Mechanism of the Effects of Storage Time and Matcha Addition on the Quality of Re-Steamed Bread: The Structure and Function of Gluten Protein and Starch

This study aimed to investigate the effects of cold storage time and matcha addition on the multi-scale structure and functionality of gluten protein and starch in re-steamed bread. Results showed that prolonged cold storage destroyed the integrity of gluten networks by breaking disulfide bonds and altering protein secondary structures, accompanied by moisture loss and migration; meanwhile, starch retrogradation was significantly promoted, resulting in increased hardness and decreased specific volume. The addition of 0.5–1.0% of matcha stabilized disulfide bonds and inhibited starch retrogradation, thus alleviating quality decline. When the addition amount exceeded 1.0%, high concentrations of polyphenols depolymerized gluten proteins and accelerated moisture transfer, causing a further drop in specific volume. Pearson correlation analysis verified the close correlations between macroscopic quality and microstructural characteristics. This study explored the mechanisms underlying the effects of cold storage time and matcha addition on the quality of re-steamed bread, providing a systematic scientific basis for the application of tea flour products in cold storage.