Regulation of Na+ diffusion and retention in oral cavity by arabinogalactan-protein fraction from gum arabic and its mechanism of enhancing saltiness perception.

The growing health hazards of high-salt diets require effective salt reduction strategies in food industry. Gum arabic (GA), as saltiness enhancer, is composed of polysaccharides and glycoproteins. However, key fraction and its role in saltiness-enhancing remain underexplored. This study aims to elucidate saltiness regulatory mechanisms by GA fractions ratio, focusing on changes in arabinogalactan-protein (AGP) fraction. GA with high AGP fractions significantly enhanced saltiness, accompanied by improved Na+ transport volume, diffusion, and retention in oral cavity. These effects were attributed to their looser, higher branching, lower ζ-potential and greater Na+ loading capacity. Micro-rheological analysis revealed that high-Mw GA exhibited higher viscosity, enhancing Na+ short-term retention on tongue. Its competitive loose binding could partially depolymerize mucin networks, promoting Na+ diffusion and mucosal adhesion to amplify saltiness perception. These results clarify AGP as key fraction in regulating GA saltiness-enhancing effect, providing theoretical and technical support for developing low-sodium liquid foods.