Effects of Pre-Cooking Degree of Germinated Highland Barley Pulp on the Quality and Digestive Characteristics of Barbecued Pork Buns During Refrigerated Storage

This study investigated the effect of pre-cooking level of germinated highland barley pulp on the staling properties and digestibility of pre-packaged barbecued pork buns during refrigerated storage (0–9 days). The addition of barley pulp significantly delayed quality deterioration, resulting in a decreased specific volume (up to 20%) and an increased hardness (up to 71.76%) across all samples. Furthermore, it effectively inhibited the rise in starch short-range order, as evidenced by a decreased FTIR ratio of 1047/1022 cm−1, and retarded the conformational transition between protein α-helix and β-sheet structures. When the gelatinization degree increased to 91.22%, rapidly digestible starch (RDS) decreased significantly while resistant starch (RS) increased. The sauce infiltration layer exhibited a higher maximum RS (23.23%) than the inner crumb (16.52%). The Glycemic Index (GI) was significantly reduced, with the lowest values observed in the BJ60 group (53.22 for the sauce infiltration layer and 60.37 for the inner crumb). α-Amylase inhibition was also enhanced with increasing gelatinization degrees. Significant correlations were found between starch structural parameters and digestibility. These results demonstrate that incorporating germinated highland barley pulp is a feasible strategy to simultaneously improve the shelf-life and nutritional quality of steamed buns.