General Information about Lupin

Family: Fabaceae

Subfamily: Faboideae

Genus: Lupinus

Common names: Lupin, lupine

Note: Lupinus is a large, diverse genus that has more than 200 species in both the Eastern and Western Hemispheres. The focus here is on Lupinus angustifolius, a species of Mediterranean origin that is becoming increasingly important in Australian agriculture.

Biogeography:

Four different centres of origin have been proposed for the genus – the Mediterranean (including northern Africa), North America, South America, and East Asia. Today, approximately 90% of the recognised species are found in alpine, temperate and subtropical zones of North and South America, ranging from Alaska to southern Argentina and Chile. The remaining species are native to the Mediterranean region and Africa, with some populations extending to highland areas of tropical East Africa. Because of their larger seeds, most of the economically important species come from the Mediterranean region.

Botanical features:

Depending on species, lupins may be either annual or perennial. Most are herbaceous, but a few are shrubs or small trees. Lupinus angustifolius, also called ‘narrow-leafed lupin’, is an annual herb that can reach 80 cm or more in height. The slender plant has large palmate leaves with 5 to 11 narrow leaflets that are covered with fine hairs. Numerous flowers are borne on a 15-30 cm tall spike, or raceme. The flowers, which are pollinated by bees, are usually blue, but can also range from white to pink. The fruits are hairy pods, from 4 to 5 cm long. When mature, the seeds can be white, yellow, reddish-brown, black or, in some cases, mottled. Domesticated species are all smooth seeded, but many of the Mediterranean species have rough coated seeds.

L. angustifolius has a long tap root and is well adapted to sandy soils with a neutral or slightly acidic pH. It needs sunny conditions and a growing season of at least five months free from serious moisture stress.

General:

The name ‘lupin’ is derived from the Latin word lupus, meaning ‘wolf.’ The Romans believed that lupins robbed the soil of nutrients in the same way that a wolf would ’steal’ domestic animals.

Although used for grazing and forage, lupins contain alkaloid toxins that may poison cattle and cause liver damage. Since the 1930s, plant breeders have been developing varieties with lower alkaloid content (called ‘sweet lupins’). A variety of Lupinus angustifolius was the first true low-alkaloid lupin developed and is currently the most widespread species grown in Western Australia. Western Australia now leads the world in lupin exports.

A single recessive gene controls sweetness. The bitter form of the gene causes seeds to have an alkaloid content that is about 1000 times greater than that of sweet seed. Bitter plants produce more seeds than sweet plants and the varieties can cross-pollinate, so mixing of seeds will lead to increasing bitterness in each new generation of plants. If bitter seeds reach a frequency of about 1%, the average alkaloid level of the seed mixture can exceed the acceptable level for food and feed use (200 mg alkaloid per kilogram of dry seed). To avoid this, seeds must be measured for contamination levels before sowing. This is done by putting them under ultraviolet (UV) light, which causes the bitter seeds to fluoresce pink.

Uses:

Lupins are used as green manure and in rotation with wheat because they are capable of fixing nitrogen from the atmosphere and converting it to a usable form. In Western Australia, sustained wheat yields are directly dependant on the rotational benefits of lupins. They are also used for weed management and between fields of cereal crops to keep diseases from spreading.

With the development of sweet varieties, use of lupin for forage and grazing is increasing.

In Europe, lupin seeds have been used for many years to replace cereal grains in flours and pasta, and use of lupin for food products is increasing in Australia. Lupin seeds are also sometimes used as a complete or partial substitute for soybeans in the production of ‘milk’, milk powder, and tofu.

Many varieties of lupin (e.g., Russell lupins) are popular as ornamental garden flowers because of the variety of colours and showy nature of the tall flower spikes.

Human health benefits & concerns:

Like soybeans, narrow-leafed lupin seeds are comparatively high in protein (about 40% by weight) and fibre (30%) but they are lower in oil than soybean (averaging 9% as compared to 20%). L. mutabilis seeds are high in oil (20%) and protein (40%). They also provide a good source of both soluble and insoluble dietary fibre. As with other legumes, lupin protein is low in sulphur-rich amino acids, but the protein can be complemented by the amino acids found in cereals.

Lupin allergies:

Lupin allergies have been recognised for some time in Europe, where lupin flour is used widely in food products. It is a relatively new food item in Australia; however, a recent study in the Medical Journal of Australia reported three cases of people who had allergic reactions after eating products containing lupin. Lupin is related to other legumes, including peanuts and soy. The major allergens in lupin are also found in peanuts, so people who are allergic to peanuts may also be allergic to lupin.

Sourced from:

http://www.cilr.uq.edu.au/UserImages/File/factsheets/Lupin%20S6.pdf