Enhancing the quality of highland barley noodles by Lactobacillus plantarum pre-fermentation: Insights into its underlying mechanism

To improve highland barley noodles (HBNs) quality, the highland barley flour (HBF) was pre-fermented by Lactobacillus plantarum in this study. The changes in the quality of HBNs, the hydration properties and microstructure of the dietary fiber (DF), and the conformation and cross-linking of the protein in HBNs were measured. With the extension of pre-fermentation time (0–4 h), the overall acceptance of HBNs increased from 7.83 to 8.27, along with a 5.9% reduction in hardness and a 4.5% increase in springiness of HBNs. Meanwhile, confocal laser scanning microscopy (CLSM) revealed that the physical structure of the DF gradually disintegrated, which caused a significant (p < 0.05) decrease in its water retention capacity. In addition, spectral analysis showed a continual increase (from 19.62% to 30.15%) in β-turn content of the protein. The content of the free sulfhydryl group and sodium dodecyl sulfate extractable protein (SDSEP) decreased by 18.1% and 4.12%, respectively. However, with the further extension of pre-fermentation time (6–8 h), the degradation in HBNs sensory quality occurred, accompanied by a significant (p < 0.05) decrease in pH (5.95–5.01). These findings suggested that a moderate duration (4 h) of HBF pre-fermentation could effectively improve the quality of HBNs.