Chitooligosaccharides enhanced saltiness perception via promoting oral sodium permeation

Excessive salt intake has been widely recognized as a major public health concern, and lowering sodium levels while maintaining saltiness perception remains a major challenge in food science. Here, we found that chitooligosaccharides (COS) concentration-dependently enhanced saltiness perception of standard NaCl solutions and different food sauces (30% enhancement in soy sauce) via reconstituting the salivary mucin layer that promotes oral sodium permeation. Molecular dynamics simulations revealed that the COS with uneven surface electrostatic-potential distribution (positive vs negative) could trigger the oligomerization at neutral pH (pH 7.0), which is more likely to partition in the salivary mucin layer. The results of QCM-D and Transwell test demonstrated that incorporation of COS led to hydration of the salivary mucin layer, and improved Na⁺ permeability through the mucin hydrogel. This finding provides support for COS as a potential sodium permeation enhancer and is expected to expand its application for designing low-salt food and sauce formulations through modulation of physicochemical properties of salivary mucin layer.