Would you like a protein smoothie with starch-potatoes and sugar beet tops? Or a bowl of good old-fashioned pea soup?
Whatever we eat in the future, we will always need proteins, the building blocks of all living things and a key part of food and animal feed.
The possibilities and challenges of plant proteins, within the frameworks of humanity’s responsible use of nature’s resources, are a key issue for the future. Many international reports have highlighted the importance of growing more legumes as part of the solution for achieving sustainable food production. Peas are one example.
In Sweden, a majority of the peas that are grown are used for animal feed. One research track aims to establish knowledge about how plant resources can be used as food, for example, how the crops currently being grown for protein feed can be developed into crops that are grown for human consumption.
Humans have grown peas for millennia, and Pisum sativum is one of the world’s oldest cultivated crops. At SLU, a plant breeding and research project called ‘Pea – the Key for Future Green Protein’ has collected hundreds of different kinds of peas from gene banks around the world. They are yellow, green, blue, red and black, big and small, wrinkly and smooth. They look nothing like a bag of frozen green peas, yet they are all the same species – but with greater genetic diversity.
Pisum Sativum. Photo: Roger Culos (CC BY-SA 3.0)
The researchers aim to take advantage of the genetic diversity of this ancient cultivated food source. They are mapping out the genes’ links to the traits of the plants and making use of the plant material for the plant-breeding programme in developing new pea varieties, for both animal feed and human food. The goal is to be able to continue to grow our peas and other protein crops in the future, sustainably and with rich harvests.
Researcher and group leader Cecilia Hammenhag explains, ‘One key goal of the project is to give added value in peas for human consumption. How do we make use of the pea protein? What do we want it for? We’re looking at what makes the peas taste good and what makes them easy to cook and process. We’re also looking at whether there are unhealthy components in the protein fractions, such as phytic acid, which inhibits iron uptake. The good news is that the amount of phytic acid in different pea varieties varies, which means that we can develop pea varieties with low phytic acid, allowing us to increase iron uptake.’
Parts of the collection of peas that the researchers are working with. The genebanks send a limited amount of seeds from each so-called accession of peas, which must then be propagated under controlled conditions to produce enough seeds to be able to do field trials. Photo: Anna Nieto Esteve
Some varieties of peas are grown for green harvesting, that is, they are harvested before they have ripened. Photo: iStock
SLU researchers looking at a flowering faba bean plant. The faba bean, Vicia faba, is another legume that is the subject of several different research projects, for example "Faba Bean for Future Food and Feed" within SLU Grogrund – Centre for Breeding of Food Crops. Using modern plant breeding techniques, the project studies specific qualities that are of interest to the development of new, healthy and tasty food products based on faba bean. Photo: Per Snell
A round-edged child’s fork scoops up a green pea and lifts it precariously towards the toddler’s mouth, but the legume rolls over the edge and hits the floor before it gets to its destination. Another pea, still in its pod, lies in a feed trough before being swept into a cow’s mouth. A stressed hand opens the glass door of a supermarket freezer, takes out a packet of meat-free sausages and turns it over to read the ingredients. Pea protein. Potato protein. RuBisCO from sugar beet. Can that be good? How can one know which foods are good for the children, now that the family is eating less meat but still needs something quick and easy to cook for dinner?
Peas in food are OK, but Swedish consumers are more hesitant to use its protein as a substitute for meat products. Photo: Mia Peterson
Consumer research from SLU shows that Swedes see legumes as nutritious, but still have a wait-and-see attitude towards processed meat substitutes. Perhaps this will change in the future.
In a field, sugar beet seeds have sprouted their first leaves in the sunlight. In a few months, the plants will stand lush and green. What will happen to them?
Summer is over; autumn has arrived. The beet harvester moves along the rows of the field, pulling up and topping the beets as it goes. The entire plant is edible, but as the name suggests, sugar beets are grown for us to extract the sugar from the roots. The rest of the plant is usually used for animal feed and the tops are either used for biogas production or just ploughed down into the soil as green manure.
Researchers at SLU are looking into unutilised protein resources embedded in our cultivated crops – those we currently use to produce other things, such as sugar, oil and starch.
In the Plant Protein Factory at SLU, researchers are looking into the possibility of making better use of the resources of green plant material, such as sugar beet leaves and beetroot tops. The GreenLeaFood research project aims to characterise and evaluate opportunities to use substances, including proteins, from green leaf biomass as high-value food components in the future.
The tops are pressed for juice, from which plant proteins are extracted following several steps. The results are green and white proteins. White protein, called RuBisCO, may be of interest to the food industry. In its pure form, it is tasteless and odourless, which is a necessity in the manufacture of nutritious meat-free products.
‘We are investigating methods of developing an efficient, sustainable way of extracting this protein,’ says researcher William Newson.
The goal has not been achieved yet. What is difficult is extracting the protein in the purest form possible, without any other part of the plant being included. This problem does not apply solely to sugar beet tops, but also things like oilseed rape and potatoes.
Plant Protein Factory - Pilot scale extraction of proteins and other plant compounds from green leaves: Researcher William Newson and Ilyas Papas, examining the fibre outlet.
Photo: Mårten Svensson
The green mass that comes to the Plant Protein Factory is pressed. It is divided into different fractions in a multi-step process. A green juice is formed which later in the process is split into a green protein and a white juice. The white juice is then split into white protein and brown juice. Photo: Viveka Sernvi Hansson
Green bubbling juice from the Plant Protein Factory. Photo: Kristina Santén
Green juice, this time from beet tops, in the Plant Protein Factory. Photo: Sara Kyrö Wissler
Potato starch is extracted from special varieties of potatoes that have been developed for the purpose through plant breeding. Photo: Jenny Svennås Gillner
Many of our food ingredients are refined in various processes before we use them.
When potatoes are harvested from the field, not all of them are intended to be boiled, fried and eaten. Starch-potato varieties are used in other ways, such as the production of various starches and fibres.
There is one issue with vegetable proteins. Sometimes they bind stubbornly to unhealthy or toxic substances that can occur naturally in the plant. In small amounts, this is not a problem, but when industrial processes isolate the protein from the other components, these toxins can become too concentrated to be acceptable in food products. The process of removing them becomes overly costly and unsustainable in terms of time, energy and money.
‘Potato protein is fully comparable with soy protein or the protein in cow’s milk. However, this costly removal process is the reason why potato protein is seldom used in food today, despite it being a by-product from potato starch and potato fibre manufacturing that could generate 3,000 tonnes of high-quality protein a year in Sweden alone,’ says researcher Folke Sitbon.
Researcher Folke Sitbon with a potato plant. Photo: Jenny Svennås Gillner
Using different tools, SLU researchers are investigating whether it is possible to alter the starch-potato’s content of unhealthy substances. The goal is to develop starch potatoes with new areas of use.
At SLU, we are researching and developing foods that we might eat in the future – products that are yet to hit our supermarket shelves, such as protein from sugar beet tops and starch-potatoes. At the same time, we research how we can make the most of our traditional crops – like peas and faba beans – in a modern, sustainable food system.
Some of the research studies with a focus on plant proteins within SLU Grogrund - Centre for Breeding of Food Crops:
GreenLeaFood - Added food value from green leaves
“Meat tastes good, legumes are healthy and meat substitutes are still strange - The practice of protein consumption among Swedish consumers” in Appetite https://doi.org/10.1016/j.appet.2022.106002
“Consumer attitudes and beliefs towards plant-based food in different degrees of processing – The case of Sweden” in Food Quality and Preference https://doi.org/10.1016/j.foodqual.2022.104673
Story:
Ida Andersson, ida.andersson@slu.se, +4640415547.
Unit for Collaboration and Development
Press / research contact:
Cecilia Hammenhag, e-mail
William Newson, e-mail
Folke Sitbon, e-mail
Production:
SLU Division of communication, e-mail.
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