Impact of salt and alkali on the cooking quality of noodles with different wheat starch granule sizes and the underlying mechanisms.

The underlying mechanisms of salt (NaCl) and alkali (kansui) on the cooking quality of wheat noodles with different B/A starch ratios were investigated from microstructural features, structural transformation of starch and protein during cooking by confocal laser scanning microscope (CLSM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and size exclusion high-performance liquid chromatography (SE-HPLC). The noodle group containing 1.0 % alkali exhibited the highest cooking loss (17.47-21.33 %) and resilience (0.60-0.63), both of which increased as the B/A starch ratio rose, while the water absorption changed conversely. For low B/A starch ratio cooked noodles, 1.0 % and 2.0 % salt gave the lowest hardness values of 51.81 N and 51.98 N, respectively, while 0.5 % and 1.0 % alkali increased the tensile strength by 30.65 % and 30.78 %, and 2.0 % salt and 1.0 % alkali led to the highest elongation of 452.63 % and 448.50 %. Notably, alkali remarkably accelerated the starch gelatinization and protein thermal polymerization in low B/A ratio noodles during cooking. Moreover, NaCl reduced the extent of gluten polymerization by increasing the sulfhydryl group (-SH) level, while kansui induced remarkable protein aggregation by promoting intermolecular disulfide bond formation during noodle cooking. This study establishes a fundamental basis for the development of white salt and yellow alkali noodles with superior cooking quality.