Lupines

Changed on: 19.10.2016

There are 200 varieties of lupines worldwide, but only four of them: namely, the white lupine, Lupinus albus, the narrow-leaf lupine, Lupinus angustifolius, the yellow or tree lupine, Lupinus luteus, and the many-leaved lupine, Lupinus polyphyllus, are found in Austria. The many-leaved lupine can often be found in wood clearings, in particular forest roads both planted and wild, and partly naturalised. The other three varieties cultivated as feed and green manure are rare and unstable in their wild form.

The narrow-leaf lupine originated in the Mediterranean region, but is cultivated predominantly in north-eastern Europe nowadays. It is currently the most important variety in Austrian agriculture. Attempts to cultivate the white lupine were made in Austria and Germany in the 1980s. However, cultivation failed in the 1990s as a result of anthracnose, a fungal plant disease. The white lupine is the most important variety of lupine in the Mediterranean region.

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There are 200 varieties of lupines worldwide, but only four of them: namely, the white lupine, Lupinus albus, the narrow-leaf lupine, Lupinus angustifolius, the yellow or tree lupine, Lupinus luteus, and the many-leaved lupine, Lupinus polyphyllus, are found in Austria. The many-leaved lupine can often be found in wood clearings, in particular forest roads both planted and wild, and partly naturalised. The other three varieties cultivated as feed and green manure are rare and unstable in their wild form.

The narrow-leaf lupine originated in the Mediterranean region, but is cultivated predominantly in north-eastern Europe nowadays. It is currently the most important variety in Austrian agriculture. Attempts to cultivate the white lupine were made in Austria and Germany in the 1980s. However, cultivation failed in the 1990s as a result of anthracnose, a fungal plant disease. The white lupine is the most important variety of lupine in the Mediterranean region.

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Botany

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Lupine petals
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Lupine flowers
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Lupine fruits
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Lupine seeds

Both species cultivated for agriculture in Austria – the narrow-leaf or blue lupine, Lupinus angustifolius -- and the white lupine, Lupinus albus, are members of the Fabaceae / Leguminosae family or Pappilonaceae / Pulses. Both varieties grow as annual plants up to 1 m in height, the white lupine may even reach up to 180 cm.

The flowers of the narrow-leaf lupine are arranged in 10-20 cm long racemes. The corolla is mostly blue -- hence the name blue lupine -- but may also be pink, crimson, spotted or white. Unlike the white lupine, the upper labium of the calyx is deeply bipartite and the five to nine (rarely up to eleven) leaflets of the palm-shaped, elongated, long-stalk leaflets are narrow and straight (4-5 mm wide). The top side of the leaflet is smooth, the underside sparsely bristled. The stalk is also slightly close hirsute. Their yellow-to-black, bristly pods are 4-6 cm long. The seeds are smooth, grey-brown and with white spots.

The flowers of the white lupine, Lupinus albus, also form a raceme. Its corolla is mainly white with blue tips or tinted blueish to almost dark blue. The upper labium of the calyx is entire, the lower labium of the calyx three-toothed. The leaflets of the long-stalked, five-to-seven oblong leaflets are obovate (10-18 mm wide), nearly smooth above and hairy beneath and ciliated on the edge. The stalk has a close velvety-bristly hirsute. The pods contain four to six flat, white seeds, sometimes with black marks.

Then, there is also the yellow lupine, Lupinus luteus, which was cultivated primarily in north-eastern Europe, but plays a very minor role in agriculture today.

The three species are also referred to as sweet lupines because they are the main, low-alkaloid varieties with non-bitter seeds on the market. However, this term is not a botanic classification, but only denotes that these cultivated lupines are grown as a sweet variety. All edible lupines are sweet lupines -- i.e. lupines without alkaloids in their seeds. These varieties were discovered by Reinhold von Sengbusch, who developed a rapid chemical method to examine one and a half million individual plants among which he found five alkaloid-free examples. 

Another species worth mentioning is the blue lupine, Lupinus pilosus, which was discovered in South Tyrol, where it has been used for many years as a coffee substitute ("Altrei coffee").
Additionally, the Andean lupine, Lupinus mutabilis, has always been used in the highlands of Peru and Bolivia in South America. The indigenous peoples of South American soaked the seeds in water before using them to remove the bitterness. This species changes the colour of its petals during the flowering stage, hence the Latin name "mutabilis", meaning "variable". It is considered a good source for lupine oil, as its seeds contain a relatively high amount of oil.
The many-leaved lupine or large-leaved lupine, Lupinus polyphyllus, is not edible. It is only cultivated as livestock feed and as an ornamental plant (garden lupine).

Nutritional contents

The lupine’s net protein content is similar to soy at 32-40 %. This includes all essential amino acids, in particular the sulfur-containing amino acids cysteine and methionine, as well as the crucial proteinogenic amino acids threonine, tryptophan and lysine.

Lupines have the highest net fat content (except soy wholewheat) with about 5-9 % compared to other cultivated legumes. The fat content of the white lupine is slightly higher than that of the narrow-leaved or yellow variety. The oil is rich in unsaturated fatty acids, of which 24-52 % are made up of the monounsaturated oleic acid and 15-48 % are made up of the polyunsaturated linoleic acid.

Moreover, the high levels of fibre (about 15 %) in lupines bears some significance from a nutritional perspective. Additionally, lupines contain vitamins A and B1, as well as minerals and trace elements potassium, calcium, magnesium, manganese and iron. The high levels of manganese of up to 1,200 mg/kg dry weight must be highlighted, in particular. Similar to the soy bean, phytoestrogens were discovered in lupines, though at 50 times lower concentrations.

Use in past and present

Use in past and present

Wild growing lupines are relatively rich in alkaloids and were used predominantly to improve light soils, by loosening the soil with their widespread taproot system, mobilising poorly soluble phosphate reserves in the soil and, being a nitrogen-fixing plant, supply the soil with nitrogen for succeeding crops, minimising the use of additional fertiliser.

As with most other agriculturally used and protein-rich Fabaceae species the protein-rich green fodder is also important, in addition to using the seeds. Especially the small-seed varieties (yellow and blue lupine) are used for this, thanks to their lower seed costs. The average protein content of the green fodder is about 20 % in the dry matter and is suited to complement energy-rich and low-protein basic feed components (corn silage) thanks to its very high digestibility.

Thanks to their ideal protein composition, the valuable lupine seeds have been used in human diets for more than 2,000 years in the Mediterranean region and South America, in addition to cereal and corn. Presently, edible lupines may contain an alkaloid maximum of 0.02 %. Lupines are gluten-free, but they also have a very low glycaemic index, keeping blood-sugar levels low, which makes them ideal for diabetics. Furthermore, they are low in uric acid producing purines.
The soaked, cooked and salted lupine seeds are a traditional snack in Portugal and Italy, but they are also eaten by themselves or together with other vegetables as side dish, in soups, stews or salads. However, these protein-rich seeds are used mainly in processed form for human consumption. Gluten-free lupine flour is available in health food stores. It gives baked goods a nice yellow colour and is supposed to improve the consistency and shelf-life of products. Lupine flour is also used as an ingredient together with wheat flour to make bread, pasta and similar baked goods or confectionary products. Bread with lupine whole grain are higher in protein and contain fewer carbohydrates. In addition, lupine beans are made into lupine milk, plant-based meat alternatives, such as lupine tofu, lupine shoyu, lupine miso or lupine mayonnaise, similar to soy beans. Moreover, vegan ice cream containing isolated lupine protein has recently appeared on the market. Methods to enrich lupine proteins have been developed, as these proteins have excellent properties for the formation of emulsions and remain stable.

The white lupine would be ideal for the food industry given its neutral taste, but - unlike the blue lupine - this species is very susceptible to anthracnose and is not used that often as a result. There are numerous varieties of the many-leaved lupine featuring different colours that are used as ornamental plants in gardens and parks.

Agricultural aspects

In general, lupines are rather low-maintenance plants. However, they still dislike compact and waterlogged soil, despite their widespread taproot system.

Lupines need a minimum temperature between +3 and +4 °C to germinate. The seeds are sown at the middle of March to the first week in April at the latest. A severe cold period during the early plant stage could lead to a cold shock, if sown too early. This halts the growth of the plant, which will then go into the flowering stage too early. When sown out too late, ripening will be delayed, which will also lead to a considerable loss of production. The seedbed must be dry and the seeds should be covered by no more than 2 – 4 cm of soil.

A minimum of 60 to 70 plants per square metre should be aimed at for harvesting. A more densely planted field mitigates the danger of weeds appearing later, which may be a problem in organic farming, in particular. The seeds can be sown by seed drill using the conventional distance used for cereals and also precision seeding.

The yellow lupine is the lowest maintenance lupine of the three species used in agriculture and is primarily grown on light soils with low pH values. The narrow-leaf or blue lupine has medium-level demands in terms of its location and is, therefore, the species cultivated the most. The slightly higher-maintenance white lupine can be found in regions with longer vegetation periods.  

Lupine speciesSoilClimate
Lupinus angustifoliusSands, sandy loams; more chalk tolerant than the yellow lupine; optimal pH values: 5.0 to 6.8; no moor or heather soils (yellow lupine is more suitable)
Yield potential: 20 to 45 dt/ha
Suitable for all climates, in particular for areas with short vegetation periods; foothills; vegetation period: 120 to 150 days (depending on variety)
Lupinus albusHighest yields on better soils (minimum: sandy loam, better: loess loam or black soil); also sand soils with pH 5.5 to 6.8; no soils with pH levels over7
Yield potential:20 to 60 dt/ha
 Warm, humid spring; high yields require cool temperatures until start of elongation growth and good water supply for the flower; vegetation period: 140 to 175 days (depending on variety)
Lupinus luteusSand and little loamy sands with low pH value (4.6 to 6.0); higher ph values will lead to chlorosis (yellowing leaves)
Yield potential:15 to 20 dt/ha
No high temperatures in their early development stage; dry weather during ripening;
Vegetation period: 135 to 150 days (depending on variety)

Table 1 Soil and climate requirements of lupine species, modified by Römer et al. (2007)


Cereals, corn and sugar beet are considered good preceding crops. Lupines are not self-compatible. A period of five years must be kept between the growing of lupines and other Fabaceae species, as well as rapeseed and sunflowers. Winter crops are especially suitable as succeeding crops because they use the nutrients supplied most efficiently. Given the development of the nodule bacteria, nitrogen should not be used to fertilise the soil. Well supplied soil can even go without using any fertiliser. Fertilising with 60-80 kg P2O5 und 120-180 kg K2O is recommended for badly supplied soils. The lupines should be harvested once they have lost all their leaves and the seeds inside the pods make rattling noises. This will be usually the case between end of August and beginning of October, depending on the region. Average yields vary depending on the species and can be found in table 1.

A Symbol of Variety

The EU common catalogue of varieties of agricultural plant species currently lists 43 Lupinus angustifolius-, 20 Lupinus albus-, und 15 Lupinus luteus varieties. The Austrian variety list includes the two 43 Lupinus angustifolius varieties, Borlu (since 22.12.2005) and Boruta (22.12.2005).

The European database for genetic resources (http://eurisco.ipk-gatersleben.de/apex/f?p=103:1::::::) currently lists 1301 lupinus accessions, which are mainly safeguarded in gene banks in Germany, Russia, Spain and Portugal. The Austrian index of genetic resources (Index Seminum) includes two accessions of Lupinus angustifolius (www.genbank.at/nationales-verzeichnis.html).

Literature

Becker, H. (1993) Pflanzenzüchtung. Verlag Eugen Ulmer, Stuttgart.

Berendes J. (1902) Des Pedanios Dioskurides aus Anazarbos Arzneimittellehre in fünf Büchern. Übersetzt und mit Erklärungen versehen. Volltext; Digitalisat: http://www.pharmawiki.ch/materiamedica/

Dirauer H., Böhler D., Kranzler A. und Zollitsch W. (2004) Lupinen. Forschungsinstitut für biologischen Landbau, FiBL-Best Nr. 1308, Ausgabe Österreich.

Fischer M. A., Oswald K., Adler W. (2008) Exkursionsflora für Österreich, Liechtenstein und Südtirol. 3. Auflage. Biologiezentrum der Oberösterreichischen Landesmuseen, Linz.

EU-Sortenkatalog: http://ec.europa.eu/food/plant/propagation/catalogues/database/public/index.cfm?event=homepage

Römer P. et al. (2007) L U P I N E N - Verwertung und Anbau. 5. Auflage, Gesellschaft zur Förderung der Lupine e. V.

Landwirtschaftskammer Oberösterreich (2010) Anbau- und Kulturanleitung SÜSSLUPINE - Die weiße oder schmalblättrige blaue Süßlupine – eine interessante Eiweißalternative (http://ooe.lko.at/)

Lebensministerium (2006) Richtlinien für die sachgerechte Düngung. Anleitung zur Interpretation von Bodenuntersuchungsergebnissen in der Landwirtschaft. 6. Auflage: http://www.ages.at/fileadmin/AGES2015/Service/Landwirtschaft/Boden_Datein/Broschueren/SGD_6_Auflage.pdf

Österreichische Sortenliste 2015 - Republik Österreich, gemäß Saatgutgesetz 1997. Schriftenreihe 3/2015: http://www.baes.gv.at/fileadmin/user_upload/%C3%96SL_2015_Gesamt.pdf

Reiner H. (2007) Die Lupinen - Warenkundliche Grundlagen für die Müllerei. Wien, Ausarbeitung für die Mantler Mühle / Rosenburg

Statistik Austria (2014) Anbau auf dem Ackerland  2014. Endgültige Ergebnisse. Schnellbericht 1.16.: www.statistik.at/web_de/.../anbau_auf_dem_ackerland_2014_081443.pdf

Sengbusch, R.v. (1934) Die Geschichte der „Süßlupinen“. Die Naturwissenschaften, 22 Jg., H. 17/18, 278-281.

www.lupinen.ch

www.genbank.at

www.naehrwertrechner.de

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