• 한국토양비료학회지
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• 제30권3호
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• pp.295-300
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• 1997

12개 지역의 한국자생차 향기성분을 기체크로마토그래프 및 질량분광계를 이용하여 분석한 결과는 다음과 같다. 다엽중의 향기성분으로 70~80개 성분을 GC를 이용해 분리할수 있었고, 그중 52개 성분은 GC/MSD로 동정하였는데, 이들을 분류하면 alcohol류 19종, aldehyde류 5종, hydrocarbon류 2종, ketone류 6종, ester류 4종, lactone류 3종, acid류 2종, phenol류 3종, pyrazine류 4종, 그리고 질소화합물 4종이였다. 이중 geraniol, linalool oxide, 1-hexanol, ehtanol등이 주요 향기 성분이었다.

• Preventive Nutrition and Food Science
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• 제15권3호
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• pp.229-232
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• 2010

Caffeine and catechins from the Yabukita, Yutakamidori, Saemidori, Okumidori, and Fushun varieties of tea leaves picked during different harvesting seasons from April to October were evaluated using HPLC. Total content of catechins increased greatly with the later harvesting time of tea leaves (i.e., picking the leaves in September versus in April) and decreased slightly after September. Yabukita tea leaves picked in August contained 43.1 mg% catechins including EGC, EC, ECG, and EGCG, with the ECGC levels constituting greater than 50% of those four compounds. Yutakamidori and Okumidori varieties picked in September contained the highest catechin values, at 43.6 mg% and 31.0 mg%, respectively. Fushun and Saemidori varieties contained lower catechin concentrations of 14.5 mg% (July) and 11.7 mg% (August) compared to other varieties. The EGCG levels gradually decreased in the late harvesting season, while levels of the other catechins, EC, EGC, and ECG, gradually increased. All varieties of green tea showed a gradual decrease in caffeine content toward the end of our harvesting efforts in October, with levels of 58～68 mg% in April and 28～57 mg% in October. Yabukita, Saemidori, and Okumidori varieties reached their highest caffeine levels in late spring/early summer, with Yabukita and Okumidori varieties reaching a high of 73.4% and 63.5% caffeine, respectively, in May, and Saemidori at 64.0% in June. In particular, Fushun still contained high caffeine of 66.8 mg% (September) during the late harvesting season.

• 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.

• 한국잠사곤충학회지
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• 제53권2호
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• pp.71-77
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• 2015

Much attention has been focused on the activity of the natural antioxidants present in fruits and vegetables, because potentially these components may reduce the level of oxidative stress. Especially, mulberry leaves containing many natural components are considerable resource for natural antioxidants. The antioxidant capacity of mulberry leaves was investigated with minilum L-100 device and ARAW-KIT (anti-radical ability of water-soluble substance), in comparison to the ascorbic acid. The antioxidant capacity of 16 varieties was 3303.4 nmol at opening stage of five leaves in spring. The highest stage of antioxidant capacity (3708.0 nmol) and yield rate was just before the coloration stage with anthocyanin in fruits, whereas the lowest stage was middle of June (2231.6 nmol) and about two months growing stage after summer pruning (2064.6 nmol). But after summer pruning, the antioxidant capacity of mulberry leaves increased gradually until just before fallen leaves stage. Even if samples were same variety, antioxidant effect of those showed different results according to collected regions. Also, antioxidant effect of mulberry leaves were higher than that of branches. The antioxidant capacity of yield-type mulberry leaves and fruits (Morus alba L., M. bombycis Koidz, and M. Lhou (Ser.) Koidz) collected from In-je, Won-ju and Yang-yang regions, Kang-won province, Korea, was investigated. The results indicated that total antioxidant capacity of yield-type mulberry leaves was 2711.2 nmol. In the antioxidant capacity analysis of Jeollabuk-Do genetic resources, autumn's mulberry leaves showed higher antioxidant capacity than that of spring's it. To investigate the effect of tea on antioxidative capacity, five kinds of tea(coffee mix, green tea added brown rice, mulberry leaf tea, Polygonatum odoratum tea and black tea added lemon) were selected and analyzed. Their's anti-oxidative capacity were 2,531.01 nmol, 1,867.42 nmol, 1,053.72 nmol, 292.71 nmol and 188.91 nmol, respectively. The antioxidative capacity of drinking water soaked with mulberry leaf showed 891.96 nmol.

• 한국식품과학회지
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• 제24권4호
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• pp.315-319
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• 1992

제주도 다원에서 생산된 녹차 생엽을 적채 시기별(1번차, 2번차, 3번차)로 혐기적으로 처리하여, ${\gamma}-aminobutyric$ acid(GABA) 및 기타 주요성분의 함량변화를 측정한 결과 차엽의 질소가스 치환처리 및 진공처리 모두 GABA와 alanine의 함량은 현저하게 증가한 반면에 glutamic acid는 현저하게 감소하였다. 또한 theanine, arginine, caffein 및 polyphenol의 함량은 거의 변화가 없었으며, vit.C의 함량은 혐기처리 시간의 경과에 따라 조금씩 감소하는 것으로 나타났다. 혈압강하작용 성분인 GABA의 생성량은 원엽의 아미노산의 함량, 특히 glutamic acid의 함량에 비례하였으며, 최적 혐기처리 시간은 약 12시간으로 나타났다. 한편, 차엽의 혐기적 처리조건에 있어서 질소가스 치환 처리와 진공처리 사이의 효과에 있어서의 차이는 거의 없었다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.478-487
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• 1996

A " plucking rolls device" was developed in this study to improve the quality of harvested tea leaves. In this report, the outline of the system and the results of performance experiments in our laboratory are discussed. Tow kinds of performance experiments were carried out. The first experiment checked harvesting accuracy by using a plucking unit that was developed for harvesting machine installation. The second experiment was a harvesting experiment which utilized a fron bar in order to prevent cutting of the tea buds which had been a problem in precious experiments . As a results of the first experiments , it was confirmed that selective harvesting obtained high quality tea leaves. but a cutting problem that, when the harvesting seed was faster than the working speed, which was non-selective harvesting , was also seen. In the second experiment, the cutting rate decreased to a maximum of 50% level, when tea buds most bent ahead by the front bar. The effect was seen that cutt ng problem was alleviated from this.

• 식품보건융합연구
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• 제5권3호
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• pp.7-20
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• 2019

The use of caffeine as a psychoactive stimulant in tea has been observed to have serious negative effects in humans' systems such as respiratory, nervous, cardiovascular, renal and skeletal systems. This study was carried out to assess the levels of caffeine in 10 different tea brands available in local market in Dutse, Jigawa State, Nigeria. Quantitative analysis of caffeine was performed by a simple and fast UV-Vis spectrophotometric methods using different solvents for extraction. The caffeine content in all the tea samples analyzed in this study were below the maximum allowable limits set by the USFDA. Tea have been associated with adverse health effects and the claims made by manufacturers about the benefits of tea do not highlight risks associated with excessive consumption of a combination of the ingredients contained in tea. Long term effects of tea consumption of children and young people have not been adequately studied. Therefore, it is recommended that further research be carried out on the adverse effects of energy drinks on children. Research is also needed to be done on the effects of the combination of ingredients on health and excessive consumption of those ingredients to children and adolescents. People need to be educated and given proper awareness on the health risks associated with caffeine containing beverages.

• 한국약용작물학회지
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• 제11권3호
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• pp.190-194
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• 2003

두물차의 수량은 관행시비 (4회 분시)에 비해 완효성 비료 9월, 3월 분시 2회 와 3월 1회 분시는 수량차가 없었으나 9월 1회 분시는 감수되었다. 관행시비에 비해 완효성비료 2회 분시가 총 질소, 총 아미노산은 많았고, tannin과 caffeine 함량은 적은 경향이었으며 엽록소, 비타민 C, 유리당 함량과 감칠맛 주성분인 theanine 함량은 차이가 없었다. 형상, 향, 맛 등 제다품질은 완효성 비료 2회 분시가 1회 분시나 관행 시비 (4회 분시)에 비해 우수하였다. 그러나 완효성 비료처리는 토양비료성분 중 질소, 인산, 칼리의 효율성을 향상시켜 차잎 수량 및 품질을 증가시킨다고 생각된다.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.337-343
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• 2010

1-Deoxynojirimycin(1-DNJ) was hardly detected by general UV detector. Therefore, in this study, we analyzed 1-DNJ, a effective functional material in which was contained the leaves of Cudrania tricuspidata and its tea by gas-chromatography. Synthesized a TMS derivative by attaching trimethylsilyl group to 1-DNJ, analyzed this by GC, and could detect a good peak. The leaves of Cudrania tricuspidata contains $1154.83{\pm}56.67$ ug/g.d.w of 1-DNJ and tea of Cudrania tricuspidata leaves does $8.01{\pm}0.61$ ug/g.d.w. This means the contents of 1-DNJ was nearly identical to each other. The larger size of the leaves had the more contents of 1-DNJ and the middle region of collection was the highest than any other collective regions of leaves.

• 한국환경보건학회지
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• 제32권1호
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• pp.53-59
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• 2006

This study was carried out to investigate the physicochemical characteristics with the elapsed time of $1\~10$ minutes after adding green tea leaves in the tap water. The results are summarized as follows: 1. $UV_{254}$ measurement increased sharply in direct opposition to increasing conductivity slowly. It is expected that the water soluble organic matters were better extracted than minerals. 2. Residual chlorine decay coefficients evaluated by assuming first-order reaction was increased in proportion to adding weights of green tea leaves. 3. In DBP formation experiments, residual chlorine decreased when reaction time was elapsed. whereas DBPs such as HAAs and THMs increased with the passing of time. From these results, it was showed that residual chlorine decay was related with the formation of DBPs. Therefore, use of boiled tap water in preparation of green tea is suggested if the residual chlorine in the tap water is high.