Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Research and Development Center for Five-Sense Devices, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Biosensors (Basel). 2024 Feb 11;14(2):95. doi: 10.3390/bios14020095.
A taste sensor employs various lipid/polymer membranes with specific physicochemical properties for taste classification and evaluation. However, phosphoric acid di(2-ethylhexyl) ester (PAEE), employed as one of the lipids for the taste sensors, exhibits insufficient selectivity for umami substances. The pH of sample solutions impacts the dissociation of lipids to influence the membrane potential, and the response to astringent substances makes accurate measurement of umami taste difficult. This study aims to develop a novel taste sensor for detecting umami substances like monosodium L-glutamate (MSG) through surface modification, i.e., a methodology previously applied to taste sensors for non-charged bitter substance measurement. Four kinds of modifiers were tested as membrane-modifying materials. By comparing the results obtained from these modifiers, the modifier structure suitable for measuring umami substances was identified. The findings revealed that the presence of carboxyl groups at para-position of the benzene ring, as well as intramolecular H-bonds between the carboxyl group and hydroxyl group, significantly affect the effectiveness of a modifier in the umami substance measurement. The taste sensor treated with this type of modifier showed excellent selectivity for umami substances.
味觉传感器采用具有特定物理化学性质的各种脂/聚合物膜进行味觉分类和评估。然而，作为味觉传感器中使用的脂类之一的磷酸二（2-乙基己基）酯（PAEE）对鲜味物质的选择性不足。样品溶液的 pH 值会影响脂质的离解，从而影响膜电位，而且对涩味物质的响应使得鲜味的准确测量变得困难。本研究旨在通过表面修饰开发一种新型的味觉传感器，用于检测鲜味物质，如 L-谷氨酸单钠盐（MSG），这种方法以前曾应用于测量非带电苦味物质的味觉传感器。测试了四种修饰剂作为膜修饰材料。通过比较这些修饰剂的结果，确定了适合测量鲜味物质的修饰剂结构。研究结果表明，苯环对位上存在羧基以及羧基和羟基之间的分子内氢键，显著影响修饰剂在鲜味物质测量中的有效性。用这种类型的修饰剂处理的味觉传感器对鲜味物质表现出优异的选择性。
