Lupins are an ancient legume, cultivated in the past above all for their ability to improve the land. They were also present on our grandparents' tables, often consumed as simply boiled snacks. Today, thanks to their nutritional properties, they are attracting renewed interest, especially as an ingredient for meat substitute products. (1)
1) Lupins, a legume with an ancient history
The lupins, or 'wolf bean', are the fruits of a herbaceous plant belonging to the Leguminosae or Fabaceae family. It is a typical crop of the Mediterranean area and the Middle East, already known in ancient times.
The first tracks they come from the Egyptians, who placed them in the tombs of the pharaohs. For the Greeks they had propitiatory functions while the Romans cultivated them and consumed them in large quantities instead of meat, exploiting their high energy and protein value.
1.1) Three species cultivated in Italy
There are numerous species of lupine, but not all suitable for human consumption. Those cultivated in Italy – especially in Calabria, Puglia, Lazio and Campania – are three:
– white lupin (Lupinus albus),
– yellow lupine (Lupinus luteus) e
– blue or light blue lupine (Lupinus angustifolius).
The plant it is annual and can reach a height of 1,5 meters. It has a very elegant flowering, with large, white flowers. Following pollination, long flattened pods are formed which contain the seeds, white and with a diameter of up to 15 millimetres.
2) Resistant to frost and drought
The lupine plant It adapts well to different types of terrain. Indeed, its nitrogen-fixing action - typical of legumes - is able to improve the structure and fertility of the soil, so much so that it was used as a rotation crop. (2)
Frost resistance allows you to sow early, already in autumn. The late flowering, between May and June, is ideal for pollinating insects. The pods are instead harvested at the end of summer, after the sun has dried the plant.
The water requirement he is modest. Lupine roots can penetrate the soil to a depth of 1,5 metres, making irrigation unnecessary except in extremely dry periods. Characteristic that makes this crop resilient to climate change.
3) Excellent nutritional properties
The protein content of lupine seeds is similar to that of soybeans and higher than all other legumes: approximately 16 g per 100 g, 34-44% of the dry weight. Furthermore, the quality of the proteins is very high thanks to the composition of amino acids and their digestibility.
They contain 7.2 g/100 g of carbohydrates, but they are practically starch-free. The fat content is significantly low, approximately 2-3 g per 100 g of product. The seeds contain a significant amount of oil rich in unsaturated and saturated fatty acids. Lupine seeds are also a rich source of vitamins - especially group B - and minerals such as calcium, phosphorus, magnesium, potassium and manganese.
4) Selection of plants with fewer alkaloids
One of the causes which has led to the low consumption of lupins in our diet is the presence of some anti-nutritional substances, in particular alkaloids. These substances are produced by some plants as a defense against predators. Other examples are solanine in potatoes, nicotine in tobacco or caffeine in coffee plants.
The alkaloids they impart a bitter taste to lupins, which can become toxic to humans and animals. Those contained in lupins are part of the quinolizidine family and are around 100 bitter components. To avoid health problems, over time varieties of sweet lupins have been selected - for example, the 3 mentioned above - which have an average content of 130-150 mg of alkaloids per kilo (0.013-0.015%) compared to the bitter lupins which contain 40-80 thousand mg per kilo (4 to 8%). (3)
5) Potential and future challenges
Thanks to its features and properties, lupine is arousing new interest for its possible applications.
5.1) In agriculture
Besides being a plant which adapts well to the most difficult soils and climates, lupine is a natural fertilizer. In particular, bitter lupins have a greater capacity to fix nitrogen. Furthermore, the alkaloids contained in the plant can be used as natural pesticides.
5.2) In medicine
Proteins of lupine have beneficial effects on lipid and glucose metabolism as well as on blood pressure levels. Furthermore, they have effects on inflammatory processes and changes in the intestinal microbiome. The high content of polyunsaturated fatty acids in relation to a low level of saturated fatty acids makes lupins useful in the prevention of numerous metabolic diseases, including cardiovascular ones.
The alkaloidsFurthermore, they can be usefully used in pharmaceuticals. In fact, they have antimutagenic, antibacterial, antifungal, antitumor and anti-inflammatory properties. In particular, lupanine enhances the release of insulin from glucose, proving useful in the treatment of type II diabetes, while sparteine is an anticonvulsant. (4)
5.3) In the food and feed industry
The demand for proteins it is growing exponentially, in line with the growth of the world population. Lupins can be a valid alternative to soya, which we import mostly today, for use in human nutrition and feed.
The lupins they are also getting more and more interest from the meat alternative food industry aimed at vegans and vegetarians. In addition to the classic recipe - boiled and salted lupine seeds - today you can find burgers, sauces, meatballs and cured meats made with lupine flour. Being practically starch-free, they are also suitable for celiacs. (5)
6) The challenges
One of the biggest problems linked to the consumption of lupins, as we have seen, is the presence of alkaloids. Only a few countries have established maximum limits for the presence of these substances in foods. Among these are France, Great Britain, Australia and New Zealand, where the maximum level is set at 200 mg/kg of alkaloids in seeds.
There is a lack of regulation at European level. Today, for their marketing, it is necessary to eliminate contaminants, as required by Council Regulation 315/93. The elimination of alkaloids can be accomplished by leaching, which however could decrease the protein content. Or by growing 'sweet' lupins which produce alkaloids in insignificant quantities.
Other contaminant source of concern regarding human and animal consumption of lupins are Phomopsins, a family of mycotoxins produced by the fungus Diaporthe toxica. Since data on the presence of phomopsins in food and feed is poorly documented, EFSA has not issued precise recommendations regarding maximum intake levels. However, given that fumopsin was found to be hepatotoxic in all species evaluated and hepatocarcinogenic in rats, EFSA suggest to keep animal and human exposure to this mycotoxin as low as possible.
7) Provisional conclusions
Given the numerous positive aspects of lupins and their promising help in the challenges that this historical period poses for us, the European legislator should prepare legislation on alkaloids to allow farmers to produce them safely. A certain regulation would also stimulate research, for an in-depth study on antinutrients and their isolation.
Further push the rebirth of this crop in Italy would be the increase in lupine collection centers and infrastructures for their processing.
Alessandra Mei
Footnotes
1) Dario Dongo, Andrea Adelmo Della Penna. Vegetable alternatives to meat, the nutritional challenges. GIFT (Great Italian Food Trade).
(2) Dario Dongo, Camilla Fincardi. The value of legumes to feed the planet, FAO report. GIFT (Great Italian Food Trade). 11.1.20.
(3) Ivraina Brändle, Christine Arncken, Ursula Kretzschmar, Ludivine Nicod, Mariateresa Lazzaro. Alkaloid analysis in lupins. Prerequisites for food production. FiBL. 2024. No 1763. DOI:10.5281/zenodo.10592310 https://www.fibl.org/fileadmin/documents/shop/1763-alkaloid-analysis-lupins.pdf
(4) Ana Pereira, Fernando Ramos, Ana Sanches Silva. Lupine (Lupinus albus L.) Seeds: Balancing the Good and the Bad and Addressing Future Challenges. Molecules. 2022, 27(23): 8557. 5.12.2022 doi:https://doi.org/10.3390/molecules27238557
(5) IRTA. LUPIPROTECH – Obtaining and functionalization of lupine protein isolates for the development of cooked meat analogues. https://www.irta.cat/en/projecte/lupiprotech-obtaining-and-functionalization-of-lupine-protein-isolates-for-the-development-of-cooked-meat-analogues/
Graduated in Law from the University of Bologna, she attended the Master in Food Law at the same University. You participate in the WIISE srl benefit team by dedicating yourself to European and international research and innovation projects.
