• Preventive Nutrition and Food Science
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• v.8 no.2
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• pp.185-190
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• 2003

Gamma irradiation was used as part of a new processing method to produce a brighter-colored and mild-flavored green tea leaf extract that retained all of its physiological activities. Dried green tea leaf was extracted with 70% ethanol and gamma irradiated at 0,5, 10, 20 kGy. Hunter color $L^{*}$- and $a^{*}$-values were increased with irradiation in a dose-dependent manner, which was a color range from dark brown to bright yellow. However, the irradiation effect gradually disappeared during 3 weeks of storage, with color reverting to that of untreated samples. There was no difference in the radical scavenging and tyrosinase inhibition effect by irradiation. Among antioxidants used, ascorbic acid was the most effective against color reversion. In contrast, cysteine was shown to protect the effect of color change with irradiation. Results indicated that enhanced color of irradiated green tea leaf extract can be effectively controlled by additives such as ascorbic acid and a low storage temperature.e.e.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.936-941
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• 2005

Green tea was extracted with different solvents such as hot water, varying concentrations of ethanol and carbon dioxide fluid. The carbon dioxide fluid extraction of green tea was a very effective extraction method in terms of antioxidant yield and stability. At pressure of 125kgf, antioxidant extract of green tea produced a yield 1.87 and 2.8 times higher than hot water and $95\%$ ethanol extract, respectively. Antioxidant extract of carbon dioxide fluid was also very stable during 7-day storage at 35?.

• Journal of Haehwa Medicine
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• v.12 no.1
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• pp.11-26
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• 2003

Alzheimer's disease (AD) is characterized by amyloid deposition and associated loss of neunons in brain regions involved in learning and memory processes. Several causes of evidence support that the congnitive disturbance is closed associated with the deficit of cerebral acetylcholine neurotransmission, and the effect of carboxyl terminal 105 amino acid fragment (CT105) of the amyloid precursor protein (APP) on the gene expression of proinflammatory cytokines. We tested it on the scopolamine-induced amnesia model of the ICR mouse using the Morris water maze with repeated orally administration of 1st Green-Tea extract (200 mg/kg) and 2nd Green-Tea extract (200 mg/kg). The Green-Tea prevents impairment of learning and memory and neuronal loss in mouse models of cognitive disturbance and it demonstrated selectivity for inhibition of acetylcholinesterase (AChE). Furthermore, the repeated administration of Green-Tea, CT105-induced alzheimer's mouse model showed central cholinergic activity by ameliorates learning and memory impairment, and isolation of CD14 microglia showed significantly decreases intracellular release of the proinflammatory cytokines tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$ and reactive oxygen species (ROS). Because of its composite profile, oral therapeutic index and a prophylactic, Green-Tea is considered the better therapeutic candidate for the treatment of Alzheimer's disease.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.842-846
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• 2004

To elucidate quality changes of pine nuts and walnuts coated with green tea extract-containing protein film during storage, pine nuts and walnuts were coated with soy protein isolate (SPI) and zein film containing green tea extract, and stored at $35^{\circ}C$ for 4 weeks. During storage, peroxide, acid, and 2-thiobarbituric acid (TBA) values increased with increasing storage time regardless of treatments. Degrees of lipid oxidation were lowest in protein coating containing green tea extract, followed by protein coating and control. After 4 weeks, for pine nuts, 40, 32, and 21% of peroxide, acid, and TBA values respectively decreased by treatment of zein film coating containing green tea extract compared with control. For walnuts, 29, 24, and 21% of peroxide, acid, and TBA values respectively decreased. With SPI film coating, 41, 36, and 8% of peroxide, acid, and TBA values of pine nuts respectively decreased. For walnuts, 26, 28, and 5% of peroxide, acid, and TBA values respectively decreased by treatment of SPI film coating containing green tea extract.

• The Korean Journal of Food And Nutrition
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• v.22 no.2
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• pp.279-285
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• 2009

Antioxidant and antimicrobial efficiency were investigated for: i) water extract of green tea(Camellia sinensis), ii) water extract of middle drying megmoondong(Liriope platyphylla Wang et Tang) and iii) water extract of drying megmoondong. The electron donating ability of the green tea(Camellia sinensis) and drying megmoondong(Liriope platyphylla Wang et Tang) extract were 88 and 79, respectively, while that of the middle drying megmoondong extract showed low levels. The relative inhibitory abilities against lipid peroxidase were: green tea(Camellia sinensis) extract > drying megmoondong(Liriope platyphylla Wang et Tang) extract > middle drying megmoondong extract. The green tea(Camellia sinensis) extract showed the strongest antimicrobial effect against Staphylococcus aureus. The middle drying(Liriope platyphylla Wang et Tang) and drying megmoondong extracts showed no antimicrobial effect against Staphylococcus aureus. The green tea(Camellia sinensis) extract had the strongest antimicrobial effect against Escherichia coli. The middle drying megmoondong(Liriope platyphylla Wang et Tang) and drying megmoondong extracts showed no antimicrobial effect against Escherichia coli.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1063-1067
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• 2004

To elucidate the effect of protein films containing an antioxidant on lipid oxidation of fish paste products during storage, zein and soy protein isolate (SPI) films containing green tea extract were prepared and their physical properties were examined. Tensile strength and elongation of the protein films decreased by the addition of green tea extract compared to the control. Due to the addition of green tea extract, SPI film had an increase in yellowness, but zein film had a decreased yellowness. Wrapping of fried fish paste products by the zein and SPI films containing the antioxidant retarded lipid oxidation at 2 day storage by 3.6 mg MDA/kg sample and 3.6 mg MDA/kg sample, respectively, for instant fish paste compared to the control. For processed fish paste, they decreased the degree of lipid oxidation by 1.6 mg MDA/kg sample and 0.6 mg MDA/kg sample, respectively.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.181-188
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• 2007

This study examined the effects of green tea extract supplementation (500 or 1,000 mg/kg b.w. per day) in conjunction with an atherogenic diet (10% coconut oil (w/w), 0.1% cholesterol) on plasma lipid composition, regression of pre-existing foam cells, and on the mRNA levels of hepatic HMG-CoA reductase and LDL receptor. Compared to groups fed only with the atherogenic diet, the addition of green tea extract to atherogenic diet-fed groups significantly down-regulated plasma triglyceride and total cholesterol levels, dose-dependently. Supplementation of 1,000 mg/kg b.w. of green tea extract with the atherogenic diet induced significant up-regulation of both HMG-CoA reductase and LDL receptor messenger RNA levels in liver as compared to the group receiving green tea extract supplementation at 500 mg/kg b.w. The F1B hamsters fed the atherogenic diet had greater foam cell accumulation compared to those fed a normal diet, or the atherogenic diet supplemented with green tea extract. Regression of fatty streak lesions was achieved by atherosclerosis in fat- and cholesterol-fed hamsters and this effect was associated with down-regulation of plasma cholesterol and up-regulation of hepatic LDL receptor expression.

• 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.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.4
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• pp.281-287
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• 2021

In this study, we analyzed the cosmetic applicability of extract from snow tea, native to Lijiang, Yunnan-province, China. After confirming the species as N. grossedentata through DNA analysis of Lijiang snow tea, experiments were conducted using representative tea, green tea, and a representative control group for each efficacy analysis. Both teas were extracted using 70% (v/v) ethanol aqueous solution. The polyphenol content in the Lijiang snow tea extract (gallic acid equivalent, 23.9 ± 3.2 mg/mL) was higher than that in green tea extract (16.4 ± 2.3 mg/mL). In contrast, the antioxidant (Radical scavenging, IC₅₀ 104 ㎍/mL), tyrosinase enzyme inhibitory (whitening agent, IC₅₀ 40.7 ㎍/mL), and Escherichia coli growth inhibitory (preservative) activities (IC₅₀ 2.85 mg/mL) were analyzed based on the solid content in the extract, and it was confirmed that the activities of Lijiang snow tea extract were superior to those of green tea extract (radical scavenging, IC₅₀ 234 ㎍/mL. It also showed similar efficacy to previously used active substances such as antioxidants (vitamin C, IC₅₀ 108 ㎍/mL), whitening agents (vitamin C, IC₅₀ 80㎍/mL), and preservatives (methylparaben, IC₅₀ 4.35 mg/mL). However, green tea was found to be better in collagenase inhibition activity (anti-wrinkle). Through this study, the cosmetic application potential of Lijiang snow tea is high.

• Food Science and Preservation
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• v.11 no.1
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• pp.126-129
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• 2004

To elucidate the effect of various natural antioxidants on the safflower oil, rosemary extract, green tea extract, isoflavon, Phaffia rhodozyma extract, tocopherol, sesamol, and BRA as a control were added to the safflower oil and stored at 60$^{\circ}C$ for 4 weeks. During storage, its viscosity and antioxidative activity were determined. Viscosity of the oil increased with increasing storage period and was related with its antioxidative acvtivity. Antioxidative avtivity among antioxidants used in this study were in order of green tea extract>BHA>tocopherol>rosemary extract>isoflavon>sesamol>Phaffia rhodozyma extract. Green tea extract was the best in terms of antioxidative acvtivity. After 4 weeks, its peroxide value decreased up to 80.4％ of the control, and 42.1％ for acid value and 47.4％ for TBA value decreased.