• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1458-1464
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• 1999

The whole body of three species of fishes, raw anchovy (Engraulis japonica), big eyed herring (Harengula zunasi), and northern sand lance (Ammodytes personatus) catched at the south adjacent coast of Korea, were analyzed for extractive nitrogen, free amino acids, combined amino acids, ATP and its related compounds quaternary ammonium bases, and guanidino compounds using specimens collected in May and July 1991, and the composition of these nitrogenous components were compared with each other. The contents of extractive nitrogen in anchovy, big eyed herring, and northern sand lance were 633 mg, 601 mg, and 455 mg/100 g, respectively. Thirty-one or thirty-two kinds of free amino acids were found in the extracts of the three species of fishes. Histidine, taurine, alanine, leucine, carnosine, glutamic acid, and lysine were the major free amino acids in every sample. The composition of the major extractive components such as free amino acids, combined amino acids, ATP and its related compounds, TMAO, and creatine in the extracts were similar to each other, but their contents were some different individually.

• Journal of the Korean Society for Environmental Technology
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• v.19 no.6
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• pp.563-569
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• 2018

The efficiency of wastewater treatment using microalgae was investigated in this study, focusing on nutrients and flocculation. In the experiments for reducing nutrients by incubation of microalgae, the total phosphorus and total nitrogen were removed over 92 % and 99 %, respectively. The higher flocculation rates as the average values 94% of Poly Aluminum Chloride(PAC) and 92 % of $FeCl_3$ were presented for the flocculation experiments under the conditions of Auto-flocculation and various additives. Also, the optimal(minimal) concentrations for over 90 % of flocculation were 30 mg/L and 40 mg/L for PAC and $FeCl_3$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.51-63
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• 1996

In order to investigate the food quality of Korean chum salmon (Oncorhynchus keta) the composition of extractive nitrogenous components including the free amino acids, oligopeptides, nucleotides and related compounds, guanidino compounds, and quaternary ammonium bases were analyzed. The extractive nitrogen from the muscle ranged from 478 to 649 mg/100 g with little discrepancies by sex, sampling seasons and areas. The large amount of anserine was noted with fairly low level of taurine, alanine, glycine, glutamic acid and lysine in each extract. After Hydrolysis of the entracts remarkable increases were found in $\pi-methylhistidine,\;\beta-alanine$ from anserine and carnosine. The sum of nucleotides and related compounds of the muscle was $3.32\~9.22\;{\mu}mol/g$, and predominant compound was the inosine 5'-monophosphate. The lower glycinebetaine, $\beta-alaninebetaine$ and homarine were also found in some samples. The trimethylamine oxide content of the muscle was ranged from 107 to 148 mg, and the trimethylamine content was no move than 11 mg in all the collections. The concentrations of creatine in the muscle extracts ranged from 477 to 642 mg, and $8\~11mg$ for creatinine, respectively. The total nitrogens of the compounds analyzed for each samples accounted for more than $90\%$ of the extractive nitrogen in this study.

• Membrane Journal
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• v.15 no.4
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• pp.310-319
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• 2005

This paper describes the preliminary study on the development of multi-stage membrane demonstration plant for removal of carbon dioxide from flue gas stream being emitted from LNG boiler in thermal power generation plant. The prerequisite requirement is to design and develop the membrane process producing a $99\%\;CO_2$ with $90\%$ recovery from LNG flue gas of 1,000 $Nm^3$/day. Asymmetric polyethersulfone hollow fiber membranes and membrane modules developed in this laboratory[1] were used in this study. Using the permeation data for the hollow fiber membranes, modelling on the membrane module and multi-stage membrane process was done to meet the requirement condition of the process design. The effects of the operating pressure of feed and permeate side and feed concentration on $CO_2$ purity and recovery were investigated experimentally with the developed hollow fiber modules. These experimental results matched well with theoretical modelling results.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.893-899
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• 2004

Method for sample preparation and quantitative analysis of 19 permitted and non-permitted synthetic colors in foods was developed based on reversed-phase ion-pairing high performance liquid chromatography. For color extraction of samples, deionized water was added, and pH was appropriately adjusted with 1% ammonia water. Any undissolved matters were extracted with 50% ethanol or 70% methanol. Lipid in snacks was first removed using n-hexane with centrifugation, water was added to extract colors, followed by clean-up and concentration using Sep-Pak $C_{18}$ cartridge. Recovery efficiencies at known concentrations of 19 standard food colors spiked into foods were in 90.3-97.9% range far soft drink, 79.2-101.9% for candy, 84.1-103.4% for jelly, 86.4-100.8% for chewing gum, 83.5-103.4% for ice cream, and 78.5-95.6% for snack.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.346-358
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• 2023

Due to the acceleration of climate change or global warming, it is important to predict rice productivity in the future and investigate physiological changes in rice plants. The research aimed to explore how rice adapts to climate change by examining the response of nitrogen absorption and nitrogen use efficiency in rice under elevated levels of carbon dioxide and temperature, utilizing the SPAR system for analysis. The temperature increased by +4.7 ℃ in comparison to the period from 2001 to 2010, while the carbon dioxide concentration was held steady at 800 ppm, aligning with South Korea's late 21st-century RCP8.5 scenario. Nitrogen was applied as fertilizer at rates of 0, 9, and 18 kg 10a^-1, respectively. Under conditions of climate change, there was an 81% increase in the number of panicles compared to the present situation. However, grain weight decreased by 38% as a result of reduction in the grain filling rate. BNUE, indicative of the nitrogen use efficiency in plant biomass, exhibited a high value under climate change conditions. However, both NUEg and ANUE, associated with grain production, experienced a notable and significant decrease. In comparison to the current conditions, nitrogen uptake in leaves and stems increased by 100% and 151%, respectively. However, there was a 25% decrease in nitrogen uptake in the panicle. Likewise, the nitrogen content and NDFF (Nitrogen Derived from Fertilizer) in the sink organs, namely leaves and roots, were elevated in comparison to current levels. Therefore, it is imperative to ensure resources by mitigating the decrease in ripening rates under climate change conditions. Moreover, there seems to be a requirement for follow-up research to enhance the flow of photosynthetic products under climate change conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.344-355
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• 2003

Korea is one of those countries that have very high usage rates of chemical fertilizers per unit area of cropland. To reduce the fertilizer application rate, a variety of agricultural polices has been introduced since the 1990s. In this study, fertilizer usage was surveyed on the farm base throughout the country in 1999, and the data were compared with those of 1992. Organic fertilizer application rates were decreased in most cereal crops with time pass, but maintained similar levels in vegetables grown in plastic-film houses and in upland soils. Chemical fertilizer application rates were decreased in most of the cereal crops and vegetables surveyed; however, this reduction was concentrated in phosphate and potassium usage, but not in nitrogen. In spite of this decrease, the fertilizer application levels to most crops were maintained at levels much higher than recommended. In the nutrient balance, which was calculated from the difference between input (chemical and organic fertilizers) and output (agricultural products), the nitrogen nutrient surplus did not decrease; however, phosphate and potassium decreased by 21% and 13%, respectively, in 1999 compared with 1992. To reduce fertilizer utilization and to conserve environment, further reduction of fertilizer application is essential.

• Korean Journal of Medicinal Crop Science
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• v.4 no.3
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• pp.241-246
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• 1996

This Experiment was conducted to know effect of cutting times and nitrogen split application rates on shoot and root-related characters of Atractylodes japonica. The cutting time was forced on none, once and twice along with three levels of nitrogen split application, all basic 50 -30 -20% and 40 -30 -30%. The plant height declined with increased cutting time and dry matter weight was increased with nitrogen split application under none and once cutting. Average yield of cutted shoot as edible wild plant was 257kg/10a at once cutting condition, but twice cutting condition was little and unfavorable to use edible wild plant because shoot was coarse. Yield 0 dry rhizome was the highest at once shoot cutting und­er 50 -30 -20% nitrogen split application by 471kg/10a.Especially, culture of Atractylodes japonka needed once shoot cutting one the 10th-30th of May.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.230-239
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• 1997

In order to investigate the composition and the actual condition of extractive nitrogenous constituents in Tohajeot (a salted and fermented freshwater shrimp, Caridina denticulata denticulata) and in seasoned Tohajeot which were sold in the markets, the extract was analyzed separately into extractive nitrogen, free amino acids, oligopeptides, nucleotides and related compounds, quaternary ammonium bases, and guanidino compounds, using specimens collected at the fish markets of Yosu and Naju cities in 1994 and 1995. The salinity of Tohajeot was very high $(23.6{\sim}25.1)%$, but seasoned Tohajeot was relatively low $(8.4{\sim}11.4%)$. The extractive nitrogen in the extracts of Tohajeot and seasoned Tohajeot was $311{\sim}531\;mg\;and\;256{\sim}429\;mg$, and the total of free amino acids in them were $1,159{\sim}2,584\;mg\;and\;1,012{\sim}1,672\;mg$ respectively. Glutamic acid, leucine, lysine, histidine, alanine, ornithine, and tyrosine were the major amino acids in Tohajeot extract, and glutamic acid, lysine, arginine, aspartic acid, histidine, leucine and alanine were the main amino acids in seasoned Tohajeot. As for nucleotides and related compounds in them were $2.64{\sim}4.82\;{\mu}mol\;and\;1.08{\sim}1.93\;{\mu}mol$ respectively. Homarine, trigonelline, glycinebetaine and ${\beta}-alaninebetaine$ were detected in them. Homarine was the most abundant, ranging from 18 mg to 86 mg, but the others were very low. The content of major nitrogenous constituents in Tohajeot extract, such as extractive nitrogen, free amino acids, oligopeptides, nucleotides and related compounds, and betaines, was more abundant than that in seasoned Tohajeot extract. But the nitrogenous constituents of Tohajeot extract were poorer than those of anchovy sauce which was sold in the markets. Possibly, the extractive nitrogenous components, which consisted of total betains, total free amino acids, and phenylalanine might be recommended as the quality indices of standardizing Tohajeot and seasoned Tohajeot.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.174-179
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• 2000

The nitrogenous compounds in the muscle extracts of cultured and wild olive flounder, Paralichthys olivaceous, were analyzed. The analyzed coumpounds were extractive nitrogen, free amino acids, oligopeptides, ATP and its related ompounds, quaternary ammonium bases, and guanidino compounds. The distribution pattern of these compounds in cultured and wild fish was found to be very similar. Although the ATP and its related compounds and creatine in the muscle of cultured fish were slightly abundant than those in the muscle of wild one, the extractive nitrogen, total free amino acid, oligopeptides, and TMAO were found to be slightly rich in the muscle of wild fish than those in the muscle of cultrued one. The moisture content of cultured fish was relatively lower but the protein and fat contents of cultured one were higher than those of wild fish. However the differences in the proximate composition, extractive nitrogen and nitrogenous compounds between two fishes were not significantly different.