• Title, Summary, Keyword: tea

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Production of Fermented Tea with Rhodotorula Yeast and Comparison of its Antioxidant Effects to those of Unfermented Tea (적색효모를 이용한 발효차의 제조 및 발효차와 비발효차의 항산화능 비교)

  • Kang, Ok-Ju
    • Korean journal of food and cookery science
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    • v.26 no.4
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    • pp.422-427
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    • 2010
  • This study was conducted to investigate the antioxidant effect and properties of unfermented tea and fermented tea made with Rhodotorula yeast. The levels of crude fat and crude protein in the fermented tea were higher than those in the unfermented tea. The water-soluble phenol levels of unfermented tea and fermented tea were 912.5 and 2,445.24 ppm, respectively. The total amino acid content of fermented tea was greater than that of unfermented tea;,- the amino acid concentrations of alanine, valine, leucine, and lysine were 25.58, 24.38, 27.96, and 14.14 ${\mu}g/mL$, respectively. The DPPH radical scavenging activities of the unfermented and fermented teas were 32.14 and 41.57%, respectively; this is in contrast to 29.73% for L-ascorbic acid(150 ppm). The reducing power activity of fermented tea was 41.57%, and that of unfermented tea was 32.14%.

A Study on the Preference and Intake Frequency of Korean Traditional Beverages (한국 전통음료에 대한 기호도와 섭취빈도 조사 연구)

  • Lee, Yeon-Jung;Byun, Gwang-In
    • Journal of the Korean Society of Food Culture
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    • v.21 no.1
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    • pp.8-16
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    • 2006
  • This study was performed by questionnaire to investigate the preference and intake frequency of Korean traditional commercial beverages. The subjects were consisted of 320 participants in Daegu and Kyungpook area. 'Chain market' scored 49.4% as purchasing place of traditional beverages. 'Tea bag' scored 31.6% as the favorite package of traditional beverages. On the reasons of drinking traditional beverage 'good for health' scored the highest with 31.3% respondents, followed by 'good smell' with 14.4%. Coffee and traditional tea were the choice of beverage after having a rich meal and on occasion of entertaining guests. The favorite foods in ordinary days were 'tea', 'alcohol', 'ice cream', 'nuts' and 'cookie'. More than thirty percent of the respondents, both male and female, raised the need of improvement in taste of traditional beverage. In the intake frequency, Korea traditional beverages obtained 1.80 points as a whole. 'Green tea' scored highest(3.40points) while 'mulberry-leaf tea' received the lowest score of 1.31 points. The preferred Korean traditional drinks were 'greed tea', 'shick hae', 'citron tea', 'misitgaru', 'maesil tea', 'rice tea' in the order. On the other hand, the preference for 'mulberry-leaf tea', 'boxthom tea', 'ginger tea', 'chrysanthemum tea' and 'omija tea' was very low. The people who are on twenties preferred 'shick hae', 'honey tea', 'citron tea', 'black tea' and 'misitgaru' more than the other generation.

Antioxidative Effect on the Green Tea and Puer Tea Extracts (녹차와 보이차 추출물의 항산화 효과)

  • Son Gyu-Mok;Bae Sung-Moon;Chung Ji-Young;Shin Dong-Joo;Sung Tae-Soo
    • The Korean Journal of Food And Nutrition
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    • v.18 no.3
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    • pp.219-224
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    • 2005
  • To see the antioxidative ability of puer tea against green tea, antioxidative effects of water and methanol extracts were compared and researched each. Water extracts from green tea and puer tea contain similar percentage of total polyphenol content while methanol extract from puer tea has about $58\%$ of total polyphenol content of that from green tea. Water extracts from both teas contain similar percentage of the electron donating ability while methanol extract from puer tea has about $54\%$ of the electron donating ability of that from green tea. Solvents made a big difference in SOD-like activities. The activations in water extracts were from $13.46\%$ to $48.93\%$, which didn't give much difference between green tea and puer tea. However, the activations in methanol extracts were $59.63\%$ in green tea and $48.93\%$ in puer tea, which was $3\~4$ times higher than that in water extracts and green tea activated better. The nitrite scavenging activity was similar in water extracts from both teas and the methanol extract from puer tea had a bit higher nitrite scavenging activity than that from green tea. The ACE inhibitory activity in water extract from puer tea was about $38\%$ higher than that from green tea while the activity of methanol extract from green tea was higher than that from puer tea. These results indicate that the antioxidative ability of water extract from puer tea is similar to that from green tea but the ACE inhibitory activity of puer tea reveals higher value and antioxidative ability of methanol extract from puer tea was lower than that from green tea while the nitrite scavenging activity of puer tea was higher.

Functional Properties of Tea-fungus Beverage (Tea-fungus 발효음료의 기능성)

  • 박찬성
    • Korean Journal of Food Preservation
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    • v.10 no.2
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    • pp.241-245
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    • 2003
  • To develope tea-fungus beverage(TB), media added various kinds of ingredients including black tea, persimmon leave tea, pine needle, mugwort mycelia and fruiting body of Cordyceps spp. were prepared fur fermentation. Tea-fungus beverage(TB) was prepared with tea-fungus by fermentation for 2 weeks at 30 $^{\circ}C$. Functional properties of antibacterial activity, electron donating ability and nitrite scavenging ability were investigated in tea-fungus beverage(TB) and 5 times diluted tea-fungus beverage(DTB). Antibacterial activity against pathogenic E. coli and S. aureus was excellent in TB added pine needle, mycelia and fruiting body of Cordyceps japonioa while no activity in TB added persimmon leave tea. Electron donating ability of TB were ranged from 41% to 87% in TB and were ranged from 11% to 63% in DFB, high ability was in TB and DTB added pine needle and persimmon leave tea, while low ability in FB and DTB added mycelia and fruiting body of C. militaris. Nitrite scavenging ability was 63% in TB added black tea and 44% in TB added persimmon leave tea. Other ingredients added TB had weak nitrite scavenging ability.

Characterization of Kombucha Beverages Fermented with Various Teas and Tea Fungus

  • Lee, Sam-Pin;Kim, Chan-Shick
    • Preventive Nutrition and Food Science
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    • v.5 no.3
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    • pp.165-169
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    • 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.

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Physiocochemical Properties of Hovenia dulcis Thunb. Leaf Tea (헛개나무잎차의 이화학적 특성)

  • 정창호;배영일;심기환
    • Korean Journal of Food Preservation
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    • v.7 no.1
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    • pp.117-123
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    • 2000
  • In order to promote the utilization of Hovenia dulcis leaf as food, leaf tea was nanufactured and its physicochemical properties were examined. Aong proximate composiotns of Hovenia dulcis leaf tea were found in both fermented tea and roasted tea the higher contents of total sugar and crude protein. In minerals component of fermented tea and roasted tea, potassium (K) was the most high amounts of 11,560.6 ppm and 11,084.6 ppm, respectively. The highest contents of free sugar in both teas were mainly consisted of sucrose, the amounts of sucrose showed 1.47% and 1.94% . In case of organic acids, oxalic acid and citric acid were revealed 631.26mg% and 660.05mg%, respectively. The highest contents of total amino acid in fermented tea and roasted tea were 812.01mg% and 709.72mg% of glutamic acid. the fatty acids of fermented tea and roasted tea were mainly composed of 40.18% of linolenic acid and 26.92% of palmitic acid, respectively. The major volatile compounds of fermented tea and roasted tea were composed of 3, 7, 11, 15-tertramethyl-2-hexadecen-1-ol and methyl palmitate and the amounts of those showed 290.1ppm and 472.97 ppm, respectively. The tannins of fermented tea and roasted tea were 1.02% and 1.26% , as the extraction steps increased the tannin contents decreased. In Hunter's color values of tea extract L and b values decreased , while a value of those increased as the extraction steps were repeated.

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Segmentation of American Green Tea Customers based on Their Green Tea Choice Attributes (녹차 선택 속성을 통한 미국 녹차소비자의 시장 세분화에 관한 연구)

  • Cho, Meehee;Lee, Kyung-Hee
    • Journal of the East Asian Society of Dietary Life
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    • v.26 no.4
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    • pp.285-296
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    • 2016
  • This study was conducted to obtain a better understanding of American green tea consumers for increasing Korean green tea sales in the US market. In doing so, this study investigated green tea choice attributes of US consumers and segmented them based upon their perceptions about important attributes of green tea. A factor-cluster segmentation approach was used for this study. An exploratory factor analysis identified five green tea choice motives: 'Sensory', 'Diet', 'Price', 'Health', and 'Brand'. Based upon these five choice attributes, cluster analyses classified all respondents into four homogeneous subgroups: 'Highly motivated', 'Taste/Price oriented', 'Health oriented', and 'Brand oriented'. Cross-tab tests proved that green tea consumption and purchasing patterns were significantly different among the four clusters. In particular, two cluster groups representing 'Highly motivated' and 'Health oriented' groups were found to offer the most utility for further American green tea market segmentation research. Findings show that American green tea consumers include a wide range of age groups and they usually buy green tea at grocery markets. Managerial implications for all cluster groups based upon their unique characteristics are provided. Korean green tea companies can apply these findings in order to develop more effective and efficient marketing strategies to attract American consumers to buy more Korean green tea.

Effect of Mulberry Leaf Tea for the Removal on Cd and Pb in drinking water (뽕잎차에 의한 음용수중 Cd과 Pb의 제거효과)

  • 김현복;이완주
    • Journal of Sericultural and Entomological Science
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    • v.40 no.1
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    • pp.17-22
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    • 1998
  • To investigate the detoxificative effect of tea, five kinds of tea(mulberry, anaerobic treated mulberry, green, barly tea and corm tea) were selected and determined their dotoxication activities for Cd and Pb in drinking water. The effect of tea on the removal of Cd and Pb were increased proportionally to the contents of teas. Anaerobic treated mulberry leaf tea showed stronger detoxication activity than the others. In drinking water contaminated with Cd, the removal effect of Cd was high 27% by anaerobic treated mulberry leaf tea and 14% by mulberry leaf tea as compared to green tea. Also, in drinking water with Pb, the removal effect of anaerobic treated mulberry leaf tea was the best among five kinds of tea. Pretreatment method on the removal effect of Cd was better than post-treatment method in the treatment method.

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A Study on Korean Green Tea (韓國産(한국산) 綠茶(녹다)에 대(對)한 연구(硏究))

  • Yu, Choon-Hie;Chung, Jae-Kie
    • Journal of Nutrition and Health
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    • v.5 no.3
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    • pp.109-125
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    • 1972
  • According to the Sam-guk Sa-gi (History of three Kingdoms: Silla, Koguryo and Paeckje) tea was first brought into Korea by Kim Tae-ryeum, a diplomat, in 828 A.D. during the reign of king Hung-dot of Silla, and planted on the hill of Mt. Chi-ri. Afterwards, the tea trees were transplanted and cultivated by Buddists in many Buddist temples in southern provinces during the Silla and Koryo dynasties. People took much delight in drinking green tea, and specially the kings, buddist monks and nobilities of Silla and Koryo enjoyed drinking green tea. And eventually, the green tea became an indispensable part in all important ceremonies during the Koryo dynasty. After the Yi dynasty came into being, the dualistic philosophy of China was introduced and respected while buddist temples declined as a result of strong oppression by the ruling class. While temples were declined, the practice of drinking green tea was also declined. Nowadays we find many tea plants grow wild, which are seemed to be planted around buddist temples during the Koryo dynasty. Today, Korean people do not drink home made green tea. Instead, they like to take coffee, black tea and other tea products imported from foreign countries. Aa a result, Korea had to pay $ 520 thousand in 1969 to import foreign made tea and coffee. The natural conditions of southern provinces of Korea are very suitable in cultivating tea plants. If we develope the skill in producing good quality tea in Korea, we would be able to save the foreign exchanges that are being spent for importing foreign made tea products, and at the same time, we would be able to export our green tea to overseas. The quality of Korean green tea is as good as that of Japanese green tea. Green tea contains vitamin C while coffee and black tea do not contain it.

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쌍끌이 중층트롤어법의 연구 ( 1 ) - 모형어구의 망구형상에 관하여 - ( A Study on the Pair Midwater Trawling ( 1 ) - Mouth Performance of the Model Net - )

  • 이병기
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.1
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    • pp.29-44
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    • 1995
  • A model experiment on the pair midwater trawl net applicable to 800 PS class Korean pair bottom trawlers was carried out in the special-prepared experimental thank. the tank was prepared as a reverse trapezoid shape in its vertical section by digging out flat soil. The dimension of the tank showed the 9.6 W$\times$43.0 L(m) of the upper fringe and the 4.8 W$\times$38.0 L(m) of the bottom with 3.0m in depth. The depth of water was maintained 2.7m during experiment. The model net was prepared based on the Tauti's similarity law of fishing gear in 1/30 scale considering the dimension of the experimental tank. Mouth performance of the model net during towing were determined by the photographs taken in front of the net mouth with the combinations of towing velocity, warp length and distance between paired boats. The results obtained can be summarized as follows: 1. Vertical opening of the model nets A and B was varied in the range of 0.18~0.88 m and 0.21~0.78 m (which can be converted into 5.4~26.4m and 6.3~23.4 m in the full-scale net) respectively, and was varied predominantly by towing speed. Vertical opening (H which is appendixed m for the model net. f for the full-scale net. A and B for the types of the model net) can be expressed as the function of towing velocity$V_t$as in the model net $V_t$ : m/ sec)$H_{mA}$=1.67$e^{-1.65V_t}$ $H_{mB}$=1.15$e^{-1.13V_t}$, in the full-scale net ($V_t$ : k't) $H_{fA}$=50.27$e^-0.37V_t$ $H_{fB}$=34.46$e^{-0.26Vt}$. 2. Horizontal opening of the model nets An and b was varied in the range of 1.03~1.54m and 1.04~1.55 m (which can be converted into 30.9~46.2 m and 31.2~46.5m in the full-scale net) respectively, and was varied predominantly by distance between paired boats. Horizontal opening (W, appendixes are as same as the former) an be expressed as the function of distance between paired boats $D_b$as in the model net $W_{mA}$=0.69+0.09$D_b$ $W{mB}$=0.73+0.09$D_b$, in the full-scale net $W_{fA}$=20.81+0.09$D_b$ $W_{fB}$=22.11+0.09$D_b$ 3. Net opening area of the model net A and B was varied in the range of 0.28~1.04 $m^2$ and 0.33~0.94$m^2$(which can be converted into 252~936$m^2$ and 297~846$m^2$ in the full-scale net) respectively, and was varied predominantly by towing velocity. Net opening area ($S$, appendixes are as same as the former) van be expressed as the function of towing velocity$V_t$ as in the model net $v_t$ : m/sec) $S_{Ma}$=2.01$e^{-1.54V_T}$ $S_{mA}$=1.40$e^{-1.65V_t}$, in the full-scale net ($V_t$ : k't) $S_{fA}$=1.807$e^-0.35V_t$ $S_{fA}$=1.265$e^{-0.24V_t}$. 4. Filtering volume of the model nets A and B was varied in the range of 0.32~0.55 $m^3$ and 0.37~0.55$m^3$(which can be converted into 8.640~14.850 $m^3$ and 9.990~14.850$m3$in the full~scale net) respectively, and was predominantly varied by towing speed. filtering volume of the model net-A showed the maximum at the towing speed 0.69 m/sec(3 k't in the full-scale net), compared with that of the model net B showed at 0.92 m/sec(4 k't in the full-scale net).

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