Dynamic distribution and transition of gluten proteins during noodle processing

Abstract

In this study, dynamic distribution and molecular transition of gluten proteins during noodle processing as well as their relationship with texture changes were systematically investigated and quantified. Confocal laser scanning microscopy (CLSM) images and network analysis confirmed that the mixed dough and dough sheet showed higher gluten junctions (919.5, 815.0, respectively) and lower lacunarity (9.28, 8.64). Scanning electron microscopy (SEM) images revealed that the gluten network gradually became orderly and compact after different processing steps such as mixing, resting, rolling, and sheeting, except for the large gaps in the cooked noodles. The mechanical force of mixing (step 2) and rolling (step 4) caused partial depolymerization of gluten protein and promoted its repolymerization, thereby forming a well-developed gluten network structure. Each step of the noodle processing was accompanied by a reduction in the content of free –SH, which induced the SH/SS exchange. From resting (step 3) to rolling (step 4), the hydrogen bond interaction was strengthened. Heating induced the weakening of hydrogen bonds and hydrophobic interaction. Changes in texture properties were highly correlated with the dynamic morphology distribution and the molecular/structural transition of gluten protein.