Taste sensor multichannel

Hayashi, K., Yamanaka, M., Toko, K., and Yamafuji, K. (1990). Multichannel taste sensor using lipid membranes. Sens. Actmtors B 2, 205-213. 

The above-mentioned 256 mixed solutions were measured with the multichannel taste sensor. Therefore, data on the output electrical potential pattern were taken for the 256 solutions. While the data on each channel output were dispersed discretely in the four-dimensional space constructed from four different concentrations, we approximated them by a quadratic function of the concentrations. As a result, eight quadratic functions were obtained. The data can be regarded as expressed by a set of eight different functions (corresponding to 8 channels) of concentrations of four taste substances. 

The taste of every drink can be quantified using the multichannel taste sensor. In other words, quantitative measurements of taste are possible by the sensor more accurately than the sense of humans because the present taste sensor has higher reproducibility, durability and sensitivity. 

Voltammetric sensors based on chemically modified electrodes (conducting polymers, phthalocyanine complexes) with improved cross-selectivity were developed for the discrimination of bitter solutions [50], The performance and capability were tested by using model solutions of bitterness such as magnesium chloride, quinine, and four phenolic compounds responsible for bitterness in olive oils. The sensors gave electrochemical responses when exposed to the solutions. A multichannel taste sensor was constructed using the sensors with the best stabilities and cross-selectivities and PCA of the signals allowed distinct discrimination of the solutions. 

Use of bilayer lipid membranes as a generic electrochemical transducer is an exciting future for food biosensors. A taste sensor with multichanneled lipid membrane electrode was recently developed (93). The electric patterns generated from the sensor are similar to human response. The sensor can distinguish different brands of beer. More details on the taste sensor can be found in Chapter 16 of this book. 

The DOPH membrane and the ammonium salt membrane responded to taste substances in different ways. The above results suggest that taste substances can be perceived satisfactorily using various kinds of lipid materials. Furthermore, we must improve the sensing reproducibility. As a second step, we have developed a multichannel lipid membrane taste sensor. Taste substances can be discriminated by the output pattern from several lipid membranes. 

Although the above lipid membranes had the ability to sense the taste by responding to many taste substances, information was insufficient to recognize quality of the taste. This weakness was overcome by means of a multichannel sensor, where transducers were composed of lipid membranes immobilized with a polymer [16-23]. We investigated responses of the sensors to various taste solutions. The electrode showed five different response patterns to five primary tastes with small experimental deviations. The patterns looked alike when the applied substance elicited the same taste in humans. 

Figure 8. Responses of the multichannel sensor to five taste qualities. The origin of the electrical potential was taken to 1 mM KC1.

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