The average protein content of lupin is just over 30 per cent, compared with 44 to 48 per cent in soybeans, and is gradually being used in food formulations to replace soya flour in speciality bakery and pasta products.
The flour, produced from the grain legume Lupinus angustifolius L. can also replace eggs and butter to enhance colour; and potential uses of lupins are believed to lie in crunchy cereals and snacks, baby formula, soups and salads.
But growing research suggests the flour could pose a risk to consumers with food allergies, notable peanuts. Researchers in the UK caution this month that people with peanut allergy - about 1 per cent of the UK population - should avoid any products containing it until they have another allergy test.
A team at the Royal Free Hospital, London, who published their findings in the latest edition of The Lancet, (2005; 365: 1360(, highlighted the case of a 25-year-old woman who, in August 2004, had an allergic reaction after eating a restaurant meal of chicken, French-fried potato, and onion rings.
Anaphylaxis - a life-threatening allergic reaction - was diagnosed. According to the UK researchers, the consumer knew she had a severe allergy to peanuts, but not to lupin, later identified in the onion ring batter she had consumed.
These latest findings build on recent reports that people allergic to peanuts may also be allergic to lupin, because the major allergens in lupin are also found in peanuts.
Tough new laws on food allergens that entered into force in Europe in November 2004 require food manufacturers to list 12 potentially allergic ingredients, and their derivatives. Lupin flour is not included in the listing.
"At the time when consultations for the European directive began about two years ago, we at the UK-based Institute of Food Science & Technology suggested that lupin flour be included in the list," leading food technologist Prof. J Ralph Blanchfield recently said to FoodNavigator.com.
But in fact the suggestion was rejected, with the final list for directive 2003/89/EC (amending Directive 2000/13/EC) applying to cereals containing gluten, fish, crustaceans, eggs, peanuts, soy, milk and dairy products, nuts, celery, mustard, sesame seed, and sulphites.
At an open meeting in 2002, the UK's Advisory Committee on Novel Foods and Processes (ACNFP) agreed that the allergenicity of lupin was an issue, but noted that "most foods are allergenic to a greater or lesser extent".
But some see strong growth for lupin as a food ingredient in the near future. Researchers at the Australian Department of Agriculture Australian have come up with a new yellow lupin (Lupinus luteus) capable of producing a grain containing up to 40 per cent of high-quality protein, which can produce a kernel meal with a protein content of 52 per cent, making it a potentially attractive option for food makers looking to source food-grade proteins.
Sofia Sipsas, a lead researcher on the new high-protein lupin, says that because the protein can be extracted from the lupin flour, it can be used as an ingredient just the same as protein taken from milk (casein and whey), or egg-whites.
In addition to the protein, the researchers say lupin flour also contains non-starch polysaccharides which act like both soluble (oat fibre) and insoluble (wheat bran) fibre.
Previous research suggests that lupin kernel fibres could lower blood cholesterol, and lupin fibre when used as an ingredient has a high satiating factor, lengthening the time before people feel hungry.
French lupin flour supplier CANA says that the flour has a high content of natural antioxidants, including tocopherols - "50 g of lupin flour provides 100 per cent of the recommended daily amount of alpha-tocopherol (RDA 2001).
"Lupin flour was reintroduced to France in the 1990s, principally for its nutritional properties," said the co-operative, based in western France.