Unveiling structural evolution during high-moisture extrusion of soy protein isolate-wheat gluten systems with soy...

This study investigated the regulatory effects of varying levels of soybean dietary fiber (SDF) addition on the high-moisture extrusion and product quality of soy protein isolate (SPI)-wheat gluten (WG) complexes. An innovative in situ "sudden shutdown" sampling strategy was developed to capture real-time structural alterations during the extrusion process. The results demonstrated that SDF incorporation significantly reduced specific mechanical energy and enhanced material flowability. The addition of an optimal SDF concentration promoted the formation of a well-defined fibrous structure and reinforced the protein network, thereby improving cooking yield and water-holding capacity. In contrast, excessive SDF addition weakened the protein network, resulting in a softer texture and a color shift toward red-yellow tones. Mechanistically, findings from the sudden shutdown experiments indicated that SDF inhibited intermolecular protein interactions through steric hindrance, while its degradation products participated in Maillard reactions, collectively modulating the texture and color stability of the extrudates. Overall, this work provides a theoretical foundation for the functional application of dietary fiber in the development of plant-based meat analogs.