• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1111-1114
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• 2007

The volatile flavor components of buckwheat (Fagopyrum esculentum Moench)-green tea were analyzed and identified. To make tea having good flavor and functional property, parched buckwheat (50%) was mixed with green tea (50%). The extraction of volatile flavor compounds of buckwheat-green tea was accomplished by a simultaneous distillation and extraction method using a Likens and Nickerson's extraction apparatus. The concentrated extract was analyzed and identified by gas chromatography and GC-mass spectrometry. The main volatile flavor components of buckwheat-green tea were compounds that originated from parched buckwheat and the green tea. The former were 15 pyrazines having roasted and nutty aroma and methylbutanals and furfural having sweet-aroma. The latter were nerolidol, linalool, indole, ${\beta}-ionone$ and geraniol etc having flower-like odor in green tea.

• Journal of Life Science
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• v.21 no.5
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• pp.739-745
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• 2011

The purpose of this study was to characterize the aroma of green tea blended with dried citrus fruits containing peeler. Whether middle or low grade green tea is consumed does not have an influence on health benefits, but it does havean influence on flavor. Therefore, two kinds of citrus fruits (mandarin orange and citron) were used to infuse the teas with aromatic flavors. This process turned unflavored tea into special tea with a good color and preferable flavor. Aroma compounds were extracted by SDE method. The concentrated aroma extracts were analyzed and identified by GC and GC-MS. The main aroma components of the green tea blended with mandarin orange were limonene (72.18%), (Z)-ocimene (8.29%), phenyl acetaldehyde (6.15%), ${\gamma}$-terpinene (5.14%), ${\beta}$-elemene (1.80%) and linalool (1.00%). The main aroma components of the green tea blended with citron were limonene (71.74%), ${\gamma}$-terpinene (9.76%), (Z)-ocimene (5.38%), (E)-ocimene (4.36%), linalool (1.00%) and ${\beta}$-mycrene (0.87%). The aromas of green tea blended with dried citrus fruits were mainly mono - and sesquiterpenic compounds.

• Journal of Life Science
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• v.20 no.3
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• pp.350-355
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• 2010

This study was carried out in order to characterize the flavor of Pueraria radix-green tea. To make a new tea with good flavor and functional properties, Pueraria radix was mixed with green tea. Volatile flavor compounds of Pueraria radix-green tea were extracted by simultaneous distillations and extraction methods using a Likens and Nickerson's extraction apparatus. The concentrated extract was analyzed and identified by GC and GC-MS. Forty-nine compounds including $\beta$-selinene, $\beta$-caryophyllene, hexanal and nonanal were isolated and identified from Pueraria radix. Sixty-four compounds including nerolidol, linalool, linalool oxide and phenylethyl alcohol were isolated and identified from green tea. Eighty-two compounds including linalool, $\delta$-cadinene, limonene, $\beta$-caryophyllene and $\beta$-ionone were isolated and identified from Pueraria radix-green tea.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.407-412
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• 2011

Free and bound aroma compounds in green and fermented teas treated with microbial-fermentation were analyzed using headspace-solid phase microextraction gas chromatography (GC) and GC-mass spectrometry. Aldehydes and ketones in green tea decreased during microbial fermentation, whereas linalool and geraniol increased in the fermented tea. After enzyme treatment, (Z)-3-hexen-1-ol increased significantly following enzymatic hydrolysis of both green and fermented teas. In addition, benzaldehyde, 3-hexenyl acetate, and geraniol also increased in green tea with enzyme treatment. Bound aroma compounds in the green and fermented teas increased at different levels of added enzyme. We demonstrated the enhancement of both green and fermented teas by enzyme treatment, which can lead to improvement in the flavor qualities of green and fermented teas.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.23-27
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• 2003

Lipoxygenase is the enzyme responsible for the formation of $C_6$-alcohols and $C_6$-aldehydes ($C_6$-compounds), which are well blown contributors to various types of 'green odor' In green tea. Changes in lipoxygenase activity and volatile compounds of green tea leaves were monitored daily during early growing season. The enzyme activity was spectrophotometrically measured using linoleic acid as a substrate. The volatile compounds were extracted through Solid Phase Micro-Extraction, and were subjected to GC and GC-MS analyses. Results showed that lipoxygenase activity and levels of $C_6$-compounds concomitantly increased or decreased during the early growing season, probably caused by the fluctuation in the daily temperature; increase in temperature led to the increase in enzyme activities and $C_6$-compound levels, whereas leaves plucked too early had low volatile compound levels. In this study, optimum plucking time of tea leaves for the production of high quality green tea with a wellbalanced aroma was determined.

• Korean Journal of Food Science and Technology
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• v.44 no.4
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• pp.383-389
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• 2012

Green tea leaves grown in Jeju island were harvested at different times in 2010 and 2011. Green teas harvested in 2010 experienced higher effective accumulative temperature than green teas harvested in 2011. The free and bound volatile compounds in green tea were analyzed using headspace-solid phase microextraction gas chromatography (GC) and GC-mass spectrometry. All green teas contained the 6 major volatile compounds ${\alpha}$-methylbutanal, pentanal, (E)-2-hexen-1-ol, ${\beta}$-linalool, geraniol and ${\alpha}$-farnesene. After enzyme treatment, (Z)-3-hexen-1-ol, benzaldehyde, (Z)-3-hexenyl acetate, ${\beta}$-linalool and geraniol were increased in all green teas. (Z)-3-hexen-1-ol increased significantly in green tea harvested in 2010, and benzaldehyde increased widely in green tea harvested in 2011. However, the total volatile compounds in green teas harvested in 2011 were remarkably decreased in comparison to harvested in 2010. It was confirmed that free and bound volatile compounds in green tea are affected by low winter temperatures.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.143.2-144
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• 2003

품종별 감잎의 주요성분과 항산화 활성을 비교하여 고기능성 감잎차의 우수성을 알리는 기초자료로 활용하고자 이 실험을 수행하였다. 상주둥시, 갑주백목, 월하시, 청도반시, 녹차(대조구)의 생엽을 7월 초순에 채엽 후 건조시켜 시료로 사용하였고, 비타민C, 카페인, 카테친, Gallic acid, 향기성분, 유리당, 유리아미노산, 칼슘, 항산화 활성을 조사하였다. 비타민C는 월하시 0.089%, 청도반시 0.079%, 갑주배목 0.032%, 상주둥시 0.015%, 녹차 0.01%로 비타민C 함량이 가장 많은 월하시가 녹차에 비해 8배정도 높았고, 카페인은 감잎 4품종 모두 발견되지 않았고, 녹차는 6.63%이었다. 카테친은 청도반시 0.35%, 갑주백목 0.34%, 월하시 0.24%, 상주둥시 0.18%, 녹차(대조구) 0.07%이였고, Gallic acid는 상주 둥시 0.32%, 갑주백옥 0.2%, 월하시 0.05%, 청도반시 0.03%, 녹차(대조구) 1.41%이었다. 칼슘은 청도반시 9516.1PPM, 영동월하시 6863.5PPM, 봉옥 6563.5PPM, 상주둥시 5420.1PPM, 녹차(대조구) 2349.7PPM이였고, 유리당은 감품종간에는 큰 차이는 없었으나 녹차에 비해 Xylose, fructose, Glucose, Sucrose의 함량이 높았고, Maltose의 함량에 일어서는 녹차가 높았다. 유리아미노산은 31항목을 조사하였고, 전체 함량은 상주둥시 60.40, 봉옥 53.21, 월하시 52.29, 청도반시 47.58, 녹차(대조구) 114.72nmo1/${\mu}\ell$이었다. 시료의 향기성분은 생엽을 건조시켜 전자코를 이용하여 분석하였고, 감잎 품종간에는 향기 패턴이 비슷한 경향이였으나, 녹차의 패턴과는 차이가 있었다. 감잎의 DPPH radical 소거활성은 상주둥시 RC$_{50}$($\mu\textrm{g}$)=64.5 청도반시 64.0, 월하시 42.0, 갑주백목 47.0, 녹차(대조구) 19.0으로 김잎품종중 월하시의 항산화 활성이 높았고, 녹차의 항산화 활성이 감잎에 비해 높았다.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.246-254
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• 2007

Fresh tea leaves grown in Jeju Island and Jeonnam Province of South Korea were plucked and processed. Volatile compounds (VCs) were analyzed and identified with SPME-GC/GC-MS/GC-O. The VCs of green teas were classified into two major categories based on their aroma characteristics: the Greenish (Group I), and Floral (Group II) odorants. It was found that the VCs were decreased significantly in fresh tea leaves as they were plucked at the later stages of cultivation. The ratio of VCs responsible for Group I and Group II compounds was well-balanced in tea leaves plucked in May, but the balances were changed when the fresh leaves were processed. The major VCs of fresh tea leaves in Jeju and Jeonnam were n-hexanal, E-2-hexenal, Z-3-hexenal, myrcene, benzyl alcohol, linalool, and phenyl alcohol. Also, Jeju and Jeonnam tea leaves had different aroma composition. n-Heptanol, ${\beta}-pinene$, benzaldehyde, and ethyl salicylate were found in Jeju fresh tea leaves, and Z-3-hexenol, E-2-hexenol, and methyl n-heptanoate were detected in Jeju dry tea leaves. On the other hand, Z-linalool oxide and myrcene were found in Jeonnam dry tea leaves. The SPME-GC method showed high reproducibility (RSD, 7.4%) with no-artifact formation. In this study, optimum plucking period of tea leaves could be determined for production of high quality green tea with a well-balanced aroma and characteristic VCs in green tea according to growing areas.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.529-533
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• 2001

This study was carried out to characterize aroma of semi-fermented teas made traditionally in Korea temple. These teas had favorable floral aroma. The extraction of aroma compounds was accomplished by a simultaneous distillation and extraction method using a Likens and Nickerson's extraction apparatus. The concentrated extract was analyzed and identified by GC and GC-MSD. The main aroma components of these teas were 3-methylbutanal, 2-methylbutanal, (E)-2-hexenal, phenylacetaldehyde, 2-phenyl ethanol, geraniol, ${\beta}-ionone$ and nerolidol. Particularly, the concentration of phenylacetaldehyde was much higher concentration in semi-fermented teas than in green tea prepared from same place. The GC patterns of the aroma components in the semi-fermented teas were slightly different, though they were prepared in same place.

• Journal of Life Science
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• v.22 no.7
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• pp.981-986
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• 2012

To produce a new tea with a good flavor and functional properties using green tea of low quality, naked barley and barley were selected to blend with the green tea. The simultaneous distillation extraction method (SDE) using Likens and Nickerson's extraction apparatus was used to extract the volatile flavor compounds from the samples. The concentrated flavor extracts were analyzed and identified by GC and GC-MS. The GC patterns of the flavor components in two parched barleys were very different. The main volatile flavor components in two of the samples were alkyl pyrazines. Compounds including 3-methylbutanal, 2-methylbutanal, dihydro-2-methyl-3(2H)-furanone, 2,5-dimethyl pyrazine, and 3-ethyl-2.5-dimethyl pyrazine were isolated from the naked barley. Compounds including thiophenes, thiazoles, sulfides, and pyrroles with burnt odor were isolated from the barley. The parched naked barley was better than barley for adding to green tea. The main aroma components of the green tea blended with the naked barley were hexanol, hexanal, trans-2-hexenal, ${\beta}$-ionone, ${\alpha}$-ionone, alkyl pyrazines, 3-methylbutanal, 2-methylbutanal, and furfural.