• Food Science and Preservation
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• v.30 no.2
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• pp.300-310
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• 2023

This study was carried out to investigate the effect of the extraction conditions for persimmon (Diospyros kaki Thunb.) leaf tea (PLT) on its color quality and antioxidant properties. The amount of persimmon leaf (PL) powder and pH influenced the PLT's color and antioxidant capacity. As the amount of PL powder in tea increased, lightness decreased while yellowness increased. The PLT with the highest amount of PL (10 mg/mL) exhibited the highest 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity and ferric reducing antioxidant power (FRAP). In addition, the PLT with the highest PL showed the highest total polyphenol and flavonoid contents. Subsequently, PLT was prepared using 10 mg/mL PL powder under varying pH conditions. As pH increased from 4 to 7, lightness decreased while redness and yellowness increased. Antioxidant capacity was determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and FRAP assay showed that lower pH exhibited higher antioxidant capacity. The PLT extracted under the lowest pH of 4 showed higher polyphenol and flavonoid contents than that extracted under higher pH conditions. Overall, PLT extraction using a solvent with pH 4.0 showed better antioxidant activities and higher amounts of polyphenolic compounds. Simultaneously, lesser lightness, redness, and yellowness were detected in PLT extracted under pH 4 conditions. In conclusion, to acquire a better functional health benefit in terms of antioxidant capacity, preparing PLT under pH 4 conditions is suggested.

• Preventive Nutrition and Food Science
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• v.12 no.1
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• pp.35-39
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• 2007

This study was conducted to investigate the effects of soil selenium (Se) supplementation level on Se contents of green tea and milk vetch. Four different concentrations of sodium selenite ($Na_2SeO_3$) solutions (0.0, 3.3, 33.0 and 165.0${\mu}g/mL$) were prepared and one liter of each solution was well mixed with 10 kg of compost (cowpea soil) to give four different levels of Se-containing soil: $T_1$, 0; $T_2$, 33; $T_3$, 330; $T_4$, and 1,650${\mu}g$/100 g soil. Green tea plants and milk vetch were individually cultivated in those soils for 60 days. Se contents of freeze-dried green tea leaves were 6.87, 10.40, 12.04, and 20.19 ${\mu}g/g$, respectively; all of which were significantly different (p<0.05) from the others except for $T_2$ and $T_3$. The results showed that Se-contents of green tea leaves were increased 1.5$\sim$2.9 times as the Se level in the soil increased. Regression equation between Se contents in green tea (Y) and soil Se supplementation level (X) was: Y=0.007X＋8.857. However, Se contents in the milk vetch were increased significantly (p<0.05) more with the same treatments $T_3$ (74 ${\mu}g/g$) and $T_4$ (187$\mu$g/g) in comparison to those at $T_1$ (5.0 ${\mu}g/g$) and $T_2$ (12.0$\mu$g/g). The increases ranged from approximately between 2.4 to 37.4 times that of the control group. Regression equation between Se contents in milk vetch (Y) and soil Se supplementation level (X) was: Y=0.1063X＋15.989. The large difference of Se contents between green tea leaves and milk vetch would be attributed by the difference of protein contents between the 30% or higher protein-content of legumes and 15$\sim$20% protein of shrubs. The present study clearly indicates that green tea leaves and milk vetch can be enriched in selenium by supplementing the soil with Se. Therefore, Se-enriched green tea or milk vetch powder could be utilized as functional foods in Se-fortified green tea drinks or salads, or as food additives to enhance the daily intake of Se.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1185-1193
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• 2006

This study investigated the effects of green tea on the disorders of lipid metabolism, oxidative system and hepatic functions induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), using adult male rats (SD) for 3 weeks. These 36 animals were divided into four groups. TCDD ($50{\mu}g/kg$ BW) was intraperitoneally injected at the beginning of experiment. Green tea powder was added 1% or 3% levels in basal diets respectively. Relative weights of thymus were decreased about one-third of control group, but those of liver, brain and testis were significantly increased in rats treated TCDD. Neutrophill% and lymphocyte% by TCDD treatment was improved by green tea diets. In liver functional enzyme, elevation of glutamic oxaloacetic transaminase (GOT) and alkaline phosphatase (ALP) activities due to TCDD treatment was lowered by green tea diets. The concentrations of serum and liver lipids were significantly increased by TCDD treatment, however, those of serum and liver triglyceride tended to decrease by green tea diets. Fecal lipid excretion was increased in rats fed green tea diets. Especially, fecal total cholesterol level was significantly elevated by 3% green tea diets. The activities of superoxide dismutase (SOD) were increased in rats fed 3% green tea diets. Increment of benzphetamine N-demethylase (BPND) activity by TCDD treatment was declined by 1% green tea diets. These results indicate that green tea can exert improving effects on liver lipid accumulation and unfavorable hepatic functions, and elevate antioxidation.

• Journal of Ginseng Research
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• v.13 no.2
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• pp.178-182
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• 1989

Red ginseng products manufactured by the Korea Ginseng and Tobacco Corporation were analyzed to determine the crude saponin , total saponin and ginsenoside contentents by gravimetry, spertrometry and HPLC, respectively, to see if effective quality control of the components in the products can be achieved. Medicinal powders, powders, tablets and capsules which were made from ginseng powder showed similarity in saponin content, the ratio of PD to PT saponin, and the ginsenoside content and composition, while extract powder, extract, extract tea, extract pills and tea, which were made of ginseng extract, showed difference in saponin content, ratio of PD to PT saponin, and the content and composition of ginsengside. It is, accordingly, believed that ginseng products which are uniform in contents and saponin composition can be produced by carrying out strict quality control throughout the processes of making raw red ginseng into final products.

• Korean Journal of Community Nutrition
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• v.11 no.1
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• pp.98-107
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• 2006

This study was performed to test food preferences of the Korean elderly for Korean elderly menu development. The elderly subjects preferred steamed rice cooked with 1.2 times water than that with 1.5 times water (p < 0.001) , whole rice grain gruel than the gruel with ground grain (p < 0.05) . Green tea powder gruels developed as a snack, there were no significant differences in the preference of the elderly between gruel with different contents of green tea powder (2, 3, $4\%$). The preferences of the salt concentration of the soup were tested by using soybean sprout soup and soybean paste soup. The elderly preferred 0.7 - $0.8\%$ salted bean sprout soup and $7\%$ soybean paste soup. The elderly preferred Kimchi cut in widths of 1 - 2 cm than that in 0.5 cm. The elderly preferred sweeter grape jam ($67\%$ vs. $50\%$ or $37\%$ sugar content) and were not concerned about chewing seeds. This result could be useful to develop menus for the elderly. (Korean J Community Nutrition 11 (1): 98$\sim$107, 2006)

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.85-94
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• 2012

The anti-obese, hypolipidemic and hepatoprotective effects of post-fermented green tea by Monascus pilosus was tested with mice fed with high-fat diet for 7 weeks. The body weight gain and feed efficiency ratio (FER) in normal control group (NC), CHA (2% non-fermented green tea powder supplemented high-fat diet group) and mCHA (2% green tea powder post-fermented by M. pilosus supplemented high fat diet group) groups were significantly lower than those of high fat diet control group (HC). Epididymal fat weight in mCHA and NC were significantly lower than HC. The hepatic lipid peroxide was dramatically higher in HC than that of NC and was significantly lower in CHA and mCHA. In addition, dehydrogenase type activity of xanthine oxidoreductase in HC was lower than that of NC, but significantly higher than CHA and mCHA. In histopathological findings, hepatic fat accumulation in HC was higher than that of NC, CHA and mCHA. Antiobese, hypolipidemic and antifatty liver effect of green tea powder post-fermented by M. pilosus was slightly higher than that of non-fermented green tea. In conclusion, the constituents of green tea fermented by M. pilosus has been proven to not only inhibit obesity and hyperlipidemia but also decrease the hepatic fat accumulation in high fat diet-induced obese mice.

• Journal of Powder Materials
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• v.12 no.3
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• pp.201-207
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• 2005

Nickel powders were synthesized by the hydrazine reduction of nickel chloride solution containing ammonia in DEA solutions. The size distribution of nickel powders were investigated as a function of ammonia concentration, hydrazine concentration and the mixed composition ratio of diethanolammine (DEA) and triethanolammine (TEA). Nickel powders with the size in submicron range were obtained at $185^{\circ}C$ for 45 minutes by hydrazine reduction of nickel chloride solution in DEA solutions. The hydrazine concentrations showed significant effects on the particle size and shape distribution of nickel powders under $NH_3/Ni^{2+}$ molar ratio of 2.0 condition. As the mixed volume ratio of TEA and DEA increased, nickel powders with relatively larger particle size and low agglomeration were obtained. Nickel powders with particle size in the ranged from 0.4 to $0.9\;{\mu}m$ were obtained at the 50 $vol.%$ of TEA.

• Food Science and Preservation
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• v.12 no.1
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• pp.1-7
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• 2005

The effect of packing methods on the green powder tea were investigated by examining quality changes during cold stroage. Packing was performed with aluminum packs having an antioxidant and a wateiproofing agent in vacuum Alumiunum packing with treatment or not showed little changes till 2 months but after this period remarkable quality degradation were found in total nitrogen, total amino acids, tannin, caffeine, chlorophyll and fatty acids. The color changes of gieeness were -16.43 in one month and -10.11 in five months, respectively. Alumininum packing in vacuum was showed extention of storage period above one month.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.47-51
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• 2004

Green tea, which is high in polyphenols, is thought to have hypocholesterolemic effects. The present study was performed to further elucidate the hypocholesterolemic actions of green tea, specially the catechin and (-)-epigallocatechin gallate (EGCG) for their effects on the diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats were fed with green tea-free diet (control), diets containing 4% green tea powder (GTP), 1.0% green tea catechin (catechin) or 0.5% epigallocatechin gallate (EGCG) for 7 wks. All diets that were provided green tea contained approximately 0.5% EGCG Hypercholesterolemia was induced by adding 1% cholesterol and 0.5% cholic acid to all diets. There were no differences in food intake among groups. The green tea treatments showed significant improvement in the serum levels of total cholesterol, LDL-cholesterol, triacylglycerides and atherogenic index in the following order; EGCG>Catechin>GTP (p<0.05). The serum HDL-cholesterol level was highest in the EGCG-treated group. The catechin or EGCG diet up-regulated by 5 times the enzyme activity of hepatic cholesterol 7$\alpha$ -hydroxylase (CYP7Al) compared to control diet (p<0.05). Hepatic CYP7Al mRNA level paralleled tile increases in the CYP7Al activity. These results suggest that the EGCG in the green tea may account for the hypocholesterolemic effect by the induction of CYP7Al gene expression.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.1011-1020
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• 2003

The present study was conducted to examine sensory characteristics of non-fermented tea and fermented teas with fermented times of 0 hr (green tea), 10 hrs (mild fermented tea), 17 hrs (medium fermented tea), 24 hrs (black tea), respectively. The lightness of tea powder and tea extract got lower, and the redness and the yellowness of those got higher as tea was more fermented. The result of sensory evaluation about the extracts of non fermented tea and fermented teas showed that the preference of flavor got higher in the more fermented tea but one got lower in a mild fermented tea according to temperatures, respectively. The preference of taste got higher at 60∼7$0^{\circ}C$ extracts in the green tea and got the highest at 80∼9$0^{\circ}C$ extracts in the medium fermented tea and black tea. A total of 76 flavor components was detected in non fermented tea and the total contents of those were 129.9 mg/kg. The major components were linalool, geraniol, nerolidol, benzyl alcohol, and linalool oxide. A total of 76 flavor components was detected in the mild fermented tea and total contents of those were 159.1 mg/kg. The major components were geraniol, linalool, linalool oxide, ethanol, benzyl alcohol, etc and were similar in those to the non fermented tea. A total of 79 flavor components was detected in the medium fermented tea and total contents of those were 455.6mg/kg. The major components were ethyl acetate, 3-methylbutanal, ethanol, (E)-2-hexenal, geraniol, linalooloxide. A total of 79 flavor components was detected in the Black tea and total contents of those were 680.5 mg/kg. The major components were 3-methylbutanal, ethyl acetate, geraniol, ethanol, (E)-2-hexenal, hexanal, linalooloxide. The amounts of flavor components was increased, but the amounts of aldehyde compounds was remarkably increased according to the degree of fermentation.