Susanne Bryngelsson
Projektledare
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From by-product to food ingredient – the potential of rapeseed cake
The demand for plant-based proteins is increasing as we seek more sustainable and healthy food options. Today, proteins from legumes and cereals dominate the market, but there is growing interest in new raw materials, such as rapeseed press cake.
When rapeseeds are pressed to produce cooking oil, a by-product known as rapeseed press cake is generated. For every litre of rapeseed oil produced, approximately two kilograms of press cake are obtained. Today, it is mainly used as animal feed, where it can often replace up to 30 percent of soybean. However, there is growing interest in using rapeseed press cake as a food ingredient. This would not only create more value for rapeseed producers but also contribute to a more resource-efficient food system. In Europe, 12 million tonnes of rapeseed press cake were produced in 2025, with several additional million tonnes imported.
To better understand the potential of rapeseed press cake as a food ingredient, I posed a number of questions to my colleagues Evelina Höglund, researcher and Head of the Food Consumption Unit, and Joshua Meyers, researcher. Both are involved in the project “Rapeseed Press Cake for Food,” funded by Formas and carried out in collaboration with Linnaeus University and Skeby Gårdar.
Strengths – high-quality protein and healthy fats
Evelina and Joshua begin by describing the composition of rapeseed press cake and how it supports its potential as a food ingredient. They explain that the composition varies depending on the oil extraction method, but it typically contains 5–15% residual oil, 20–40% protein and 20–50% dietary fibre. The protein is of relatively high quality, with a complete amino acid profile, including methionine and cysteine, which are often lacking in other plant proteins. They also highlight that rapeseed press cake contains fibre and polyunsaturated fats, which is beneficial from a health perspective.
When further processed into protein isolates, the protein also exhibits good functional properties, such as emulsification and gel formation, making rapeseed press cake a promising raw material for future plant-based foods. Taken together, these characteristics make rapeseed press cake a promising ingredient for the next generation of plant-based foods, Evelina and Joshua conclude.
Challenges – taste, texture and antinutrients
Transforming a by-product into a food ingredient usually involves several challenges. For rapeseed press cake in particular, Evelina and Joshua highlight that taste is a major issue, as ingredients derived from it have a naturally bitter flavour and impart an astringent mouthfeel, partly linked to phenolic compounds that are difficult to remove. The high fibre content and residual hull material can also affect the texture and appearance of finished products.
They also point out that rapeseed press cake contains so-called antinutrients, such as phytate and glucosinolates, which can affect nutrient absorption or be broken down into undesirable compounds that may be toxic at high intake levels. There are no general maximum limits for glucosinolates in food, and acceptable levels are instead assessed during product approval, Evelina and Joshua explain.
There is also a potential, albeit debated, allergenicity risk for individuals with mustard allergy, which requires further study, particularly for processed ingredients.
Processing – a matter of balance
Joshua and Evelina highlight the need for rapeseed press cake to be processed in order to function as a food ingredient, both to reduce the content of glucosinolates and to improve its functionality. This may involve processes such as solvent extraction, protein extraction, washing, fermentation, or enzymatic treatment. Processing in the form of pasteurisation is also required to ensure microbiological safety, for example to prevent the presence of Bacillus cereus. At the same time, each processing step increases resource use, raises costs, and generates additional side streams. Processing therefore often becomes a question of balance, where different considerations must be weighed against each other.
Moreover, processing can both improve and impair the properties of the final product. As an example, they mention that wet extraction with pH shifting combined with solvent washing and heat is effective for producing protein isolates with high protein content and low levels of antinutrients. However, it requires several complex processing steps and often results in a product with high sodium content, which may also affect the functional properties of the protein. From a health perspective, reducing sodium content in foods is generally desirable. Other, milder processing methods often yield a product with better functionality and higher fibre content, but at the expense of a lower protein content.
Novel food – three approved products
In the EU, new foods are classified as “novel foods” and must be approved before they can be marketed. Evelina and Joshua explain that there are currently three rapeseed-based ingredients with such approvals: one protein isolate and two protein concentrates that also contain significant amounts of fibre. In one case, fermentation with lactic acid bacteria has also been approved as a processing step to improve flavour, nutritional value, and functionality. At the same time, several rapeseed-based ingredients are available on the market in the United States, where they have been granted GRAS status (Generally Recognised As Safe).
For new foods, or when ingredients are developed using new technologies, a new application is often required. This entails extensive analyses and can take several years to obtain approval. It is therefore important to consider already approved ingredients when further developing processing methods in order to ensure a shorter path to market introduction, Evelina and Joshua emphasise.
Great potential with increased knowledge
Despite the challenges, Evelina and Joshua see great potential for rapeseed press cake as a food ingredient. They argue that advances in research, evolving regulations, and strong innovation capacity are creating new opportunities. However, realising this potential will require a deeper understanding of how processing can be used to optimise functionality, taste, and nutritional value, while also taking cost, environmental sustainability, and regulatory requirements into account. With increased knowledge in these areas, they see strong prospects for developing rapeseed-based ingredients that can contribute to a more sustainable food system in the future.