Sensory Preference of Drinking Water Influenced by Subthreshold-Level Mineral Salt Mixtures.

This study investigated the impact of subthreshold-level mixtures of KCl and MgSO4 on the sensory preference of drinking water and identified key sensory drivers. Absolute thresholds were first determined, followed by sensory evaluation of individual and blended salt solutions using a 9-point hedonic scale and CATA test. Design of Experiments (DOE) approach with quadratic polynomial regression optimized the binary mixtures. Results showed samples near the absolute thresholds (0.95 mg/L KCl; 0.65 mg/L MgSO4) were most preferred. Beyond these thresholds, mineral salt concentration negatively correlated with hedonic rating. Sweetness was identified as a key positive driver, while astringency was a strong negative driver. The significant model revealed a nonadditive effect with a negative KCl × MgSO4 interaction (antagonism), with a maximum predicted liking of 6.34 at 0.92 mg/L KCl and 0.60 mg/L MgSO4. These findings demonstrate that subthreshold-level mixtures of mineral salts within a narrow concentration window can enhance water sensory quality by promoting sweetness and suppressing astringency, providing a foundation for developing premium bottled water.