• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.431-437
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• 2010

This study was carried out to determine the effect of gamma irradiation (3-20 kGy) on the antioxidant, antimicrobial activities and physical characteristics of Sargassum thunbergii (ST) extracts. When ST powder was treated by gamma irradiation, the yields and total phenolic compounds (TPC) of water extracts were increased, but radical scavenging activities were not changed. When ST extract was irradiated, the TPC and DPPH radical scavenging activities were increased. In addition, gamma irradiation of ST extract decreased viscosity and removed color. These results suggest that gamma irradiation would be a useful method for improving the physical characteristics of ST extract while maintaining native biological activities.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.317-324
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• 2013

This study investigated the changes in physicochemical characteristics of adzuki bean (Vigna angularis var. nipponensis) tea depending on the variety and roasting times, for the development of functional foods. The levels of total polyphenol, flavonoids, and tannin contents were 12.72 mg gallic acid equivalent (GAE)/g, 3.01 mg catechin equivalent (CE)/g, and 3.56 mg tannic acid equivalent (TAE)/g, respectively, for the Jeolgangsung-ipat sample roasted for 16 min. The highest DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity was 7.81 mg Trolox equivalent (TE)/g in Bulgeun-ipat sample that was roasted for 14 min. The highest total polyphenol content in the hot water-leached liqueur of adzuki bean tea was $26.55{\mu}g$ GAE/100 mL in Yungum-pat that was roasted for 12 min. The total flavonoids and tannin contents of Whin-ipat and Jeolgangsung-ipat roasted for 10 min were $15.10{\mu}g$ CE/100 mL and $14.60{\mu}g$ TAE/100 mL, respectively. The highest DPPH and ABTS (2,2'-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid) radical scavenging activities of hot water-leached liqueur of adzuki bean tea were 488.72 and 728.25 mg TE/100 mL, respectively, in Yungumpat roasted that was for 12 min. The results of this study show that roasted adzuki bean tea has notable antioxidant activity and is considered to have significant health benefits.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.203-211
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• 2015

Forest vegetation of Hwangjangsan (1,077.3 m) in Woraksan National Park is classified into mountain forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, mountain valley forest, coniferous forest, riparian forest, afforestation and other vegetation. Including 55 communities of mountain forest vegetation and 4 communities of other vegetation, the total of 59 communities were researched; mountain forest vegetation classified by physiognomy classification are 28 communities deciduous broad-leaved forest, 12 communities of mountain valley forest, 3 communities of coniferous forests, 2 communities of riparian forest, 10 afforestation and 4 other vegetation. As for the distribution rate for surveyed main communities, Quercus mongolica and Quercus variabilis communities account for 65.928 percent of deciduous broad leaved forest, Fraxinus rhynchophylla - Quercus mongolica community takes up 41.459 percent of mountain valley forest, Pinus densiflora community holds 86.100 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Pinus densiflora, Quercus variabilis, Fraxinus rhynchophylla, and Quercus serrata are distributed as dominant species of the uppermost part in a forest vegetation region in Woraksan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Quercus variabilis, and Fraxinus rhynchophylla which are climax species in the area.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.767-776
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• 2016

The aim of this study was to evaluate key properties of the prickly pear cactus (Opuntia ficus-indica var. saboten (OFI) ie, levels of key chemicals (carotenoids, flavonoids and polyphenolic compounds as well as phenolic acid) and its antioxidative potential, depending on where the plant had been cultivated in Korea. The levels of flavonoids and polyphenolic compounds in OFI were 55.45~65.32 mg (+)-catechin/g and 149.00~181.15 mg gallic acid/g, respectively. Protocatechuic acid was the most abundant phenolic acid in the ON1 and ON2 (161.90 and $196.25{\mu}g/g$ DW (dry weight)). Nineteen flavonoids were identified and analyzed by LC-ESI-MS in cladodes from OFI. Narcissin was the most abundant flavonoid in all of the samples ($1,241.89{\sim}1,775.10{\mu}g/g$ DW). Capxanthin and zeaxanthin were the most abundant carotenoids in OFI (64.88~128.08 and $48.10{\sim}93.82{\mu}g/g$ DW). The level of DPPH radical and ABTS radical scavenging activities in OFI were 10.78~25.35 and 16.85~34.16 mg AA eq/100 g, respectively. OFI by cultivar has different kind of phenolic acid, flavonoids, and carotenoids. Therefore, dietary intake of cladodes from OFI may be helpful for improving human health.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.17-28
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• 2007

This study was conducted to analyze the optimum heading period according to the recent climatic change for improvement of rice yield and grain quality in the Yeongnam area. We analyzed climatic elements including daily mean air temperature, daily range of air temperature, sunshine hours, and amount of precipitation from 1996 to 2005 in comparison with those of the 1971 to 2000 normal. Daily mean air temperature and amount of precipitation in the recent 10 years increased, but daily range of air temperature and sunshine hours decreased in comparison with the norm. Also, monthly mean air temperature was lowered remarkably in July and August. The monthly amount of precipitation largely increased in August and September. The daily range of air temperature and sunshine hours were greatly decreased from August to October, Possible cultivation periods for rice in the recent 10 years ranged from 171 days in Boughwa to 228 days in Busan and was expanded about $1{\sim}13$ days in comparison with the normal. Optimum heading date by local regions for the maximum climatic yield potential was estimated as July 31 at Bonghwa to September 7 at Busan, Masan, and Tongyeong in the recent 10 years. There was a wide difference in optimum heading date according to local legions of the Yeongnam area. Compared to the normal, optimum heading date in the recent 10 years was delayed about I~8 days in most local regions except Bonghwa, Mungyeong, and Yeongdeok. These results suggested that it is necessary to develop late maturity rice cultivars for producing high yield and quality rice grain due to the recent climatic change. Moreover, it is still more important to select the most suitable cultivation period appropriate to the changed climate of each local region in Yeongnam area.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.4
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• pp.245-263
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• 2013

This study was conducted to find out the influence of elevated atmospheric $CO_2$ concentrations and air temperature on photosynthesis and fruit quality of 'Fuji'/M.9 apple trees and to investigate these to the effects of climate change during the last four years (2009-2012). The treatments employed were: 'Ambient' (ambient temperature + ambient $CO_2$ concentration); 'High $CO_2$' (ambient temperature + elevated $CO_2$ concentration); 'High Temp'. (elevated temperature + ambient $CO_2$ concentration); and 'High $CO_2$ + High Temp'. (elevated temperature + elevated $CO_2$ concentration). The elevated temperature plots were maintained at $4^{\circ}C$ higher than ambient air temperature, while the elevated $CO_2$ plots were maintained at 700 ${\mu}mol{\cdot}mol^{-1}$. Annual treatment period was applied from end of April to beginning of November for four years. Results showed that elevated $CO_2$ decreased stomatal conductance and leaf SPAD value, but increased photosynthetic rate, intercellular $CO_2$ concentration (Ci), and starch content of mesophyll tissue. In the vegetative growth, elevated temperature increased total number of shoot and total shoot growth per tree, but elevated $CO_2$ decreased average shoot length. In the fruit quality, elevated $CO_2$ increased soluble solid content, fruit red color, and ethylene production. In conclusion, elevated $CO_2$ increased photosynthetic rate of apples during the early growth, but effect of increased photosynthetic rate due to elevated $CO_2$ was decreased during latter growth stage. Elevated temperature, on the other hand, tended to decrease photosynthetic rate of apples during the early growth, but that tended to increase during latter growth stage. Both elevated $CO_2$ and temperature tended to decrease the degree of decreased photosynthetic rate due to each factor.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.2
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• pp.175-182
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• 2018

Knowledge of the optimum cultivation period for Chinese cabbage would help growers especially in spring in Korea. Growth and yield of Chinese cabbage in a temperature gradient chamber was evaluated for the growing periods of 64 days from three set of transplanting dates including March 6, March 20, and April 3 in 2017. Air temperature in the chamber was elevated step-by-step, by $2^{\circ}C$ above the ambient temperature. This increment was divided into three phases; i.e. low (ambient+$2^{\circ}C$, A), medium (ambient+$4^{\circ}C$, B), and high temperature (ambient+$6^{\circ}C$, C). The fresh weight of Chinese cabbage was greater under B and C conditions in the first period and A in the second period, which indicated that GDDs affected the fresh weight considerably. However, leaf growth (number, area, length, and width) did not differ by GDDs. Bolting appeared under A condition in the first period, which was caused by low temperature in the early growth stage. Soft rot was developed under C condition in the second period and all temperature conditions in the third period, which resulted from high temperature in the late stage. Fresh weight increased when GDDs ranged from 587 to 729. However, it decreased when GDDs > 729. The maximum expected yield (16.3 MT/10a) was attained for the growing period of 64 days from transplanting date during which GDDs reached 601. The GDDs for optimum cultivation ranged from 478-724 under which the yield was about 95% (15.5 MT/10a) of maximum fresh weight. Such an optimum condition for GDDs was validated at five main cultivation regions including Jindo, Haenam, Naju, Seosan, and Pyeongtaek in Korea. In these regions, GDDs ranged from 619-719. This suggested that the optimum GDDs for Chinese cabbage cultivation would range from 478-724, which would give the useful information to expect the cultivation periods for ensuring maximum yield.

• Korean Journal of Environmental Agriculture
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• v.35 no.4
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• pp.270-277
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• 2016

BACKGROUND: Significant amount of bisphenol A has been released from the manufacturing process of plastics, epoxy resins, dental material and flame retardants. Bisphenol A has been detected at trace levels in wastewater, surface water, landfill leachate and drinking water. However, the residual survey of bisphenol A has not been performed in agricultural reservoir beside agricultural environment cultivating crops. This study was conducted to monitor the residual bisphenol A in national agricultural reservoirs and understand a level of contamination of bisphenol A in the agricultural environment in Korea. METHODS AND RESULTS: The water and water sediment were collected at agricultural reservoirs in Chungnam, Chungbuk, Kyunggi, Jeonnam, Jeonbuk, Kyungnam and Kyungbuk province. Bisphenol A was analyzed by the LC-MS/MS with triple quad 4500. The recovery of water and water sediment in the agricultural reservoirs showed the level of 95.7~97.2% and 91.5~100.3%, respectively. CONCLUSION: Bisphenol A was detected at the level of $0.05{\mu}g/L{\sim}0.18{\mu}g/L$ and $0.1{\mu}g/kg{\sim}34{\mu}g/kg$ in water and water sediment of the reservoirs, respectively. Based on the results, the residue of bisphenol A will be tried in the crops surrounding these agricultural reservoirs where bisphenol A detected above $10{\mu}g/kg$ of bisphenol A.

• Journal of Preventive Medicine and Public Health
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• v.27 no.2 s.46
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• pp.200-216
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• 1994

In present study, the authors investigated the possible effect of coffee consumption on serum cholesterol level in 1017 men between the ages of 40 and 59 years, who were randomly selected from the members of Seoul Cohort Study. Serum total cholesterol data was collected with other serologic indices (e.g. systolic blood pressure, diastolic blood pressure, hight, weight, etc.) through the program of biennial health check-up offered by Korean Medical Insurance Corporation (KMIC). The amount of coffee consumption was assessed by a self-administered questionnaire through mailing. Other confounding factors, such as age, body mass index, cigarette smoking, alcohol consumption, physical activity, and other dietary intake pattern were also determined by the questionnaire. The differences in means of serum total cholesterol in compared to non consumers were $-0.4{\pm}3.56mg/dl$ for those drinking less than 1 cup a day, $-0.6{\pm}3.60mg/dl$ for those drinking 1 cup a day, and $7.1{\pm}3.41mg/dl$ for those drinking more than 2 cups a day. Since smoking interacted the relationship between coffee consumption and serum total choleaterol, we re-analyzed those relationship in smokers and non-smokers separately Other atherogenic behaviors were well correlated with total cholesterol, so we adjusted the mean values of serum total cholesterol through multivariate model selection with age(r=0.12), total cigarette index (cigarette-years; r=0.10), Quetelet's index ($Kg/m^2$, r=0.16), daily calory expenditure (kcal/day, r=0.06), weekly meat and poultry consumption(g/week, r=0.05), weekly fish consumption (g/week, r=0.08), other caffeinated beverage intake (cups/week), and the amount of sugar and prim added to the coffee. Among those variables only age, Quetelet's index, fish consumption, and total cigarette index (in smokers) were remained in the models. After adjustment, the corresponing differences of total cholesterol in smokers were changed to $0.4{\pm}5.24mg/dl,\;-0.5{\pm}4.97mg/dl,\;and\;8.9{\pm}4.78mg/dl$, which were significantly different among themselves (P=0.011). In non-smokers, however, the differences were not statistically significant (P=0.76). Adjusted mean values of systolic blood pressure and diastolic blood pressure were also determined to evaluate the direct effect of coffee to cardiovascular system, but their means were not significantly different by coffee consumption(p=0.18 for SBP, p=0.48 for DBP). Asuming instant coffee in the most popular type of coffee in Korea, the association observed in our study between coffee and serum total cholesterol, especially in smokers, is very interesting finding for the connection between coffee and serum total cholesterol, because only 'boiled coffee' tend to show significant lipid raising effect rather than to other types of coffee, like filtered or espresso, in most of the western countries. We concluded that people who drink coffee more than 2 cups a day have significantly higher serum total cholesterol level than those who never drink coffee, especially in smokers.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.2
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• pp.67-73
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• 1979

The effect of liming on the potassium equilibrium activity ratio ($AR^k_e$) of Chinese cabbage cultivated soil and on the potassium uptake by the plant summarize as follows: 1. $AR^k_e$ is raised by the application of 1.6 ton of $Ca(OH)_2$ per hectare that required amount to adjust pH 6 for the soil. Generally, it could be confirmed that both liming and potassium placement to the soil show the combined effects to raise $AR^k_e$. 2. The exchangeable potassium and the electrical conductivity increase by liming. The mean value of the exchangeable potassium is 0.71 m. equ. per 100g of limed soils while the control give 0.64 m. equ. per 100g. For the electrical conductivity, limed soil show $766{\mu}mho$ and $750{\mu}mho$ is for the control. 3. The reason $AR^k_e$ value increase by liming could be considered that concentrations of $K^+$ and $Ca^{{+}{+}}+Mg^{{+}{+}}$ in the equilibrium solution are increased owing to release both K and $Ca^+$ Mg into the liquid from solid phase in the potassium equilibrium system of the soil. 4. For considering that the energies of exchange of calcium by potassium in the limed soils at different potassium treatment, that is without K, 200 kg $K_2O/ha$ and 350 kg $K_2O/ha$, give -3887 and -3778 and -3737 calories per chemical equivalent respectively. On the other hand in case of the controls which received the same amounts of potassium as mentioned above, energy values are -3983, -4392 and -4228 calories respectively. 5. The absorbed amount of potassium and weights of dry matters of the plant which grown in the limed soils show little higher values than the controls.