Tarwi (Lupinus Mutabillis)

Lupinus Mutabillis is a South American legume grown in the Andes for its edible bean. Pre-Incan people first domesticated this lupine more than 1,500 years ago. Tarwi is notable for its high protein and oil content. The bean contains 46% protein and 20% oil, rivaling the protein content of the soybean. It is also exceptionally rich in the essential amino acid lysine, which is a beneficial aspect of the legume since lysine cannot be synthesized, only supplied through diet. Tarwi has a soft shell that makes it convenient to cook with. The Andean people began cooking with the bean centuries ago, primarily using it in soups, stews, salads, boiled with maize or eaten by the handful as a snack. Today, if mixed with cereal, Tarwi creates the ideal nutritional balance of essential amino acids. Despite the bean's nutritional values, Tarwi is largely unknown outside the highland areas of Peru, Bolivia, and Equador. Tarwi may not have been more widely used due to an overwhelming bitter taste that the bean possesses. The bitterness is due to alkaloids, naturally occuring chemical compounds containing nitrogen that can be toxic and give off a bitter taste when eaten. However, the alkaloids are water soluble and can be removed by soaking the seeds in water for an extended period of time (usually a day or two.) The bean is no longer bitter and completely edible after being soaked.

areas in which tarwi is grown

the tarwi bean

Physical Characteristics and Cultivation Details

The tarwi plant is 1 to 2.5 meters tall (3 to 8 feet) with palmately compound leaves and purplish blue flowers. It is in leaf from May to October, in flower from June to August, and the seeds ripen from August to September. The plant flowers and ripens continuously until killed by weather. Plants generally take 5-11 months to fully produce their crop. The flowers are hermaphrodite (they have both male and female organs) and give off a honey-like scent. They are pollinated by Bees. Although tropical, tarwi grows well in temperate regions since it has adapted to the cooler conditions of high altitudes. It can tolerate a wide range of environmental conditions including frost, drought and nutritionally poor soil. The plant is a nitrogen fixing legume and can grow in any moderately good soil that is in a sunny position. It cannot grow in the shade. The genes for low-alkaloid tarwi are recessive. In order to produce naturally sweet beans with reduced levels of alkaloids, the plants have to be grown separated from other forms if the strains are to be kept pure.

the tarwi flower

Classification Chart

Plantae – Plants
Tracheobionta – Vascular plants
Spermatophyta – Seed plants
Magnoliophyta – Flowering plants
Magnoliopsida – Dicotyledons
Fabaceae – Pea family
Lupinus L. – lupine
Lupinus mutabilis Sweet – tarwi
The tarwi plant is a member of the Leguminosae family and the Lupinus Genus. Fabaceae or Leguminosae is a large and important family of the flowering plants, more often noted as the legume family, pea family or bean family. It is the third largest family of flowering plants, with 730 genera and over 19,400 species. The different species of this family grow throughout the world in a variety of different environments. Many are important agricultural plants such as the soybean, beans, peas, chickpeas, alfalfa and peanuts.

Additional Uses

There are currently no found medical uses for the tarwi plant. The seed does yield up to 18% of an edible oil with uses similar to soya and peanut oil. Tarwi has the ability to fix as much as 400kg of atmospheric nitrogen per hectare (a unit of surface, or land, measure equal to 100 ares, or 10,000 square meters.) It acts as an excellent green manure for agricultural farms. Tarwi is currently being grown experimentally in Europe, Australia, South Africa, and Mexico to develop its potential as a world crop.

tarwi used as green manure

Works Cited

"Edible, medicinal and useful plants for a healthier world." Plants for a Future. Web. 8 Dec 2009. <http://www.pfaf.org/database/plants.php?Lupinus+mutabilis>.

Levetin, Estelle, and Karen McMahon. Plants and Society. fifth edition. New York, NY: McGraw-Hill, 2006. Print.

"USDA Natural Resources Conseration Service." PLANTS profile. United States Department of Agriculture, Web. 8 Dec 2009. <http://plants.usda.gov/java/profile?symbol=LUMU8>.