Published On 3/6/2026
Protein is considered one of the most important nutrients that our bodies need for growth, muscle building, and tissue repair. It is available – as is known – in animal sources such as meat, eggs, and dairy, and plant sources such as legumes, soybeans, and nuts. But did you know that plant leaves are the most prominent source of proteins at all?
Plant leaves contain a protein known as Rubisco, which is the most abundant protein on the planet. As the global demand for protein increases, entrepreneurs are working to introduce it into the human diet.
The New Zealand company Leavet, for example, produces the so-called “Leaft Blade”, a liquid protein drink based on Rubisco that has recently entered the American market, according to the American “Time” magazine.
“Today almost no one knows about it, but within the next 10 years Rubisco will become one of the main proteins,” says the company’s CEO, Ross Milne.
What is rubisco?
Rubisco is found in every green leaf and is the protein primarily responsible for photosynthesis. Scientists describe it as having multiple properties: it contains all the essential amino acids, can be turned into an almost tasteless white powder, and can be formed and digested with relative ease compared to most other plant proteins.
It also does not usually cause allergies, unlike products such as dairy or soy, in addition to being easy to digest and extremely abundant in nature.
“From a food component perspective, it’s one of the best natural proteins out there,” says Slavko Komarnitsky, a biologist at NC State University’s Plants for Human Health Institute.
This is confirmed by the founder of Impossible Foods, which specializes in alternative meats, Pat Brown. In an interview with The New Yorker magazine in 2019, he said that Rubisco was the best protein the company had tested while developing a prototype for a plant-based burger, but the company did not use it in the end due to the inability to provide sufficient quantities of it.
Why is Rubisco so hard to get despite its abundance?
Although Rubisco is the primary protein in leaves, it only makes up about 3% of the leaf content, compared to legumes and soybeans, which have about 80% protein. This means that huge quantities of leaves must be harvested to obtain a commercial quantity of Rubisco.
Although growing this amount of plants is not a problem in itself, it leads to the production of huge quantities of liquid and pulp waste after extraction. The process of extracting Rubisco from inside plant cells is very difficult and complex, as the cell wall and chloroplast membrane must be broken, and each stage of these processes adds additional costs.
Ultimately, Rubisco becomes more expensive to produce than other proteins, causing companies to lose interest in it.
The leaves also turn brown quickly after harvest, which forces companies to extract the protein within only a few hours, otherwise it will not be usable.
“One of the biggest challenges companies face is that they don’t get a fine white powder, but rather a sticky brown substance, because everything turns brown once they start processing,” Pierce says.
Companies have tried pressing the leaves immediately after they are harvested, but chemically isolating Rubisco and removing the green color to obtain a pure white powder is still a complex process.
How are companies trying to make Rubisco viable?
Although difficult to produce, Rubisco supporters argue that extracting it directly from the leaves is more efficient than many traditional protein production methods. In today’s food system, plants are used as animal feed, and then we obtain protein through meat or milk, a process associated with methane emissions, resource waste and water pollution.
Direct extraction of protein from leaves avoids this “middleman,” as it is possible to produce about 5 times the amount of protein per hectare compared to raising cows for dairy production.
This is important in cases of global crises or food shortages in the future. A study published in May by the Alliance to Feed the Earth in Disaster (ALLFED) showed that leaf protein, including Rubisco, could meet the world’s emergency protein needs, given the ease of growing green plants in multiple regions of the world.
From a scientific discovery to a deferred nutritional dream
Since its discovery in the 1960s and 1970s, Rubisco has received widespread attention in food science circles. But despite its abundance, only a few companies have been able to turn it into a practical food product over the past decades.
Leaft is among the few companies providing Rubisco directly to consumers. It operates a 30,000-square-foot production facility in Canterbury, New Zealand, works with local alfalfa growers, and launches into the US market in early 2026.
The use of the product is not limited to drinks, as the company also produces biscuits containing Rubisco. It also cooperates with the Palmetto Superfoods chain to include it in juices, and sells protein powder to food companies in Japan and New Zealand for use in their products.
Wisconsin-based Fudi Protein also markets Rubisco as an alternative to egg whites, but is still in the fundraising phase to build a large-scale production facility. Plantible, one of the most prominent players in the market today, does not sell its products directly to consumers, but rather focuses on supplying raw protein to food companies.
The company grows duckweed in Texas and extracts Rubisco from it, which it markets under the name “Rubi protein.” The company’s CEO says that the demand for this protein is increasing globally, especially with the rising prices of traditional protein sources, noting that in February the company obtained approval from the US Food and Drug Administration (FDA), which means it is considered safe for food use.
