• Title, Summary, Keyword: teas

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Rapid Measure of Color and Catechins Contents in Processed Teas Using NIRS (근적외선 분광광도계를 이용한 차 제품의 색상 및 카테킨류의 신속 측정)

  • Chun, Jong-Un
    • Korean Journal of Plant Resources
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    • v.23 no.4
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    • pp.386-392
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    • 2010
  • This study was done to measure the color and catechins contents in processed teas using the whole bands (400~2500 nm) with near-infrared spectroscopy(NIRS). The powder colors of 109 processed teas were measured with a colorimeter. The a/b ratios in Hunter color scale in processed teas accounted for about 98.9% of the variation in the fermentation degree(FD), indicating that the a/b ratio was a very useful trait for assessing fermentation degree. Also tea powders were scanned in the visible bands used with NIRSystem. The calibration equations for powder colors were developed using the regression method of modified partial least squares(MPLS) with the internal cross validation. The equations had low SECV (standard errors of cross-validation), and high $R^2$ (coefficient of determination in calibration) values with 0.996~1.00, indicating that the visible bands(400~700 nm) with NIRS could be used to rapidly measure the variables related to powder color and fermentation degree. Also another powders of 137 processed teas were scanned at 780~2500 nm bands in the reflectance mode. The calibration equations were developed using the regression method of MPLS with the internal cross validation. The equations had low SECV, and high $R^2$ (0.896~0.983) values, showing that NIRS could be used to rapidly discriminate the contents of EGC($R^2$=0.919), EC(0.896), EGCg(0.978), ECg(0.905) and total catechins(0.983) in processed teas with high precision and ease.

Contents of Total Flavonoid and Biological Activities of Edible Plants (식물성 식품중 총플라보노이드 함량과 생리활성 탐색)

  • Son, Eun-Shim;Oh, Sang-Suk;Han, Dae-Suk;Lee, Jong-Mee
    • Journal of the Korean Society of Food Culture
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    • v.16 no.5
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    • pp.504-514
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    • 2001
  • The contents of total flavonoids, total antioxidant status and superoxide scavenger activity of edible plants were measured. Among twenty one samples of leafy vegetables and teas, mugwort (Artemesia capillaris) and green teas gave high total flavonoids contents, 48.2 mg/g sample and 44.7 mg/g sample, respectively. The highest concentration of total flavonoids among eighty nine samples analyzed was 52.1 mg/g sample from propolis. When samples were tested for total antioxidant status, a kind of groundsel showed the highest Total Antioxidant Status(TAS) value, 13.4 mM among leafy vegetables and teas and green tea gave high TAS value, 11.84 mM. On the other hand, purslane gave the lowest TAS value, 0.01 mM. The superoxide scavenge activity was measured from the extracts of all edible plants. The superoxide scavenge activity of polygonatum(81.1%) and chrysantemum (78.5%) were the highest among leafy vegetables, teas and medicinalplants. On the other hand, ginseng, poria, cassiae semen and dioscoreae rhizoma showed no superoxide scavenge activities.

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Analysis of Theanine Contents in Commercial Green Tea (시판 녹차로부터 Theanine 함량의 분석)

  • Choi, Sung-Hee;Rhyu, Mee-Ra
    • Korean Journal of Food Science and Technology
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    • v.24 no.2
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    • pp.177-179
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    • 1992
  • The theanine contents of commercial green teas manufactured by the different harves times(1st tea, 2nd tea and 3rd tea) and processes(steamed and parched teas) were determined by amino acid analyzer. There were remarkable differences in the theanine contents among teas of the different harvest times. The theanine content in 1st steamed green tea was 2235 mg% and one in 1st parched green tea was 2106 mg%. The theanine contents in 2nd, 3rd tea were gradually decreased. There were slight differences in the theanine contents among teas of the different process.

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Protective Effect of Green Tea Extracts on Oxidative Stress (녹차추출물의 산화적 스트레스에 대한 억제효과)

  • Kim, Nam-Yee;Lee, Jin-Ha;Heo, Moon-Yaung
    • Korean Journal of Medicinal Crop Science
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    • v.14 no.6
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    • pp.322-328
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    • 2006
  • Green tea is of particular source as it has been found to have strong antioxidant activities. The extracts of green tea during the commercial harvest seasons from April, 2003 to August, 2003 were compared. The purpose of this study was to determine the correlation between the polyphenol content of green teas and its antioxidant activities. The con-tent of total polyphenols was analyzed and several antioxidant testings were performed. The levels of total polyphenols were higher in the green teas (e.g. Woojeon, Sejak) harvested during very early spring and lower in the green teas harvested late(eg. Ipha, Yepcha). In particular, the free radical scavenging, the inhibition of LDL oxidation, the cytoprotective effect and the inhibition of DNA damage were correlated with the total polyphenol contents of green tea extracts harvested early spring such as Woojeon, Sejak and Jungjak. The results obtained here show that all extracts of green teas including purified green tea catechin, GTC, have strong antioxidant activities on oxidative stress in vifrθ. The variation in polyphenol content and antioxidant activities among various types of green tea by the harvesting time may provide critical information for investigators and consumers using tea in purposes of nutrition and chemoprevention.

Study on Intakes and Preferences related to Korean Traditional Tea of Adults in Korea (전통차류에 대한 한국 성인의 이용현황 및 기호도 연구)

  • Kim, Jin-Kue;Kim, Jin-A;Lee, Sim-Yeol
    • Journal of the East Asian Society of Dietary Life
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    • v.27 no.3
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    • pp.313-320
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    • 2017
  • This study was conducted to investigate the intakes and preferences related to Korean traditional teas in each of the age groups. The survey was conducted from March $9^{th}$ to $23^{rd}$, 2015. The subjects in this study were 642 adults aged more than 20 years that resided in the Seoul and Gyeonggi areas. The health status score was 3.57, and the health concern score was 3.54. The reason for preferring traditional tea was 'health' (40.5%) and 'good taste, color, and aroma' (29.7%). The most important factor in drinking a traditional tea was health (37.1%). Acceptance of each type of traditional tea was ranked in order of 'grain tea', 'fruit tea', 'floral leaf tea', 'assorted tea', 'medical root tea', and 'tonic tea'. A total of 92.8% of respondents said traditional teas should be popularized. Regarding problems for popularization of traditional teas, the most common response was 'not popularized yet' (39.7%). Regarding the method for popularization of traditional teas, the most common response was 'convenience of purchase for ingredients'. As a result, preferences for traditional tea and popularization method were different according to age. It is thus necessary to develop traditional tea products considering the age range.

Development and Application of Non-Destructive-Type Device of Ingredients in Mulberry Leaf Tea (뽕잎 차에서의 성분 비파괴형 기기 기술 개발 및 응용)

  • Cheun, Byeung-Soo;Min, Je-Ho
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.10
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    • pp.1595-1600
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    • 2013
  • In the present study,effect of natural mulbelly leaf tea on DMEM MDCK cell line. Mulbelly leaf teas inhibited the proliferation in primery MDCK cells in a dose dependent manner. These results show that mulbelly teas potent inhibits the reactive oxygen species (ROS) and not destruction a component. Therefore, mulbelly teas might improve overall quality of the color and taste. And might be applied newly to development of componant mulbelly teas quality and biochemical change by ROS in living things.

The Changes of Benzo[α]pyrene in Herbal Teas containing Astragalus membranaceus, Schizandra chinensis, Liriope platyphylla and Platycodon grandiflorum Which are affected by the Puffing Conditions (Puffing 조건에 따른 황기, 오미자, 맥문동 및 길경을 첨가한 한방차의 Benzo[α]pyrene 변화)

  • Oh, Sung-Cheon
    • The Korean Journal of Food And Nutrition
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    • v.27 no.1
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    • pp.75-79
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    • 2014
  • The following study is the result of herbal teas puffed at different temperatures between $140{\sim}220^{\circ}C$. Depending on treatment temperatures, the water contents decreased, while some carbonization occurred and crude ash contents relatively increased. Also, the crude protein and crude fat experienced little changes. B(${\alpha}$)P contents (0.16~0.17 ppb) showed little change according to treatment temperatures. From this result, the B(${\alpha}$)P content differed depending on the treatment temperature and raw materials. Solid elution rate figures of the herbal teas ranged from 0.27~0.45% (w/w) and the rate of solid elution increased along with higher puffing temperatures. The reason for the increase in solid elution rates is due to the breakage of cross bridges between the raw materials in the herbal tea which are carbohydrates, proteins, lipids and etc. after treatments of physical changes rather than chemical ones.

Investigation of Antifungal Activity for Plant Disease Control by Compost Teas Fermented under Different Temperatures (식물병 관리를 위해 다양한 온도조건에서 발효한 퇴비차의 항진균 활동에 관한 연구)

  • Tateda, Masafumi;Yamada, Kanae;Kim, Youngchul;Sato, Yukio
    • Journal of Korean Society on Water Environment
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    • v.24 no.3
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    • pp.280-284
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    • 2008
  • Efficacy of antifungal activity on plant pathogens by compost teas fermented under different temperatures was studied. Compost teas are recently chosen by agricultural producers for the better method of controlling plant diseases under increase of public consciousness against use of chemicals for controlling the diseases. Compost tea has been intensively studied; however, understanding of compost tea is still not well developed, and temperature influence during fermentation of compost tea on its antifungal activity has not been investigated. In this study, antifungal activities of compost teas fermented at 10, 20, 30, and $40^{\circ}C$ against selected 10 pathogens were observed. From the results, antifungal activities of compost teas at 20 and $30^{\circ}C$ of fermentation-temperatures showed the strongest while the weakest activity was observed with the compost tea at $10^{\circ}C$. Change of the activity by the fermentation-temperature apparently implied that microbes in the compost tea were strongly involved in its antifungal activity.

Study on Antioxidant Potency of Green Tea by DPPH Method (DPPH 방법을 통한 녹차의 항산화 활성에 대한 연구)

  • 오중학;김은희;김정례;문영인;강영희;강정숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.7
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    • pp.1079-1084
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    • 2004
  • The present study was conducted to compare antioxidant activity of green teas, fermented teas and other related common teas by examining radical scavenging activity using DPPH (2,2 diphenyl l-picryl hydrazyl). Scavenging activity ($SC_{50}$/) of epigallocatechin gallate (EGCG) for 0.1 mM DPPH radical was 5.5 $\mu$M or 4.2 mg/L by weight, then catechin, 14 $\mu$M or 2.5 mg/L and vitamin C, 22 $\mu$M or 3.9 mg/L, respectively. Kyokuro tea (okro) powder of 24.2 mg/L or green tea powder of 25.2 mg/L was used to reach $SC_{50}$/ for 0.1 mM DPPH. One serving of 2 g green tea provides antioxidant activity equivalent to 109∼147 mg EGCG, 145∼185 mg catechin or 131∼168 mg vitamin C. Teas from the first harvest had the highest radical scavenging activity when compared with later harvest green teas grown in the same region, but there is virtually no difference by the harvest time. A Chinese green tea, Dragon well had the highest antioxidant activity among other green teas tested providing antioxidant capacity equivalent to 168 mg EGCG or 188 mg vitamin C per 2 g serving, but partially fermented Chinese teas had much lower antioxidant activity than any green tea tested. Black tea which is fully fermented showed as strong antioxidant activity as green teas (76.3 mg vs 86.7∼67.6 mg per tea bag). One tea bag of green teas from market provided antioxidant capacity equivalent to 52∼86 mg EGCG, 70∼105 mg catechin or 63-96 mg vitamin C. Teas made of persimmon leaf, pine needle, mulberry leaf had comparatively low anti-oxidant activity equivalent to 2.5∼4.8 mg EGCG or 15∼21 mg vitamin C per teabag. The third brewed green tea still had enough antioxidant activity, while tea from tea bag brewed for 3 min or 5 min did not have any difference in their antioxidant activity. More systemic studies are needed to clarify the relationship between tea catechins and antioxidant capacity focusing on how growing, harvest time, fermentation and other processes can influence on this.

Electrokinetic Ions Injection into Kaolinite and Sand for Bioremediation (카올리나이트와 모레에서의 Bioremediation을 위한 Electrokinetic 이온 주입 특성)

  • 이호창;한상재;김수삼;오재일
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.405-410
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    • 2001
  • Bioremediation is a degradation process of existing organic contaminants in soils and groundwater by indigenous or inoculated microorganisms. This process can provide economical solution as well as safe and effective alternative in remediation technologies. However, it has been suggested that the rate of bioremediation process of organic contaminants by microorganisms can be limited by the concentration of nutrients and TEAs(Terminal Electron Accepters). In in-situ bioremediation, conventional pumping techniques have been used for supplying these additives. However, the injection of these additives is difficult in low permeable soils, and also hindered by preferential flow paths resulting from heterogeneities in high permeable ground. Therefore, the Injection of chemical additives is the most significant concern in in-situ bioremediation. Most recently, electrokinetic technique has been applied into the bioremediation and the injection characteristics under electrokinetics have not been examined in various soil types. Therefore, in this study, electrokinetic injection method is investigated in kaolinite and sand, and the concentration of ammonium(nutrients) and sulfate(TEAs) in soil is presented.

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