• Food Science and Preservation
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• v.18 no.5
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• pp.803-810
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• 2011

This study was performed to evaluate the quality of the commercial brown-rice vinegars of South Korean and Japanese origins, which were prepared via static acetic-acid fermentation. The major free amino acids of Korean brown-rice vinegars were proline, glutamic acid and phenylalanine, while those of the Japanese were proline, valine, phenylalanine, lysine, ${\gamma}$-aminobutyric acid, alanine and isoleucine. The ${\gamma}$-aminobutyric acid (GABA) and total amino acids (3686.37~4212.27 mg%) contents were found to be significantly higher in the Japanese than in the Korean brown-rice vinegars. The key volatile compounds of the Korean brown-rice vinegars, analyzed with GC-MS, were acetic acid, benzaldehyde, phenethyl alcohol and phenethyl acetate while those of the Japanese brown-rice vinegars were acetic acid, ethyl acetate, ethyl alcohol, isoamyl acetate, phenethyl acetate and benzaldehyde. The volatile patterns of the Korean and Japanese commercial brown-rice vinegars were effectively distinguished from each other using an electronic nose, through which it was also elucidated that the volatiles profiles were similar among the Japanese vinegars but were different among the Korean vinegars.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.201-208
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• 2007

Functional oils (FOs) were produced from commercial diacylglycerol oil and red yeast rice extracts from 80% ethanol for 1 hr in a shaking water bath at $35^{\circ}C$ and 175 rpm. FOs contained (A) 600, (B) 1200, (C) 1800, and (D) 2280 ppm of red yeast-rice extracts, respectively. The Hunter a value and b value were risen whereas L value was reduced along with the increase of extract concentration. Content of monacolin K and total phenolic compounds in FOs significantly increased according to the increase of extract concentration. The oxidation stability of FOs was observed by Rancimat at $98^{\circ}C$. Induction time decreased according to the increase of extract concentration. The major volatile compounds of FOs were compared using the electronic nose (EN) system and solid phase microextraction (SPME) method combined with gas chromatograph/mass spectrometry (GC/MS). EN was composed of 12 different metal oxide sensors. Sensitivities (Rgas/Rair) of sensors from EN were analyzed by principal component analysis (PCA), whose proportion was 99.66%. For qualitative or quantitative analysis of volatile compounds by SPME-GC/MS, the divinylbenzene/carboxene/polydimethyl-siloxane fiber and sampling temperature of $50^{\circ}C$ were applied.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1307-1313
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• 2011

This study was conducted to evaluate the effects of irradiation temperature on the physicochemical and sensory properties of Tarakjuk, milk porridge. Tarakjuk was gamma-irradiated at different temperatures of $25^{\circ}C$ (in room), $4^{\circ}C$ (in ice), and $-20^{\circ}C$ (in dry ice) at a dose of 10 kGy, and then autoclaved at $120^{\circ}C$ for 15 min for comparison. pH and Hunter's color value of Tarakjuk were not changed by irradiation regardless of the temperature. However, the TBA (2-thiobarbituric acid) value decreased as irradiation temperature was decreased. The viscosity of Tarakjuk irradiated in dry ice was significantly higher than that irradiated at room temperature and in ice (p<0.05). For the sensory evaluation, there were no significant differences in overall acceptability between non-treated Tarakjuk and that irradiated in dry ice. Flavor pattern analysis using an electronic nose with a SAW (surface acoustic wave) sensor determined that the main peaks at retention times 3.88 and 7.34 sec were related with off-flavor induced by irradiation and unique flavor of Tarakjuk, respectively. These results indicated that irradiation at freezing temperature improved quality deterioration of Tarakjuk by gamma irradiation. However, sensory quality of Tarakjuk irradiated at freezing temperature was still lower than that of non-irradiated Tarakjuk. Therefore, further research is needed to improve the quality of Tarakjuk using combined treatment such as addition of antioxidants and vacuum packaging method.

• Food Science and Preservation
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• v.19 no.3
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• pp.328-336
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• 2012

The objective of this study was to investigate the storage effects of the packaging method of blanched namul(Gosari, Torandae, Chwinamul and Siraegi). The samples were packaged with three packaging types (Vinyl packaging, sealing packaging and vacuum packaging) and were stored for 10 days at $10^{\circ}C$. The quality characteristics were evaluated via a microbiological test, hardness, pH and flavor patterns analysis. The pH values of the samples were not affected by packaging method. The total aerobic and coliform plate counts were high, in the order of vacuum packaging < sealing packaging < vinyl packaging. Vacuum packaging resulted in the highest hardness value. The flavor patterns of blanched namul by packaging type were analysed with electronic nose system equipped with 12 metal-oxide sensors, and the storage shelf life of namul was evaluated by measuring the change in volatile production. As a result, it was shown that namul in vacuum packaging had few volatile production changes with higher storage time.

• Food Science and Preservation
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• v.22 no.5
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• pp.690-698
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• 2015

Effects of roasting on physical (weight, volume, density and color) and chemical properties (total phenol, caffeine, chlorogenic acid and antioxidant properties) of three Arabica coffee beans (Brazil Bourbon, Indonesia Mandheling and Kenya Tatu) were investigated. A steady weight loss, volume increase, and bean density decrease were observed during the roasting process. The $L^*$, $a^*$, and $b^*$ values tended to decrease as the roasting temperature and time increased. Caffeine level was approximately 0.73% in green beans, and increased to 40-67% for darker roasts. Green beans contained the highest chlorogenic acid content, which decreased as the roasting temperature and time increased. The light- and medium-roasted coffee showed the highest total phenolol contents. The antioxidant activities were measured using DPPH and ABTS. The light-roasted coffee beans showed the highest antioxidant activities, and an approximately 36-51% loss in antioxidant activity was observed after further roasting. The flavor patterns of roasted coffee beans were analyzed using an electronic nose system based on gas chromatography. This analysis demonstrated that an electronic nose system can be applied to identify the green bean variety and the degree of roasting.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.823-833
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• 2020

The Manila clam Ruditapes philippinarum, is an important marine bivalve that is widely distributed along the west and north coasts of South Korea. It has been used in a variety of Korean foods owing to its superior umami taste. In the present study, we developed a flavoring with an excellent sensory preference from Manila clam using extrusion cooking processing. Optimization of extrusion cooking conditions was performed using response surface methodology (RSM). Barrel temperature (X1, 140-160℃) and screw speed (X2, 400-560 rpm) of the extruder were chosen as independent variables. The dependent variable was overall acceptance (Y, points). The estimated optimal conditions were as follows: overall acceptance (Y): X1=140℃ and X2=560 rpm. The indicated value of the dependent variable overall acceptance (Y) under the optimal conditions was 8.94 points, which was similar to the experimental value (8.82 points). Overall acceptance of the Manila clam flavoring was related to its umami and Manila clam tastes. The electronic nose and tongue results successfully segregated different clusters of the samples between the lowest and highest sensory scores. The sample with the highest sensory score had higher sourness, umami, and sweetness intensities, and the lowest sensory scored sample showed more off-flavor compounds.

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

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.717-720
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• 2005

Acoustic loads generated by a rocket propulsion system cause severe random vibrations on payloads. In developing a new launch vehicle, a random vibration level must be specified before the detailed design of payloads or electronic equipments. This paper deals with prediction procedures of a random vibration level on payload section of KSLV-I. The prediction is based on statistical energy analysis. In order to verify the prediction methodology, test and analysis on a sub-scale payload section are performed. The predicted results subject to very high level of acoustic loads show a good agreement with the test results performed in the high intensity acoustic chamber. The predicted random vibration level on payload section of KSLV-I is also presented in this paper.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.2122-2122
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• 2001

The ultra-high pressure technology fur the preservation of foods is under intense research to evaluate its potential as an alternative or complementary process to traditional methods of food preservation. Traditional processing methods usually need a large amount of energy, may cause unwanted reactions in the food, leading to cooked flavor and loss of vitamins, etc. The application of ultra-high hydrostatic pressure for food processing consists of subjecting the food to pressures in the range of 100-1000 ㎫. The ultra-high pressure inactivates the microorganisms and some enzymes, promotes the germination of spores and extends the shelf-life of the foods. This new technology follows the “minimal processing” concept minimizing the quality degradation, saving the vitamins, essential nutrients and flavors as well as utilizing less energy. We joined the research team at our University involved in the mentioned technology using an ultra-high pressure equipment, recording of the near infrared spectra and signal response of a chemosensor array (electronic nose) of their meat (beef and pork), vegetable and fruit samples exposed to different pressure. The results of our investigations achieved by evaluating the measured data using PCA and PQS methods will be presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.118-122
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• 2000

Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. For composition of this technology, the development of system with high speed and high resolution is needed. At start point and end position vibration must be repressed on this system for composition of position control. This vibration is arisen nose, is increased setting time, is reduced accuracy. Especially, repressed for the lead with high speed. The small actuator with high speed and high resolution is need to repression against this residual vibration. This actuator is, for example, piezo actuator, piezoelectric material that converting from electronic signal to mechanical force is adequate material, beacause of control of control to position and force. In this study, piezo electric material is used to actuator, ultra precision positioning apparatus with stage of hinge structure is designed, simulation is performed, control performance is tested by producing apparatus. For easy usage and stability in industrial field, we perform to simulation and to position control test by digital PID controller.