Freezing dynamics of dough under molecular hydrogen-fumigation assisted immersion: quality and structural responses to freezing and thawing cycles

The effects of hydrogen fumigation-assisted −25 °C immersion freezing (HFIF) on the freezing process of frozen dough (FD) and quality attributes throughout freeze-thaw cycles were elucidated in this study. Results showed that HFIF significantly increased the phase transition rate to 1.82 times and 2.18 times that of −25 °C immersion freezing (IF) and −80 °C quick freezing (QF), respectively. LF-NMR and MRI analyses indicated that HFIF accelerated phase transition and overall freezing rate. HFIF minimized the freezing-induced morphological damage of FD and retained superior mechanical properties. It also prevented gluten disulfide bond cleavage (39.61 % and 14.20 % higher than in IF and QF, respectively) while curtailing gluten macromolecule depolymerization and increasing α-helix content by 14.53 % and 14.05 % relative to IF and QF (p < 0.05) after four cycles. These findings suggested molecular hydrogen as an innovative freezing accelerator and frostbite protector to mitigate freeze-thaw damage.