• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.261-267
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• 1994

Parched mugwort tea was manufactured from mugwort (Artemisia asicatica nakai) leaves by traditional green tea preparation method. Volatile flavor compounds were collected by Tenax GC and they separated on DB-5 capillary column ($60m\;\times\;0.25mm$ i.d.) Fifty eight compounds were isolated and identified by GC-MS from the volatiles. Eleven compounds incucluding benzaldehyde, pinene, myrcene, cineole, 2-phrrolidinonoe, camphor, thujong, 1-acetylpiperidine, caryophyllene, coumarin, and farnesol among the compounds identified were considered as important compounds contributing mugwort-like flavor to the parched mugwort tea. The mixture of these eleven authentic compounds could reproduce aroma of mugwort leaves harvested in April. As results, the concentrations of these eleven flavor compounds in parched mugwort tea may indicate the strength of mugwort-like aroma of the tea.

• KSBB Journal
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• v.31 no.2
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• pp.91-99
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• 2016

Tea is an aqueous infusion of dried leaves of the plant Camellia sinensis L. and is the second most widely consumed beverage around the world after water. Aroma compounds of tea differ largely depending on the manufacturing process, even from the same categories of different origins. The flavor of tea can be divided into two categories: taste (non-volatile compounds) and aroma (volatile compounds). In the present study, we review the formation mechanism of main aromas generated from carotenoids, lipids, glycosides as precursors, and Maillard reaction during the tea manufacturing process, with biological and chemical mechanisms.

• Preventive Nutrition and Food Science
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• v.19 no.4
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• pp.314-320
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• 2014

Flavor quality of Liriopis tuber tea that was made using a steaming process was studied by measuring changes in headspace volatile compounds. Headspace volatile compounds of the prepared samples were isolated, separated and identified by the combined system of purge & trap, automatic thermal desorber, gas chromatography, and mass selective detector. As steaming frequencies were increased, the area percent of aldehydes decreased from 32.01% to 3.39% at 1 and 9 steaming frequency times, respectively. However, furans and ketones increased from 18.67% to 33.86% and from 9.60% to 17.40% at 1 and 9 times, respectively. The savory flavor of Liriopis tuber tea was due to a decrease in aldehydes contributing a fresh flavor at the 1st steaming process and newly generated furans from nonenzymatic browning with repeated steaming frequencies. These results will provide basic information for quality control of the newly developed Liriopis tuber tea.

• 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.

• Journal of Life Science
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• v.7 no.4
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• pp.309-315
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• 1997

The fermented black tea with tea fungus (FBTF) was prepared by culturing tea fungus biomass in black tea with 10% sucrose (BT) at 30$\circ$ for 14 days. The flavor quality of FBTF was investigated by sensory and chemical analysis, and the results were compared with BT. The data of sensory analysis indicated that fruity, wine-like, sharp-pungent, and vinegar-like flavor notes were increase, while earthy note was reduced during fermentation. GC-MS analysis of volatile compounds collected from FBTF and BT by Tenax trap showed that linalool, liinalool oxide other flavor compounds known as black tea flavor compounds were disappeared. Some major flavor compounds produced during fermentation were acetic acid, ethanol, limonene, $\alpha$-terpineol, and these volatiles may be attributed to the flavor of characteristic FBTF. Biosynthetic pathway for the formation of limonene and $\alpha$-terpineol are proposed through mevalonic acid pathway using acetic acid as precusor and/or through transformation of linalool and linalool oxide.

• 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.

• 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.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.

• Journal of the Korean Home Economics Association
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• v.43 no.2
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• pp.33-40
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• 2005

This study compared the volatile aroma components in high grad Korea, Chinese and Japanese green tea. The aroma components of green tea were analyzed and compared. Aroma compared. Aroma compounds were extracted by a simultaneous distillation and extraction method using Likens and Nickerson's extraction apparatus. The concentrated aroma extract was analyzed and identified by GC and GC-MS. All the green tea samples contained relatively large amounts of terpene alcohols such as linalool, geraniol and nerolidol. The Korean green tea (A) manufactured in Cheju island contained remarkably large amounts of geraniol (9.12 %) and linalool (5.18 %). The Korean green tea (B) manufactured in Hawgae contained remarkably large amounts of geraniol (5.85 %) and linalool (5.33 %). The Korean green tea (C) manufactured in Bosung contained remarkably large amounts of linalool (7.79 %) and Z-jasmone (3.08 %). The Chinese green tea (D) manufactured in Longjing contained remarkably large amounts of geraniol (3.43 %) and linalool (2.86 %). The Japanese green tea (E) manufactured in Shizuoka contained remarkably large amoung of linalool (3.95 %) and nerolidol (2.76 %).

• 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.