''Canavalia gladiata'', the sword bean
or scimitar bean,
is a domesticated plant species in the legume family
Fabaceae
Fabaceae () or Leguminosae,[International Code of Nomen ...](_blank)
. It is used as a vegetable in interior central and south central India, though not commercially farmed. The unripe pods are also eaten as a vegetable in Africa and Asia.
[
The term "sword bean" is also used for other ]legume
Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...
s, notably the common jack bean '' Canavalia ensiformis''.
Description
Appearance and Leaves
Sword beans are a climbing, herbaceous
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of ...
vine that can reach lengths of up to 10 meters under optimal conditions.
Inflorescence and Flowers
The inflorescence is a raceme
A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...
bearing 10 to 20 flowers, which are either white or light purple. Each flower measures approximately 3 cm in length.
Fruits and Seeds
The fruits are shaped as long, straight, slightly compressed pods, measuring 20-40 (up to 60) cm with a rough surface. Each pod contains 8 to 16 seeds, which are oblong-ellipsoid, variable in color, ranging from red and red-brown to white or black. The hilum is dark brown and extends the full length of the seed.
Origin
''Canavalia gladiata'' is believed to have come from the Old World
The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...
, probably in eastern Asia, where domestication
Domestication is a multi-generational Mutualism (biology), mutualistic relationship in which an animal species, such as humans or leafcutter ants, takes over control and care of another species, such as sheep or fungi, to obtain from them a st ...
likely started. Still today, sword beans are widely distributed in those regions. Sword beans are most commonly cultivated in the south, southeast, and east Asia. It is also common in Saudi Arabia, East Africa, South Africa, and Madagascar. Historically, its primary use was for food and traditional medicine
Traditional medicine (also known as indigenous medicine or folk medicine) refers to the knowledge, skills, and practices rooted in the cultural beliefs of various societies, especially Indigenous groups, used for maintaining health and treatin ...
.
Taxonomy
The genus '' Canavalia'' includes about 60 species, two of which are cultivated for food, cover crop
In agriculture, cover crops are plants that are planted to ground cover, cover the soil rather than for the purpose of being harvested. Cover crops manage soil erosion, soil fertility, soil quality, water, weeds, Pest (organism), pests, diseases ...
, green manure
In agriculture, a green manure is a crop specifically cultivated to be incorporated into the soil while still green. Typically, the green manure's Biomass (ecology), biomass is incorporated with a plow or disk, as is often done with (brown) man ...
and medicine: jack beans ('' Canavalia ensiformis'' (L.) DC.) and sword beans (''C. gladiata'' (Jacq.) DC).
Sword beans are originally described as ''Dolichos gladiatus'' by Jaquin in 1788. In 1825, Augustin-Pyrame de Candolle published the species as ''Canavalia gladiata (Jacq.) DC.'', which is the scientific name currently used for sword bean. Over time sword beans have been known by several names based on varying classifications (see list of synonymes below).
Synonymes
Source:
Cultivation
Sword beans can be found from sea level up to 900 m elevation. They need temperatures between 20 and 30 °C to grow and about 900 – 1500 mm evenly distributed rainfall per year.
Diseases
Sword beans are relatively resistant to diseases and pests.Anthracnose
A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...
, which is caused by fungal pathogens of Colletotrichum
''Colletotrichum'' (sexual stage: ''Glomerella'') is a genus of fungi that are symbionts to plants as endophytes (living within the plant) or phytopathogens. Many of the species in this genus are plant pathogens, but some species may have a mu ...
species. Severe lesions can be found both on the stem and leaves.
Research has also shown that Bean Common Mosaic Virus (BCMV) can infect the sword bean. Previously it has been known to infect several legumes and cause some of the most economically important diseases on legume crops. BCMV could gain importance in sword bean production in the future, if sword bean is grown more widely as BCMV is reported to cause major yield losses in legumes.
Nutritional Composition and Toxicity
Nutritional Composition
Dried sword beans are a highly nutritious wild legume, notable for their high protein content on a dry weight basis. Each 100g of seed flour provides 59g of carbohydrate
A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...
s, 24.5g of protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
, and 2.6g of fat
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers specif ...
, along with 7.4g of fiber, while retaining 10.7g of moisture. This nutrient profile delivers an energy value of 1,453 kJ per 100g.
Mineral Content
The beans are also rich in minerals, containing 109.3 mg of sodium, 1639.5 mg of potassium, 510.1 mg of calcium, 480.9 mg of magnesium, and 601.2 mg of phosphorus. Additionally, trace minerals are present, including 10.9 mg of iron, 0.8 mg of copper, 6.6 mg of zinc, and 2.2 mg of manganese.
Nutritional value per 100 g
Toxicity
Despite nutritional potential in terms of protein content sword beans are not used as food. This is partly due to the presence of harmful factors such as haemagglutinis (concanavalin A
Concanavalin A (ConA) is a lectin (carbohydrate-binding protein) originally extracted from the jack-bean (''Canavalia ensiformis''). It is a member of the legume lectin family. It binds specifically to certain structures found in various sugars, ...
), protease inhibitors
Protease inhibitors (PIs) are medications that act by interfering with protease, enzymes that cleave proteins. Some of the most well known are antiviral drugs widely used to treat HIV/AIDS, hepatitis C and COVID-19. These protease inhibitors pre ...
, hydrocyanic acid, tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and Precipitation (chemistry), precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' is widel ...
s, phytates
Phytic acid is a six-fold dihydrogenphosphate ester of inositol (specifically, of the ''myo'' isomer), also called inositol hexaphosphate, inositol hexakisphosphate (IP6) or inositol polyphosphate. At physiological pH, the phosphates are partial ...
and canavanine
L-(+)-(''S'')-Canavanine is a non-proteinogenic amino acid found in certain leguminous plants. It is structurally related to the proteinogenic α-amino acid L-arginine, the sole difference being the replacement of a methylene bridge ( unit) in ...
. Canavanine is contained in the seeds of the plants (the content is between 10% and 13%).
Uses
Food
Records of food usage can be found in multiple countries. Multiple methods were developed to deal with the antinutritive components of sword beans.
Young leaves, flowers, tender green pods and seeds are edible after cooking. The young pods are sliced and cooked or eaten raw. Young seeds are edible after cooking, and the mature seeds are as well, but only after prolonged cooking. In Japan, the young, tender pods are processed into several kinds of pickles called “'' Fukujin-zuke”'', “'' Nuka-zuke''”, and “'' Miso-zuke”''. In Java, the de-skinned and twice-boiled seeds are left in running water for 2 days, allowed to ferment for 3–4 days and cooked before being eaten as flavouring. After steaming, they also use young leaves and flowers as flavoring.
In Cuba, seeds are used as a substitute for coffee.
Feed
Fewer information about historical use as feed is available. However, two recent studies investigated its potential as such.
Sword bean nutritive value was investigated for rats’ nutrition. A diet made exclusively of raw sword bean seeds proved to have a negative effect on weight gain compared to a reference diet. However, this negative effect was decreased when beans were processed to decrease their toxicity.soybean
The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean. Soy is a staple crop, the world's most grown legume, and an important animal feed.
Soy is a key source o ...
s in broiler
Breed broiler is any chicken (''Gallus gallus domesticus'') that is bred and raised specifically for meat production. Most commercial broilers reach slaughter weight between four and six weeks of age, although slower growing breeds reach slaug ...
s’ diets. Results showed that replacing 30% of soybean with processed sword bean did not result in any adverse effect on broilers’ health and growth. Additionally, its foliage provides a good leaf meal for use in animal feeds.
Traditional medicine
Multiple countries have used sword beans in their traditional medicine. In Korea, it is thought to help with many ailments such as vomiting, abdominal dropsy, kidney-related lumbago
Low back pain or lumbago is a common disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can vary from a dull constant ache to a sudden sharp feeling. ...
, asthma
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
, obesity, stomach-ache, dysentery
Dysentery ( , ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications may include dehyd ...
, coughs, headache, intercostal neuralgia
Neuralgia (Greek ''neuron'', "nerve" + ''algos'', "pain") is pain in the distribution of a nerve or nerves, as in intercostal nerve, intercostal neuralgia, trigeminal neuralgia, and glossopharyngeal nerve, glossopharyngeal neuralgia.
Classifica ...
, epilepsy
Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
, schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
, inflammatory diseases, and swelling.otitis media
Otitis media is a group of Inflammation, inflammatory diseases of the middle ear. One of the two main types is acute otitis media (AOM), an infection of rapid onset that usually presents with ear pain. In young children this may result in pullin ...
, boil
A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium ''Staphylococcus aureus'', resulting in a painful swollen area on the skin caused by ...
s, cancers, inflammatory diseases and atopic dermatitis
Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin. Atopic dermatitis is also often called simply eczema but the same term is also used to refer to dermatitis, the larger group of skin conditi ...
.
In Peninsular Malaysia, the leaves were used by the Malays to treat gonorrhoea. The leaves were used with other substances in a tonic that was squeezed into the eyes. The plant was pounded and applied to boils. The seeds were also used medicinally.antioxidant
Antioxidants are Chemical compound, compounds that inhibit Redox, oxidation, a chemical reaction that can produce Radical (chemistry), free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants ...
, anti-cancer, anti- HIV, vasodilator
Vasodilation, also known as vasorelaxation, is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. Blood vessel wal ...
, and anti-osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk.
It is the most common reason f ...
.
Green Manure
Canavalia gladiata is often grown as a cover crop, as green manure (due to its nitrogen-fixing ability) and as forage crop.
References
{{Taxonbar, from=Q1937714
gladiata
Edible legumes
Flora of Japan
Flora of China
Flora of tropical Asia
Taxa named by Augustin Pyramus de Candolle