• Journal of dental hygiene science
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• v.22 no.1
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• pp.57-66
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• 2022

Background: This study aimed to investigate the effect of selecting commercially available blending teas and applying them to bovine teeth on color change over time. Methods: After selecting healthy bovine teeth, using a cutting-disc, 105 specimens with a dimension of 5×5×3 mm were prepared, and 15 specimens were distributed to each group. Black tea was used as a positive control, water was used as a negative control, and blended tea of five types was used as an experimental group. First, pH and buffering capacity were measured with a pH meter, and tooth color was determined using a spectrophotometer before immersion in the blending tea solution and 1, 5, 7, 14, and 21 days after immersion. Thereafter, the shape change of the enamel surface was observed using a scanning electron microscope, and SPSS ver.26 was used to analyze the color change. Results: The average pH of the five blending teas in the experimental group was 3.78, and the pH of group 3 (strawberry rhubarb) was the lowest at 3.22. The pH levels of black tea and water were 5.19 and 7.30, respectively. The buffering capacity was the highest in group 3 at both pH levels of 5.5 and 7.0. The L^*a^*b^* color change according to immersion time was the largest in group 4 (rooibos yellow flower), and the amount of color change was large in black tea and group 4. As a result of observing the enamel surface of bovine teeth, changes in the surface shape were noted in all groups immersed in the experimental solution for 21 days, except for water. Conclusion: There was a significant difference between the experimental groups in terms of color change according to the immersion time, and color and enamel surface changes were observed in black tea and all experimental groups, except for water.

• Plant Disease and Agriculture
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• v.1 no.2
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• pp.26-28
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• 1995

Anthracnose of tea tree, Camellia sinensis, occurred severely at tea plantation of Boseung, Chonnam. Irregular, dark brown spots appeared on tips and margins of mature leaves in early stage. As the disease progresses, the lesions were covered with numerous, small, black, slightly raised pustules (acervuli). The causal fungus of anthracnose was identified as Colletotrichum theae-sinensis (Miyake) Yamamoto. Symptoms by C. theae-sinensis appeared around 20 days after artificial inoculation.

• Journal of the Korean Society of Food Culture
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• v.21 no.1
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• pp.8-16
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• 2006

This study was performed by questionnaire to investigate the preference and intake frequency of Korean traditional commercial beverages. The subjects were consisted of 320 participants in Daegu and Kyungpook area. 'Chain market' scored 49.4% as purchasing place of traditional beverages. 'Tea bag' scored 31.6% as the favorite package of traditional beverages. On the reasons of drinking traditional beverage 'good for health' scored the highest with 31.3% respondents, followed by 'good smell' with 14.4%. Coffee and traditional tea were the choice of beverage after having a rich meal and on occasion of entertaining guests. The favorite foods in ordinary days were 'tea', 'alcohol', 'ice cream', 'nuts' and 'cookie'. More than thirty percent of the respondents, both male and female, raised the need of improvement in taste of traditional beverage. In the intake frequency, Korea traditional beverages obtained 1.80 points as a whole. 'Green tea' scored highest(3.40points) while 'mulberry-leaf tea' received the lowest score of 1.31 points. The preferred Korean traditional drinks were 'greed tea', 'shick hae', 'citron tea', 'misitgaru', 'maesil tea', 'rice tea' in the order. On the other hand, the preference for 'mulberry-leaf tea', 'boxthom tea', 'ginger tea', 'chrysanthemum tea' and 'omija tea' was very low. The people who are on twenties preferred 'shick hae', 'honey tea', 'citron tea', 'black tea' and 'misitgaru' more than the other generation.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.375-381
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• 2005

The aims of this study were to evaluate the anti-obese effects of pine needle, black tea and green tea in rats and overweight people. Supplementation of 1, 2, 4 and 8% amount to the control diet of pine needle extract and mixture groups significantly decreased body weight gain and visceral fat mass compared with that of control diet group. Supplementation of 1, 2 and 4% amount to the control diet of black and green tea extracts groups significantly decreased body weight gain and visceral fat mass compared with that of control diet group. Anti-obese effect in body weight gain and visceral fat mass of mixture group was higher than in other groups. In human study, extracts mixture supplementation to overweight subjects significantly decreased both body weight and body fat compared with placebo control group. In vitro study, black and green tea extracts significantly inhibited both the pancreatic lipase and ${\alpha}-amylase$ activities dose dependently. In conclusion, the anti-obese effects of pine needle, black, and green teas in rats were found. In overweight human subjects, extracts mixture decreased body weight and body fat compared with placebo control group. Anti-obese effect in black and green tea groups might be from an decrease in carbohydrate and fat digestions via inhibition of pancreatic ${\alpha}-amylase$ and lipase activities in part.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.273-279
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• 1999

Forty plants used as tea materials were chosen for determining the contents of total phenolics, selenium (Se), ${\beta}-carotene$, ${\alpha}-tocopherol$ and ascorbate. Total phenolics and ascorbate contents were analyzed colorimetrically. The Se contents were measured by hydride-atomic absorption spectrometry. The contents of ${\beta}-carotene$ and ${\alpha}-tocopherol$ were simultaneously determined by high performance liquid chromatography using separate detectors, UV for ${\beta}-carotene$ and FL for ${\alpha}-tocopherol$ analyses. The contents of these antioxidants were as follows (per 100 g dry plant); Contents of total phenolics in green tea leaf, black tea leaf, oolong tea leaf and instant coffee were about 7 g and the Se contents in corni fructus and arrowroot were found to be about $4{\mu}g$, which were the highest among all plants used. Contents of ${\beta}-carotene$ in eucommiae cortex, persimmon leaf and green tea leaf were 8587, 6222 and $3652\;{\mu}g$ respectively. The persimon leaf contained the highest ${\alpha}-tocopherol$ content (33 mg) and then followed by eucommiae cortex (26 mg), green tea leaf (16 mg) and black tea leaf (13 mg) in order. Ascorbate contents were found to be high in green tea leaf (199 mg) and black tea leaf (117 mg).

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.740-744
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• 1994

This study was undertaken to prove the suppressing effect of green tea on the intestinal absorption of heavy metals using in vitro membrane filtration system. From drinking water contaminated with 10 and 100 times level of water quality standard for heavy metals, the removal ratio of lead (Pb) was $50{\sim}70%$ by green and black teas, and $30{\sim}40%$ by roasted barley tea. The removal ratio of cadmium (Cd) was $30{\sim}40%$ by green tea and black teas, and $10{\sim}20%$ by roasted barley tea. The removal effect from drinking water contaminated with both lead and cadmium was lower than that from water contaminated singly with lead or cadmium. It appears that tea components and filter membrane compete toward the adsorption of two heavy metals. Among the extraction conditions of raw tea materials at $70^{\circ}C$, 2 minutes and $95^{\circ}C$ , 10 minutes, the removal ratios of heavy metals were similar.

• Biomedical Science Letters
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• v.25 no.4
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• pp.302-312
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• 2019

The aim of this work was to investigate the effect of black tea extract (BTE) on collagen -induced platelet aggregation. In this study, BTE (10~500 ㎍/mL) was shown to inhibit platelet aggregation via thromboxane A₂ (TXA₂) down-regulation by blocking cyclooxygenase-1 (COX-1) activity. Also, BTE decreased intracellular Ca²⁺ mobilization ([Ca²⁺]_i). Additionally, BTE enhanced the levels of both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are aggregation-inhibiting molecules. BTE inhibited the phosphorylation of phospholipase C (PLC) γ2 and syk activated by collagen. BTE regulated platelet aggregation via cAMP-dependent phosphorylation of vasodilator-stimulated phosphoprotein (VASP) Ser¹⁵⁷. The anti-platelet effects of BTE in high fat diet (HFD)-induced obese rats were evaluated. After eight weeks of BTE treatment (300 and 600 mg/kg), the platelet aggregation rate in the treated groups was significantly less than that in the HFD-fed control group. Also, BTE exhibited a hepatoprotective effect and did not exert hepatotoxicity. Therefore, these data suggest that BTE has anti-platelet effects on collagen-stimulated platelet aggregation and may have therapeutic potential for the prevention of platelet-mediated thrombotic diseases.

• Journal of the Korean Chemical Society
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• v.63 no.2
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• pp.78-84
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• 2019

High-resolution $^1H$ NMR spectroscopic technique has been widely used as one of the most powerful analytical tools in food chemistry as well as to define molecular structure. The $^1H$ NMR spectra-based metabolomics has focused on classification and chemometric analysis of complex mixtures. The principal component analysis (PCA), an unsupervised clustering method and used to reduce the dimensionality of multivariate data, facilitates direct peak quantitation and pattern recognition. Using a combination of these techniques, the various green teas and black teas brewed were investigated via metabolite profiling. These teas were characterized based on the leaf size and country of cultivation, respectively.

• Food Science and Preservation
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• v.23 no.2
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• pp.188-193
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• 2016

Black tea is rich in phenolic antioxidants that has shown diverse health benefits such as protection against cardiovascular diseases and cancers. Thus, it is rational to incorporate black tea into suitable food products such as sponge cakes to enhance their nutritional and functional qualities. The aim of this study was to investigate the effect of the addition of black tea powder (BTP) on the quality of sponge cake. The pH of cakes ranged from 7.00~7.17, with no remarkable differences. Height decreased while baking loss rate and hardness significantly increased with increases in the content of BTP in the formulation (p<0.05). For crumb color values, $L^*-value$ decreased while $a^*$ and $b^*-values$ increased as a result of BTP substitution. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities were significantly increased (p<0.05) with increases in the content of BTP which were well correlated. Hedonic sensory results indicated that sponge cakes supplemented with 2~4% BTP obtained the most favorable acceptance scores. On the basis of the overall observations, sponge cakes supplemented with 2~4% BTP were found to be benefit from the functional properties of BTP, without compromising on consumer acceptance.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.1
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• pp.47-53
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• 2022

In this study, the conditions for efficiently extracting polyphenols contained in black tea were optimized. In order to confirm the polyphenol content according to the degree of fermentation, the polyphenol content in black tea of the three fermentation degrees was compared. As the degree of fermentation increased, the polyphenol content increased, and it was confirmed that the theabrownin content, the largest in size, increased significantly. In addition, it was confirmed that the amount of theabrownin extraction increased by about 150% or more compared to other extraction water when extracting using mineral water, which was hard water. The antioxidant effects of black tea extract and the theabrownin was confirmed using ABTS assay. As a result, both extracts had antioxidant effects, and IC₅₀ values were confirmed to be 10.60 ppm and 13.21 ppm, respectively. And also, the anti-inflammatory effect of the theabrownin was confirmed that the mRNA expression of IL-8 increased by UVB irradiation was inhibited in a concentration dependent manner by the theabrownin. In addition, when theabrownin was treated with 10 ppm, the mitochondrial function decreased by UVB irradiation was restored to 86 ± 1.9% compared to the control group. Therefore, we concluded that theabrownin could protect mitochondrial damage caused by UVB irradiation.