In the summer sun, duckweed (Wolffia globosa) can be a menace. It grows so fast it covers a pond in a few days, blocking out the light for the life below. But it is this ability to multiply and its high nutritional value that has made it a potentially valuable food.
Although commonly eaten in Asia, where varieties of duckweed are also known as water lentils or watermeal, it has taken nearly 10 years for scientists to convince the European Food Safety Authority that it is a vegetable that is safe to eat.
Water lentils commercially grown in greenhouses are rich in vitamins and minerals. They have a high protein content when dried, making them potentially a replacement for meat. The other great advantage is that they can be grown in shallow water in layers in a greenhouse, stacked on top of one another, and so use little land.
Volunteers were asked to eat the lentils in soups, quiches and with spinach. They liked the dishes and careful monitoring showed there were no ill effects.
Chefs are currently experimenting with various recipes containing duckweed to try out on their customers in restaurants. Duckweed apparently freezes in cubes and stores well in bags.
The next step is to get the new food on supermarket shelves.
