Valorizing Press Cakes as Ingredients in Textured Vegetable Proteins: Processing, Structure, and Texture

In this study, press cakes (PCs)—the by-products from almond, coconut, flaxseed, pumpkin seed, rapeseed, and sunflower oil production—were used to create textured vegetable proteins (TVPs) that offer both nutritional and sustainability benefits. Several technological and textural properties were measured to evaluate the potential of the PCs for use as ingredients in meat alternatives.

After raw material characterization, 15 PC flours were mixed with pea protein isolate at three levels (25%, 45%, and 50–100% PC, depending on composition) and low-moisture extruded in a pilot-scale co-rotating twin-screw extruder (11% feed water content, 150°C barrel temperature, 10.18 kg/h throughput). Extrusion response parameters were recorded. The structure and texture of the resulting extrudates were analyzed by light microscopy, fracture test, and texture profile analysis. Finally, the PC-TVPs were compared to reference products and meat.

Oil and protein content are the most important factors influencing processing and TVP properties because they reduce shear forces and cross-linking. The decrease in protein network stability seen as PC content increases results in denser TVPs with smaller pores and thicker lamellae. These TVPs—especially those made with sunflower seed, flaxseed, and pumpkin seed PCs—are more chewy and less spongy than higher protein TVPs, making the texture more meat-like.

Press cakes possess the techno-functional properties to (partially) replace protein isolates or concentrates in TVP production, thereby improving the nutritional profile, texture, and sustainability of meat alternatives.

Practical Applications

Technological insights gained from this study will facilitate the production of TVPs from press cakes in new plant-based products. Drawing on the results of this study, producers will be able to choose press cake ingredients and concentrations to achieve the desired textural properties while diversifying their raw materials. Starting from the specified extrusion and formulation conditions indicated here, future research can further optimize processes and TVP properties.