Mitigative effects of carboxymethyl chitosan on the deterioration of gliadin tractility in frozen rice dough during frozen storage.

Frozen storage deteriorates the texture and digestibility of frozen rice dough by damaging gliadin structure and starch integrity. This study investigated carboxymethyl chitosan (CMCh) and sodium carboxymethyl cellulose (CMCNa) as cry-oprotectants to mitigate these effects. Comprehensive analysis utilizing nuclear magnetic resonance (NMR), texture profile analysis (TPA), dynamic contact angle measurement (DCAT21), reversed-phase high-performance liquid chromatography (RP-HPLC), and circular dichroism (CD) demonstrated that 1.5 % CMCh-B optimally preserved gliadin integrity relative to both control and CMCNa treatments, it inhibited bound water conversion, enhanced protein cross-linking, minimized γ-prolamin loss (15.8 % less decline), stabilized secondary structure (reducing α-helix increase by 40.42 % and β-sheet decrease by 45.70 %), lowered surface hydrophobicity (75.17 %), and limited ice crystal damage. Consequently, texture significantly improved (hardness reduced 25.90 %, springiness reduced 38.24 %) and starch digestibility moderated (SDS increased 22.62 %, RS decreased 71.51 %). CMCh-B's hydroxyl-mediated hydrogen bonding forms a protective hydration layer, effectively inhibiting gliadin depolymerization and ice crystal growth, demonstrating significant potential for enhancing frozen rice dough quality.