Sweetness-independent bitterness suppression of rebaudioside A by sucrose in a cocoa model

Taste interactions have been a focus of research in recent decades; however, many underlying mechanisms remain unclear. This study investigated the sweet-sweet and sweet-bitter interaction mechanisms between sucrose and 60% rebaudioside A (REBA) in a complex cocoa model system. A split-tongue method was used to assess peripheral and central interaction effects, allowing the tongue to serve as its own control. The study was conducted under normal conditions and under a sweetness-blocked condition induced by a pre-rinse with Gymnema sylvestre extract. Participants (n = 65) were aged 18-35 years and evaluated sweetness and bitterness intensity during each of the two sessions.

Under normal conditions, no discernible difference in bitterness ratings was observed between the sucrose-REBA mixture and their separate presentations on opposing sides of the tongue. However, under sweetness-blocked conditions, the sucrose + REBA mixture was perceived as less bitter than when the components were presented individually.

The results indicated that sucrose has a bitterness-suppressing effect on REBA that is independent of sweetness. Rebaudioside A sweetness was blocked more efficiently than sucrose sweetness. Overall, the observations suggest that taste interactions within this model system may occur primarily at the peripheral level. © 2026 Society of Chemical Industry.