• Food Science and Preservation
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• v.19 no.4
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• pp.525-531
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• 2012

This study was conducted to evaluate the quality and anti-oxidant characteristics of different granule tea variants (WSMGT: granule tea prepared from sea mustard hot water extract; ASMGT: granule tea prepared from sea mustard autoclave extract; WSTGT: granule tea prepared from sea tangle hot water extract; and ASTGT: granule tea prepared from sea tangle autoclave extract) from sea tangle and sea mustard powder. The Color of WSTGT showed the highest $L^*$, $b^*$ values, and the lowest $a^*$ value. The water absorption binding agents in ASMGT were higher than those in WSMGT, WSTGT. and ASTGT. Binding agents on water absorption in ASMGT were higher than those of WSMGT, WSTGT, and ASTGT. The alginic acid content of ASMGT was highest. The total polyphenol and total flavonoid contents of ASMGT and ASTGT were highest. The electron donating ability and ferrous ion chelating activity in WSTGT greatly increased compared to those in the other granules tea variants. These results suggest that pressure extraction can be used in functional foods.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.338-345
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• 2019

The selection of a suitable solvent is very important when preparing an extract. However, the effect of ethanol solvent concentration in the extraction of sweet wormwood tea has not been reported. Thus, extracts were prepared from sweet wormwood tea using water and various ethanol concentrations, and the phenolic compounds, antioxidants and anti-enzyme activities of the extracts were analyzed. The phenolic acid and flavonoid components differed according to extraction solvent, which also resulted in different antioxidant and antienzyme activities. In particular, flavonoid rhamnetin was not extracted using 80% and 99.5% ethanol and was highest when 60% ethanol was used for extraction. In the case of chlorogenic acid, the highest extraction efficiency was obtained with 80% ethanol. These results suggest the need for research to increase specific extraction efficiency by targeting major compounds that affect physiological activity.

• Korean Journal of Pharmacognosy
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• v.49 no.4
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• pp.328-335
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• 2018

'EGCG(epigallocatechin gallate) rich Green Tea extract(EGTE)' was prepared by a convenient chromatographical manner using water and alcohol which was regarded as the most suitable and appropriate process for food manufacturing. The EGCG content in EGTE was estimated above 97%. Analysis of polyphenol components in green tea, i.e., catechin(C), epigallocatechin(EGC), epicatechin(EC), epigallocatechin gallate(EGCG), epicatechin gallate(ECG) and caffeine was performed by HPLC. The optimized HPLC method exhibited a good linearity of calibration curve, accuracy and precision. The long-term stability evaluation of EGTE was carried out with a powdered formulation and solution formulation by estimating the color change and measuring the EGCG content by HPLC analysis for one year. The EGCG content of the powdered EGTE stored in a transparent bottle at room temperature was retained over 97% at the end of the experimental period. The EGCG content of 0.1% water solution of EGTE stored in a transparent bottle at RT were observed to decrease below 30%, whereas that stored at $2^{\circ}C$ retained over 70%, respectively. These results suggested that a powdered formulation could be recommended for the commercialized nutraceutical product of EGTE rather than a solution formulation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.765-770
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• 2017

Green tea (Camellia sinensis L.) is consumed as a popular beverage worldwide, particularly in Asia. In this study, the effects of green tea powder addition on the antioxidant activities and texture properties of cooked rice were investigated. Texture analysis was carried out by texture profile analysis. Total polyphenols and total flavonoids were determined using spectrophotometric methods, and antioxidative activities were determined based on DPPH and ABTS radical scavenging activities, reducing power, and lipid peroxidation inhibitory activity. Antioxidant contents and antioxidative activities increased with a higher amount of green tea powder. However, there was no difference in texture properties between cooked rice with green tea powder and the control group. In conclusion, addition of green tea powder to cooked rice would be useful to increase antioxidant contents and antioxidative activities without alteration of texture properties.

• Environmental Mutagens and Carcinogens
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• v.26 no.3
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• pp.63-68
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• 2006

There are $10{\sim}30%$ polyphenol and $2{\sim}4%$ caffeine in green tea. Caffeine is a kind of alkaloid containing nitrogen which cause stimulation, impatience, headache, insomnia, low birth weight infant. Because of these negative effect, decaffeined beverage came out and decaffeined coffee already have a big market since 1970s. Having proving the physiologic functions of green tea, high consumption of coffee is shifting to green tea. Because of the carcinogenic effect of the organic solvents, decaffeine processing with supercritical carbon dioxide has industrialized and have an advantage in environment-friendly and minimized flavor loss. Decaffeined green tea using supercritical carbon dioxide is considered to be safe but there are not enough study, We investigated the chromosome aberration test with mammalian cell line, CHL. When the cells were treated with 5000, 2000, 1000 ${\mu}g/ml$ and compared with the negative controls, there were no significant (P>0.05) increased chromosome aberration. Same results was observed when adding S9 mixture or not. As a result, water extract of decaffeined green tea using supercritical carbon dioxide does not induce chromosome aberration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1025-1029
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• 2008

Fresh green tea leaf extracts were prepared by different enzyme treatment conditions, such as concentration, treating time and treating temperature using complex enzyme, Rapidase TF, and then extracted for 30 min at $80^{\circ}C$ to investigate their physicochemical properties. The results showed that free sugar content in every sample tended to increase, especially glucose content was increased up to 7.25 times compared to the control. Total amino acid was barely affected by the enzyme treatment and caffeine content was increased with reaction temperature. Total polyphenol and total catechin content was increased according to the amount of enzyme added and reaction temperature. Regardless of enzyme treatment conditions, composition of catechins were epigallocatechin, epicatechin, epicatechin gallate and epigallocatechin gallate by descending order of the content. Gallic acid content increased up to 0.04% and $45^{\circ}C$ with no further significant changes thereafter. From the results above, we could conclude that a simple and new method to extract green tea materials directly from fresh green tea leaves with improved extract ratio may be introduced by adding $0.08{\sim}0.1%$ of Rapidase TF to heat treated fresh green tea leaves and keeping temperature at $37{\sim}45^{\circ}C$ for $180{\sim}240\;min$ in order to skip existing complicated procedures.

• Food Science and Preservation
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• v.24 no.1
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• pp.21-26
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• 2017

This study was performed to determine the effects of preconditioning process (Con, roasting; SR, steaming and roasting; HDR, hot air drying and roasting; SHDR, steaming hot air drying and roasting) and roasting on the antioxidant and physicochemical properties of acorn (Quercus species) tea. Each sample was extracted in $95^{\circ}C$ hot water for 5 min. The color values of lightness and yellowness were the highest in HDR, and redness were the highest in the control. The total sugar content was the highest in SHDR. Total polyphenol and total flavonoid contents of HDR tea were higher than those of teas prepared by the different processes. DPPH and ABTS radical scavenging abilities of HDR were 75.66% and 98.16%, respectively, which were higher than those of other teas. In the sensory evaluation, HDR tea was ranked significantly higher than other teas in terms of flavor, taste and overall acceptability. Finally, acorn tea treated with drying was superior to other treatments in antioxidant and quality properties. The result suggests that HDR can be applied to acorn tea to achieve better quality and functionality.

• Environmental Mutagens and Carcinogens
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• v.26 no.4
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• pp.119-124
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• 2006

There are $10{\sim}30%$ polyphenol and $2{\sim}4%$ caffeine in green tea. Caffeine is a kind of alkaloid containing nitrogen which cause stimulation, impatience, headache, insomnia, low birth weight infant. Because of these negative effect, decaffeined beverage came out and decaffeined coffee already have a big market since 1970s. Having proving the physiologic functions of green tea, high consumption of coffee is shifting to green tea. Because of the carcinogenic effect of the organic solvents, decaffeine processing with supercritical carbon dioxide has industrialized and have an advantage in environment-friendly and minimized flavor loss. Decaffeined green tea using supercritical carbon dioxide is considered to be safe but there are not enough study. We investigated the chromosome aberration test with mammalian cell line, CHL. When the cells were treated with 5000, 2000, 1000 ${\mu}g/ml$ and compared with the negative controls, there were no significant(P>0.05) increased chromosome aberration. Same results was observed when adding S9 mixture or not. As a result, water extract of decaffeined green tea using supercritical carbon dioxide does not induce chromosome aberration.

• Food Science and Preservation
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• v.30 no.6
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• pp.960-968
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• 2023

The rhizome of Phragmites communis Trin. is used for vomiting and belching by clearing stomach and the sprout is used as tea. Phragmites japonica is similar with P. communis except the color of sheath is purple. This study is aimed to compare the in vitro antioxidant activity, total polyphenol and flavonoids contents of P. communis and P. japonica. The antioxidant activities of fractions from the two Phragmites plants were evaluated by 1,1-diphenyl-2- picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay. The antioxidant activity varied with plant parts and extract solvents. The fractions of leaf extract from the two Phragmites plants (4.06±1.32-16.47±1.28%) showed higher antioxidant activity by DPPH assay compared with rhizome fractions of two Phragmites plants (0.00±0.00-14.15±0.07%), these are lower compared with ascorbic acid and butylhydroxyanisole (BHA). The highest ABTS radical scavenging activity was found for rhizome ether fraction, namely 74.95±0.56% and 73.04±1.85% for P. communis and P. japonica, these are higher than BHA. The total polyphenol and flavonoids contents were different with plant parts and extract solvents, likewise antioxidant activity. A significant correlation was shown between DPPH and ABTS radical scavenging activity. Considering the results of this study, the leaves and stems of P. communis and P. japonica are expected to be used as natural antioxidants.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.807-819
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• 2012

To evaluate the functional characteristic and availability for drinking of the fermented Smilax china leaf tea by using different microbial species, various fermented leaf tea was prepared by non-fermentation (C), or the fermentation of Saccharomyces cerevisiae (S), Bacillus sp. (B), Bifidobacterium bifidus (L), Monascus pilosus (M) and Aspergilus oryzae (A), and sensory and antioxidant parameter of each brewed tea was observed. The color of the A tea was red, but the other teas were yellow in color. Furthermore, the aesthetic quality of the A and M tea was 3.95 and 3.30 point, respectively, and other teas (2.55~2.28) were similar to that of the C tea. TP of fermented tea water extract was lower than that of the C, although TF was not significantly different between the fermented and non-fermented tea. Especially, TF of the A tea was significantly lower than those of the other teas. The range of EDA ($1mg/m{\ell}$) of water and ethanol extracts of tea C and the fermented teas was 19.25~22.48%; however, tea A was only 8.04~12.49%. In addition, FRAP, FICA and LPOIA of teas were not significantly different between the fermented and non-fermented teas. On the other hand, XOIA and AOIA of tea ethanol extracts were slightly higher than those of water extracts. XOIA of water extract derived from the teas was 4.83~9.20%, while ethanol extract of these was 9.00~19.00%. However, XOIA of B and L teas water extract was not detected. Furthermore, AOIA of fermented tea water extract (30.17~48.52%) were lower than those of ethanol extract (44.09~66.93%). In this study, interestingly, antioxidant parameters, such as FRAP, FICA, LPOIA and AOIA, of the A tea water extract (0.1%) was higher than that of the other tea in spite of high decreasing rate in the contents of TP and TF. Therefore, above results imply the possibility of fermented Smilax china leaf tea as a functional food.