Effect of Tamarind Seed Polysaccharide on the Quality Characteristics and In Vitro Digestibility of Frozen Steamed Buns

This study evaluated the effects of tamarind seed polysaccharides (TSP) on the quality characteristics and in vitro starch digestibility of steamed buns made from doughs with different freezing storage times (0, 30, and 60 days). The pore structure, specific volume, water distribution, and starch digestibility were analyzed. TSP significantly altered the dough microstructure by increasing pore density and pore volume while reducing the average pore area, forming a more uniform pore network. During freezing storage, the specific volume of control samples decreased, whereas steamed buns with 1–2% TSP maintained a relatively high specific volume (~1.65) after 60 days, indicating improved gas retention and structural stability. TSP also increased bound water and restricted water migration. Additionally, TSP increased resistant starch (RS) from 15.96% to 24% and reduced rapidly digestible starch (RDS). Overall, TSP improved the structural stability of frozen steamed buns by regulating water distribution, strengthening the gluten-starch network, and altering starch digestibility. These findings provide insights into the use of natural polysaccharides to enhance the quality and nutritional function of frozen wheat-based foods.