화학성분으로 본 각국 시판녹차의 품질

박장현(Jang-Hyun Park),최형국(Hyoung-Koog Choi),박근형(Keun-Hyung Park) 한국차학회 1998 한국차학회지 Vol.4 No.2

Forty-one green tea samples including Korean, Japanese, Chinese, and Vietnamese green tea were collected from the market. The tea samples were analyzed for total nitrogen(T-N), total free amino acid(FAA), tannin, caffeine, chlorophyll, vitamin C, individual free amino acid and sensory teste. The content of T-N in Japanese green tea(4.41~6.05%) was higher than that of other green tea including Korean green tea(3.15~5.37%). The content of FAA in Japanese green tea was the highest as 1,652~3,791mg/100g, and that of Vietnamese green tea was the lowest as 1,671mg/100g. The content of tannin in Korean green tea(11.30~15.01%) was lower than that of Chinese(15.45~17.33%) and Vietnamese (20.61%). The content of caffeine in Korean green tea was the lowest as 3.28~2.68%, and that of Vietnamese was the highest as 3.31%. The content of chlorophyll in Japanese green tea mading stemmed tea was higher than that of Korean, Chinese, and Vietnamese mading pan-fire blanched tea. The content of vitamin C in Korean green tea(201.8~402.3mg/100g) was the higher than that of Japanes(195.3~378.5mg/100a), Chinese(193.3~341.5mg/100g), and Vietnamese(276.6mg/100g). Eleven kinds of individual amino acid was isolated from forty-one green tea which the content of aspartic acid, glutamic acid, theanine, and arginine occupied over 80-90%. In scoring test, Korean pan-fire blanched tea as 58.7~78.9 point received higher point compared to Japanese(55.3~76.2 point), Chinese(50.1~72.0 point), and Vietnamese(70.5 point). Results of this study suggest that Korean pan-fire blanched tea show excellent in terms of abundance of T-N and FAA, and less contents of tannin, and good sensory teste.

질소 비료 시용량에 따른 첫물차의 수량 및 품질

박장현(Jang-Hyun Park),최형국(Hyoung-Koog Choi),김용웅(Yong-Woong Kim) 한국차학회 1998 한국차학회지 Vol.4 No.1

Recently the excessive application of nitrogen fertilizer in tea farming has attracted attention due to environmental contamination. Therefore, the reasonable level of nitrogen fertilizer are a key factor to reduce environmental contamination as well as to increase crop yield and quality. The treatments are N=42 kg/l0a, N=48 kg/10a, N=54 kg/10a, N=60 kg/10a, N=72 kg/l0a and N=150 kg/10a. Analytical results of yield and quality of first harvested leaves of tea are summarized as follows. As the application amount of nitrogen fertilizer increased, the yield of tea leaves, the contents of total nitrogen, total free amino acid, caffeine, tannin, anions(PO₄³- , SO₄²- , Cl- , NO₃- and F ), and cations(Na+ and NH₄+) increased; however, excessive level(N=150 kg/l0a) showed decreaed the yield of tea leaves. On the other hand, the increased level of nitrogen fertilizer did not show difference in contents of vitamin C, tannin and cations(K+, Ca²+ and Mg²+). Eleven kinds of amino acids was isolated from first harvested leaves of tea where the content of theanine occupied over 50%. The contents of fatty acids and catechin did not show correlation with application level of nitrogen fertilizer. N=60 kg/l0a treatment showed maximum content of fatty acid followed by catechin. In scoring test, N=60 kg/l0a treatmemt was 0.5~5.5 point higher compared to other treatments. Consequently, N=60 kg/l0a is considered to be best level of nitrogen fertilizer in terms of abundance of total nitrogen and free amino acid, and scoring test.

玉露茶葉 生産에 適合한 肥種選拔試驗

박장현(Jang-Hyun Park),신기호(Ki-Ho Shin),최형국(Hyoung-Koog Choi) 한국차학회 2000 한국차학회지 Vol.6 No.3

To select the proper fertilizer for the production of Okro tea, four types of fertilization (Urea-Fused phosphate-Potassium chlaride, Urea-Fused phosphate-Potassium sulfate, Ammonium sulfate-Fused phosphate-Potassium chloride, Ammonium sulfate-Fused phosphate-Potassium sulfate) were applied. The soil fertility of the experimental field was higher in organic matter (47.9g kg-1) and available phosphate(1.065mg kg-1), but lower in pH(5.4) compared to the common field. The growth and yield were more excellent in the second treatment (Urea-Fused phosphate-Potassium sulfate) compared with other treatments. The amount of chemical components such as total nitrogen, total amino acid, chlorophyll and vitamin C were higher in the second treatment compared with other treatments. Sixteen kinds of free amino acid including theanine as a good taste component of Okro tea were isolated and measured by HPLC. Theanine content, the second treatment. was the highest value of 120~290mg/100g compared to other treatment. `rhe tea appearance and interal factors were better in the second treatment than in other treatments. Consequently, Urea-Fused phosphate-Potassium sulfate is considered to be the best kind of fertilizers for both quality and yield.

두물차(6월차), 세물차(8월차)의 製造中 蒸熱時間이 茶의 品質에 미치는 影響

趙慶淑(Kyoung-Sook Cho),房極必(Geuk-Pil Bang),崔炯局(Hyoung-Koog Choi),殷鍾邦(Jong-Bang Eun) 한국차학회 1996 한국차학회지 Vol.2 No.2

This study was conducted in order to investigate the relationship between pluking season and the quality of steam tea by steaming time during steam tea processing. steaming time of 2nd crop of green leaf were 25, 45, 65 second and 3rd crop of green leaf were 45, 65, 85 second. Steaming leaf and cooling steamed leaf temperature, 3rd crop of green leaf which was abunfand supply of steam were higher 1˚C than 2nd crop of green leaf. Moisture content rate of cooling steamed leaf to green leaf was increased according to longer steaming time, and 2nd crop of green leaf was increased than 3rd crop of green leaf. 3rd crop of green leaf was lower dry moisture content decrease rate. Color of made tea was changed green color into yellow color according to steam time is longer. 25 second of 2nd crop of green leaf and 45 second 3rd crop of green leaf were couldn't taste of mild because of the strong smell of greens, bitterness and astringency. 65 second of 2nd crop of green leaf and 85 second of 3rd crop of green leaf was lusterless and having much sifting, ball lump Optimum steam condition of 2nd crop of green leaf and 3rd of green leaf were each of 45, 65 second consider of shade color, aroma, color of liquor, taste of made tea.

An Exploratory Study on Inter-regional Tea Industry between Chollanamdo Province in Korea and Shizuoka Prefecture in Japan.

Jae-Ki Kim(김재기),Ill-Sup Nou(노일섭),Hyoung-Koog Choi(최형국) 한국차학회 1999 한국차학회지 Vol.5 No.2

Korea and Japan have a long history of Green Tea plant cultivation and tea drinking. Currently, the methods of tea cultivation and processing in korea are still of conventional type, but Japan's tea plant cultivation and processing methods are more advanced and modern. By the way. Koreans' tea consumption quantity have been increased every year throughout the country. Also, the whole quantity of black tea is imported and an low price green tea is likely to be imported to Korea by an open import policy. Originally, Korea have a lot of genetic resources of tea plants. Also, some good flavors of panning tea enables to export to Japan and have an international competitiveness.

國內産 茶葉의 유리아미노산, 데아닌, 카테친 含量에 관한 硏究

朴章鉉(Jang-Hyun Park),金廣植(Kwang-Sik Kim),金冑,喜(Ju-Hee Kim),崔炯局(Hyoung-Koog Choi),金善雨(Sun-Woo Kim) 한국차학회 1996 한국차학회지 Vol.2 No.2

The contents of total free amino acid, theanaine and catechin were analyzed and compared in tea shoot of native korean tea plant (Camellia sinensis var. sinensis) picking from thirteen places and Yabukita(Camellia sinensis var. yabukita), and excellent Japanese variety. Results of this investigation are summarized as follow. The content of total free animo acid of the Yabukita(2376mg/100g) was higher than that of the average of native korean tea plants(1947mg/100g). The content of total free amino acid of Hadong - gun and Tamyang - gun was higher than that of the average of other districts. Theanine content among free amono acids was the highest as 1281 mg/100g in Yabukita and the average content of wild varieties was 1060 mg/100g. The contents of catechin at Koksong - gun was the highest as 12.56%, and that of Yongkwang - gun was the lowest as 8.83%. The main ingredients had order of (-)EGCG > (-)EGC > (-)ECG > (-)EC >(+)C.

茶種子 發芽에 關한 硏究 : 採種時期와 溫度 處理가 茶種子의 發芽에 미치는 影響

趙慶淑(Kyoung Sook Cho),房極必(Guk Pil Bang),金正云(Joung Woon Kim),金冑禧(Ju Hee Kim),崔炯局(Hyoung Koog Choi) 한국차학회 1995 한국차학회지 Vol.1 No.1

This experiment was conducted to find out tea seed germination by six tea seed picking periods from September 5 to November 25 at intervals of twenty days. Low temperature treatment did cold moist prechilling storage for 30 days at 0, 5, 10˚C and then germinated at 20˚C. The normal temperature germinated respectively at 15, 20, 25 and 30˚C. Tea seed optimum germination temperature was between 20˚C~25˚C. Cold moist prechilling effect(Storage 30 days at 5, 10˚C) was not only shorter germination period but germination percentage was increased too. In case of doing cold moist prechilling, during the period of September 25 to November 5 between ±20 days from October 15 of optimum picking period could expect high rate of the germination more than 90%.