• Food Science and Preservation
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• v.15 no.5
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• pp.675-681
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• 2008

This study investigatedthe quality of mashed red pepper after application of various freezing and thawing conditions. Two freezing temperatures ($-70^{\circ}C$, $-10^{\circ}C$), two thawing temperatures ($0^{\circ}C$, $40^{\circ}C$), and two thawing methods (water-thawing, air-thawing), were employed. Changes in levels of capsaicinoids, vitamin C, free sugars, organic acids, and capsanthin were measured. Capsaicinoids, vitamin C,and free sugar contents were lowest in pepper treated at $-10^{\circ}C/40^{\circ}C$ (freezing/thawing), and the loss rates were 38.0, 79.4 and 24.6%, respectively. When thawing methods were compared, chemical contents were higher in air-thawed samples than in water-thawed peppers, but there was a statistically significant difference only in vitamin C content. Free sugar content after $-70^{\circ}C$ freezing were higher than after $-10^{\circ}C$ freezing, irrespective of the thawing method used. Initial citric acid, malic acid, and succinic acid contents were 44.90, 30.76 and 20.65 mg/100 g, and there was no significant difference between peppers treated with different freezing and thawing conditions. It is recommended that the best method for preserving the overall quality of mashed red pepper is freezing at $-70^{\circ}C$ and thawing at $0^{\circ}C$ in air.

• Food Science and Preservation
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• v.24 no.3
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• pp.464-471
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• 2017

The purpose of this study was to evaluate the effect of superheated steam drying on physicochemical and microbial characteristics of Korean traditional actinidia (Actinidia arguta) leaves. Actinidia leaves were dried at steam temperature of $350^{\circ}C$ and oven temperature of $150^{\circ}C$ for 40-200 sec. Moisture content and water activity decreased with increasing the drying time, while color values including L, a, and b values and total color difference (${\Delta}E$) increased as drying time increased. The relationship between moisture content and water activity showed an exponential fit with high correlation vlaue ($R^2=0.9909$). Total phenolics and flavonoids content and antioxidant activity such as DPPH radical scavenging activity, ABTS radical scavenging activity, and FRAP assay of dried actinidia leaves increased with increasing the drying time up to 160 sec, but dramatically decreased at drying of 200 sec. The numbers of total areobic bacteria of leaves was not detected at drying time over 120 sec and coliform of all the samples was not detected. As a results, the superheated steam was an very effective drying method of increase to the nutritional and sanitary quality of dried Korean traditional actinidia leaves.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.9-13
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• 1972

On the seventh day of mounting male and feamale cocoons are distinguished. A part of those male and female pupae is irradiated for 40 min. with 1,000r-ray irradiation. Those eggs obtained from the irradiated pupae are divided into six groups of 5, 15, 45, 90, 720 and 2,400 minutes after laying. The cahanges of accid soluble phosphorus in the each group of eggs are as follows. 1. In the control group of the maximum quantity in acid soluble phosphorus was 1,456r/100mg D.P. in the 2,400 minutes group, while the minimum quantity was 1,233r/100mg D.P. in the 720 minutes group. 2. In the mated group of ＊irradiated female moths and control male moths, the quantity of acid soluble phoshorus was small as compared with the control group in the five minute group of 1,288r/100mg D.P. and in the 15 minutes group of 1,299r/100mg D.P. while the quantity increased to 1,484r/100mg D.P. in the 45 minutes group. The quantity began to decrease again to 1,400r/100mg D.P. in the 2,400 minutes group which was smaller than that of the control group. The quantity was slightly small in the silkworm eggs laid in the early stage when compared with that of mated group of ＊irradiated male moths and control female moths. Both groups showed the larger quantity in the 720 minutes group than that of the control group. The quantity of acid soluble phosphorus in the mated group of control female moths .and ＊irradiated male moths was larger in variation than in the mated group of control male moths and ＊irradiated female moths. 3. In the mated group of ＊irradiated male and female moths the largerst quantity was 1,760r/100ms D.P. in 2,400 minutes group and second was 1,736r/100mg D.P. in 90 minutes group, and third was 1,288r/100mg D. P., in 5 minutes group. Generally the quantity was small in silkworm eggs laid by the irradiated one in the early stage than the control group, but in the later period of egg the quantity began to increase more than that of control group.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.154-159
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• 1995

In order to find out the effects of shading and nitrogen fertilizer on $NO_3^-$ accumulation in the edible parts of chinese cabbage, Cutivar, "Seoul", was cultivated in the pots under glasshouse condition with different rates of shading(0, 15, 30, 50, 75%) and nitrogen fertilization(recommended level, and double rate of recommended level). Leaf length, leaf width, yield (leaf weight), root width and root weight in the 15% shading rate showed the highest value, but decreased in the over 30% shading rates. The highest yield showed in the plot of the 15% shading rate with double rate application of recommended N level. High rate of shading increased the $NO_3^-$ accumulation, especially in midrib and outer leaf compared to leaf blade and inner leaf, respectively. The average $NO_3^-$ accumulation of edible parts of chinese cabbage are $4,872mg\;kg^{-1}$(outer midrib), $2,363mg\;kg^{-1}$(inner midrib), $1,405mg\;kg^{-1}$(outer leaf blade) and $727mg\;kg^{-1}$(inner leaf blade). $NO_3^-$ accumulation of outer midrib in the plots of double application of recommended N level were no difference between shading rate containing $5,000{\sim}6,000mg\;kg^{-1}$ $NO_3^-$, while in the plots of recommended N level it was increased by elevating shading rate. It was concluded that overuse of nitrogen fertiliration for chinese cabbage in glasshouse condition might lead to increase $NO_3^-$ accumulation. It could be advisable to cut out both the out leaf blade and outer midrib which might accumulate the high concentration of $NO_3^-$ before consumption.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1107-1111
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• 2011

Organic fertilizers application has become a popular alternatives to reduce the dependence on chemical fertilizer in Korean farming systems. In this study, we evaluated the nitrogen (N) use efficiency and growth performance of Chinese cabbage grown by black vinyl mulching after application of organic and chemical fertilizers compared with no-mulching. The treatments included chemical fertilizer alone as control (NPK, N-$P_2O_5-K_2O$ : $320-78-198kg\;ha^{-1}$), organic fertilizer alone (OF100), 70% organic fertilizer and 30% chemical fertilizer (OF70+N30), and 30% organic fertilizer and 70% chemical fertilizer (OF30+N70), which were all applied in the no-mulching plots and in plots with black vinyl mulching. Daily means soil temperature was $2^{\circ}C$ higher in the black vinyl mulched treatments throughout the 54 days compared with no-mulched treatments. OF100 with black vinyl mulching gave highest soil inorganic N content. Also, Chines cabbage yield increased 46% by black vinyl mulched compared with no-mulching in OF100 treatment. Without mulching, N use efficiency was, 44, 26, 29, and 27% in NPK, OF100, OF70+N30, and OF30+N70, respectively. However, black vinyl mulching much more effectively increased N use efficiencies by 56, 55, 51, and 39% in the same treatments in the order as mentioned above. Conclusively, combined organic and chemical fertilizers application with black vinyl mulching could be good practical technique to reduce a amount of used nitrogen because of its greater ability to enhance N use efficiency.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.702-708
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• 2011

There are considerable areas of wet paddy fields in Korea that requires improvement of its drainage system. In poorly drained sloping paddy fields, upland crops can be damaged by either rainfall or capillary rise of the water table caused by percolating water beneath the upper fields during summertime rainy season. The purpose of this study is to evaluate excess water stress of soybean yield by drainage systems. Four drainage methods namely open ditch, vinyl barrier, pipe drainage and tube bundle were installed within 1-m position at the lower edge of the upper paddy fields. Stress Day Index (SDI) approach was developed to quantify the the cumulative effect of stress imposed on a soybean yield throughout the growing season. SDI was determined from a stress day factor (SD) and a crop susceptibility factor (CS). The stress day factor is a measure degree and duration of stress of the ($SEW_{30}$). The crop susceptibility factor (CS) depends of a given excess water on crop stage. The results showed that SDI used to represent the moisture stress index was most low on the pipe drainage 64.75 compared with the open ditch 355.4, vinyl barrier 271.55 and tube bundle 171.55. Soybean grain yield increased continuously with the rate of 3% in Vinyl Barrier, 32% in Pipe Drainage and 16% in Tube Bundle.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1071-1079
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• 2011

In this study, coal combustion ash (CCA) was evaluated for its stabilization effect on acidic mine waste with column experiment. Total of six treatments were installed depending on mixing ratio between coal wastes and CCA (0, 20, 40%) and mixing method (completely mixing and layered). Artificial acidic rain (pH 5.6) was used for feeding solution with flow rate of $0.05mL\;min^{-1}$. Result showed that higher pH of leachate was observed as more CCA was mixed. The highest pH in leachate was measured when 40% of CCA was mixed with coal waste (pH of 5.8). Also, complete mixing with CCA and coal waste was more effective to increase the pH of leachate than layered treatment. Regarding the reduction of soluble Fe amount, the highest efficiency (78%) was observed when 20% of coal ash was completely mixed with mine waste. Based on those result, optimum mixing ratio of coal ash with mine waste can be ranged 20-40% depending on environmental circumstances in the field.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.981-986
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• 2010

This study was carried out to investigate the effects of fertilizer and organic resource annual dressing for 30 years of Jeonbug series (silt loam) on soil properties and rice N uptake in paddy field soil. In the study field, treatments including control (NPK), NPK+rice straw, NPK+rice straw compost and nitrogen fertilization levels at 0, 100, 150, 200, 250 kg $ha^{-1}$ have been imposed for 30 years. Soil hardness and bulk density decreased from 15.7 mm and 1.381 Mg $m^{-3}$ in the control to 12.5 mm and 1.244 Mg $m^{-3}$ in NPK+rice straw compost treatment, respectively, indicating improvement of soil physical conditions such as porosity. Co-application of straw compost with NPK also result in a better chemical properties than NPK alone as it increased available phosphate (from 96 to 133 mg $kg^{-1}$), available silicate (from 81 to 116 mg $kg^{-1}$), and cation exchange capacity (from 9.8 to 11.4 $cmol_c\;kg^{-1}$). Soil organic matter concentration of top soil (0 to 7.5 cm in depth) was higher in NPK+rice straw and NPK+rice straw compost than in control. Fertilizer N uptake amount was much higher in NPK+rice straw (nitrogen fertilization level; 250 kg $ha^{-1}$) and NPK+rice straw compost (nitrogen fertilization levels; 200, 250 kg $ha^{-1}$) plots compared to the control (nitrogen fertilization level; 100 kg $ha^{-1}$) plot. Nitrogen use efficiency was showed significantly high in the NPK+rice straw compost (nitrogen fertilization levels; 100, 150 kg $ha^{-1}$) plot compared to the control (nitrogen fertilization level; 100 kg $ha^{-1}$) plot. Therefore, it was suggested that application of organic inputs is helpful in improving soil fertility and physical conditions and thus in N uptake.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.898-903
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• 2010

This study was carried out to estimate carbon emission using LCA (Life Cycle Assessment) and to establish LCI (Life Cycle Inventory) database of soybean production system. Based on collecting the data for operating LCI, it was shown that input of organic fertilizer was value of 3.10E+00 kg $kg^{-1}$ soybean and it of mineral fertilizer was 4.57E-01 kg $kg^{-1}$ soybean for soybean cultivation. It was the highest value among input for soybean production. And direct field emission was 1.48E-01 kg $kg^{-1}$ soybean during soybean cropping. The result of LCI analysis focussed on greenhouse gas (GHG) was showed that carbon footprint was 3.36E+00 kg $CO_2$-eq $kg^{-1}$ soybean. Especially $CO_2$ for 71% of the GHG emission. Also of the GHG emission $CH_4$, and $N_2O$ were estimated to be 18% and 11%, respectively. It might be due to emit from mainly fertilizer production (92%) and soybean cultivation (7%) for soybean production system. $N_2O$ was emitted from soybean cropping for 67% of the GHG emission. In $CO_2$-eq. value, $CO_2$ and $N_2O$ were 2.36E+00 kg $CO_2$-eq. $kg^{-1}$ soybean and 3.50E-01 kg $CO_2$-eq. $kg^{-1}$ soybean, respectively. With LCIA (Life Cycle Impact Assessment) for soybean production system, it was observed that the process of fertilizer production might be contributed to approximately 90% of GWP (global warming potential). Characterization value of GWP was 3.36E+00 kg $CO_2$-eq $kg^{-1}$.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.53-57
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• 2009

Heavy metal pollution may be one of the most serious challenges confront crop production and human health. Therefore, the selection of heavy metal tolerance cultivars which adapted to the contaminated fields will introduced a suitable solution for management this critical environmental risk. The objectives of this research is to assess human health risk using geochemical analyses and exposure assessment of heavy metals in rice cultivars. Risk for inhabitants in the closed mine area was comparatively assessed for As, Cd, Cu and Pb in 10 rice varieties as a major exposure pathway. The average daily dose (ADD) of each heavy metal was estimated by analyzing the exposure pathways to rice and soil. For the non-carcinogenic risk characterization, Hazard Quotient (HQ) and Hazard Index (HI) were calculated using toxicity indices provided by US-EPA IRIS. The different rice varieties revealed a wide range of HI values from 23.6 to 34.3, indicating that all rice varieties have a high potential toxic risk. The DA rice variety showed the lowest HI value while the TB rice variety the highest. The probabilities of cancer risk for As via rice consumption were varied with rice varieties ranging from 2.0E-03 to 3.5E-03 which exceeded the regulatory acceptable risk of 1 in 10,000 set by US-EPA. The DA rice variety also showed the lowest value while the TB rice variety gave the highest value. Our results indicate that risk assessment can be contribute to screen the pollution safe rice cultivars in paddy fields affected by the mining activity.