• 동아시아식생활학회지
• /
• 제21권2호
• /
• pp.243-249
• /
• 2011

This study investigated the physiological and antioxidant activities of green, oolong, and black tea extracts. The crude catechin extract yields of green, oolong, and black tea were 4.9%, 3.4%, and 2.5%, respectively. Total phenol contents of green, oolong, and black tea were 40.9%, 43.0%, and 38.5%, respectively. The order of the electron donating abilities of green, oolong and black tea were green tea>oolong tea>black tea extracts. The SOD-like activities of green, oolong and black tea extracts at 5,000 ppm were 21.2%, 17.5% and 13.9%, respectively. The nitrite-scavenging abilities of green, oolong and black tea extracts were higher than that of ascorbic acid (p<0.05). Antioxidant activities in soybean oil substrates at 500 ppm were in the order of green tea>oolong tea>black tea${\geq}$BHT (200 ppm). Therefore these results showed that the physiological and antioxidant activities of green tea were better than those of oolong and black tea.

• 한국식품조리과학회지
• /
• 제21권3호
• /
• pp.346-353
• /
• 2005

본 연구는 국내에서 시판되고 있는 녹차, 현미녹차, 홍차 2종류, 오룡차 1종류 및 자스민 차 1종류의 티백 제품을 $80\%$ 에탄올과 물로 추출하여 7종의 catechins, 4종의 theaflavins 및 2종의 methylxanthins의 함량을 HPLC로 동시에 분석하였으며 그 결과는 다음과 같다. 1. 총 catechins의 함량은 에탄올과 물 추출 모두 자스민 차가 가장 높았으며 다음으로 에탄을 추출은 녹차, 홍차(II), 오룡 차, 현미 녹차, 홍차(I)의 순이었으며 물 추출은 홍차(II), 녹차, 현미 녹차, 오룡 차, 홍차(I)의 순이었다. 또한 두 추출법에서, 녹차, 현미녹차, 오룡차, 홍차(II)의 경우는 총catechi 중 EGCG가 차지하는 함량이 가장 높았으며 홍차(I)과 자스민 차는 ECG의 함량이 가장 높았다. 2. Theaflavin류는 TF, TF3G, TF3'G, TF33'G의 4종류가 홍차에만 분석되어 에탄을 추출은 홍차(I)과 홍차(II) 모두 TF33'G가 가장 높았으며 물 추출은 홍차(I)은 TF33'G가 홍차(II)는 TF가 가장 높았다. 3. Methylxanthin류로 caffeine과 theobromine은 에탄올과 물 추출에서 홍차(II)와 자스민차가 다른 차에 비하여 높았으며, 모든 시료에서 caffeine이 theobromine 보다 훨씬 더 많은 함량을 보였다. 이상의 결과, 13종의 차 성분 중 홍차(I)에서 caffeine이 가장 높은 함량을 나타낸 것을 제외하고는 대부분의 차에서 catechin 중 ECG와 EGCG의 함량이 많은 것으로 나타났으며, 이 성분이 차의 기능성 물질로 지배적인 물질이었다.

• Archives of Pharmacal Research
• /
• 제29권9호
• /
• pp.786-794
• /
• 2006

We observed the suppressive effect of a powder formulation of African black tea extract prepared from the leaves of Camellia sinensis on type 2 non-insulin dependent diabetic mice, $KK-A^y/TaJcl$. Black tea extract significantly showed suppressive effect of the elevation of blood glucose on oral glucose tolerance test of 8 week-old $KK-A^y/TaJcl$ mice (p<0.05). Long-term treatment with black tea extract showed significant suppression of post-prandial blood glucose and obesity (p<0.05). The weight of the intestine of mice treated with black tea extract was significantly reduced (p<0.05). From these results, African black tea used in this study showed a suppressive effect on the elevation of blood glucose during food intake and the body weight.

• 생명과학회지
• /
• 제7권4호
• /
• pp.309-315
• /
• 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.

• 한국식품영양학회지
• /
• 제15권4호
• /
• pp.377-381
• /
• 2002

시판 녹차, 오룡차 및 홍차에서 추출된 조카테킨 조성 및 이들 카테킨의 2성분 항산화시스템, 3성분 항산화 시스템의 항산화 효과를 조사하고자 하였다. 녹차, 오공차 및 홍차의 조카테킨의 수율은 각각 5.4%,3.5% 및 2.5%이 었다. EGC, EC, EGCg 및 ECg의 4개의 카테킨류가 확인되었으며, EGCg 성분이 가장 많은 함량을 보였다. 녹차, 오룡차 및 홍차의 총 카테킨의 함량은 각각 926.3ug/g, 713.8ug/g 및 318.0ug/g이었다. 녹차, 오룡차 및 홍차 조카테킨 첨가구의 항산화 효과는 오룡차 > 녹차 > 홍차의 순이었다. 녹차, 오룡차 및 홍차 조카테킨(100ppm)에 $\alpha$-tocopherol(50ppm)을 첨가했을 때의 항산화효과는 녹차 > 오룡차 > 홍차 조카테킨 순으로 녹차에서 가장 강한 상승작용을 나타냈다. 녹차, 오룡차 및 홍차 카테킨(100ppm)에 $\alpha$-tocopherol(50ppm) 및 ascorbyl palmitate(50ppm)를 함께 첨가한 경우, 조카테킨(200 ppm)을 단독으로 첨가한 경우보다 항산화 효과가 강하였다.

• Preventive Nutrition and Food Science
• /
• 제5권3호
• /
• pp.165-169
• /
• 2000

Kombucha beverages were made from sweetened tea by Oriental, European and Tibetan tea fungus starters. The hot water extracts o green tea, black tea, Gugija and Omija were mixed with white and/or brown sugar, and were fermented under a static culture at 3$0^{\circ}C$. Titrable acidity, pH, color and cellulose production in kombucha beverages were evaluated. All tea fungus starters showed a higher acid production in green/black tea extracts rather than Gugija and Omija extracts. In green/black tea extracts Oriental tea fungus produced a kombucha beverage with a higher titrable acidity and lower pH than those of European and Tibetan tea fungus starters. By the static fermentation of green/black tea extract for 18 days, Oriental, Tibetan and European tea fungus starters produced cellulose pellicles of 0.43g, 0.16g, and 0.19 g (dry weight) on the top in the culture, respectively. As a mother starter, the cellulose pellicle was more efficient in acid production compared with tea fungus broth. Oriental/Tibetan mixed tea fungus showed the best acid production in the green/black tea extract supplemented with brown sugar.

• Journal of Biosystems Engineering
• /
• 제41권2호
• /
• pp.85-92
• /
• 2016

Background: The same plant, Camellia sinensis, is used to produce all types of tea, and the differences among the various types arise from the different processing steps that are used. Based on the degree of fermentation, tea can be classified as black, green, white, or oolong tea. Of these, black tea is the most or fully fermented tea. The oxidized polyphenolic compounds such as theaflavins (TF) and thearubigins (TR) formed during fermentation are responsible for the color, taste, flavor, and aroma of black tea. Results: Research indicates that an optimum ratio of TF and TR (1:10) is required to ensure a quality cup of tea. The concentrations of TF and TR as well as desirable quality characteristics increase as fermentation time increases, reaching optimum levels and then degrading if the fermentation time is prolonged. It is also necessary to control the environment for oxidation. There are no established environment conditions that must be maintained during the fermentation of the ruptured tea leaves. However, in most cases, the process is performed at a temperature of $24-29^{\circ}C$ for 2-4 h or 55-110 min for orthodox tea or crush, tear, and curl (CTC) black tea, respectively, under a high relative humidity of 95-98% with an adequate amount of oxygen. Conclusion: The polyphenolic compounds in black tea such as TF and TR as well as un-oxidized catechins are responsible for the health benefits of tea consumption. Tea is rich in natural antioxidant activities and is reported to have great potential for the management of various types of cancers, oral health problems, heart disease and stroke, and diabetes and to have other health benefits such as the ability to detoxify, improve urine and blood flow, stimulate, and improve the immune system.

• 한국식품영양학회지
• /
• 제28권5호
• /
• pp.766-773
• /
• 2015

This study analyzes the chemical composition of green tea, white tea, yellow tea, oolong tea and black tea with respect to extraction temperature and time. The optimum extraction conditions for these teas were determined by assessing the chemical composition of tea brewed at different temperature (50, 60, 70, $80^{\circ}C$) and extraction times (1, 3, 5, 10 minute). Catechins contents were the largest at 5 minutes and generally declined by 10 minutes. Green tea catechins contents were highest when brewed at $70^{\circ}C$ and besides other teas a change of the trend variation at 70 and $80^{\circ}C$. These temperatures did not extract theaflavins in green tea. Extract temperature and time did not significantly affect theaflavins content of white tea, yellow tea, and oolong tea. Black tea, however, was noticeably dependent on extract conditions, which were most effective at $70^{\circ}C$, brewed for 5 minutes. Caffeine content of green tea, yellow tea, and oolong tea was highest at 5 minutes, but temperature did not appear to affect the content. White tea and black tea caffeine content was highest when brewed at $70^{\circ}C$ for 5 minutes. Theobromine content of green tea, yellow tea, oolong tea, and black tea did not show major differences between the study times or temperature, though the content in white tea increased with higher temperatures when brewed for 5 minutes. The extraction of phenolic compounds increased until 5 minutes, and showed not further increase at 10 minutes. Antioxidant capacity of green tea, white tea, and yellow tea were maximized at $70^{\circ}C$ for 5 minutes or $80^{\circ}C$ for 3 minutes, while oolong and black tea were reached maximum antioxidants at $70^{\circ}C$ for 5 minutes. In general, to optimize the beneficial chemical content of brewed tea, a water temperature of $70^{\circ}C$ for 5 minutes is recommended.

• 한국식생활문화학회지
• /
• 제24권3호
• /
• pp.308-314
• /
• 2009

In this study, we examined the composition of catechins, theaflavins and alkaloids in leaves during processing to fermented black tea, which is produced by withering, roll breaking, and fermentation of Korean Yabukida tea plant. In addition, we determined the optimal conditions for the production of fermented black tea. The average moisture content in fresh leaves was 70.85%, which dropped to 3.07% in fermented black tea at the last stage of production. When the leaves were analyzed by HPLC, seven types of catechins, four types of theaflavins and three types of alkaloids were identified. The levels of catechins, theaflavins, and alkaloids were then evaluated after being processed into fermented tea. From these experiments, we found that the level of theaflavins, which determines the property of the tea, increased during fermentation. This effect resulted from the change in EGCG, ECG, EGC, EC during the process of fermentation. We also found that the maximal amount of theaflavins was created after 1-2 hours of fermentation. Thus, our results imply that the best condition for producing fermented black tea would be to ferment for 1-2 hours.

• 한국의류학회지
• /
• 제22권4호
• /
• pp.477-481
• /
• 1998

Colored components in black tea were extracted, freeze-dried, and analysed to investigate the possibility using as a natural dye. Fractionation of the colored components was carried out by gel permeation chromatography. The colored components in black tea were elected into seven fractions. Each fraction was analyzed by UV spectrophotometer. The early fluted fractions 1-4 did not show any absorption peaks in 320-700 nm and showed the increase in absorption as it approaches to short wavelength and are considered as highly polymerized colored substances. Fractions 5-6 showed tar at 350 m and are considered as thearubigins. Fraction 7 showed absorption peaks at 376 nm and 456 nm and is considered as theaflavin. IR spectra of each fraction show: Strong C=0 stretching band at 1650 cm-1 appears in fractions 1-4, but not in fractions 5-7. Strong C=0 stretching band at 1700 cm-L appears in fraction 3-7. C=0 stretching band at 1610 cm-1 appears as a shoulder in fraction 4 and progressively changes into strong peak in fraction 5-7. From these results, it is assumed that colored components in black tea consist of polyphenolic substances having different molecular weight which were formed during tea manufacturing process. The colorants from black tea infusion were applied to silk, wool, cotton and nylon fabrics. Black tea colorants showed high affinity to wool, silk and nylon, but very low affinity to cotton fabrics.