Dynamic behavior of zein-gluten interaction during extruded noodle processing

The impact of adding zein on the gluten network during extruded noodle processing and the quality of the noodles by extrusion-cooking were investigated. These changes were studied by size exclusion-high performance liquid chromatography (SE-HPLC), free sulfhydryl (SH) measurement, non-covalent interactions, Fourier-transform infrared spectroscopy (FTIR), particle size analysis, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). Zein reduced the protein aggregation, resulting in a higher free sulfhydryl content and increased hydrogen bonds and hydrophobic interactions during noodle processing. Moreover, Zein reduced the relative content of β-sheets by 4.54% and 7.48% at the extrusion and cooking stages, respectively. Zein decreased the particle size during extrusion but increased it during cooking. Zein improved the compactness and strength of noodle microstructure during cooking, exhibited higher hardness and impeded water mobility compared to extruded noodles made only with wheat flour (WF). The extruded noodles containing zein showed a significant increase of 26.10% and 61.11% in tensile strength and distance, respectively. Zein did not cause significant changes in the cooking loss and water absorption in the extruded noodles. Research on the impact of zein on protein during the processing of extruded noodles could provide a dependable approach and valuable mechanistic insights for improving the quality of extruded noodles.