Cryoprotective Role of Soybean Oligosaccharides in Frozen Dough: Enhanced Gluten Stability and Bread Quality

Frozen dough technology faces persistent quality deterioration due to ice crystal formation and gluten network disruption during storage. This study investigated the cryoprotective effects of soybean oligosaccharides (SBOS) on frozen dough quality. Wheat flour doughs supplemented with 0%, 0.2%, 0.5%, and 0.8% SBOS (w/w flour basis) were rapidly frozen at −40 °C, stored at −18 °C for 0, 2, and 4 weeks, and subsequently analyzed for fermentation performance, rheological properties, water distribution, protein secondary structure, microstructure, and bread quality. Results demonstrated that SBOS supplementation significantly attenuated freeze-induced quality deterioration. SBOS effectively inhibited bound-to-free water conversion, preserved gluten network integrity, and maintained higher α-helix content in gluten proteins. Dough with 0.5% SBOS exhibited superior fermentation volume, dynamic rheological properties, and microstructural stability throughout frozen storage. Corresponding bread showed increased specific volume, reduced hardness (15.27% decrease), and improved springiness, cohesiveness, and pore uniformity. Correlation analysis confirmed that SBOS concentration was not linearly associated with quality improvements, with 0.5% identified as the optimal dosage. These findings establish that SBOS is an effective, natural, clean-label cryoprotectant for frozen dough under the tested conditions, offering significant quality preservation benefits for the frozen bakery industry. Future studies are warranted to investigate potential additional functionalities.