Comparing cooking qualities, microstructure, and sodium distribution of air-dried guar gum-coated yellow alkaline noodles with and without salt application

The impact of salt coating on sodium (Na) content, cooking qualities, microstructure and Na distribution of yellow alkaline noodles (YAN) were investigated in guar gum-coated (GG) YAN without salt coating (GG-YAN0) and GG-coated YAN with salt (GG-YAN10). No significant difference was reported in the quantity of Na released into the cooking water between the two samples. Despite the higher initial Na content in raw GG-YAN10, it exhibited a lower percentage of Na loss (P < 0.05) than GG-YAN0. GG-YAN10 demonstrated similar Na content to commercial YAN (COM-YAN) after cooking, with a reduced Na percentage loss in the cooking water, even though COM-YAN had a higher initial Na content. Microstructure analysis revealed a honeycomb-like and porous structure with a continuous gluten network in GG-YAN10, potentially contributing to a significantly lower optimum cooking time and cooking loss than GG-YAN0. SEM-EDX analysis and line scan techniques highlighted Na concentration on the outer surface of GG-YAN10 and lower Na concentration in the central core, indicating the ability of guar gum coating to retain salt on the surface of noodles both before and during cooking. The enhanced salt retention of GG-YAN10 yielded noodles with Na content similar to COM-YAN after cooking while also improving overall cooking qualities.