• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.298-304
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• 1996

Thirty-nine samples of roasted sesame seed oils were sensorially evaluated in terms of nutty odor, burnt odor and overall desirability, and their volatile compounds quantitatively analysed using direct sampling capillary GLC. Five volatile compounds were appeared to be significant for the sensory Properties of sesame oils through the multivariate analytical techniques such as stepwise discriminant analysis. canonical discriminant analysis, discriminant analysis and principal component analysis. The most important compounds were 2,5-dimethylpyrazine and 2-methylpyrazine which could be effectively used as chemical indicators related to nutty and burnt odor of sesame oils, respectively. The sesame oils which have represented a good grade of overall desirability have been always kept $35.82{\sim}4.43$ ppm of 2,5-dimethylpyrazine and also $28.90{\sim}6.35$ ppm of 2-methylpyrazine.

• Fisheries and Aquatic Sciences
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• v.26 no.6
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• pp.393-405
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• 2023

The aim of this research was to enhance the flavor of visceral extracts from skipjack tuna. Flavor precursors and the optimum condition for the Maillard reaction were determined. The flavor extract was prepared from the tuna viscera using Endo/Exo Protease controlled in 3 factors; temperature, enzyme amounts and incubation time. The optimal condition for producing tuna viscera protein hydrolysate (TVPH) was 60℃, 0.5% enzyme (w/w) and 4-hour incubation time. TVPH were further processed to tuna viscera flavor enhancer (TVFE) with Maillard reaction. The Maillard reactions of TVFE were conducted with or without supplements such as xylose, yeast extract and methionine. The Maillard volatile components were analyzed with gas chromatography-mass spectrometry. Sixteen volatiles such as 2-methylpropanal, methylpyrazine, 2,5-dimethylpyrazine, dimethyl disulfide and 2-acetylthaizone were newly formed via Maillard reaction and the similarity of volatile contents from TVPH and TVFE were virtualized using Pearson's correlation integrated with heat-map and principal component analysis. To virtualize aromagram of TVPH and TVFE, odor activity value and odor impact spectrum (OIS) techniques were applied. According to OIS results, 3-methylbutanal, 2-methylbutanal, 1-octen-3-ol 2,5-dimethylpyrazine, methional and dimethyl trisulfide were the potent odorants contributed to the meaty, creamy, and toasted aroma in TVFE.

• Journal of the Korean Society of Combustion
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• v.4 no.2
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• pp.11-22
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• 1999

Combustion characteristics of the wood chips(balsa chips) were experimentally investigated with respect to the thermal recycle system of the urban waste. The urban waste contains plastics, vegetable and wood materials. Wood was chosen as an example of the one of the component of urban dust. A small wood chip was burned in a electric furnace by the micro-electric balance. The mass reduction rate was normalized by the initial mass of test piece and the time of volatile combustion end. When the mass of the wood chips(balsa chips) was larger than 0.5g, the combustion similarity was found on the normalized mass reduction rate.

• Fibers and Polymers
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• v.2 no.2
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• pp.75-80
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• 2001

The thermal degradation of poly(ethylene terephthalate-co-isophthalate)s (PETIs) is investigated by using isothermal thermogravimetric analysis at the temperature range of 280-31$0^{\circ}C$. The degradation rate of PETIs is increased as the mole ratio of ethylene isophthaloyl (EI) units in PETIs increases. The activation energies for the thermal degradation of poly(ethylene terephthalate), PETI(5/5), and poly(ethylene isophthalate) are 33.4, 16.6, and 8.9 kcal/mole, respectively. The degradation rate of PETIs is influenced by their volatile cyclic oligomer components formed during the polymerization and the thermal degradation. It is simulated by the rotational isomeric state model that the content of cyclic dimer in PETIs, which is the most volatile cyclic oligomer component, increases with the EI units in PETIs.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.2
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• pp.143-148
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• 1989

Field experiment was conducted to find out the chemical characteristics of 12 Korean local varities, Local varities were compared with oriental, flue-cured and burley tobacco. Among tested varities, Hyangcho and Matskawa were desirable in respect of flavor, leaf color and texture. Hyangcho and Matskawa were higher in the content of nicotine and petroleum ether extract. Gajacho, Byeolcho and Kukjuo were higher in the content of reducing sugar, but lower nicotine, total nitrogen and petroleum ether extract. The nicotine and total nitrogen content of Kwangcho, Daruma and Catterton were lower than that of Br. 21. In the content of volatile organic acid which were major characteristic component of oriental tobacco, the Korean local varities were lower in the content of 3-methyl butanoic and 3-methyl pentanoic acid, but hirities, Hyangcho, Matskawa and Daruma were higher in the content of volatile organic acid. Korean local varities, especially small leaf group, were higher in the content of benzyl alcohol and furfural than any other type tobacco.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.139-146
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• 1999

Combustion Characteristics of the wood chips(balsa chips) were experimental studied as fundamental investigation of the thermal recycle system of the urban dust. The urban dust contains plastics vegetable and lot of wood material. Then, a wood was chosen as an example of the component of urban dust. A small wood chip was burned in a electric furnace and mass reduction rate during volatile and combustion states were recorded by the micro-electric balance and the combustion flame shape took a photograph by video camera at the mass of wood chips and ambient temperature in the furance. Ignition delay took the minimum value when the mass of the test chip was 0.3g. When a mass of the test chip was smaller then 0.001g, combustion with flame did not burnt.

• Natural Product Sciences
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• v.7 no.4
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• pp.120-123
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• 2001

To develop systems for economic production of useful essential oil compounds, callus was induced from the seedlings of Agastache rugosa and cultured on MS medium. The volatile oil fraction was extracted from the callus and investigated by mean of GC-MS. The composition of the oil was compared with that of the mother plant. As a result, sixty five compounds including ferruginol were identified in the essential oil fraction. The main component of the oil from the leaves of Agastache rugosa was methyl chavichol (53.6%). Methyl jasmonate and jasmonic acid were added to the culturing cell suspension, separately and the composition of induced oil were compared. The oils from cultured cells treated with jasmonates showed considerably different patterns. Especially, the peak of estragole was found in callus oil after treatment with methyl jasmonate as though the amount was limited to 0.58%. In general, the TIC pattern of GC-MS of the callus oil became more similar to the oil from the leaves after elicitation.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.180-185
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• 2002

Volatile flavor components in three pear varieties (Pyrus pyriforia N.) of traditional cultivar, Bongri, Hwangsilri and Yongmokri, were collected by SDE method using the mixture of n-pentane and diethylether as an extract solvent and were identified by GC/MS. Among 97 compounds identified from all varieties, there were 72, 58 and 66 components in Bongri, Hwangsilri and Yongmokri, respectively. Ethyl acetate was the dominant constituent in all cultivars and also volatile profiles contained large quantity of ethanol and acetic acid. Butyl acetate identified as a main component in Bongri was not found in other pears, but in Hwangrilri and Yongmokri only 4 to 5 esters played important role in total volatile flavor composition. The volatile profiles of these three varieties were characterized by compounds in group of aldehydes, esters, alcohols, acids and ketones. As classified by functional group of separated and identified components, esters and alcohols in Bongri, alcohols in Hwangsilri, and esters in Yongmokri were roled as the title in composition of volatile flavor components. Although small amount, Yongmokri had the highest rate of volatile production at 6.552 mg/kg of pear while Hwangsilri produced the lowest at 4.175 mg/kg of pear.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.120-131
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• 2005

The evaporation characteristics of single and multicomponent droplets hanging at the tip of a quartz fiber are studied experimentally at the different environmental conditions under normal gravity. Heptane and Hexadecane are selected as two fuels with different evaporation rates and boiling temperatures. At the first step, the evaporation of single component droplet of both fuels has been examined separately. At the next step the evaporation of several blends of these two fuels, as a binary component droplet, has been studied. The temperature and pressure range is selected between 400 and 700 $^{\circ}C$, and 0.1 and 2.5 MPa, respectively. High temperature environment has been provided by a falling electrical furnace. The initial diameter of droplet was in range of 1.1 and 1.3 mm. The evaporation process was recorded by a high speed CCD camera. The results of binary droplet evaporation show the three staged evaporation. In the the first stage the more volatile component evaporates. The droplet temperature rises after an almost non evaporating period and in the third stage a quasi linear evaporation takes place. The evaporation of the binary droplet at low pressure is accompanied with bubble formation and droplet fragmentation and leads to incomplete microexplosion. The component concentration affects the evaporation behavior of the first two stages. The bubble formation and droplet distortion does not appear at high environment pressure. Nomenclature

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.220-228
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• 2004

Dynamic headspace purge conditions were investigated to obtain minimum loss of high volatile compounds by breakthrough and maximum recovery of low volatile components of roasted perilla seed oil (RPSO). A response surface methodology was applied to evaluate the effect of purge temperature, purge time, and sample weight on $\ell$ n (total peak area), breakthrough ratio, and peak area of perilla ketone the least volatile component of RPSO. Sample weight was the most important factor on the $\ell$ n (total peak area) but it did not affect peak area of perilla ketone. All process variables significantly influenced breakthrough ratio. The optimum condition was determined by superimposing contour plots at purge temperature of 48$^{\circ}C$ for 12 min purge time at sample weight of 0.60 g. 2-Propanone, 2-butanone, acetic acid, 2-methyl propanal were main breakthrough compounds in RPSO flavor.