{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T16:47:44Z","timestamp":1778345264206,"version":"3.51.4"},"reference-count":33,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,6,18]],"date-time":"2020-06-18T00:00:00Z","timestamp":1592438400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"New Energy and Industrial Technology Development Organization","award":["16100863-0"],"award-info":[{"award-number":["16100863-0"]}]},{"name":"New Energy and Industrial Technology Development Organization","award":["16100863-0"],"award-info":[{"award-number":["16100863-0"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A taste sensor with lipid\/polymer membranes is one of the devices that can evaluate taste objectively. However, the conventional taste sensor cannot measure non-charged bitter substances, such as caffeine contained in coffee, because the taste sensor uses the potentiometric measurement based mainly on change in surface electric charge density of the membrane. In this study, we aimed at the detection of typical non-charged bitter substances such as caffeine, theophylline and theobromine included in beverages and pharmaceutical products. The developed sensor is designed to detect the change in the membrane potential by using a kind of allosteric mechanism of breaking an intramolecular hydrogen bond between the carboxy group and hydroxy group of aromatic carboxylic acid (i.e., hydroxy-, dihydroxy-, and trihydroxybenzoic acids) when non-charged bitter substances are bound to the hydroxy group. As a result of surface modification by immersing the sensor electrode in a modification solution in which 2,6-dihydroxybenzoic acid was dissolved, it was confirmed that the sensor response increased with the concentration of caffeine as well as allied substances. The threshold and increase tendency were consistent with those of human senses. The detection mechanism is discussed by taking into account intramolecular and intermolecular hydrogen bonds, which cause allostery. These findings suggest that it is possible to evaluate bitterness caused by non-charged bitter substances objectively by using the taste sensor with allosteric mechanism.<\/jats:p>","DOI":"10.3390\/s20123455","type":"journal-article","created":{"date-parts":[[2020,6,18]],"date-time":"2020-06-18T12:21:46Z","timestamp":1592482906000},"page":"3455","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":36,"title":["Development of Taste Sensor to Detect Non-Charged Bitter Substances"],"prefix":"10.3390","volume":"20","author":[{"given":"Jumpei","family":"Yoshimatsu","sequence":"first","affiliation":[{"name":"Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819\u20130395, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kiyoshi","family":"Toko","sequence":"additional","affiliation":[{"name":"Institute for Advanced Study, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819\u20130395, Japan"},{"name":"Research and Development Center for Five-Sense Devices, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819\u20130395, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yusuke","family":"Tahara","sequence":"additional","affiliation":[{"name":"Research and Development Center for Five-Sense Devices, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819\u20130395, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Misaki","family":"Ishida","sequence":"additional","affiliation":[{"name":"Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819\u20130395, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1144-3697","authenticated-orcid":false,"given":"Masaaki","family":"Habara","sequence":"additional","affiliation":[{"name":"Intelligent Sensor Technology, Inc., 5\u20131\u20131 Onna, Atsugi-shi, Kanagawa 243-0032, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hidekazu","family":"Ikezaki","sequence":"additional","affiliation":[{"name":"Intelligent Sensor Technology, Inc., 5\u20131\u20131 Onna, Atsugi-shi, Kanagawa 243-0032, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Honami","family":"Kojima","sequence":"additional","affiliation":[{"name":"Faculty of Pharmaceutical Science, Mukogawa Women\u2019s University, 11\u201368 Koshien 9-Bancho, Nishimiya, Hyogo 663-8179, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Saeri","family":"Ikegami","sequence":"additional","affiliation":[{"name":"Faculty of Pharmaceutical Science, Mukogawa Women\u2019s University, 11\u201368 Koshien 9-Bancho, Nishimiya, Hyogo 663-8179, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Miyako","family":"Yoshida","sequence":"additional","affiliation":[{"name":"Faculty of Pharmaceutical Science, Mukogawa Women\u2019s University, 11\u201368 Koshien 9-Bancho, Nishimiya, Hyogo 663-8179, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takahiro","family":"Uchida","sequence":"additional","affiliation":[{"name":"Faculty of Pharmaceutical Science, Mukogawa Women\u2019s University, 11\u201368 Koshien 9-Bancho, Nishimiya, Hyogo 663-8179, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"147","DOI":"10.2116\/analsci.19R008","article-title":"Taste Sensor: Electronic tongue with lipid membranes","volume":"36","author":"Wu","year":"2020","journal-title":"Anal. 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