Molecular basis for detection of sweet taste perception of mannitol depending on pH condition

Abstract

Mannitol is a sugar alcohol component naturally present in various kinds of seaweed and fruits. During the late stages of kimchi fermentation, considerable quantity of mannitol is produced. In this work, the activity of mannitol binding to sweet-tasting receptor T1R2/T1R3 was studied. It was confirmed that mannitol's sweet receptor binding force shows stronger activity owing to changes in pH. It was inferred that the acidity increases as kimchi is fermented, which may impart a unique sweet and refreshing taste to fresh kimchi. Site-directed mutagenesis and molecular-docking studies showed that mannitol binds to S165 (of T1R2) of T1R2/T1R3 receptor. The analysis of mannitol intake in mice confirmed that the sweetness of mannitol increased at varying pH values through functional evaluation at appropriate concentrations. These findings indicate that the differences in taste perception of mannitol, i.e., sweetness, depend on pH conditions, which could help understand fermented kimchi's conjugative taste perception. © 2024 Elsevier Ltd