• Applied Biological Chemistry
• /
• v.40 no.6
• /
• pp.536-540
• /
• 1997

Volatile terpenoids of carrots were measured by the direct headspace sampling method(DHS) with gas chromatography as a study for the breeding of high quality carrots. Using this method, 7 terpenoids such as ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, ${\alpha}-terpinene$, limonene, ${\gamma}-terpinene$, and terpinolene were clearly separated. However ${\alpha}-phellandrene$ was not clearly separated from ${\beta}-myrcene$. In addition to this, higher boiling point compounds such as terpinen-4-ol, bornyl acetate, and ${\alpha}-bisbolol$ were not found. The coefficients of $determination(r^2)$ for the 7 terpenoids were higher than 0.99 and the standard curves were highly significant. Four replicated samples using this method demonstrated great reproducibility; the coefficidnt of variation (C.V.) for ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, limonene, ${\gamma}-terpinene$, terpinolene, and total terpenoids were 6.8, 6.8, 8.4, 7.1, 3.8, 10.1, 7.1%. Sixty five carrot cultivars breeded worldwide were evaluated for the 7 terpenoids and total terpenoids; the range for ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, ${\alpha}-terpinene$, limonene, ${\gamma}-terpinene$, terpinolene, and total terpenoids were $0.28{\sim}2.48\;ppm$, $0.35{\sim}1.87\;ppm$, $0.56{\sim}1.51\;ppm$, 0 ppm, $0.59{\sim}1.84\;ppm$, $0.87{\sim}3.33\;ppm$, $5.15{\sim}35.81\;ppm$, and $9.07{\sim}42.30\;ppm$, respectively. Big differences in each terpenoid and total terpenoids were found among cultivars. On the total terpenoids of the 65 cultivars, 5 cultivars(7.7%) contained less than 10 ppm, 15 cultivars (23.1%) $10{\sim}11.99\;ppm$, 14 cultivars(21.5%) $12{\sim}13.99\;ppm$, 9 cultivars(13.8%) $14{\sim}15.99\;ppm$, 10 cultivars(15.4%) $16{\sim}17.99\;ppm$, 4 cultivars(6.2%) $18{\sim}19.99\;ppm$, 5 cultivars(7.7%) $20{\sim}29.99\;ppm$, and 3 cultivars(4.6%) were higher than 30 ppm. Generally, cultivars developed in Japan contained less total terpenoids than cultivars developed in Europe and America.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.5
• /
• pp.638-648
• /
• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of haloacetic acid (HAAs). In this study, headspace solid-phase microextraction (HS-SPME) was studied as a possible alternative to liquid-liquid extraction for the analysis of HAAs in drinking water. The method involves direct derivatization of the acids to their methyl esters without methyl tert-butyl ether (MTBE) extraction, followed by HS-SPME with a $2cm-50/30{\mu}m$ divinylbenzene/carboxen/polydimethylsiloxane fiber. The effects of experimental parameters such as selection of SPME fiber, the volume of sulphuric acid and methanol, derivatization temperature and time, the addition of salts, extraction temperature and time, and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The $2cm-50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, sulphuric acid of 1ml, methanol of 3ml, derivatization temperature of $50^{\circ}C$ derivatization time of 2hrs, sodium chloride salt of 10g, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were selected as the optimal experimental conditions for the analysis of HAAs. The linearities ($r^2$), relative standard deviations (%RSD) and limits of detection (LOD) for HAAs were 0.9978~0.9991, 1.1~9.8% and $0.05{\sim}0.2{\mu}g/l$, respectively.

• Analytical Science and Technology
• /
• v.24 no.2
• /
• pp.119-126
• /
• 2011

Abstract: The amount of benzene, toluene, ethylbenzene, and o-xylene (BTEX) in 30 kinds of bottled waters purchased from market and 9 kinds of tap waters from home were determined using headspace solid phase microextraction (HS-SPME). The sample was stirred at 1200 RPM G for 4 min using a magnetic bar with $100\;{\mu}m$ PDMS as adsorbent for BTEX. Then it was desorbed from the fiber for 1 min at room temperature. Quantitation was achieved using standard calibration method. The limit of detection was determined as benzene 0.39 (${\pm}0.04$) ng/mL, toluene 0.08 (${\pm}0.04$) ng/mL, ethylbenzene 0.04 (${\pm}0.01$) ng/mL, and o-xylene 0.05 (${\pm}0.02$) ng/mL. Benzene and o-xylene were not detected in any samples, but toluene was detected in 11 samples, and ethylbenzene was detected just in 3 samples among 30 investigated bottled waters. The concentration range of investigated materials for toluene and o-xylene were $0.24({\pm}0.09)\sim2.95\;({\pm}0.08)\;ng/mL$, $0.08({\pm}0.06)\sim0.93({\pm}0.10)\;ng/mL$, respectively.

• Korean Journal of Food Science and Technology
• /
• v.42 no.5
• /
• pp.533-540
• /
• 2010

Effects of pH (1.8-10.2) and time (56 sec-15 min 4 sec) at high hydrostatic pressure (500 MPa) on the reduction of volatile compounds in garlic were studied. Volatile components of garlic were obtained from the headspace, analyzed, and identified by gas chromatography (GC)-mass spectrometry and an electronic nose. Nineteen sulfur compounds were identified as major compounds in garlic, and furan, aldehydes, alcohols, and ketones were also detected. Off-flavor compounds were more effectively reduced under strong acidic conditions. As the residence time at 500 MPa increased from 56 sec to 15 min 4 sec, the total amount of volatile compounds decreased significantly. The total amount of sulfur compounds decreased about 70% compared to those of raw garlic when the garlic was soaked in buffer (pH 6.0) and treated at 500 MPa for 15 min 4 sec. A principal component analysis showed that the off-flavors of garlic were reduced by the operating time of high hydrostatic pressure as well as pH treatment. The correlation coefficient of the results between GC and the electronic nose analysis was 0.9620. Therefore, pH and high hydrostatic pressure treatment could be used as an efficient method for reducing of garlic off-flavor.

• Applied Biological Chemistry
• /
• v.27 no.1
• /
• pp.14-20
• /
• 1984

Volatiles from Mallus pumila Miller Var. Fuji, Ralls Janet and Jonathan during maturity were examined. The volatiles of apples were collected by the headspace trapping method using. Tenax GC and identified by gas liquid chromatography and GC-mass spectrometry. Among over 34 GLC peaks, 23 esters, 9 alcohols and 2 aldehydes were identified. The quantity of volatiles produced was increased in proportion to the degree of maturity, and 1-butanol, isobutyl butyrate, 2-pentanol, ethyl valerate and hexanal were major.

• Korean Journal of Food Science and Technology
• /
• v.27 no.6
• /
• pp.921-927
• /
• 1995

Peach pulp was separated into serum and insoluble pulp by centrifugation at 11,000 rpm for 10 min. The serum portion was concentrated at $50{\sim}55^{\circ}C$ and $30{\sim}50\;mmHg$ with aroma recovery. Vapor generated at the early stage of vacuum evaporation was condensed and taken as aroma fractions: AR-1($0{\sim}5%$), AR-2($5{\sim}10$), AR-3($10{\sim}15%$), AR-4($15{\sim}20%$). Dynamic headspace concentration method was used to trap volatile compounds in aroma fractions and identification of aroma compounds was made by GC/MS. The yield of serum separated from peach pulp was 70.5% and the serum fraction contained the most of aroma compounds. Thirty-one aroma compounds, including ethylene, benzaldehyde, l-limonene and ${\gamma}-dodecalactone$ were identified. The efficiency of aroma recovery was reduced, as the recovery time was extended, as indicated by less peak numbers and peach areas of aroma fractions.

• Biomolecules & Therapeutics
• /
• v.3 no.1
• /
• pp.91-96
• /
• 1995

The effects of toluene inhalation on the contents of amino acid neurotransmitters in rat brain were investigated and blood toluene concentrations inducing changes of behavior and amino acid neurotransmitter contents in rat brain were observed. Male wistar rats were exposed to toluene vapor (single dose : 1700, 5000 and 10000 ppm for 2 hrs, repeated dose : 1700 and 5000 ppm for 2 hrs/day$\times$6 days). Toluene concentrations in blood and the inhalation chamber were assayed by GC with headspace sampler. HPLC method following PITC derivatization was used to measure the amino acid contents in brain tissues such as frontal cortex, caudate, hippocampus, cerebellum and brain stem. Glutamic acid and aspartic acid levels were increased by single inhalation of toluene (5000 ppm) in all the brain areas assayed in this experiment. In caudate and cerebellum, taurine levels were decreased by single inhalation of low dose toluene (1700 ppm), but increased by repeated administration. At high blood toluene concentration, GABA levels were increased in all the brain areas assayed in this experiment and the increasing extents of inhibitory amino acid contents measured in caudate and hippocampus were greater than those of excitatory amino acids. These results suggest that the changes of amino acid neurotransmitter contents in brain by exposure to toluene may modulate toluene-induced behaviors.

• Korean Journal of Food Science and Technology
• /
• v.45 no.3
• /
• pp.267-273
• /
• 2013

We aimed to improve the flavor quality of plain yogurt, which is known to be sour and less desirable in flavor, varying concentrations of a buckwheat saccharification solution (BSS) were added to milk, followed by fermentation with commercially available mixed strains of lactic acid bacteria. Volatile compounds were analyzed using the gas chromatography-headspace-solid phase microextraction (GC-HS-SPME) method. Fermentation properties, including pH, titratable acidity, viable cells, viscosity, and color value were also measured. Eleven volatile compounds were identified with GC-MS. Of which, diacetyl, butanoic acid, and 2-heptanone proportionally increased as the levels of BSS increased. Undesirable compounds such as acetic acid and 2-butanone, decreased as BSS concentration increased. Fermentation properties were significantly altered with the addition of BSS. Our findings indicate that the flavor quality of plain yogurt can be improved by adding BSS for fermentation, with an additional health benefit from buckwheat.

• Journal of Korean Society of Forest Science
• /
• v.88 no.4
• /
• pp.490-497
• /
• 1999

The objectives of this study were to identify aroma characteristics of Tricholoma matsutake(S. Ito et Imai) Sing. growing in different geograghic ranges in South Korea. Mushrooms were collected from 11 major sites which included four sites(Bonghwa, Uljin, Goryung and Chungdo) in Kyongbuk Province, three sites(Changnyung, Hadong and Hamyang) in Kyongnam Province, two sites(Yangyang and Inje) in Kangwon Province, one site(Goisan) in Choongbuk Province, and one site(Namwon) in Chonbuk Province. One of three mushrooms from each site were used for measurements of aromatic characteristics. Aromatic compounds were identified using a dynamic headspace trap method at $40^{\circ}C$ and GC-MSD(gas chromatograph-mass spectrometric detector) method. A total of 25 aromatic compounds were identified. Large variations in the composition and amount of aromatic compounds were noticed. Major aroma compound was 1-octen-3-ol, while methyl cinnamate known as the major aroma compound in matsutake was not detected at all. The total amount of aromatic compounds was highest in Bonghwa, and decreased in the order of Chungdo, Inje, Hamyang, Uljin, and Yangyang. Based on the total amount, kinds and amounts of individual aromatic compounds, the mushrooms from 11 major sites were grouped into following four types : 1) Bongwha Type : the total amount of aromatic compounds was highest, with major compound being 3-methyl 1-butanol. 2) Hamyang Type including Chungdo, Yangyang and Inje : 1-octen-3-of comprised 2/3 of total aromatic compounds, with second major being 3-methyl butanal. 3) Uljin Type : 1-octen-3-ol comprised 94% of total aromatic compounds, with other compounds being almost nothing. 4) Goisan Type including Goryung, Namwon, Changnyung, and Hadong : the total amount of aromatic compounds was lower than other three types.

• Korean Journal of Food Science and Technology
• /
• v.31 no.2
• /
• pp.441-447
• /
• 1999

Changes in flavor characteristics of roasted coffee in 6 package models during storage were investigated by GC/MS analysis and sensory evaluation to establish the criteria of the shelf-life of the roasted coffee in three flavor quality-'fresh', 'satisfying' and 'minimally acceptable' levels. In direct headspace method of GC/MS, 47 volatile compounds were analyzed and the light volatile compounds were reduced sharply at initial stage of storage and faster in the package with air. The correlation between % retention of 2,3-butanedione and overall aroma of roasted coffee showed good linear-relation, of which correlation coefficient (R) were from 0.999 to 0.904 depending on package models, indicating that 2,3-butanedione would be an index chemical for evaluating the freshness of roasted coffee. In sensory evaluation of 6 package models during storage, roasted whole beans (RB) and roasted and ground (RG) coffee in air-package were preserved in 'fresh quality' for $0.5{\sim}1$ week, 'satisfying quality' for $2{\sim}3$ weeks and 'minimally acceptable quality' for 12 weeks, while roasted whole beans in valve-package and roasted and ground coffees in vacuum-package, nitrogen-package and oxygen absorbent-package were preserved in 'fresh quality' for $2{\sim}4$ weeks, 'satisfying quality' for $12{\sim}24$ weeks and 'minimally acceptable quality' for 52 weeks. The oxygen absorbent-package was slightly less effective than other three methods.