Biological characteristics of the gluten-free sourdough system fermented by Lactobacillus plantarum ST-III and its effect on dough quality and nutritional value during freezing

In this study, the biological characteristics of wheat, tartary buckwheat, and wheat-tartary buckwheat sourdough systems fermented by Lactobacillus plantarum ST-III at different times were explored, and the quality and nutritional characteristics of sourdough frozen dough bread products with different fermentation substrates were investigated. Comparing the metabolic properties of sourdough during fermentation, it was found that the density of colony growth in TBS was the best, when fermented for 12 h, the protein degradation effect was the best, and the content of EPS (3.109 g/kg) and free amino acid was the highest. Although the quality of fresh TBS bread was worse than that of WS, after 13 weeks of frozen storage, the quality deterioration of TBS frozen dough bread was the smallest, the water migration rate was slower, and the protein digestibility was higher. Therefore, tartary buckwheat sourdough system can delay the degradation of bread quality and nutrition.