• Journal of Sensor Science and Technology
• /
• v.27 no.2
• /
• pp.69-75
• /
• 2018

In this study, we propose a multichannel interdigitated capacitor (IDC) sensor for detecting the bitterness of coffee. The operating principle of the device is based on the variation in capacitance of a sensing membrane in contact with a bitter solution. Four solvatochromic dyes, namely, Nile red, Reichardt's dye, auramine-O, and rhodamine-B, were mixed with polyvinylchloride (PVC) and N,N-dimethylacetamide (DMAC), to create four different types of bitter-sensitive solutions. These solutions were then individually inserted into four interdigitated electrodes (IDEs) using a spin coater, to prepare four distinct IDC sensors. The sensors are capable of detecting bitterness-inducing chemical compounds in any solution, at concentrations of approximately $1{\mu}M$ to 1 M. The sensitivity of the IDC bitterness sensor containing the Reichardt's dye sensing-membrane was approximately 1.58 nF/decade. The multichannel sensor has a response time of approximately 6 s, and an approximate recovery time of 5 s. The proposed sensor offers a stable sensing response and linear sensing performance over a wide measurement range, with a correlation coefficient ($R^2$) of approximately 0.972.

• The Korea Journal of Herbology
• /
• v.27 no.6
• /
• pp.37-42
• /
• 2012

Objectives : Angelica Gigantis Radix is prescribed as the root of different Angelica species on the pharmacopoeia in Korea, Japan and China. Chemical components and their biological activities were also different according to their species. A study for the development of simple method to compare Angelica roots was needed. In order to classify them, the methods such as DNA sequencing analysis and taste sensor were applied to three Angelica species like Angelica gigas, Angelica acutiloba and Angelica sinensis. Methods : PCR amplification of intergenic transcribed spacer (ITS) region was performed using ITS1 and ITS4 primer from nine Angelica roots, and then nucleotide sequence was determined. Taste pattern of samples were measured using the taste-sensing system SA402B equipped with a sensing unit, which consists of artificial lipid membrane sensor probes of anionic bitterness, astringency, saltiness, umami, and cationic bitterness (C00, AE1, CT0, AAE, and AN0, respectively). Results : As a result of comparing the similarity of the ITS region sequences, A. sinensis was discriminated from the others (A. gigas and A. acutiloba). Equally this genetic result, A. gigas and A. acutiloba showed similar taste pattern as compared to A. sinensis. Sourness, bitterness, aftertaste of bitterness, astringency, and aftertaste of astringency of A. sinensis were significantly high as compared with A. gigas and A. acutiloba. In contrast, richness was significantly low. Conclusions : These taste pattern can be used as a way of comparison of Angelica species and this technic could be applied to establish a taste pattern marker for standardization of herbs in various purposes.

• The Korea Journal of Herbology
• /
• v.26 no.1
• /
• pp.35-39
• /
• 2011

Objectives : Genetic analysis and taste pattern were performed to identify species between Glycyrrhiza uralensis and G. glabra which are officially listed in Korean Pharmacopoeia IX as origin of Gamcho(g$\={a}$nc$\v{a}$o, licorice root, Glycyrrhizae Radix et Rhizoma). Methods : Genetic analysis showed that identification between two species was done by comparing base sequence of ITS(intergenic transcribed spacer) and trnH-psbA regions from eleven Gamchoes sold in market. There was different taste pattern using by taste sensor in Glycyrrhiza uralensis and G. glabra. Results : Genetic analysis showed that six Gamchoes from China were identified as Glycyrrhiza uralensis and five Gamchoes from Uzbekistan were G. glabra. From the results of taste pattern, sourness and astringency of Glycyrrhiza uralensis from China were significantly higher than G. glabra from Uzbekistan, and aftertaste of astringency, aftertaste of umami, and saltiness of Glycyrrhiza uralensis were signicantly low as compared to G. glabra. There is no significant difference between two species in terms of bitterness, aftertaste of bitterness, and umami. Conclusions : Taken together, Glycyrrhiza uralensis from China and G. glabra from Uzbekistan were identified by taste sensor, and this technic could be applied to establishment of taste pattern marker for identification of different species located in various regions.

• Journal of Sensor Science and Technology
• /
• v.9 no.5
• /
• pp.365-372
• /
• 2000

In this study, a multichannel taste sensor using the evanescent field absorption in fiber optic was developed, and evaluated its characteristics for several basic taste substances. This sensor is based on the change of evanescent field absorption at the surface of optical fiber core layer. The sensor device was made of a plastic-clad-silica fiber (3M Co., FP-400-UHT, core diameter $400\;{\mu}m$) and a middle portion of cladding layer was removed and the surface of stripped fiber core was dip-coated with a sensing membrane. And then, it was determined the difference of evanescent field absorption into the sensing membrane, according to various taste substances and its concentrations variance. The sensing membranes were prepared with six kinds of dyes, were known as potential sensitive dye together with silicone polymer the same refractive index of cladding. Each output patterns were obtained from the sensor devices could be distinguished not only five kinds of basic taste substances such as sweetness, saltiness, sourness, bitterness and umami, but also various mixed taste substances.

• Molecules and Cells
• /
• v.43 no.6
• /
• pp.530-538
• /
• 2020

The Gustatory system enables animals to detect toxic bitter chemicals, which is critical for insects to survive food induced toxicity. Cucurbitacin is widely present in plants such as cucumber and gourds that acts as an anti-herbivore chemical and an insecticide. Cucurbitacin has a harmful effect on insect larvae as well. Although various beneficial effects of cucurbitacin such as alleviating hyperglycemia have also been documented, it is not clear what kinds of molecular sensors are required to detect cucurbitacin in nature. Cucurbitacin B, a major bitter component of bitter melon, was applied to induce action potentials from sensilla of a mouth part of the fly, labellum. Here we identify that only Gr33a is required for activating bitter-sensing gustatory receptor neurons by cucurbitacin B among available 26 Grs, 23 Irs, 11 Trp mutants, and 26 Gr-RNAi lines. We further investigated the difference between control and Gr33a mutant by analyzing binary food choice assay. We also measured toxic effect of Cucurbitacin B over 0.01 mM range. Our findings uncover the molecular sensor of cucurbitacin B in Drosophila melanogaster. We propose that the discarded shell of Cucurbitaceae can be developed to make a new insecticide.

• Journal of Food Hygiene and Safety
• /
• v.36 no.6
• /
• pp.537-545
• /
• 2021

This study investigated the characteristics of taste and flavor in various wintering-radish extracts using electronic sensors. Sourness showed the highest sensor value (6.9) in hot brewed extracts of white radish part. Saltiness showed the highest sensor value (8.0) in cold brewed extracts of green radish part. Umami showed the highest sensor value (8.3) in hot brewed extracts of white radish part. Sweetness showed the highest sensor value (6.8) in cold brewed extracts of green radish part. Bitterness showed the highest sensor value (7.5) in espresso extracts of green radish part. A total of 16 volatiles were identified using electronic nose. Among these volatile compounds in radish extracts, methanethiol was found to be the predominant volatile compound. These sensory characteristics in radish extracts can be used as basic research data in the food industry.

• Journal of Food Hygiene and Safety
• /
• v.35 no.5
• /
• pp.430-437
• /
• 2020

This is an approach study on the sensory properties (taste and odor) of 15 types of Korean conventional soups and stews using electronic nose and tongue. The relative sensor intensity for the taste components of the samples using electronic tongue was demonstrated. By SRS (sourness) sensor, sogogi-baechuguk (beef and cabbage soup) had the highest rate of 9.0. The STS (saltiness) sensor showed the highest score of 8.2 for ojingeoguk (squid soup). For the UMS (umami) sensor, which identifies savoriness, the sogogi-baechuguk was the highest at 10.1. The SWS (sweetness) sensors showed relatively little difference, with sigeumchi-doenjangguk (spinach and bean paste soup) at the highest of 7.3. According to the BRS sensor, which tests for bitterness, the siraegi-doenjangguk (dried radish green and bean paste soup) was the highest at 7.8. By principal component analysis (PCA), we observed variances of 56.21% in principal component 1 (PC1) and 25.23% in PC2. For each flavor component, we observed -0.95 and -0.20 for factor loading of PC1 and PC2 for SRS sensors, 0.96 and 0.14 for STS sensors, and -0.94 and 0.22 for PC1 and PC2 for UMS sensors, and PC1 and 0.22 for PC1 and PC2 loading for SWS sensors. The similarity between the samples identified by clustering analysis was largely identified by 4 clusters. A total of 25 kinds of volatile compounds in 15 samples were identified, and the ones showing the highest relative content in all samples were identified as ethanol and 2-methylthiophhene. The main ingredient analysis confirmed variances of 28.54% in PC1 and 20.80% in PC2 as a result of the pattern for volatile compounds in 15 samples. In the cluster analysis, it was found to be largely classified into 3 clusters. The data in this study can be used for a sensory property database of conventional Korean soups and stews using electronic sensors.