For decades, an unusual plant has been a part of the diet of the inhabitants of Southeast Asia, both for humans and animals. It is a plant known as water lentil.

As scientists involved in food technology, we believe it is necessary to draw attention to this fascinating world of high-protein plants. Water lentil has the potential to transform our diet!

Small plants, big potential
Water lentils are aquatic plants that inhabit the surface of freshwater bodies around the world. There are several species of water lentils, which mainly differ in the size of their leaves. These plants are incredibly simple: a small leaf that floats on water with a tiny root that is not attached to the soil.

At first glance, water lentil may seem insignificant and too ordinary to be interesting. However, beneath its modest appearance lies an incredible potential for protein production.

Under optimal conditions, water lentil can contain up to 45 percent protein, making it an excellent source of this essential nutrient. Studies have shown that one hectare of water lentils can produce between 10 and 18 tons of protein annually. In comparison, soybeans, the most widely grown legume in the world, produce only 0.6 to 1.2 tons.

Moreover, these plants have the ability to reproduce very quickly. The amount of water lentils in a single lake can double in less than 48 hours. This impressive growth rate raises a crucial question: how can we harness the proteins from water lentils for human consumption?

Extracting protein from leaves: a big challenge
The idea of using plant leaves for human consumption dates back to World War II when ways to feed hungry populations from this protein source were sought. Rubisco, the main enzyme involved in the photosynthesis process and the most abundant protein in leaves, has long attracted scientists' attention.

Besides being the most abundant protein on Earth, Rubisco has a number of other qualities. Its pale color, lack of taste and smell, and excellent amino acid composition make it an ideal ingredient for the food industry. For example, the first prototypes of the famous 'Impossible Burgers', made from plant-based meat, were made with Rubisco.

But a major challenge remains: trapped in the leaf cells, Rubisco is surrounded by other compounds with undesirable colors and flavors. This limits its use as a food ingredient. Although it is possible to produce flour concentrates with Rubisco, the process involves a lot of grinding, heating, and chemical separation, and each step involves losses and costs. Currently, to obtain an ingredient that can be used in the industry, between 75 and 95 percent of the proteins present in the leaf are lost.

If we wanted to produce several tons of this ingredient, the amount of water lentil leaves that would need to be processed would be enormous, even for these protein champions. Because of this, Rubisco has never achieved the success it deserves as a food product. To solve this problem, our research team set out to free Rubisco from its shackles. And we succeeded!

How we did it
Our team developed an innovative experimental protocol that led to the production of concentrated flour with Rubisco. We managed to extract 60 percent of the proteins, one of the highest yields ever recorded in scientific literature.

Our secret? Mathematics. More precisely, statistical modeling. Statistical modeling is an invaluable tool for exploring the effects of multiple parameters on a precise response with a very small number of experiments. In just a few months, we were able to identify optimal conditions in terms of pH, temperature, and concentration to maximize the extraction and purification of proteins from water lentils.

The biggest reward is that this protein concentrate has excellent properties that are crucial for any good food ingredient: it is very soluble in water and can form foams (like egg white), gels (like yogurt), or emulsions (like mayonnaise).

Towards your plate and beyond
Our research is still in its early stages. But we can already see a promising future for water lentil proteins. They could find wide application in food formulation, but also in the field of nutrition and human health. Some of the compounds they contain could help reduce high blood pressure.

In short, thanks to their high content of versatile proteins, water lentils could very easily change our diet. And, most importantly, they will help shape a more sustainable and nutritious future for all of us.

Original:
Tristan Muller
PhD candidate in food science, Laval University
Laurent Bazinet
Professor of food science and technology at Laval University