• 한국식품영양과학회지
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• 제24권2호
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• pp.293-298
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• 1995

Antimicrobial effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Minimal inhibitory concentration(MIC) of tea extraxcts against 9 well known strains of foodborne pathogenic bacteria such as the Gram positive and Gram negative bacteria was determined at 37$^{\circ}C$. Significant antimicrobial activity was observed in the steamed green tea and the roasted green tea of the water-soluble fraciton, and the steamed green tea of the methanol-soluble fraction, and the steamed green tea, roasted green tea and the oolong tea of the crude catechin fraction. The MIC of these extracts against B. subtillis were 700$\mu\textrm{g}$/ml, 500$\mu\textrm{g}$/ml and 120 $\mu\textrm{g}$/ml, respectively. The crude catechin fraction possessed greater antimicrobial activity than did the other fractions. Among tea extracts, extracts of steamed green tea, roasted green tea and oolong tea showed higher antimicrobial activity than them of black tea. The MIC of the crude catechin fraction obtained from tea extracts against Gram-positive bacteria such as M. Iuteus, B. subtillis and S. mutans were 30~50$\mu\textrm{g}$/ml, 120~240$\mu\textrm{g}$/ml and 120~180$\mu\textrm{g}$/ml, and against Gram-negative bacteri such as e. aerogenes and V. parahaemolyticus were 50~60$\mu\textrm{g}$/ml and 60~70$\mu\textrm{g}$/ml in the broth medium, respectively. Especially, the MIC to Streptococcus mutans which has known as a causative bacteria of a decayed tooth were 120$\mu\textrm{g}$/ml, 140$\mu\textrm{g}$/ml, 180$\mu\textrm{g}$/ml and above 1,000$\mu\textrm{g}$/ml in steamed green tea, roasted green tea, oolong tea and black tea, respectively. Tea extracts had strong growth inhibition activity against foodborne pathogenic and dental bacteria.

• 한국식품영양과학회지
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• 제24권2호
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• pp.299-304
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• 1995

Antioxidative effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Antioxidative activities of the crude catechin fraction were the most effective in oolong tea which contained the highest level of (-)-epigallocatechin gallate(EGCg). The water-soluble fraction obtained from oolong tea exhibited binding with more ferrous than copper ions. It showed a synergistic effect when used with an antioxidant such as BHT(0.5mg) and $\alpha$-tocopherol(2mg). Especially, this synergistic effect was exhibited more with BHT than with $\alpha$-tocopherol. Also steamed green tea, roasted green tea and oolong tea showed remarkable free radical scavenging action. The SC50(the concentration of a water-soluble fraction which is required to scavenge 50% of 100$\mu$M 1, 1-diphenyl-2-picryl hydrazyl radicals) of steamed and roasted green tea, oolong tea and black tea extracts were 11.3$\mu\textrm{g}$/ml, 11.4$\mu\textrm{g}$/ml, 12.7 $\mu\textrm{g}$/ml and 14.9$\mu\textrm{g}$/ml, respectively. It is assumed that the antioxidative activity of tea extracts is due to inhibition of peroxidation free radical scavenging and binding action of ferrous ions by mainly tea polyphenol compounds.

• 한국식품영양과학회지
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• 제24권1호
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• pp.154-159
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• 1995

Inhibition of xanthine oxidase by tea extracts obtained from non-fermented tea(steamed green tea and roasted green tea), semi-fermented tea(oolong tea) and fermented tea(black tea) were investigated. The crude catechin fraciton had a hgher inhibitory effect against xanthine oxidase, and the effect was increased with the addition of tea extracts. Their inhibitory effect were hardly influenced until extracted three times with hot water. According to the investigation of catechins in the crude catechin fraction obtained from tea extracts, (-)-epicatechin-(EC), (-)-epicatechin gallate(ECg). (-)-epigallocatechin(EGC) and (-)-epigallocatechin gallate(EGCg) were 80.1$\mu\textrm{g}$/mg 113.5$\mu\textrm{g}$ /mg, 186.3$\mu\textrm{g}$/mg and 367.7$\mu\textrm{g}$/mg in steamed green tea, and 75.6$\mu\textrm{g}$/mg, 114.7$\mu\textrm{g}$/mg, 193.7 $\mu\textrm{g}$/mg and 381.9$\mu\textrm{g}$/mg in roasted green tea, and 69.4$\mu\textrm{g}$/mg, 110.0$\mu\textrm{g}$/mg, 127.1$\mu\textrm{g}$.mg and 464.9$\mu\textrm{g}$/mg in oolong tea, and 78.1$\mu\textrm{g}$/mg, 171.8$\mu\textrm{g}$/mg, 80.7$\mu\textrm{g}$/mg and 51.4$\mu\textrm{g}$/mg in black tea, respectively. Order of the content of these catechins was (-)-EGCg>(-)-EGC>(-)-ECg>(-)-EC in steamed green tea, roasted green tea and oolong tea, and was (-)-ECg>(-)-EGC>(-)-EC>(-)-EGCg in black tea. Also the concentration of catechins was hardly influeced until extracted three times. The inhibition ratio of xanthine oxidase by autherntic catechins was hardly influenced until extracted three times. The inhibition ratio of xanthine oxidase by authentic catechins was 94.9% and 87.6% by addition of 5.0$\mu\textrm{g}$/ml of (-)-EGCg and (-)-ECg, respectively. the inhibitors of xanthine oxidase were supposed to be due to (-)-ECg and (-)-EGCg in tea polyphenol compounds.

• 한국식품조리과학회지
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• 제15권5호
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• pp.475-482
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• 1999

This study was carried out to prepare green tea by traditional roasting process, Kujeungkupo, and to determine its sensory characteristics. The carotenoid content in green tea was increased by roasting and reached 1,317 mg/100 g by Kujeungkupo. Of all carotenoids, the contents of lutein and $\beta$-carotene were 1,170 mg/100 g and 111.1 mg/100 g, respectively. The total cathechin content in green tea was 14.57 g/100 g after 9th roasting. The more the number of roasting the little contents of cathechin in green teas. Of all cathechin, epigallocathechingallate was the highest(6.80g/100 g) followed by epicathechingallte and epicathechin. total cholrophyll content was 141 mg/100 g of green tea. The free sugar content in Kujeungkupo green tea wet 2.18 g/100 g, of which sucrose comprised 46% (1.01 g/100 g). The color value ($\Delta$E) of Kujeungkupo green tea was 16.25. In sensory evaluation, sweet taste was the highest in green tea roasted 3 times and the flavor was best in that roasted 5 times. The sweet and astringent tastes of green tea had negative relationships with a and b values. The content of cathechin in green tea had a negative relationship with sweet taste and a positive relationship with astringent taste.

• 한국식품조리과학회지
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• 제15권2호
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• pp.95-101
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• 1999

This study was carried out to prepare green teas by traditional roasting manufacturing process, Ku Geung Ku Po and to determine the quality charateristics of the green teas by examining the change of their main components induced during this roasting process. The content of total sugars in unroasted tea leaves was 7.82%. Its content of roasted teas was decreased by increasing the number of roasting and there was significantly differences between samples. The content of total sugars in 9th roasted green tea was 3.98%. The total nitrogen contents of green teas produced by this process were 4.96∼6.38%. The more the number of roasting and the less content of tannin in green teas. And the ratio of total nitrogen and tannin in tea leaves 21.97 but its ratio in 9th roasted tea was increased to 45.54. The ascorbic acid in tea leaves consisted in 1,820.3 mg/100g but its content was decreased by increasing the number of roasting process. Whereas the content of caffeine in green teas was not reduced significantly by this traditional method. Of all amino acids, green tea produced by Ku Jeung Ku Po was rich glutamic acid, lysine and aspartic acid. And especially, phenylalanine, which was rarely found in other green teas, was abundant in these green teas. The compositions of glutamic acid and methionine were increased as increasing the number of roasting process but those of aspartic acid and arginine decreased by these processing. The main fatty acids of Ku Jeung Ku Po green tea were linolenic acid, linoleic acid and palmitic acid and the contents of unsaturated fatty acid in green teas were composed over 70% of total fatty acid. And the fatty acid contents in green teas were not affected during Ku Jeung Ku Po's process. The contents of minerals in these teas was rich in the oder of potassuim. magnessuim and calciumim, and these contents were not observed the prominant change during the process.

• 한국작물학회지
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• 제40권4호
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• pp.518-524
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• 1995

국산 녹차의 채엽시기 및 제차법에 따라 회분, 조지방 및 무기성분 등 일반성분의 변화를 분석한 본 연구의 결과는 다음과 같았다. 채엽기의 신엽의 엽면적은 다엽(평균 7.23$cm^2$)이 봉산리 다엽(평균 6.93$cm^2$)보다 컸으며 엽면적의 변화폭은 2번 채엽기와 3번 채엽기 사이에 봉산리, 부춘리 각각 2.74$cm^2$에서 7.98$cm^2$, 3.10$cm^2$에서 8.23$cm^2$로 가장 컸다. 건물량은 봉산리 평균 26.3%, 부춘리 평균 26.6%이었으며 채엽기에 따라 일정한 경향은 증감을 보이지 않았다. 녹차의 일반성분 중 수분 및 회분 함량은 봉산리 평균 5.6, 6.1%, 부춘리 평균 6.2, 5.8%이었다. 총당함량 및 조지방은 봉산리 평균 4.6, 2.8%, 부춘리 평균 2.8, 2.2%이었으며 후기채엽기에 다소 높은 양을 보였다. 총질소량 및 수용성 단백질은 봉산리 평균 5.1, 1.08%, 부춘리 평균 5.7, 1.02%이었으며 총질소량은 후기채엽기에 감소하였다. 가용성 고형분은 봉산리 평균 33.1%, 부춘리 평균 35.2%이었으며 봉산리의 경우 후기채엽기에 감소를 보였다. 무기성분은 봉산리 평균 2.557%, 부춘리 평균 2.338%, 비타민 C, 비타민 E 및 비타민 A 함량은 각각 봉산리 평균 413, 71.8mg%, 32.15IU, 부춘리 평균 311, 52.3mg%, 25.68IU이었으며 채엽기에 따라 비타민 C와 비타민 E는 후기채엽기에 증가를 보였다. 재차시 증차법 및 부초법 처리에 의한 다엽의 일반성분의 변화는 가용성 고형분함량은 증차법 평균 0.111%, 부초법 평균 0.086% 증가하였으며 조지방은 증차법 평균 0.125%, 부초법 평균 0.241% 감소하였고, 총질소는 증차법 평균 0.019%, 부초법 평균 0.036%, 수용성 단백질은 증차법 평균 0.125%, 부초법 평균 0.078% 증가를 보였다.

• Food Science and Biotechnology
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• 제17권2호
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• pp.349-356
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• 2008

The green tea market is rapidly growing and identifying the driving factors of consumers' liking for the green tea is important in the tea industries. The objectives of this study were to investigate the effects of manufacturing conditions of the green tea on its sensory characteristics, to elucidate its relationship with the consumer liking. A descriptive analysis and consumer acceptability test were conducted for various green tea samples. The samples differed with regard to the source of the tea, the amino acid content, and the processing methods including the roasting temperature. Partial least square regressions (PLS-R) were performed to establish the relationship between the descriptive data and the consumer acceptability data. The PLS-R results showed that the majority of the consumers liked a green tea which has a stronger 'sweet taste' and roasting-related flavors such as 'roasted barley' and 'burnt leaf'. Such sensory characteristics were produced when a sample made of tea leaves mixed with the tea stem was roasted at a high temperature ($250^{\circ}C$) in this study.

• 생명과학회지
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• 제17권8호통권88호
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• pp.1111-1114
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• 2007

생리활성을 갖는 것으로 알려진 메밀을 고소하게 볶은 시판 메밀차를 중급 정도의 녹차에 혼합하여 메밀녹차를 제조하고 기호도와 관련이 있는 향기 성분을 동시증류추출(SDE) 장치를 사용하여 분석하였다. 메밀차와 녹차를 1:1로 혼합한 메밀녹차의 향기성분으로 42종류를 동정하였다. 메밀녹차에는 메밀차의 향기성분 23종류와 녹차의 향기 성분 16종류 및 공통으로 포함된 3종류의 화합물들로 구성되어 있었다. 메밀녹차의 향기성분으로는 15종류의 pyrazine류를 동정하였다. 이는 메밀녹차의 향기 성분 중 약 32%를 차지하는 비율이었다. 메밀녹차의 향기 성분은 본래 녹차가 가지고 있는 향에 구수하고 달콤한 향을 띄는 볶음 메밀의 향기성분들이 부여되어 생성된 것으로 밝혀졌다. 본 연구에서 사용한 녹차는 중급 정도에 해당되는 덖음차로 고급녹차에 많았든 linalool이나 geraniol은 적은 함량 포함되어 있었으나 녹차향에 기여하는 꽃향기를 띄는 nerolidol의 함량은 많았으며 nonanal, 2-phenylethanol, cis-jasmone, indole 및 ${\beta}-ionone$ 등도 함유되어 있었다. 복은 향의 중요성분으로는 roasted flavor인 pyrazine류와 pyrrole류, 달콤한 향을 띄는 methylbutanal류와 furan류 등으로 밝혀졌다. 특히, pyrazine류는 종류도 많고 함량도 메밀차 전체 면적의 56%로서 녹차에 혼합되었을 때 메밀녹차의 고소한 향에 크게 기여하는 것으로 나타났다.

• 한국작물학회지
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• 제40권6호
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• pp.775-781
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• 1995

국산녹차에 있어서 보건적 효능과 관련된 특수성분의 유엽시기 및 제다법에 따른 변화를 조사한 결과는 다음과 같다. 수용성 펙틴은 후기유엽기에 점차적으로 증가를 보였으며 평균함량은 봉산리 녹차가 2.05% 부춘리 녹차가 1.84%이었다. 생엽에 대한 제다엽의 변화는 증다법 22.8%, 부초법 17.9% 증가하였다. 총엽록소는 후기유엽기로 갈수록 증가하여 1번 유엽기에서 5번 유엽기까지 봉산리는 233mg%에서 334mg%로, 부춘리는 198mg%에서 4번유엽기 까지 331mg%로 증가하였으나 5번 유엽기에 다소 감소를 보였다. 평균함량은 봉산리 평균 293mg%, 부춘리 평균 275mg%이었으며, 엽록소 a : 엽록소 b는 봉산리 평균 70.0:30.0, 부춘리 평균 67.3:32.7이었고 제다법에 따라 엽록소 a와 엽록소 b의 감소 정도에 차이가 있었다. 총 아미노산 함량은 봉산리 2,156mg%, 부춘리 평균 1,723mg%로 갈수록 큰 폭으로 감소를 보였다. 카페인은 후기유엽기에서 다소 적은 함량을 보였으나 부춘리는 3번 유엽기에 2.86%까지 증가를 보이다 감소하였다. 평균 카페인함량은 봉산리가 2.033%, 부춘리가 2.620%이었다. 카테친류는 후기유엽기로 갈수록 증가를 보였으나 봉산리의 경우 4번 유엽기 이후 급격히 감소하였다. 평균 카테친함량은 봉산리가 11.52%, 부춘리가 14.05%이었으며 유리형의 카테친은 봉산리 평균 35.59%, 부춘리 평균 42.73%, easter형 카테친은 봉산리 평균 58.09%, 부춘리 평균 44.47%이었다. 카테친류 및 카페인의 식용시 용출량은 침출온도가 $65^{\circ}C$에서 85$^{\circ}C$로 높을수록, 침출시간이 3분에서 9분으로 길수록 증가하였으며, 85$^{\circ}C$, 9분 침출시 카테친류는 89.3%, 카페인은 97.3%가 용출되었다.

• 대한소아치과학회지
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• 제44권4호
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• pp.437-445
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• 2017

이 연구의 목적은 한국인들이 일상적으로 마시는 서로 다른 네 종류의 차 티백을 이용하여 차가운 생수나 뜨거운 생수로 5분 또는 10분 동안 우려내는 일상적인 방법으로 차를 추출하였을 때 각각의 추출물이 Streptococcus mutans 세균막 성장에 미치는 효과를 알아보고자 하였다. 균주는 S. mutans UA 159를 이용하였고 1%의 sucrose와 각각의 차 추출물을 웰 플레이트에 넣고 배양하였다. 추출 온도에 따른 세균막 형성을 비교 했을 때 녹차와 홍차에서 추출 온도가 높을 때 세균막 형성이 적었고 통계적으로 유의하였다(p < 0.05). 추출 시간을 달리 하고 $72^{\circ}C$ 온수로 많은 양을 추출 했을 경우 세균막 형성을 비교 했을 때는 네 종류 차 모두 추출 시간에 대해서 통계적으로 유의하지 않았다. 한편 추출량에 따른 비교에서는 녹차와 홍차의 경우 같은 시간, 같은 온도로 추출하였을 때 추출량이 적다면 오히려 세균막 성장이 증가하였다.