Small pea, big potential

It is small, ancient and somewhat forgotten – despite its impressive capabilities. The yellow pea was cultivated as early as 7000 BCE in the Near East, spread throughout Central Europe during the Neolithic period and was still a staple food in Switzerland as recently as 200 years ago, typically consumed dried or as a purée. But then the green pea came along, bred for the nobility who wanted to distinguish themselves from the purée-eating common people. Eventually, industrialisation would bring greater prosperity – and thus also more meat for everyone. Although the yellow pea is somewhat better known today, it remains overshadowed by other legumes such as chickpeas. The yellow pea is grown in Switzerland, but has mostly been used for animal feed – and for a number of years now also for vegan substitute products. The potential offered by the Swiss yellow pea was explored at the ZHAW between April 2021 and September 2024 as part of the CREATE research project, generating results that could inspire further research and lead to new products.

Susanne Miescher Schwenninger, research group leader and lecturer at the Institute of Food and Beverage Innovation, headed up the CREATE project. “The yellow pea is a protein-rich food,” she says. “With our research project, we wanted to find out whether and how we could make the pea even healthier and more digestible.” Focus was placed on the future use of yellow peas – or their flour – in products designed for plant-based diets. These are increasing in popularity and are viewed as both healthy and sustainable: according to representative studies, the number of people in Switzerland who have a vegetarian or vegan diet has increased steadily over the past five years. In 2024, the Swissveg association counted some 308,000 people who follow a vegetarian diet, with 50,000 eating a vegan diet. One challenge of a purely plant-based diet: “Vitamin B12 is missing. As it is essential for our health, it has to be consumed in supplement form,” says Miescher Schwenninger. Within the framework of the project, the research team has now succeeded in enriching yellow pea flour with B12, among other things. And it has done so using fermentation. “We already had experience in fermenting proteins from other legumes,” explains the researcher.

During fermentation, microorganisms such as bacteria or yeasts convert certain components of specific raw materials into other substances in a natural way. A well-known example is sourdough: the activity of lactic acid bacteria and yeasts in the dough produces acids and carbon dioxide, among other things.

The aim of Miescher Schwenninger and her team of researchers was now to ferment the yellow pea flour using microorganisms that produce folic acid in addition to B12. Folic acid works together with B12 in human metabolism and is a vitamin that is also somewhat difficult to absorb through food intake – even when animal products are included. “Our third objective was to break down so-called FODMAPs through fermentation,” continues Susanne Miescher Schwenninger. FODMAPs are a group of carbohydrates and sugar alcohols found in yellow peas and other legumes that can give rise to digestive problems. “Without FODMAPs, yellow peas are easier to digest.”

One of the challenges faced in the research project was to find microorganisms that during the fermentation of yellow pea flour do precisely the following three things: produce vitamin B12 and folic acid and break down FODMAPs. The team had a wealth of options to choose from, as more than 14,000 strains of microorganisms are stored at minus 86 degrees Celsius in the freezer of the Institute of Food and Beverage Innovation in Wädenswil. A literature review helped narrow down the candidates. In the end, the team tested around 500 strains on the yellow pea flour, experimenting with temperature and water quantity, and ultimately identified the three microorganisms that performed best. This was followed by attempts to process the fermented mass. “We quickly realised that it was not suitable for meat substitutes in this form, even though this had originally been a focus,” says the research group leader. “However, we do see there to be great potential for the production of pasta or snacks, similar to peanut flips.”

Three ZHAW research groups joined forces for the project. “Over the course of more than three years, we worked closely together on an interdisciplinary and complementary basis,” says Susanne Miescher Schwenninger. While her team, Food Biotechnology, researched aspects such as the temperatures at which the microorganism strains fermented the pea flour best, the Food Technology team of Nadina Müller investigated how the fermented pea flour could be processed into end products. A wide range of analyses were carried out by Irene Chetschik’s Food Chemistry Research Group and ETH Zurich's Laboratory of Food Biochemistry. The project was also supported by Planted Foods Ltd.

According to Susanne Miescher Schwenninger, the CREATE project has clearly highlighted further research potential in the field of legume fermentation. And even if some might perceive their work as artificial at first glance, perhaps because it happens in a laboratory: “There is actually nothing more natural than fermentation. So, in the CREATE project, we did not create anything artificial. Instead, we skilfully used natural organisms in such a manner that they are able to make something natural even better in a natural way.” And who knows – maybe this approach will one day in future lead to a small, ancient and somewhat forgotten legume coming back into the spotlight.