Development and Optimization of a Highly Sensitive Sensor to Quinine-Based Saltiness Enhancement Effect

• Published in: Sensors (Basel, Switzerland) Vol. 23; no. 6; p. 3178
• Main Authors: Jing, Yifei, Watanabe, Kentaro, Watanabe, Tatsukichi, Kimura, Shunsuke, Toko, Kiyoshi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16.03.2023; MDPI
• Subjects: Analytical chemistry; Branched chain amino acids; Chain branching; Citric acid; Food; ionophore; Ionophores; lipid/polymer membrane; Lipids; Membranes; Polymers; Polyvinyl chloride; Quinine; Salinity; Salt; saltiness enhancement effect; saltiness sensor; Sensors; Sodium; Sodium chloride; Tartaric acid; Taste; taste sensor; Japan; lipid/polymer membrane; saltiness sensor; saltiness enhancement effect; ionophore; taste sensor
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s23063178

The saltiness enhancement effect can be produced by adding specific substances to dietary salt (sodium chloride). This effect has been used in salt-reduced food to help people forge healthy eating habits. Therefore, it is necessary to objectively evaluate the saltiness of food based on this effect. In a previous study, sensor electrodes based on lipid/polymer membrane with Na ionophore have been proposed to quantify the saltiness enhanced by branched-chain amino acids (BCAAs), citric acid, and tartaric acid. In this study, we developed a new saltiness sensor with the lipid/polymer membrane to quantify the saltiness enhancement effect of quinine by replacing a lipid that caused an unexpected initial drop in the previous study with another new lipid. As a result, the concentrations of lipid and ionophore were optimized to produce an expected response. Logarithmic responses have been found on both NaCl samples and quinine-added NaCl samples. The findings indicate the usage of lipid/polymer membranes on novel taste sensors to evaluate the saltiness enhancement effect accurately.