Impact of spring rape varieties on protein extraction from press cake, emulsifying properties and antinutrient...

Rapeseed is the second most cultivated oilseed globally after soybean and a protein-rich press cake is generated after liberation of the oil. However, its use in food applications is limited by high levels of anti-nutrients such as glucosinolates and phytic acid. Although differences between botanical varieties are known, controlled comparisons of modern spring varieties for protein functionality and antinutrient reduction are scarce.

Protein was extracted from five spring rape varieties by the pH shift method, yielding 29-37% recovery. The variety Edda exhibited the best emulsifying capacity, stabilizing emulsion droplets of 44 μm (d₄₃). Glucosinolate concentrations in the protein-rich precipitates were reduced by 89-94% compared to the press cakes, with Sigrid showing the lowest concentration (0.45 g kg^-1). Phytic acid content decreased by 53-81% during the extraction, with Fergus having the lowest concentration (7.6 μmol g^-1).

The study demonstrates that emulsifying properties and anti-nutritional content differ significantly between spring rape varieties. Selecting suitable cultivars, such as Edda for emulsification or Fergus and Sigrid for reduced anti-nutrients, can improve rapeseed protein functionality for food applications. Future studies should include multiple harvest years to strengthen these findings. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.