• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1153-1158
• /
• 1999

Propolis is a resinous bee-hive product that honeybees collect from plant exudates, flower and leaves. Flavor characteristics of two varieties of propolis collected from different plant origins, falseacacia(Robinia psedoacacia L.) and chestnut tree(Castanea crenata), were analyzed using Aroma Scan and GC/MS. Two varieties of propolis were grouped with quite different aroma profiles by Aroma Scan. Fifty five flavor compounds were identified by GC/MS, of which 44 compounds were found from the propolis of falseacacia and 47 compounds from chestnut tree. Five aldehydes, eight alcohols. five ketones, three esters, one fatty acid, twenty seven hydrocarbons. two terpenes and four phenolic derivatives were identified. Thirty six compounds including benzaldehyde, cinnamyl alcohol, eudesmol and benzyl benzoate were detected in both propolis, eight compounds including geraniol and n-undecane only in propolis of falseacacia and eleven compounds including piperitenone and valencene only in chestnut tree.

• Korean Journal of Plant Resources
• /
• v.21 no.4
• /
• pp.237-248
• /
• 2008

The chemical composition of the volatile constituents from broad-leaved indeciduous trees was determined by GC and GC/MS spectrometric analysis with the aid of NBS, Wiley Library and RI indice searches. The major constituents were identified as hotrienol (9.21%) from Ligustrum japonicum flowers, undecane (32.12%) from Pittosporum tobira leaves, 1,8-cineole (45.32%) from Illicium religiosum leaves, ${\gamma}$-terpinene (15.62%) from Neolitsea aciculata leaves, 1,8-cineole (14.66%) from Cinnamomum japonicum leaves, 2-acetyl-5-methylfuran (54.51%) from Camellia sinensis leaves, and ${\gamma}$-elemene (18.59%) from Dendropanax morbifera leaves.

• Journal of Korean Society for Atmospheric Environment
• /
• v.13 no.3
• /
• pp.221-229
• /
• 1997

Wax is a protectant for floors that is used widely in Korea and is considered an emission source of volatile organic compounds (VOCs) in the indoor environment. This study examined the concentration change of indoor VOCs due to waxing and also due to wiping the floor with an oiled dustcloth. VOCs were identified using a cryogenic concentration/thermal desorption system with capillary GC that utilized a liquid nitrogen cryostat and induction heating. The major components emitted from the waxing were nonane, decane, undecane, $C_2$-benzene, and $C_3$-benzene. The concentrations of nonane were 1,276 $\mu\textrm{g}$/㎥ an hour after wax applications, 832 $\mu\textrm{g}$/㎥ after 3 days, and less than 10$\mu\textrm{g}$/㎥) after 15 days. Another emission source of VOCs in indoor was the oiled dustcloth used for cleaning the floor. The oiled dustcloth gave VOCs concentrations three times higher than the normal undusted floor.

• Journal of the Korean Magnetic Resonance Society
• /
• v.10 no.1
• /
• pp.59-73
• /
• 2006

Spin-lattice relaxation pathway of $CH_2$ spin system by two dimensional NOESY sequence has been discussed. Two-dimensional spectra governed by dipolar relaxation mechanism were simulated in term of transfer mode, the generalization of conventionally used magnetization mode in one dimension. The transfer matrix directly related to the Redfield relaxation matrix can be constructed by the multiplet of transfer mode. The observable relaxation transfer modes causes to variation of the off-diagonal signal intensity of phase sensitive NOESY spectra from which variable spectral density can be extracted with simple group theoretical calculation. The variation of the J-coupling peak intensity as a function of the mixing time in 2-D spectra for $n-Undecane-5-^{13}C$ and Bromoacetic $2-^{13}C$ acid has been theoretically traced.

• Journal of the Korean Magnetic Resonance Society
• /
• v.2 no.1
• /
• pp.1-23
• /
• 1998

The motions of carbon-chain backbone in n-undecance and n-dodecane dissolved in CDCl3 are investigated by 13C NMR relaxation study. For this purpose a model of C - C backbone motions for these molecules is introduced that takes into account the cooperativities between rotations about two $\beta$-coupled C - C bonds. In this model it is assumed that the major conformational interconversions occurring in the inner part of the chain involve the type II jumps only, although at terminal part of the chain both type II and type III motions are assumed to take place. Information of the rate constants of these conformational transitions could be extracted by comparing the T1's calculated on the basis of the assumed model with those observed over the temperature range of 248 - 308 K. The calculations were performed according to the method proposed by Wittebort and Szabo. The activation energies, ranging from ca 12 to 20 kJ/mol, could be obtained from the Arrhenius plots of these calculated rate constants.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2012.04a
• /
• pp.23-25
• /
• 2012

• Bulletin of Food Technology
• /
• v.12 no.4
• /
• pp.28-35
• /
• 1999

밀원식물을 달리하여 채집된 두 종류의 국내산 propolis의 향기성분을 Aroma Scan과 GC/MS로 분석하였다. Aroma Scan으로 아까시나무와 밤나무 유래의 두 propolis는 서로 다른 향기를 지닌것을 확인하였다. GC/MS로 분석한 propolis의 향기 성분은 아까시나무 유래 propolis의 44종과 밤나무 유래 propolis의 47종을 포함한 총 55종이 검출되었다. Aldehydes 5종, alcohols 8종, ketones 5종, esters 3종, fatty acid 1종을 비롯하여 27종의 hydrocarbons과 2종의 terpenes 및 4종의 phenolic derivatives가 검출되었다. Benzaldehyde, cinnamyl alcohol, dudesmol 및 benzylbenzoate 등을 포함한 36종의 화합물은 두시료에서 공통적으로 검출되었고, geraniol과 n-undecane을 포함한 8종의 성분은 아까시나무 유래의 propolis에서만 확인되었으며, piperitenone과 valencene을 포함한 11종의 화합물은 밤나무 유래의 propolis에서만 검출되어 밀원식물에 따라 향기성분에 차이가 있는 것으로 나타났다.

• Food Science and Preservation
• /
• v.13 no.4
• /
• pp.483-489
• /
• 2006

Considering the development of fusion ingredients rom red ginseng and Cheonggukjang (soybean-fermented food), their commercial powders were evaluated in their Hunter's colors, volatile compounds, and sensory properties depending on manufacturing companies and mixing ratio of both powdered products. Hunters L, a and b values of red ginseng powders were $75.56\sim85.50,\;1.90\sim6.30,\;and\;23.29\sim35.08$, respectively, while those of Cheonggukjang powders were $64.96\sim71.69,\;4.64\sim8.30,\;and\;30.45\sim36.50$, respectively. Volatile compounds were mainly composed of hexanal, $\beta-pinene$, methyl benzene, 3,5-methyl propyl nonane, 2-propanone, decane, and 2,8-dimethyl undecane in red ginseng samples, and of 2,3-butanedione, decane, 2,2,7,7-tetramethyl octane, and 3-methyl butanal in Cheonggukjang samples. Total volatiles of the mixed samples decreased as ginseng decreased and Cheonggukjang increased. The mixed sample of both red ginseng and cheonggukjang in same amounts was the highest in its sensory acceptability, which was composed in the order of 2-propanone, 2-butanone, pentane, hexanal and 3-methyl butanal. The above results indicate that red ginseng and Cheonggukjang showed a potential as fusion ingredient for preparing new functional produce through further processing.

• Analytical Science and Technology
• /
• v.25 no.5
• /
• pp.292-299
• /
• 2012

GC/MS has been utilized for many applications due to great resolution and reproducibility, which made it possible to build up the database of mass spectrum, while HS-SPME has the advantage of solventfree extraction of volatile compounds. The combination of these two methods, HS-SPME GC/MS, enabled many scientific applications with various possibilities. In this study, the analysis of trail pheromone excreted from live Camponotus japonicus with the feature of solvent-free extraction was carried out and the optimization for this analysis was performed. The major compounds detected were n-decane, n-undecane, and n-tridecane. Optimization for the best detection of these hydrocarbons was processed in the point of SPME parameter (selection of fiber, extraction temperature, extraction time, etc.). The advantage of the analysis of live sample is to analyze phenomenon right after it is excreted by ants. But the experimental process has restriction of extraction temperature and time because of the analysis of live ants. Establishing the process of HS-SPME GC/MS applied to live samples shown in this study can be a breakthrough for the ecofriendly and ethical research of live things.

• Korean Journal of Food Science and Technology
• /
• v.42 no.6
• /
• pp.699-704
• /
• 2010

Rapeseed oil was stored under different conditions such as in the dark, with UV treatment, and with prooxidantscytochrome C and copper ion. The rapeseed oils stored at different temperatures were analyzed by a mass spectrometrybased electronic nose and discriminant function analysis (DFA). Volatile components in the rapeseed oil increased with storage time, and the discriminant function first score (DF1) moved from a positive position to a negative position as storage time increased. Changes in DF1 were higher under UV treatment than under the dark condition (DF1: $r^2$=0.9481, F=307.03). The different DF1 values (F1) under the dark condition were 0.099, 0.187, and 0.278 as storage temperature increased. The different values under UV treatment were 0.554, 0.588, and 0.542, as storage temperature increased from 4 to $26^{\circ}C$. As concentrations of prooxidants copper ion and cytochrome C increased, amounts of volatile components also increased. These were confirmed by DFA. Furthermore, changes in responses at each ion fragment agreed with reported results for GC/MS, which formed after rancidity of the oil, including pentane, pentanal, 1-pentanol, hexanal, n-octane, 2-hexenal, heptanal, 2-heptenal, decane, 2-octenal, undecane, and dodecane.