Enhancement of sodium salty taste modulate by protease-hydrolyzed Gum Arabic

Salt reduction strategies in liquid foods remains a significant challenge. The oral perception of Na + is strongly dependent on its salivary penetration and mucosal adsorption. To understand the mechanism of Na + saltiness enhancement modulated by polysaccharide , protease hydrolysis (trypsin and acid protease) was used to modify the molecular conformation of Gum Arabic (GA), a highly branched polyanionic polysaccharide . The salivary permeation, mucosal retention in mucin layer, and salty taste of Na + were investigated. Saltiness-enhanced effect of GA is strongly influenced by its molecular conformation. Compared to native GA, protease-hydrolyzed GA exhibited a higher saltiness-enhanced effect due to more rapid Na + diffusion in saliva and stronger mucosal retention. Protease-hydrolyzed GA, especially acid protease-hydrolyzed GA (GA-AcPr), exhibited lower zeta potential (from original −22.5 to −27.96) and stronger Na + loading capacity. The obvious decreases in molecular weight (M w ) and the radius of gyration ( R g ) were observed for trypsin-hydrolyzed GA (GA-Trypsin), which may be responsible for the higher Na + diffusion effect of GA-saliva solution due to decreased molecule twine around each other. GA-AcPr exhibited looser and highly branched conformation, as evidenced by a more pronounced "U-shaped" curve and higher R g /R h . Moreover, Quartz crystal microbalance with dissipation (QCM-D) results verified stronger affinity between GA-AcPr and mucin, indicating that the saltiness-enhanced effect of GA-AcPr may be mainly achieved by increasing adhesive retention of Na + . These results would be useful to better understand the structure-function relationship of polysaccharides and the taste perception of Na + .