestinal tract.
The PRAL value of black turtle beans has been calculated to be -1.4. The negative value shows that black turtle beans are acid-forming.
The average serving size of black turtle beans per one person is considered to be 130g for beans in sauce or canned in liquid and refried beans prepared, 90g for beans prepared otherwise, and 35g for dry black gram beans (9).
It has been known for centuries that the right diet can have an important role in maintaining health and protecting from various diseases.
Now that everything about the nutrition of black turtle beans has been discussed, we can look at how the consumption of black beans affects health overall.
Black beans contain various phytochemicals that can have a positive effect on cardiovascular health. Black beans are also rich in dietary fiber and protein while being low in fats.
High carbohydrate and high fiber meals have been researched to lead to a decreased level of a pro-inflammatory agent named interleukin-18. This compound, while relatively newfound, has been associated with metabolic syndrome and cardiovascular disease (10).
By improving insulin sensitivity and helping manage postprandial metabolic responses, black bean meals can contribute to metabolic health and the delay of cardiovascular disease and diabetes mellitus type 2 in adults with metabolic syndrome (10).
Regular consumption of pulses, such as black turtle beans, has been researched to reduce metabolic syndrome risk factors in overweight and obese adults, by increasing high-density cholesterol levels, also known as “good” cholesterol, and decreasing waist circumference, and systolic blood pressure (11).
Some evidence suggests that bean intake can lead to a reduced risk of ischemic heart disease, likely due to its cholesterol-lowering qualities. Bean consumption has been associated with reduced levels of low-density lipoproteins, which are known as “bad” cholesterol (12).
Regular consumption of black beans, high in phytochemicals, also has the potential to be used as a natural agent to reduce blood pressure, through the positive effects on vascular remodeling and stiffness (13).
Cooked black turtle bean supplementation in a high-fat diet has health-promoting effects in terms of lipid and glucose metabolism. A diet high in black turtle beans can ameliorate insulin resistance and lower plasma low-density lipoprotein levels (“bad” cholesterol) through a glucose signaling pathway in mice fed a high-fat diet (7).
A diet high in black turtle beans also had a significantly beneficial effect on diabetes-related biomarkers and inflammatory cytokines (7).
The anthocyanins found in black turtle beans have been studied to have the ability to lower postprandial glucose by inhibiting the activity of certain enzymes that break down carbohydrates into glucose, such as α-amylase, maltase, and sucrase (14).
A high intake of dietary anthocyanins has also been correlated with improved insulin sensitivity and decreased inflammation markers (15).
Overall, the inclusion of black beans in meals has been researched to lead to improved postprandial metabolic responses through a reduced insulin response (10).
The extract of black beans has shown abilities to reduce postprandial glucose, insulin, and C-peptide levels, as well as suppressing the so-called “hunger hormone” ghrelin, increasing satiety, and inducing a lower desire to eat (16).
Cooked common beans may have the ability to protect against the damage of insulin-producing beta cells of the pancreas in drug-induced diabetic rats (17).
Depending on various factors, the food you eat can either decrease or increase the risk of developing certain types of cancer. Black turtle beans, in particular, are rich in several antioxidants, which can help protect against cell damage, mutation, and cancer.
Black turtle beans have been studied to play a protective role against human breast cancer cell lines. The extract of black turtle beans had apoptotic effects on the cancer cells, by activating a pathway called caspase 3/7, which leads to the programmed death of the cell. The extract also affected other programmed death pathways, increasing the expression of proapoptotic Bax regulating proteins and decreasing anti-apoptotic Bcl-2 and Bcl-xL proteins (18).
Black beans can also strengthen the immune system to recognize and terminate cancer cells, as well as inhibiting the development of new blood vessels, with such angiogenesis being necessary for the development of the tumor. Black beans reduce the metastatic potentials of cancer cells by weakening their adhesiveness and invasiveness (18).
Certain phenolic compounds, which black turtle beans are rich in, can play a role in decreasing the risk of developing colon cancer (5, 19). In addition, the dietary fiber that can be found in ample amounts in black turtle beans has also been extensively researched to protect against colorectal cancer (20).
A negative association has been found between a high intake of foods such as beans and a decreased risk of pancreatic cancer (21).
Anti Inflammatory Effects
Consumption of black beans has been correlated with a decreased level of multiple inflammation markers.
Compared to a high-fat diet, a diet high in cooked black turtle beans resulted in significantly lower concentrations of inflammatory cytokines, particularly plasma interleukin-4, interleukin-5, interleukin-10, interleukin-12, interferon-γ, and tumor necrosis factor-α (7).
By reducing tumor necrosis factor-α concentrations, black turtle beans can also help reduce the accumulation of fat in the liver, called hepatic steatosis, as TNF-α plays a key role in its development (22).
Downsides and Risks
Despite the numerous beneficial effects, for certain individuals, or when used incorrectly, black turtle bean consumption can also lead to negative impacts on health.
Like any other food, black turtle beans contain compounds that can present themselves as allergens in some people.
Legume allergies are not uncommon in adults. A legume allergy includes sensitization to beans, peas, lentils, and peanuts. Some people with legume allergies are hypersensitive to all foods of these groups, while others are allergic only to specific foods.
If allergic to one food in the legume family, the chances of being allergic to another food of the same family are higher, as a result of cross-reactivity.
Symptoms of a black turtle bean allergy are the same as other food allergies: hives and rash, oral allergy syndrome (which includes swelling, redness, itching, or tingling of the mouth area), difficulty breathing, asthma, nausea and vomiting, abdominal pain, and in rare severe cases, anaphylactic shock. The allergy can also sometimes present itself with contact dermatitis: hives and rash after touching the bean.
A common allergen found in black turtle beans is the protein called lectin. Research has been carried out on ways to reduce the allergenicity of the lectin found in black turtle beans. Results have indicated that a low-pH treatment might be an efficient method to improve the safety of legume protein consumption (23).
Like most members of the common bean family, raw black turtle beans contain a significant amount of a toxic compound called phytohaemagglutinin, which belongs to the lectin family of proteins. However, the phytohaemagglutinin in black turtle beans can be detoxified simply by cooking the beans (7).
Research indicates that the toxin is destroyed when boiled at 212°F (100°C) for 10 minutes, but scientists recommend boiling for 30 minutes to be certain the beans reach the proper temperature for the amount of time necessary. Using a slow cooker is not recommended as it may not reach a high enough temperature to deactivate the toxins (24).
As canned beans are already processed at a high temperature and pressure during production, they are safe to eat without cooking (25).
Symptoms of common bean poisoning include nausea, vomiting, and diarrhea within a few hours after eating the food.
The consumption of beans is often associated with bloating, flatulence, and gastrointestinal discomfort. The effect of beans on the gastrointestinal system is individual. Different people find different beans easier to digest.
The cause of these disturbances are compounds found in legumes called raffinose family oligosaccharides, which can not be broken down by the human organism due to the lack of an enzyme called α-galactosidase. These carbohydrates are instead digested through the intestinal microflora, causing a buildup of gas in the intestines (26).
However, soaking and boiling black turtle beans can decrease the content of raffinose oligosaccharides, and therefore, the risk of flatulence. Adding various herbs, such as caraway, black cumin, ginger, and black anise, may also help reduce flatulence (26).
Black Turtle Bean in Diets
Black turtle beans are high in calories and carbohydrates, providing 130 calories and 24g of carbohydrates per every 100g serving. For this reason, black turtle beans usually do not fit well in low-calorie weight-loss diets.
However, this does not exclude black turtle beans from a healthy diet that can lead to weight loss. Black turtle beans are a great source of protein and dietary fiber while being very low in fats.
Animal studies have shown that a diet high in black turtle beans leads to a lesser weight gain compared to a high-fat diet (7).
A calorie-restricted weight loss diet high in legumes has also been shown to lead to a greater reduction of weight in comparison to a calorie-restricted weight loss diet without legumes. A low-calorie diet rich in legumes also demonstrated improved metabolic markers, such as lipid profile and blood pressure, in overweight or obese individuals (27).
A keto diet allows up to 20g of carbohydrate consumption per day. One average serving size of black turtle beans provides 22g of carbohydrates, therefore, these beans are not a good option for the keto diet.
Black turtle beans are high in fiber, potassium, magnesium, and calcium while being low in sodium, saturated fat, and sugar. Multiple studies have also researched pulses, black beans, in particular, to have qualities that help reduce systolic blood pressure (11, 13).
Black turtle beans can certainly be used on a DASH diet.
Black turtle beans should be avoided during the first two phases of the Atkins diet, Induction and Balancing, as they are high in carbohydrates. These beans can be slowly reintroduced to the diet during the third, Pre-maintenance, phase and used in moderation throughout the fourth, Maintenance, phase.
Whilst black turtle beans originated in North America, beans and legumes are generally an important part of the Mediterranean diet. Black turtle beans can be used on this diet.
Beans and legumes are often excluded from the paleo diet, as they are high in toxic compounds, such as phytic acid and lectins (28). For this reason, black turtle beans are not considered to be paleo.
Vegan/ Vegetarian/ Pescetarian
Due to its high protein content and meaty texture, the black turtle bean is often used in vegan and vegetarian foods. Being a plant product, naturally, these beans also fit into a pescetarian diet.
Black turtle beans are naturally gluten-free and can be a good source of protein, vitamins, and minerals on a gluten-free diet.
The Dukan diet discourages the consumption of black beans as they are relatively high in starch. One or two servings of black turtle beans can be added to the diet during the Consolidation phase, as a starchy food. During the Stabilization phase, black turtle beans can be consumed in moderation.
Like all foods, black turtle beans can be used on this diet during eating periods but should be refrained from during fasting periods.
Low Fat & Low Calorie
Black turtle beans are naturally very low in fats, however, a 100g serving of cooked black turtle beans provides 130 calories. Therefore, these beans are suited for a low-fat diet, but not a low-calorie diet.
Despite the high dietary fiber content, providing 22g of carbohydrates per one serving, black turtle beans are advised to avoid on a low-carb diet.
Black turtle beans are rich in antioxidants, such as anthocyanin, and other phytochemicals.
As discussed previously, the consumption of cooked black turtle beans has been correlated with reduced concentrations of multiple proinflammatory agents (7, 22). A diet high in black beans has also been researched to reduce inflammation during colitis (29).
For these reasons, black turtle beans can be a good addition to the anti-inflammatory diet.
Black turtle beans are not considered to be a bland food, as they are high in insoluble fiber and can cause bloating and worsening of symptoms in some people. Black turtle beans should be avoided on a BRAT diet.
Cooking and Use
Black turtle beans are popularly used in national dishes throughout the South and Central Americas.
Black turtle beans are versatile in the kitchen and can be boiled, canned, refried, pureed, baked, etc. Black beans can also be added to a salad or used to make a dip.
Black turtle beans, having a mild taste and a soft texture, are used as an ingredient in many dishes. In Mexican cuisine, black turtle beans are often used in burritos, tacos, and enchiladas. In Brazillian cuisine, black turtle beans are used to make the national dish feijoada. Refried black beans are popular in Guatemala, while Venezuelan cuisine uses black turtle beans for the soup called sopa de frijoles negros (30).
Before use, dry black turtle beans can be soaked overnight by adding three cups of water to one cup of black beans and optionally adding a teaspoon of salt. This makes the cooking process faster the next day.
Beans can also be soaked quickly before use by boiling the beans soaked in water for two minutes and letting them rest for two hours. However, this method of soaking can break down the beans during the cooking process.
The actual cooking process of the beans includes bringing the pot of black turtle beans with water to a boil and letting it simmer for around two hours while stirring.
Storage, Keeping, and Conservation
Dry black turtle beans should be kept in a dark, dry, and cool place, in airtight containers. In these conditions, black beans can be kept for up to a year. Older beans, while safe, can take longer to cook.
Canned beans should also be stored in a cool and dry space before opening. Open canned beans should be stored in the fridge.
After being cooked, black turtle beans should be kept in the refrigerator for three to five days. Cooked black turtle beans can also be frozen for longer storage. Frozen black turtle beans can stay in the freezer for up to 6 months.
Black turtle beans are known as dry beans, shelled beans, or field beans, as these beans are harvested in shells when dry. The Phaseolus vulgaris plant has ovate-triangular leaves and can grow up to 20 inches (51cm) on its own.
This plant grows best in full sun, in well-drained and warm soil. The black turtle bean plant prefers slightly acidic to neutral soil with a pH of around 7 (31).
The maturing of the Phaseolus vulgaris plant takes from 60 to 90 days (31).
Production and Consumption
The common beans are being considered the most important source of protein especially in North America, Latin America, Asia-Pacific, and several parts of Africa. According to the U.N. FAOSTAT, the global bean production shot up in 2011 and has been growing ever since (30).
Parts of the reason for the growth of bean consumption worldwide are the environmentally aware consumers switching meat for beans out of ethical and ecological reasons.
Major common bean-producing regions are found in all parts of Africa, Southeast Asia, Europe, and the Andean (30).
Despite the nutritional and economic importance of common beans, it has however turned out to be a low-yielding crop in African and Latin American regions (30).
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Important nutritional characteristics for Black turtle bean
Black turtle bean Glycemic index (GI)
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NEW NUTRITION FACTS LABEL
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Black turtle bean nutrition infographic
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Mineral chart - relative view
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Protein quality breakdown
Fat type information
Fiber content ratio for Black turtle bean
All nutrients for Black turtle bean per 100g
|Nutrient||DV%||In TOP % of foods||Value||Comparison|
|Protein||19%||50%||8.18g||2.9 times more than Broccoli|
|Fats||1%||83%||0.35g||95.2 times less than Cheese|
|Carbs||8%||30%||24.35g||1.2 times less than Rice|
|Calories||7%||65%||130kcal||2.8 times more than Orange|
|Sugar||0%||73%||0.32g||28 times less than Coca-Cola|
|Fiber||33%||13%||8.3g||3.5 times more than Orange|
|Calcium||6%||32%||55mg||2.3 times less than Milk|
|Iron||36%||23%||2.85mg||1.1 times more than Beef|
|Magnesium||12%||22%||49mg||2.9 times less than Almond|
|Phosphorus||22%||52%||152mg||1.2 times less than Chicken meat|
|Potassium||13%||15%||433mg||2.9 times more than Cucumber|
|Sodium||0%||94%||3mg||163.3 times less than White Bread|
|Zinc||7%||59%||0.76mg||8.3 times less than Beef|
|Copper||30%||26%||0.27mg||1.9 times more than Shiitake|
|Vitamin E||6%||49%||0.87mg||1.7 times less than Kiwifruit|
|Vitamin B1||19%||32%||0.23mg||1.2 times less than Pea|
|Vitamin B2||4%||79%||0.06mg||2.3 times less than Avocado|
|Vitamin B3||3%||77%||0.53mg||18.2 times less than Turkey meat|
|Vitamin B5||5%||77%||0.26mg||4.3 times less than Sunflower seed|
|Vitamin B6||6%||70%||0.08mg||1.5 times less than Oat|
|Folate||22%||26%||86µg||1.4 times more than Brussels sprout|
|Vitamin K||3%||60%||3.3µg||30.8 times less than Broccoli|
|Tryptophan||0%||79%||0.1mg||3.1 times less than Chicken meat|
|Threonine||0%||77%||0.34mg||2.1 times less than Beef|
|Isoleucine||0%||78%||0.36mg||2.5 times less than Salmon|
|Leucine||0%||79%||0.65mg||3.7 times less than Tuna|
|Lysine||0%||75%||0.56mg||1.2 times more than Tofu|
|Methionine||0%||81%||0.12mg||1.3 times more than Quinoa|
|Phenylalanine||0%||77%||0.44mg||1.5 times less than Egg|
|Valine||0%||78%||0.43mg||4.7 times less than Soybean|
|Histidine||0%||78%||0.23mg||3.3 times less than Turkey meat|
|Saturated Fat||0%||82%||0.09g||66.2 times less than Beef|
|Monounsaturated Fat||0%||87%||0.03g||326.6 times less than Avocado|
|Polyunsaturated fat||0%||82%||0.15g||316.6 times less than Walnut|
The source of all the nutrient values on the page (excluding the main article and glycemic index text the sources for which are presented separately if present) is the USDA's FoodCentral. The exact link to the food presented on this page can be found below.