• Journal of Digital Convergence
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• v.13 no.7
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• pp.431-436
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• 2015

To determine fusion-complex activity of Camellia extract extracted hot water, this study was conducted. Special catechin was identified at this extract by analysis of catechin. In analysis of antioxidant activity, the extract was contained antioxidant material and flower among the other parts showed high antioxidant activity. flavonoid showed most high content of Camellia. Flavonoid content was found to be $223.29{\pm}0.005mg/g$ to measured most high to stem, a control group was measured Green tea new leaves $126.14{\pm}0.005mg/g$. Total polyphenol content exhibited most high content at new leaves and flavonoid showed most high content at stem. ${\gamma}$-Amino butyric acid (GAVA) among the free amino acid showed highly at all parts.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.96-106
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• 2004

Response surface methodology (RSM) was applied in roasting processes of perilla leaves to develop a high quality perilla leaf tea. The Hunter color parameters and electron donating ability were monitored to optimize organoleptic properties of perilla leaf tea. The roasting processes were based on the central composite design with primary variables-roasting temperature $(140{\sim}220^{\circ}C)$, time $(5{\sim}25)$, and reaction variables-sensory test, electron donating ability. From the variables, the roasting condition was optimized using statistical analysis system (SAS) program as developing the functional tea using perilla leaf. Hunter color L and b values of the powdered samples increased with the roasting processes, but Hunter color a value decreased. Electron donating ability was influenced by roasting temperature (p<0.01) and time (p<0.01), and optimum condition selected was at $220^{\circ}C$ for 15 min with coefficient of determinations $(R^2)$ above 0.98. After preference test of perilla leaf tea using parameter of taste, color, and flavor, we can estimate that the optimal roasting condition of preilla leaf for function tea manufacturing are $210{\sim}220^{\circ}C$ for $10{\sim}20$ min by response surface methodology (RSM). Tyrosinase, xanthine oxidase and electron donating ability were 10.14, 14.37 and 59.19% of perilla leaf tea.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.33-39
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• 2001

The split application of a nitrogen fertilizer was applied at the levels to 3, 4, 5, 6 and 7 time. The results of yield and quality of Okro tea are summarized as follows: Among five treatments, the growth and yield were somewhat more excellent in the five time split treatments compared with other treatments. The chemical components such as total nitrogen, total amino acid and vitamin C were somewhat higher in the five time split treatment compared with other treatment. However, the content of components such as tannin, caffeine, chlorophyll were not different among plots of $4{\sim}7$ time split application except three time split application manuring. The content of fatty acid was producted $2,888{\sim}2,933mg/100g$. Especially, the content of oleic acid, linoleic acid and linolenic acid was the higheat in the five time split application. Sixteen kinds of free amino acid including theanine as a good taste component of Okro tea were isolated and measured by HPLC. Theanine in the five time split application was higher with value of $72{\sim}513mg/100g$ than in other treatment. In scoring test, tea appearance and interal qualities of 3 time split application become lower than any other treatment as 80.2 point, while five time application had the highest with 84.7 point. Conquently, those results meant that five time split application was optimum split application of fertilizer for high yield and good quality of Okro tea.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.21-26
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• 2010

Microbial-fermented tea (MFT), which is made by microorganisms through fermentation, is a popular beverage in Asia, especially in the Yunnam province, China. In this study, changes of the chemical constituents and antioxidant activity during the manufacturing process of MFT were investigated. MFT were respectively prepared from fresh leaves of three different tea species (Yabukita, Daecha, and Korean wild cultivar) and a processed green tea (Korean wild cultivar). The color of the tea infusions gradually changed to red and yellow as a function of fermentation time. Total nitrogen and caffeine contents were not significantly changed. Whereas, the chlorophyll, tannin, and total catechins contents gradually decreased. Interestingly, the epicatechin and epigallocatechin contents increased up to 25 days of fermentation and then decreased. Change of the chemical constituents of all samples showed the same patterns. The antioxidant activity of MFT from Daecha and Yabukita slightly decreased as increasing fermentation time. However, the range over which the antioxidant activity of MFT from Korean wild cultivar and green tea were not changed. This research suggests that it may be possible to manufacturing possibility of MFT using Korean wild cultivar and processed green tea.

• Journal of Sericultural and Entomological Science
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• v.49 no.1
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• pp.18-23
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• 2007

The importance of genetic resources conservation and utilization for economy and the health and well-being of societies in general is recognized all over the world. Mulberry genetic resources contain many natural components and are considerable resource for functional sericulture. We carried out antioxidative capacity analysis of mulberry leaves that were collected from Korea and some of foreign countries and preserved in the greenhouse. The mean antioxidant capacity of 34 accessions was 892.30nmol(ascorbic acid equivalent). Also we evaluated fruity characteristics and selected 4 accessions as breeding resources for the production of mulberry fruit. 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 antioxidative capacity were 2,531.01nmol, 1,867.42nmol, 1,053.72nmol, 292.71nmol and 188.91nmol, respectively. The antioxidative capacity of drinking water soaked with mulberry leaf showed 891.96nmol.

• Food Science and Preservation
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• v.30 no.6
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• pp.1043-1055
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• 2023

This study was conducted to suggest an extraction method for preparing the extract from green tea leaves that possess enhanced antioxidant and antibacterial activities. Different ethanol concentrations were tested to recover phenolics and flavonoids, and 50% ethanol was the best under heat treatment (121℃, 15 min). The ethanol extract exhibited excellent DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and growth inhibition against B. cereus, B. licheniformis, S. aureus subsp. aureus, and A. hydrophila subsp. hydrophila. To enhance the antioxidant and antibacterial activities, cell-wall degrading enzymes (2.5% cellulose+2.5% pectinase, v/w dry sample) treatment and Saccharomyces cerevisiae fermentation were applied singly or in combination. The enzymatic treatment of green tea leaves notably increased extraction yield. However, the antioxidant and antibacterial activities of the extract were lower than those of the control (heat-treated 50% ethanol extract). In contrast, the yeast fermentation alone did not affect the yield, but enhanced antioxidant and antibacterial activities, contributing to the increase in the extract's total phenolic and flavonoid contents.

• 한국약용작물학회:학술대회논문집
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• 2007.11a
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• pp.301.2-301.2
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• 2007

• Proceedings of the Korean Society of Crop Science Conference
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• 2007.11a
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• pp.226.1-226.1
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• 2007

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.101-106
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• 1999

These studies were carried out to investigate the quality of green tea processed by different 1st-pan-firing time and to select the best conditions of green tea processing. The results were as follows. At harvesting tea plant leaf, tea plants had 4 leaves, each leaf size was $6.4cm\;{\times}\;2.4cm$, and weight of 100 buds was 40.2g. The content of moisture of green tea was decreased with the prolongation of 1st-pan-firing time, and the yield of green tea at 10 min. pan-firing time was the highest value of 20.12%. After processing green tea, 1st 10 min. pan-fired one had much more contents of total nitrogen(TN 5.41%) and total amino acid(T.A.A; 3,282mg/100g) and less content of tannin(13.22%) and caffeine(1.64%) than the other treatments. The content of chlorophyll and vitamin C went down with the extension of 1st pan-firing period. Sixteen kinds of free amino acid including theanine as a good taste component of green tea were isolated and measured by HPLC. T.A.A contents were in the range of $2,447{\sim}3,192mg/100g$ and among various pan-firing methods, 10 min. 1st pan-fired one had the highest content of T.A.A. The taste-determinants such as theanine, aspartic acid, serine, glutamic acid and arginine in green tea liquor, occupied as much as $89.4{\sim}90.0%$ of T.A.A.s. Among these, theanine was more than 50%, Lightness and yellowness of green tea were increased with delay of pan-firing time, while green color appeared to be more distinct at 10 min. 1st pan -firing time than other treatments. Besides, it gained the highest score of sensory evaluation among them. These above results suggested that 10 min. pan-fired green tea was considered to be the best level as pan-firing time of green tea processing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.720-726
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• 1995

Chemical components relevant to the characteristic taste of the Korean native persimmon(Diospyros kaki, Thumb) leaf tea were analyzed. Samples were processed by using three different methods ; SHT(steamed and then hot-air dried), DHT(dried in the shade, steamed and then hot-air dried) and RHT(roasted and then hot-air dried). The components analyzed were general compositions of dried perisimmon leaves and extracted solution. The composition of moisture, ash, crude lipid and total nitrogen did not show significant variation among different processing methods of the persimmonleaf tea. The contents of caffeine, tannin and vitamin C in persimmon leaf tea were in the range of $178.4~209.8{\mu}mol/g$, 29.1~38.5mg% and 325.3~2084.7mg%, respectively. The vitamin C content was significantly higher in the RHT than other treatments. The contents of caffeine, tannin and vitamin C in the tea extracted solution were in the range of $101.5~130.1{\mu}mol/g$, 15.4~25.9mg% and 111.0~1274.3mg%, respectively. The vitamine C in the tea solution was the highest in the RHT treatment and 61.1% of vitamin C in the leaf tea was extracted out in these processing methods. The major amino acids contained in the leaf tea were in decreasing order glutamic acid, aspartic acid, leucine and phenylalanine, these four amino acids consisting 38.9~39.8% of the total amino acid contained in the persimmon leaf tea. The major amino acids contained in the tea solution were glutamic acid, proline, histidine and arginine. Six kinds of 5'-nucleotides, CMP, AMP, UMP, IMP, GMP and hypoxanthine were detected and CMP was the most abundant component in fresh leaf, leaf tea and tea solution. The second highest 5'-nucleotides in both leaf tea and tea solutions were GMP, AMP and UMP in all processing method. The highest free sugar contained in the fresh leaf tea and tea solution was sucrose.