• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.251-252
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• 2006

A development of surface acoustic wave gas sensor to detecting volatile gas has been observed by monitoring output signal as function of time onto the network analyzer. The SAW sensor with a center frequency of 200MHz was fabricated on $42^{\circ}$ S-T Quartz substrates. Using the gas chromatography column has been selectivity. Experimental results, which show the phase change of output signal under the absorption of volatile gas onto sensors, were presented. The proposed sensor has the properties of high sensitivity compare to the conventional SAW gas sensor and chemical selectivity. Thus, it is thought these results are applicable for use in sensor array of an high performance electronic nose system.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.652-656
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• 2013

The geographical origin of red ginseng extract (RGE) was studied using a mass spectrometry based electronic nose. Imported RGE and domestic RGE were diluted to 12oBx. The treated RGE was analyzed, and discriminant function analysis (DFA) was used for discriminating of geographical origins. The DFA plots indicated a significant separation of imported RGE and domestic RGE. The F-value of discriminant function first score (DF1) was much higher than that of discriminant function second score (DF2), indicating that discrimination was mainly affected by DF1. Based on DF1, the concentration of domestic RGE to imported RGE shifted to the left side of DFA plot, and the mixing ratio highly correlated to DF1 value. Unknown sample (#2) was closely located to the sample of mixed imported : domestic (6:4) RGE. In the bar graph, the DF1 value correlated to the mixing ratio. Unknown samples (#2) were thought to be mixed with the imported RGE. This technique could be used to efficiently differentiate the geographical origin of RGE.

• Food Science and Preservation
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• v.6 no.2
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• pp.200-205
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• 1999

This experiment was carried out to search mm reasonable and scientific method to distinguish Korean sesame with Chinese sesame. Sesame samples used in this study were Korean variety cultivated in Chochiwon City of Korea (KvKc), Chinese variety cultivated in Jilin Province of China (CvCc), Chinese variety cultivated in Chochiwon city of Korea (CvKc) and Korean variety cultivated in Jilin Province of China (KvCc). In volatile flavor components analysis, 41 component were identified from KvKc and 39 components from CvCc. Major flavor components were pyrazines and furans. Pyrazines compositions of KvKc and CvCc were 55.4% and 56.8%, respectively while furans compositions of KvKc and CvCc were 27.0% and 20.4%, respectively. Other flavor components pattern showed no difference. When the headspace volatiles of sesame oils were analyzed using Electronic Nose System and the obtained data were interpreted using statistical method of MANOVA and Discriminant analysis, characteristic patterns of sesame oil odors were different from each other according to variety as well as cultivated area. These results suggest that Korean sesame oils may be distinguished from Chinese sesame oils by using Electronic Nose System.

• Food Science of Animal Resources
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• v.31 no.4
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• pp.596-602
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• 2011

The objective of this study was to analyze the pattern recognition of volatile compounds from different types of milk under LED (Light Emitting Dioxide) irradiation for 6 d. Yellow, red, blue, dark, and fluorescent light were produced using LED equipment. A mass spectrometry-based electronic nose and DFA (discriminant function analysis) were used to determine the change in volatiles from different types of milk under LED irradiation. As the LED exposure time was increased, DF1 of whole milk changed considerably under blue light, while that of skim milk changed significantly under red and yellow light irradiation. Among the types of milk tested, the most light-induced oxidation sample was LTLT milk under blue light. The volatile compounds that were shown to increase due to LED treatment in the electronic nose analysis, which was based on MS, were mainly acetaldehyde, propanal, pentanal, hexanal, heptanal, nonanal, 3-methyl butanal, 2-methyl propanal, 2-butanone, 2-pentanone, 2-hexanone, and 2-heptanaone and 2-nonanone.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.763-769
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• 2013

Soybean oil was stored in polyethylene for 12 weeks at $20^{\circ}C$. The influence of LED (light emitting diode) irradiation on four different wavelengths and fluorescent light was investigated. The pattern changes of volatile components in soybean oil was analyzed by electronic nose based on mass spectrometer. The obtained data from electronic nose were analyzed by discrimination function analysis. Under fluorescent light, the discriminant function first score (DF1) was significantly moved from positive position to negative one after 4-12 weeks. It means that the volatile compounds related to quality of lipid. It was shown to increase slowly due to green light of LED treatment, while blue and white LED light was influenced significantly as well as fluorescent light irradiation. Selection of LED irradiation would provide to keep good quality of soybean oil under distribution chain system.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.527-532
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• 2010

The properties of volatile flavor components were compared in commercial brown rice vinegars that were fermented with and without ethanol addition, for which solid phase microextraction-gas chromatography (SPME-GC), electronic nose, and sensory evaluations were performed. A total of 24 volatile compounds, mainly composed of acetic acid, ethyl acetate, benzaldehyde, iso-valeric acid, phenylethyl alcohol, 2-phenylethyl acetate, acetoin, and isobutyric acid, were identified in the brown rice vinegar fermented without ethanol, while major volatiles in the brown rice vinegar fermented with ethanol were acetic acid, ethyl acetate, 1-hexyl acetate, benzaldehyde, 2-phenylethyl acetate, and phenylethyl alcohol. The electronic nose patterns of samples indicated a significant difference in the brown rice vinegars fermented with and without ethanol. Pungent flavor and off-flavor intensity were high in the brown rice vinegar fermented without ethanol. According to the results, fermentation conditions affect the volatile properties of brown rice vinegars.

• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.476-482
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• 1997

A portable electronic nose system has been fabricated and characterized using an oxide semiconductor gas sensor array and pattern recognition techniques such as principal component analysis and back-propagation artificial neural network. The sensor array consists of six thick-film gas sensors whose sensing layers are Pd-doped $WO_{3}$, Pt-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$ + Pd coated layer, $Al_{2}O_{3}$-doped ZnO and $PdCl_{2}$-doped $SnO_{2}$. The portable electronic nose system consists of an 16bit Intel 80c196kc as CPU, an EPROM for storing system main program, an EEPROM for containing optimized connection weights of artificial neural network, an LCD for displaying gas concentrations. As an application the system has been used to identify 26 carbon monoxide/hydrocarbon (CO/HC) car exhausting gases in the concentration range of CO 0%/HC 0 ppm to CO 7.6%/HC 400 ppm and the identification has been successfully demonstrated.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.720-727
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• 2001

This study was carried to investigate the changes in physical and chemical properties of Yukwa during preparation with addition of antioxidants and to develop its storage condition. Antioxidants (tocopherol and Oxyfos) were used in syrup coating and the packaging materials used were PET/EVOH $(16\;{\mu}m)/PL$ : P1 and PET/EVOH $(24\;{\mu}m)/PL$ : P2 (YOP1: P1 with Oxyfos, YOP2 : P2 with Oxyfos, YTP1 : P1 with tocopherol, YTP2 : P2 with tocopherol). Color values measured for Yukwa showed that L values of YOP1, YOP2, YTP1 and YTP2 were changed little during storage while a and b values of YOP1, YOP2, YTP1 and YTP2 were slightly decreased. Hardness and chewiness in textural properties were also decreased during storage. Yukwa packed in YOPl and YOP2 maintained less than 40 in peroxide value during for 12 weeks of storage period. The major fatty acid composition of frying oil were linoleic acid (54.2%), oleic acid (23.4%), palmitic acid (11.3%), linolenic acid (6.5%) and stearic acid (4.6%). There was no difference in composition of fatty acid during storage. Sensory evaluation (Yukwa odor and rancid odor) showed very similar results with determined by electronic nose. YTP1 and YTP2 had maintained sensory characteristics of Yukwa during 10 weeks storage.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.728-736
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• 2001

Effects of packaging material and oxygen absorbant on physical and chemical properties of Yukwu were studied during storage to develop packaging conditions. The packaging materials used were PET/EVOH $(16\;{\mu}m)/PL$ : P1 and PET/EVOH $(24\;{\mu}m)/PL$ : P2 with or without oxygen absorbent (E1A : P1 and E2A : P2 for w/ $O_2$, absorbent, E1EA : P1 and E2EA : P2 for w/o $O_2$, absorbent). Color values for Yukwu indicated that L values of E1A, E1EA, E2A and E2EA were decreased during storage while those b values were increased. Hardness and chewiness of Yukwa were generally decreased, however those of E1A and E1EA were rather increased after 6 weeks of storage. Acid value of E2A had maintained less than 2.0 during 12 weeks of storage. E1A, E2A had the below of 20 in peroxide during 12 weeks. Aroma data by using electronic nose showed that there was no difference after 6 week storage time in different packaging materials. Sensory evaluation (Yukwa odor and rancid odor) showed very similar results with electronic nose one. E2A had the highest value of overall acceptability for sensory evaluation. Hardness and cheweness in physical measurement results had the highest correlation with hardness, crispness, overall-acceptability in sensory evaluation results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1405-1411
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• 2006

The presence and content of residual hexane in the olive oils were studied. Total 41 olive oils of imported and domestic brands, which were labeled as extra virgin and refined (mixed), were collected from the market. For analysis, electronic nose and headspace SPME-GC/MS were used. Electronic nose equipped with 12 metal oxide sensors was used for the discrimination of odor pattern of olive oils against the different concentrations of hexane. From the results, it is assumed that the contents of residual hexane in the collected olive oils were below 5 ppm. For Qualitative and quantitative analysis of hexane, polydimethylsiloxane (PDMS) fiber was employed for SPME-GC/MS. In the results, the peak of residual hexane was detected in 8 samples from 41 olive oils. But the detected level was no more than 1 ppm that is under the regulation limit (5 ppm) by Korea Food Additive Code.