Duckweed Can Provide New Plant Based Protein, Say Researchers

13 Jan 2017 --- The potential of various duckweeds as a human food source has been investigated by researchers at the University of Jena. Working with colleagues in India and Germany, the researchers say that Wolffia globosa, a tiny, rootless duckweed, or water lens, has what it takes to achieve great things.

The results have been published under the title 'Nutritional value of duckweeds (Lemnaceae) as human food' in the leading journal Food Chemistry.

“Duckweeds can definitely serve as a source of protein in human nutrition,” says Prof. Gerhard Jahreis of the Friedrich Schiller University Jena.

“It is not without reason that duckweeds are dubbed “green machines,”” the nutritional scientist adds.

Jahreis explains that the protein content of duckweeds is comparable to that of lupins, rape or peas, with a protein yield of 30 per cent of dry weight. What is more, the tiny plants contain valuable omega-3 fatty acids such as stearidonic acid and alpha-linolenic acid.

Possible uses for duckweeds would be in the ever-popular smoothies or gluten-free baked goods.

“Duckweeds multiply very rapidly, but do not require any additional cultivable land,” says Dr Klaus Appenroth, associate professor at Friedrich Schiller University Jena.

Speaking last year with our sister publication, FoodIngredientsFirst, about a research project investigating how safe Duckweed is for human consumption, a Wellcome Trust spokesperson said, “Duckweed has a protein content of up to 43 percent when dried and, under optimal conditions, can yield 10 times more crude protein per hectare compared to soy.”

“It’s essential amino acid composition closely resembles animal protein, and therefore duckweed could be a high-quality protein source for human food or domestic animal production, replace soy import, and reduce soy import related carbon dioxide emissions.”

“It is also grown on water so does not require arable land and is very easy to grow and harvest.”

In view of the decrease in areas of farmland, this gives duckweed a huge advantage over alternative plant protein such as soya.

For thousands of years, duckweed species have been on the menu in Asian countries such as Thailand, Cambodia and Laos.

As a plant physiologist, Appenroth has dedicated nearly his entire research career at the University Jena to the tiny plants, and he has built up an extensive collection of Lemnaceae (commonly known as duckweeds or water lenses), among other things.

He singles out in particular the species Wolffia globosa, which is served up in Asia in the form of soup, as a vegetable or in omelette. In the latest tests by the research group, Wolffia globosa showed itself to be the most promising.

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 favor 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.