Researchers at the University of Jena (Germany), together with colleagues in India and Germany, have investigated the potential of various duckweeds as a human food source. The results, which are very promising, have been published under the title ‘Nutritional value of duckweeds (Lemnaceae) as human food’ in the leading journal ‘Food Chemistry’.
“Duckweeds multiply very rapidly, but do not require any additional cultivable land,” says Dr Klaus Appenroth, associate professor at Friedrich Schiller University Jena. In view of the decrease in areas of farmland, this gives duckweed a huge advantage over soya, for example. For thousands of years, duckweed species have been on the menu in Asian countries such as Thailand, Cambodia and Laos.
As yet these duckweeds have not been cultivated, but simply ‘harvested’ from bodies of water. However, there are some initial experimental facilities in Israel and the Netherlands, where duckweeds are produced on an industrial scale. Wolffia globosa measure only 0.7 to 1.5 mm, are oval in shape and rootless. They multiply so rapidly that in a short time they can cover the entire surface of a body of water. A further argument in favour of having these plants as part of the human diet is that duckweeds easily absorb trace elements that are dissolved in water. This means that with little expense and effort, they can be used to relieve deficiency symptoms due to malnutrition.
Other potential applications for duckweeds are fish farming and water purification. The minute plants could also be used for producing bio-ethanol.