Effect of extrusion on the protein structure and digestibility of extruded soybean protein

BACKGROUND: Extrusion is the main method for the preparation of plant-based meat. Current studies have focused on the effect of different extrusion parameters on the texture and quality of plant-based meat, but there has been less research on their digestibility. This study determined the textural properties of extruded soybean protein (ESPro) for different extrusion parameters and the digestibility after in vitro simulated digestion experiments. The effect of extrusion on the structure and digestibility of ESPro and the relationship between them were elucidated. RESULTS: The results demonstrated a significant improvement in the digestibility of ESPro through extrusion, with the highest values for cohesiveness, springiness, chewiness, fibrous degree, digestibility, and proportion of digested peptides with <1 kDa molecular weight at an extrusion temperature of 160 °C and a screw speed of 30 rpm (ESPro1). In addition, β-sheet content in the secondary structure of the ESPro showed a significant negative association with ESPro digestibility. CONCLUSION: In this study, extrusion could improve the digestibility of ESPro by altering the protein structure. This advancement holds the potential for more effective applications in plant-based meats. © 2023 Society of Chemical Industry.