Diffusion behaviors of sweeteners in the saliva layer: effects of interactions between oral mucin and sweeteners

Abstract In this work, the behaviors diffusion of sweeteners (sucrose, erythritol and stevioside) through the mucin layer were investigated based on the mucin-sweeteners interactions. Several techniques including fluorescence spectroscopy, rheological measurement, QCM-D and TEM were applied to investigate the interactions between the sweeteners and mucin at different pH values. The results point to the relatively fast diffusion behavior of sweeteners at pH 5.0 or pH 7.0, which was associated with the molecular weight of sweeteners and mucin-sweeteners interactions. The rheological measurement and QCM-D results indicated that hydrogen bonding and hydrophobic interactions may play an important role in mucin-sweeteners interactions. A homogeneous mucin network with large network pore size at pH 5.0 or pH 7.0 favored the diffusion of sweeteners through the mucin layer. Additionally, the relatively weak interactions between mucin layer and sweeteners at pH 5.0 or pH 7.0 contributes to the rapid penetration of sweeteners, enhancing the sweetness perception.