Mechanism of Textural Reorganization in Silkworm Chrysalis and Pea Protein Extrusion: Structural Evolution and Quality Characteristic

Abstract

Mixed extrusion of animal and plant proteins has great potential in meat substitution studies. In this study, we analyzed the mechanism of change in the reorganization of animal and plant proteins during extrusion by exploring the changes in physicochemical properties with different percentages of silkworm chrysalis protein (SCP) additions (3%, 6%, 9%, 12%, 15%) mixed with pea protein isolate (PPI). The results showed that the moderate addition of SCP (12%) reduced the stiffness and denseness of the protein structure of the extrudates, and increased the total amino acid content of the extrudates, up to 74.83. Meanwhile, the addition of SCP changed the rearrangement of the proteins to form new chemical cross-linking bonds with higher bonding energies. Enthalpy of the sample up to 252.6 J/g, enhancing the denaturation energy requirement of the sample. Notably, the addition of SCP weakened the textural properties of the product, resulting in a minimum fibrous degree of 0.88, and improved the overall color of the sample, resulting in an L* value of up to 114.61. Such a change makes the product more suitable for further processing. Scanning electron microscopy (SEM) revealed that the addition of SCP changed the microstructure of the product, resulting in a looser, more porous sample overall. These results systematically elucidate the microscopic mechanisms of SCP and PPI restructuring during high-moisture extrusion.