Biomimetic Sensor Technology

From a health viewpoint, the number of persons who begin to drink tea is increasing yearly. There are over 500 traditional medicine books and papers describing the usefulness of tea for health, medicine, and pharmacy purposes in China. Tea is a type of beverage that humans prefer because of its color, aroma, and taste. Thus, the value of tea is determined on the basis of a comprehensive human sense. The senses of sight, hearing, and touch are used to perceive such single physical quantities as light, sound waves, and pressure (or temperature), respectively, whereas the senses of taste and smell are used to perceive chemical quantities derived from many types of chemical substances. Therefore, there is difficulty in developing sensors for taste and smell. For this reason, sensory tests to evaluate the taste and smell of tea have been used although they are subjective. Most types of tea are made from the same plant but with different fermentation processes. In this work, using a taste sensing system TS-5000Z that has been successfully used for evaluating the taste of various foodstuffs, first, we evaluated the effects of fermentation, from fresh leaves, withering leaves, and rolling leaves, on the taste of tea. We found that the astringency level and umami taste level are decreased, whereas the bitterness level is increased with the degree of fermentation. Next, as an experiment to obtain actual proof, we evaluated the differences in the tastes of green tea, oolong tea, black tea, and postfermented tea, which were made with different degrees of fermentation. The result shows that it is possible to distinguish the differences in these teas. All these results show the possibility that the taste sensing system can be used in the quality control of tea fermentation. 502

Section: Measurement Setupmentioning

confidence: 99%

Evaluation of the Taste of Tea with Different Degrees of Fermentation Using a Taste Sensing System

2011

“…The functional membranes fabricated by synthesizing lipids and polymers are used to sense taste substances, and the interactions of the membranes with tastants are converted into electrical signals by membrane potential measurement and loaded onto a computer to distinguish between and identify different tastes. (13,14) …”

Section: Experimental Methodsmentioning

confidence: 99%

“…(12)(13)(14) We also carried out an experiment on detecting surfactants in pseudopesticides using the sensor with the membranes that we fabricated.…”

Section: Introductionmentioning

confidence: 99%

Simple Screening Method for Pesticide Residues by Detecting Coexistent Adjuvants Using Potentiometric Measurement

Umino

Habara

Toko

2012

The screening method for pesticide residues by detecting anionic surfactants used as pesticide adjuvants was examined by membrane potential measurement using a surfactant-sensing membrane composed of tridodecylmethylammonium chloride. A sulfonate anionic surfactant, sodium dodecyl sulfate, was detected at under 10 ppb. In the experiments on pseudopesticides obtained by mixing standard pesticides (i.e., chlorfenapyr, imazalil, and glyphosate) and sodium dodecyl sulfate, our membrane showed no response to the active ingredients of the pesticides but showed a specific response to a coexisting surfactant, indicating the feasibility of our method as a primary screening method.

“…(1)(2)(3) This sensor enables the analysis of the taste of foodstuffs, because the changes in the electric potential difference produced by lipid polymer membranes are measured. In other words, it is an instrument that enables the digitization of taste.…”

Section: Introductionmentioning

confidence: 99%

Taste Sensor Chip for Portable Taste Sensor System

2008

A taste sensor chip miniaturized on the basis of the one-chip-size receptor part of a conventional taste sensor, which can measure taste using lipid/polymer membranes, was fabricated. The reference electrode in the taste sensor chip realized the miniaturization and stabilization of potential using a multilayer structure of a pHEMA layer and other polymer layers. In this study, we improved the stability of the taste sensor chip during the measurement by changing the material of the partition of the taste sensor chip to plastic. We successfully integrated the working and reference electrodes on the chip. The portable taste sensor system was composed of the taste sensor chip, an integrated electric signal processing part and a laptop computer. We considered that the design of the portable taste sensor facilitates the easy manual measurement of taste. By realizing the taste sensor chip and the portable taste sensor, taste measurement can be easily performed anywhere.