Combined protective effects of xanthan gum and maltitol on multi-scale properties of frozen dough under repeated freeze-thaw cycles.

This study systematically investigated the combined protective effects of xanthan gum (XG) and maltitol (Mal) against freeze-thaw (FT) damage in dough across multiple organizational scales. After five FT cycles, unprotected dough exhibited quality deterioration: yeast viability decreased by 62.8%, moisture loss reached 24.6%, wet gluten content declined by 22.7%, and tensile force decreased by 37.0%. Individual incorporation of XG or Mal provided partial protection, but their combination (composite treatment) achieved substantially greater efficacy. The composite treatment enhanced yeast survival by 90.1% (vs. FT), reduced moisture loss to 22.8% and mass loss to 1.96%, restored wet gluten content to 17.60% (95.1% of Control), and recovered tensile force to 95.2% of Control levels. The observed improvements may be attributed to complementary actions of XG and Mal: XG's high-molecular-weight polyelectrolyte network is proposed to provide macroscopic physical confinement that restricts ice crystal growth and reinforces the gluten matrix, whereas Mal's nine hydroxyl groups are thought to deliver microscopic osmoprotection through preferential hydration and hydrogen bonding. Low-field NMR revealed that the composite group achieved the lowest freezable water content (40.30%) and enthalpy of fusion (55.64 J/g), while SEM and laser diffraction confirmed substantial preservation of gluten-starch microarchitecture. Consequently, Chinese steamed bread from composite-treated dough exhibited textural parameters approaching fresh product quality. This multi-scale combined protection strategy provides a promising approach for frozen dough stabilization, although further direct mechanistic validation is required.