## 3 Results and Discussion
### Integration into Circular Protein Systems
Furthermore, the presence of residual lipids improves lubrication during extrusion, reducing mechanical torque and energy consumption, while enhancing product uniformity and stability [57]. This processing efficiency adds economic value in industrial applications and supports the scalability of ESC-based formulations. Collectively, the nutritional, functional, and technological characteristics of ESC position it as a promising ingredient for innovative plant-based protein systems aligned with current health, sustainability, and consumer trends. The dual-product model developed in this study, yielding both expanded soybean cake (ESC) and soybean oil from non-GMO soybeans, exemplifies a circular processing approach that maximizes the valorization of local agricultural resources. By integrating both agronomic and bioprocessing innovations, the model addresses multiple strategic challenges facing European protein self-sufficiency, particularly under the EU Green Deal and Farm to Fork frameworks [34; 35]. The ability to stabilize nutritional quality across variable growing seasons demonstrates that the combination of semi-organic cultivation (P1 system) with controlled barothermal processing can deliver protein-rich soy products that are resilient to climatic fluctuations. This resilience is especially relevant for Central and Eastern European regions where drought episodes and photothermal variability are becoming more frequent due to climate change [36; 37]. The circularity of the model is further reinforced by its efficient partitioning of protein, oil, and fiber fractions without generating significant processing waste. ESC offers a high-protein, fiber-enriched matrix suitable for both food and feed chains, while the co-produced oil can be utilized in culinary applications, animal feed formulations, or bio-based industries, depending on market demands. Moreover, the integration of such systems into regional supply chains reduces reliance on imported genetically modified soybean meals, supports local economies, and enhances traceability and food sovereignty. This aligns with growing consumer preferences for non-GMO, locally sourced, and sustainably produced plant proteins. ESC consistently demonstrated superior oxidative stability during storage compared to FFS. This can be attributed to two main factors: (i) the reduced residual lipid content, which limits the availability of substrates for lipid peroxidation, and (ii) the retention of natural antioxidants, such as phenolic compounds, during mild barothermal treatment. Together, these characteristics significantly mitigate oxidation and extend shelf-life, particularly under ambient conditions without synthetic stabilizers. At the breeding level, the observed inter-annual variability in yield and composition also highlights the continuing need to select and develop soybean genotypes optimized for Central European agro-climatic conditions, with traits for both agronomic performance and compositional stability [23; 38]. Collectively, the proposed circular processing platform provides a scalable and environmentally aligned alternative to conventional soybean supply chains, bridging primary production, functional processing, and health-oriented food innovation. Its implementation offers both economic and ecological benefits, contributing to resilient protein systems capable of addressing future global protein challenges. The compositional and functional attributes of ESC--particularly its clean-label profile, high protein and fiber content, and oxidative stability--make it well-suited for scalable integration into sustainable food and feed chains. These characteristics directly support EU policy objectives for protein self-sufficiency, reduced reliance on GMO imports, and circular bioeconomy models under the Green Deal and Farm to Fork frameworks. ESC also aligns with growing industry demand for functional, plant-based ingredients that enable innovation in meat analogs, sports nutrition, and therapeutic formulations. However, this study has certain limitations.