Effect of sanxan on the composition and structure properties of gluten in salt-free frozen-cooked noodles during freeze–thaw cycles

Abstract

In this study, the mechanisms by which sanxan protected the quality of salt-free frozen-cooked noodles (SFFCNs) were investigated, with a focus on the composition and structural properties of gluten. The results showed that sanxan facilitated the formation of glutenin macropolymer and maintained the stabilization of glutenin subunits in freeze–thaw cycles (FTs). In terms of protein structure, sanxan weakened the disruption of secondary structure caused by FTs and increased the proportion of gauche-gauche-gauche (g-g-g) conformations in the disulfide (SS) bonds bridge conformation. Simultaneously, sanxan reduced the exposure degree of tryptophan (Trp) and tyrosine (Tyr) residues on the protein surface. Moreover, the intermolecular interaction forces indicated that sanxan inhibited SS bonds breakage and enhanced the intermolecular crosslinking of gluten through ion interactions, which was crucial for improving the stability of gluten. This study provides a more comprehensive theoretical basis for the role of sanxan in improving the quality of SFFCNs.

Keywords

• Sanxan
• Salt-free frozen-cooked noodles
• Gluten
• Freeze–thaw cycles
• Conformational change