• Journal of Sensor Science and Technology
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• v.23 no.5
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• pp.320-325
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• 2014

Volatile flavor compounds from milk were analyzed and identified by using the analysis methods of headspace solid phase microextraction gas chromatography/mass spectrometry (HSPME-GC/MS) and electronic nose (E-Nose) system. About 30 volatile compounds were identified by HSPME-GC/MS for the fresh and off-flavor milk samples. Also, the correlation between rancidity and ageing days of milk was obtained by the aid of principal component analysis algorithm. It shows that the E-Nose system can identify the various types of milk flavor. These results imply that the analysis method based on the E-nose system can apply to the quality control of milk flavor and the rancidity.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.462-469
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• 2009

The aim of this study was to develop a portable electronic nose system for freshness measurement of stored pork. An electronic nose system was constructed using seven different MOS sensor array. To determine the quality change of pork with storage time, the samples were divided into ten groups in terms of storage time with an increment of 2 day up to 19 storage days. GC-MS, total bacteria's count (TBC), thiobarbituric acid reactive substance (TBARS), and pH analyses as well as the analysis of the electronic nose system measurement were performed to monitor the freshness change of the samples. To investigate the performance of the electronic nose system for detecting the change of freshness of pork, the acquired signal values of the system were compared with those of GC-MS, TBC, TBARS, and pH analysis values. According to principal component analysis (PCA) and linear discriminant analysis (LDA) with the signals of the electronic nose system for the pork samples, the sample groups were clearly separated into two groups of 1-9 days and 11-19 days, and four groups of 1-3 days, 5-9 days, 11 days, and 13-19 days respectively. The results show that the electronic nose system has potential for evaluating freshness of pork.

• Journal of Sensor Science and Technology
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• v.13 no.1
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• pp.41-46
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• 2004

There is currently much interest in the development of instruments that emulate the senses of humans. Increasingly, there is demand for mimicking the human sense of smell, which is a sophisticated chemosensory system. An electronic nose system is applicable to a large area of industries including environmental monitoring. We have designed a protable electronic nose system using an array of commercial chemical gas sensors for recognizing and analyzing the various odours. In this paper, we have implemented a portable electronic nose system using an array of gas sensors for recognizing and analyzing VOCs (Volatile Organic Compounds) in the field. The accuracy of a portable electronic nose system may be lower than an instrument such as GC/MS (Gas Chromatography/Mass Spectrometer). However, a portable electronic nose system could be used on the field and showed fast response to pollutants in the field. Several different algorithms for odours recognition were used such as BP (Back-Propagation) or LM-BP (Levenberq-Marquardt Back-Propagation). We applied RBF (Radial Basis Function) Network for recognition and quantifying of odours, which has simpler and faster compared to the previously used algorithms such as BP and LM-BP.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.851-859
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• 2010

This study was conducted to investigate the application of a model system using an MS-electronic nose based on the discriminative function analysis on volatile flavors, to prediction of the shelf-life of market milk by preservation temperature and differently-loaded heat treatment. On mass spectrum, the ion fragments of volatile flavors of milk obtained from MS-electronic nose could be distinguished at amu 60, 91, 92, and 93. The response levels of volatile flavors at each amu increased in proportion to the heat treatment loaded to the milk, in the order of LTLT, HTST, and UHT. This study indicated that the discriminative function scores of the volatile flavors seemed to correlate with the preservation temperature, storage period, and heat treatment conditions; DF1 (discriminative function first score) showed a strong relationship to storage periods, with $r^2$ of 0.9965, 0.9965, and 0.9911 at temperatures of 4, 7, and $10^{\circ}C$, respectively, while DF2 was influenced by heat treatment conditions with an $r^2$ of 0.9861 at $4^{\circ}C$. It is suggested that the discriminative function analysis given by an MS-electronic nose could be used to construct a new quality control model system for the evaluation of heat treatment loaded during the processing of milk, and for predicting storage periods of market milk.

• FLOWER RESEARCH JOURNAL
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• v.19 no.4
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• pp.219-224
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• 2011

Phalaenopsis (P.) has various species, and some of them have strong fragrance. There are fragrant species such as P. bellina, P. violacea, P. schilleriana and used in breeding program for fragrant Phalaenopsis. This study was performed for establishment of fragrance analysis system using GC-MS and electronic nose in eight P. resources. We analyzed fragrant compound using the tissue of sepal, petal, column, and lip of P. '3010'. The percentage of the major compound was high in the petal and lip tissues. The main compound emitted from P. bellina was linalool (21.21%). It was possible that fragrance pattern could be analyzed among the resources using the electronic nose. Discriminant function analysis (DFA) was more useful than the principal component analysis (PCA) in statistics program. We utilized GC-MS method for the major compounds of flower from our breeding materials. This study would be useful to the fragrant analysis system for the fragrant orchid breeding in the future.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.313-320
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• 2010

The purpose of this study was to evaluate the freshness of chicken meat during 19 d of storage at $4^{\circ}C$ using a portable electronic nose. The portable system consisted of six different metal oxide sensors and a moisture sensor. Determination of volatile compounds with gas chromatography-mass spectrometry, total bacterial count (TBC), and 2-thiobarbituric acid reactive substances (TBARS) monitored the quality change of the samples. These results were compared with the results measured by the electronic nose system. TBC and TBARS measurements could be separated into five groups and seven groups, respectively, among ten groups. According to principal component analysis and linear discriminant analysis with the signals of the portable electronic nose, the sample groups could be clearly separated into eight groups and nine groups, respectively, among ten groups. The portable electronic nose demonstrated potential for evaluating freshness of stored chicken.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.105-109
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• 2011

To determine mixing ratios for mixtures of rapeseed oil and other oils, an electronic nose (E-nose) based on a mass spectrometer system was used. Rapeseed oil was blended with soy bean oil or corn oil at ratios of 100:0, 97:3, 94:6, 91:9, 88:12, 85:15, and 80:20, respectively. The intensities of each fragment from the mixed rapeseed oil by E-nose based on MS were completely different from those of the soy bean oil and corn oil. The obtained data were used for discriminant function analysis (DFA). DFA plots indicated a significant separation of pure rapeseed oil and soy bean oil or corn oil and their mixtures. The added concentration of soy bean oil or corn oil to rapeseed oil was highly correlated to the first discriminant function score (DF1). When soy bean oil was added to rapeseed oil, it was possible to predict the following equation: DF1=-0.170*conc. of soy bean oil+0.431 ($r^2=0.989$). For corn oil the equation was: DF1=-0.1*conc. of corn oil+0.4 ($r^2=0.844$). The use of an E-nose based on a MS system is as an efficient method for the authentication of pure rapeseed oil.

• Food Engineering Progress
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• v.13 no.4
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• pp.275-281
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• 2009

Sesame oils are partially mixed with other vegetable oils due to high price in a Korean market. To find out authentic sesame oil, a mass spectrometer-based electronic nose (MS-based E-nose) was used. Sesame oil (Se) was blended with soybean oil (So) or corn oil (Co) at the ratio (Se:So, Se:Co) of 97:3, 94:6, 91:9, 88:12 and 85:15, respectively. Intensities of each fragment from sesame oil by MS-based E-nose were completely different from those of soybean oil or corn oil. The obtained results were used for discriminant function analysis (DFA). Volatile organic components (VOC) of soybean oil or corn oil were similar to those of fresh air and DFA plot indicated a significant separation of pure sesame oil and pure other oil. The group of the mixed oil was seperated with that of sesame oil in DFA plot and the added amount of soybean oil to sesame oil was correlated with discriminant function first score (DF1). MS based E-nose system could be used as an efficient method to investigate the purity of sesame oil.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.609-614
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• 2009

Sesame oil was sometimes replaced by mixed oil due to high price in Korean market. To find out authentic sesame oil, electronic nose (E-nose) based on mass spectrometer system was used. Sesame oil was blended with perilla oil at the ratio of 97:3, 94:6, 91:9, 88:12 and 85:15, respectively. Intensities of each fragment from sesame oil by E-nose based on MS were completely different from those of perilla oil. The obtained data was used for discriminant function analysis. For quantitative analysis, the partial least square algorithm was used. The added concentration of perilla oil to sesame oil was correlated with discriminant function first score (DF1) and second score (DF2). From this relationship it could be found out how much perilla oil added. DFA plot indicated a significant separation of pure sesame oil and pure perilla oil. The different geographical origin of sesame oil was used for blending with perilla oil were closed to that of sesame oil. Korean sesame oil mixture and Indian sesame oil one were well separated. And the correlation between mixing ratios and DF1 values was found at the ratio of 97:3, 91:9, and 85:15 (SE vs PE oil), respectively. But the added concentration of perilla oil to sesame oil was correlated with discriminant function first score (DF1). E-nose based on MS system could be used as an efficient method for purity of oil quality.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.238-252
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• 2002

In order to screen out indicators for the discrimination of ginseng habitat, some physical and chemical characteristics of Korean red ginsengs (94 kinds) and Chinese red ginsengs (50 kinds) were analyzed by using a rheometer, an electronic nose system, a combined technique of solid phase micro-extraction (SPME) and gas chromatograph equipped with an electron capture detector (GC/ECD), an X-ray fluorescence spectrometer (XRF), an inductively coupled plasma mass spectrometer (ICP/MS), a near infrared spectrometer (NIRs) and high performance liquid chromatography equipped with evaporative light scattering detector (HPLC/ELSD). The results are summarized as follows: (i) The rhizome strengths of Korean red ginsengs were significantly higher than those of Chinese red ginsengs. (ii) The electronic nose patterns of Korean red ginsengs were significantly different from those of Chinese red ginsengs. (iii) Some unidentified peaks were detected not in the headspace of Korean red ginsengs but in the headspace of Chinese red ginsengs when the headspace volatiles prepared by the SPME technique were analyzed by GC/ECD. (iv) Either the content ratios of K to Ca or Mn to Fe were significantly different between Korean red ginsengs and Chinese red ginsengs. (v) The reflectance ratios of NIRs wavenumbers such as $904\;cm^{-1}\;to\;1088\;cm^{-1}$ for Korean red ginsengs were significantly different from those for Chinese red ginsengs. (vi) The content ratios of ginsenoside-Rg to ginsenoside-Re of Korean red ginsengs were significantly higher than those of Chinese red ginsengs. These results indicate that the rhizome strength, the electronic nose pattern, the occurrence of ECD-sensitive headspace volatile components, the content ratios of K to Ca and Mn to Fe, the NIRs pattern and the content ratio of ginsenoside-Rg to -Re may be indicators for the discrimination of ginseng habitat.