Diffusion of sodium ions based on the interactions between gum arabic and oral mucin: Effects from the molecular weight of gum arabic

Diffusion behaviors of sodium ions in mucin layers plays an important role in saltiness perception. The influence of mucin-gum arabic interactions on the diffusion behaviors of sodium ions was investigated, in which the gum arabic was hydrolyzed to change its molecular weight. Results showed that the hydrolysis of gum arabic led to its structural changes, showing a lower zeta-potential. Gum arabic hydrolysates with lower molecular weight increased the diffusion of sodium ions through the mucin layer, which might be related to the conformation changes of mucin chains and the swelling expansion of mucin network. This mechanism was further confirmed by transmission electron microscopy, and a more swelling and looser structure of mucin layer was revealed, which contributed to the high diffusion rate of sodium ions. This work can improve our understanding of mucin network affects the penetration and perception of sodium ions, which may be useful for other molecular tastants.