• Korean Journal of Organic Agriculture
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• v.29 no.4
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• pp.613-623
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• 2021

This study was conducted to investigate the effect of addition levels of coffee and green tea by products extract including polyphenols through hot water extraction on rumen fermentation. The treatment groups consisted of coffee extract (CO), green tea extract (GR) and mixed extract (MIX), and the addition level was 10 µL, 20 µL and 30 µL of three levels. The experiment consisted of a total of 10 experimental groups including the control group, and a full factorial design was used. The effect of polyphenol addition in coffee and green tea by-products was analyzed through main and interaction effect of statistical analysis. The total polyphenol content of the extracts was 106.15, 79.10 and 185.25 ㎍ GAE/g DM for coffee by-product, green tea by-product and mixture, respectively. Total gas production was significantly lower in the treatment groups than in the control (114.00 mL/gDM) (p<0.05). Methane emission tended to decrease as the polyphenol addition level increased. Moreover, the MIX showed the lowest methane emission when 30 µL was added (p<0.05). Volatile fatty acids showed a significant difference compared to the treatment group as a control (98.06 mM) (p<0.05), but there was no change according to the level of polyphenols. As a result of the main effect and interaction, it is thought that the effect on methane reduction and improvement of rumen fermentation in MIX20 can be expected. In a series of studies, the addition of 20 µL of a blended extract of coffee and green tea by-products is thought to reduce methane to levels that do not inhibit rumen fermentation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.295-299
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• 2004

The prices of domestic green tea products are relatively expensive and price differences within products of the same levels of quality are various. Also, there is no basic criteria on evaluation of green tea quality. To group 43 commercial green tea products into several parts by the principal component and cluster analyses, this work was done by use of 8 chemical constituents which were analyzed by NIR system. The principal component and cluster analyses revealed 8 groups. The first group included 16 products that had lower free amino acid and theanine contents. The second group included 5 products having higher free amino acid and theanine contents, but lower ash contents. The third group included 13 products showing medium values of 8 constituents. The IV group included 4 products having higher contents of moisture, free amino acids, and theanine. The V group included 1 product showing higher moisture but lower catechins contents. The VI group included 2 products that had higher moisture and catechins contents, but lower free amino acid and theanine contents. The VII group had higher moisture and catechins contents. The VIII group had higher ash and vitamin C contents. The free amino acid contents which were the most important in flavor evaluation of green tea quality did highly positively correlate with the contents of total nitrogen $(0.956^{**}),\;theanine\;(0.981^{**}),\;and\;caffeine\;(0.793^{**})$, but negatively with the contents of ash $(-0.884^{**})$. The catechins used as for functional ingredients did correlate with contents of caffeine(+) and vitamin C(-), respectively.

• The Korean Journal of Community Living Science
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• v.22 no.3
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• pp.327-339
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• 2011

This study aims to investigate relationships between benefit sought and selection attributes of green tea consumers. For data collection, a total of 595 copies of questionnaires were collected by convenience sampling in the Seoul and Gyeonggi-do area. The data were analyzed by using SPSS 15.0. The factor analysis identified four dimensions of the benefit sought : health benefit, sensory, sociality, and self-esteem. Six dimensions of selection attributes were identified as manufacturing, design, sensory appeal, recommendation, utility and brand. The results of the canonical correlation analysis indicated that health benefit, sensory, sociality of benefit sought and manufacturing, design, sensory appeal, recommendation, utility, brand of selection attributes were highly correlated, and the self-esteem of benefit sought and recommendation of selection attribute were highly correlated. This means it is important to place an emphasis on safety production, package design, sensory characteristics, product description, utility and brand for consumers who seek health benefit, flavor and sociality. It is also important to place an emphasis on product description for consumers who pursue self-esteem benefits. Green tea marketers should consider benefit sought aspects as the most important factors affecting selection attributes on green tea purchasing.

• Natural Product Sciences
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• v.19 no.4
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• pp.281-285
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• 2013

This study was designed to investigate the nervous sedative effects of green tea. The sedative effect was evaluated by examination of Monoamine oxidases (MAOs) inhibitory activity in vitro in the brain and liver of rat fed on green tea cultivated and harvested from the different regions and periods. It showed that methanol extracts of green tea inhibited significantly the brain MAO-A activity. Especially late harvested green tea extracts showed potential inhibitory activity. The liver MAO-B activity was also inhibited by all of the green tea extracts with strong intensity. This study confirmed that major compounds of green tea such as catechin, epigallocatechin-3-gallate (EGCG) and L-theanine, which were well known for the main bioactive components in the tea plants, were not associated with the MAO inhibitory activities of green tea. These results suggested that a MAO inhibition activity comes from other minor tea components we have to search in the future.

• Natural Product Sciences
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• v.19 no.2
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• pp.166-172
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• 2013

Caffeine and epigallocatechin gallate (EGCG) are major constituents of green tea, the leaves of Camellia sinensis (Theaceae). Although EGCG is well known for diverse beneficial effect, caffeine is sometimes harmful with adverse effects. Therefore, the extraction efficiency was investigated using different extraction method such as extraction solvent, extraction time, extraction method, and repeated extraction. The content of EGCG and caffeine in green tea extract was quantitated by HPLC analysis. The extraction condition exerted difference on the extraction yield. The content of EGCG was also affected by different extraction condition. Especially, the extraction solvent greatly affected the content of EGCG in the extract. However, the content of caffeine was less affected compared to that of EGCG. The inhibitory effect of green tea extract on pancreatic lipase was almost similar regardless of extraction condition. Taken together, optimization of extraction condition will provide best efficacy for further development of green tea as anti-obesity therapeutics.

• Korean journal of food and cookery science
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• v.19 no.3
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• pp.318-323
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• 2003

This study was aimed at investigating the physicochemical characteristics of a freeze-dried soybean paste block with sea mustard. In the proximate composition, the crude protein, lipid and ash contents were higher in the product prepared with commercial doenjang than in a green tea product, whereas the carbohydrate content was high in the green tea doenjang than in the commercial product. There was a rich composition of free amino acids, alanine, phenylalanine, hydroxyproline, valine, leucine, isoleucine and lysine in both products. The majoity of the free amino acids were more abundant in the green tea doenjang product than in the commercial doenjang product. There were no differences between the two products in the total saturated, mono- and polyunsaturated fatty acids. The order of the abundance of the fatty acid contents in both products were linoleic acid, oleic acid and palmitic acid. The major of the organic acid in both the commercial soybean paste product and the green tea product was oxalic acid, followed by tartaric acid and citric acid. In the sensory evaluation test, the taste, color and overall acceptability were not significantly different between both products, but the odor was significantly higher in the commercial product than in the green tea product. The freeze-dried doenjang product could be convenient for cooking nutritious sea mustard soup, without tedious preparations for a husband and wife that are both working.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.257-257
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• 2017

Being producing and evaluating oat-chocolate were a major goal in this study. There were various steps to make oat-chocolate. First, oat was roasted with an optimum roasting-temperature. Second, discovered the best natural antioxidant to extend storage period and improve quality of goods. Third, developed processing goods and made an evaluation of quality properties. We selected optimum roasting condition of $160^{\circ}C$ for 15 min based on the acid value and the sensory characteristics such as color, taste, smell and overall preference of oat flour. As for natural antioxidants, we made use of 3 kinds of antioxidants (cactus, lavender and green tea) and two concentrations (0.5 and 1%). In investigating antioxidants, an acid value was significantly decreased as the antioxidants were added (p<0.05). Nothing was as low in acid value as a chocolate with 1 % lavender flour in 7 days. Findings showed the sensory characteristics of products containing antioxidants such as green tea and cactus, were higher than those of Cont. in 7 days. A product including 0.5% green tea marked the best sensory score among antioxidants. Compared cost among 3 antioxidants, green tea was the cheapest. In the end, 0.5% green tea was selected as an optimal antioxidant to make high-quality oat chocolate. We made an end product by mixing green tea (0.5%) and oat. With respect to Hunter's color L (whiteness), a (redness) and b (yellowness), as green tea added, L and a level showed an increasing tendency. However, an opposition result was expressed in b level. When compared pH value and total acidity, it was statistically identical between Cont. and product with 0.5% green tea (G-0.5). There was different acid value among specimens. The acid value of G-0.5 was lower than that of Cont. up to 7 days, resulting in lower acid value than a ready-made product (D-Co.). When we assessed the sensory characteristics, G-0.5 was higher than other specimens such as Cont. and ready-made products (D-Co. and H-Co.) up to 6 days after manufacture. Put previous findings together, the addition of 0.5% green tea increased an antioxidative effect as well as the sensory acceptability of oat-chocolate.

• Biomedical Science Letters
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• v.28 no.1
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• pp.50-57
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• 2022

In this study, we tried to examine the possibility of developing a dental product such as tooth decay prevention and oral hygiene by manufacturing a natural polymer film for oral use. Natural polymer films were prepared from shark byproduct extract (SBE) and gellan gum (GG). As an antibacterial substance, the antibacterial activity of green tea extract against tooth decay-causing bacteria was measured. An film was prepared by adding green tea extract to the composition of SBE and GG. The mechanical, solubility, moisture content and antibacterial function of the prepared film were investigated in detail. Also, the incorporation of GTE into the SBE/GG film improved the physical performance of the film. Increasing the content of GTE improved the antioxidant and antibacterial properties of the film. Formulation of antimicrobial SBE/GG film containing green tea extract was established and these results evidently showed potential for cavity prevention products application.

• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.231-235
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• 2010

The effects of various natural antioxidant sources on oxidation of olive flounder (Paralichthys olivaceus) and fish diet during storage was determined. Juvenile fish were distributed among 18 flow-through tanks (40 fish per tank). Six experimental diets were prepared in triplicate: control (CT), antitox (AT), green tea extract (GE), fig extract (FE), Haeroc product (HP) and by-product of green tea (BG). The experimental diets were stored at two temperatures: room temperature ($26.8^{\circ}C$) for 14 days and frozen ($-30^{\circ}C$) for 16 weeks. Thirty fish were sampled from each tank at the end of the 8-week feeding trial. Whole bodies of fish were homogenized and stored in a home freezer ($-9.6^{\circ}C$) for 24 weeks. Acid values (AVs) and peroxide values (POVs) of the diets and frozen fish during storage were monitored. AVs of the experimental diets tended to increase with the storage period except for that of the HP diet at room temperature. POVs from FE, CT, and BG diets peaked at day 7 and then decreased through the remainder of the experiment. AVs of the experimental diets and fish increased with time at $-30^{\circ}C$ and $-9.6^{\circ}C$. Results of this study show that by-products of green tea and Haeroc product seem to have potential as antioxidants in fish feed to inhibit oxidation of both the feed and fish during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.980-986
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• 2005

This study was carried out to investigate the effect of diet (1:1 ratio) added with meat product (seasoning chicken product, patty) containing natural extracts (green tea, Schizandra chinensis) on body weights, internal organs weights, the contents of total cholesterol, HDL-cholesterol, triglyceride and total lipid in plasma and liver. The experimental diets were prepared with basal diet added with $1\%$ natural extracts. These diets were supplied to SD (Sprague-Dawley) rats for 45 days. The body weight of SD rats supplied seasoning chicken and patty containing green tea and Schizandra chinensis tended to be lower than that of SD rats dieted seasoning chicken product and patty product. The contents of plasma cholesterol, HDL-cholesterol, triglyceride and total lipid were decreased in SD rats dieted seasoning chicken and patty with green tea and Schizandra chinensis. However, the contents of plasma cholesterol, HDL-cholesterol, triglyceride and total lipid tended to be increased in SD rats supplied seasoning chicken product and patty only. Hepatic lipid peroxidation measured by TBARS method was not different, compared to that of control. In conclusion, the diets with meat products containing $1\%$ natural extracts were effective in reducing plasma and hepatic cholesterol levels in rats.