• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.398-406
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• 1992

In order to develop a new flavourant using the fish skin gelatin, the proteolytic renditions for the gelatin hydrolysate of the alkali (B-type) and Alcalase (E-type) pretreated flounder (Limanda aspera) skin gelatin were investigated, and some physical properties, molecular weight and amino acid compositions of the hydrolysates were, also, compared with each other. The proteolytic conditions of the gelatins (B-type and E-type) by trypsin were as follows : reaction temperature, 55$^{\circ}C$ : pH, 9.0 : enzyme concentration, 0.1% : re-action time, 4hrs for B-type and 1 hr for E-type. The degrees of hydrolysis of the B-type and E-type gelatin un-der the renditions stated above were 63% and 82%, respectively. The rnajor molecular weights of the hydrolysates were 15,000 dalton for B-type and 12,400 dalton for E-type. Among the amino acids in the hydrolysates, glycine, alanine, proline, hydroxyproline and serine having a sweet taste were responsible for 57% of the total amino acid. But valine, leucine, phenylalanine, tyrosine, methionine, arginine and histidine having a bitter taste were only 18%.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.279-285
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• 2013

To establish sample preparation method for detection of food-borne pathogens from lettuce, perilla leaves, cucumber, pepper, and cherry tomato, the influences of diluent composition, processing time, and proportion of diluent to sample were examined. Each produce was inoculated with 6.0 log $CFU/cm^2$ of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus. Each produce was treated with 0.1% peptone water, and D/E neutralizing broth. Processing time of produce was 30, 60, 90, and 120s, and the proportion of diluent to sample was 2 : 1, 4 : 1, 9 : 1, and 19 : 1. The number of bacteria after treatment of D/E neutralizing broth was higher than that of 0.1% peptone water (P<0.05). In cherry tomato, the population of S. typhimurium recovered from treated with D/E broth was higher than that recovered from treated with 0.1% peptone water by 1.05 log $CFU/cm^2$ (P<0.05). No difference in numbers of pathogens was observed in processing time. Optimum proportion of diluent to perilla leaf, iceberg lettuce, cucumber, green pepper, and tomato was 9 : 1, 4 : 1, 2 : 1, 2 : 1, and 2 : 1, respectively. These data suggest that D/E neutralizing broth should be recommend as diluent, and the diluent volume applied to produce should be determined in proportion to produce surface area per weight (g).

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.406-413
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• 2016

This study was performed to evaluate and establish a sample preparation method for the detection of food-borne pathogens in animal origin foods. Ham, yogurt, and Korean beef inoculated with Escherichia coli O157:H7, Staphylococcus aureus, and Salmonella Typhimurium, were tested for the effects of diluent composition, processing time, and proportion of diluent to sample. The diluents used were peptone water (PW), Saline solution (SS), Butterfield's phosphate buffered dilution water (BPD), and Buffered peptone water (BPW). The processing time periods considered for the samples were 30, 60, 90, 120, and 300 sec, and the proportions of diluent to samples tested were 1:2, 1:4, 1:9, and 1:19. Yogurt and beef showed the highest number of bacteria when treated with BPW (p < 0.05). However, ham showed no significant difference between the treatments with four different diluents. Optimum proportions of diluent to ham, yogurt, and beef were 1:9, 1:2, and 1:4, respectively. The processing time of 120 sec was chosen as optimum, because it showed the best recovery rate in all sample types. In this manner, detection of food-borne bacteria with the selected optimal conditions was indicated by a recovery rate of more than 85%. These data suggest that an appropriate diluent composition and diluent volume should be used depending on the type of sample, which would thereby increase the accuracy of detecting food-borne bacteria in animal origin foods.

• Journal of Food Hygiene and Safety
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• v.18 no.2
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• pp.43-50
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• 2003

A liquid chromatographic method, using matrix solid-phase dispersion (MSPD) is developed for the extraction of residual furazolidone in chicken eggs. Blank or fortified egg samples (0.5 g) were blended with Octadecylsilyl (Bulk $C_{18}$, 40${\mu}{\textrm}{m}$, 18%. load, endcapped. 2 g) derivatized silica. After homogenization, $C_{18}$/egg and Na$_2$S $O_4$matrix were transferred to a column made of 10 ml glass syringe and filter paper and compressed 4.0∼4.5 ml volume. The column was washed with 8 ml of hexane and dried under $N_2$ gas. Furazolidone was eluted with acetonitrile (8 ml) under gravity. The eluate containing furazolidone was free from interfering compounds when analyzed by HPLC with UV detection (365 nm, photodiode array). Calibration curves were linear (r = 0.99985) and inter- (1.47%) and intra-assay (5.29%) variabilities for the concentration range examined (7.8∼497 ng/g of eggs, 20 ${mu}ell$ injection volume) were indicative of an acceptable methodology for the analysis of furazolidone. Average recovery of furazolidone added to egg was 96.2%. The limit of detection for the proposed method was 1 ng/g for furazolidone. The method using MSPD is proposed as an alternative assay to the classical method which involves the use of large volumes of a harmful solvent and requires a long tedious separation and clean-up processes prior to its determination.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.595-601
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• 2010

It is evident that Korea will continue its battle with water shortage and alternative program are being taken into action. One of the main actions is reusing 1,800 tons of effluent of 357 sewage treatment plant located nationwide. Therefore this study supplemented ozone oxidation methods that would increase the efficiency of organic oxidation and coagulation. Through this method, fouling will be controled sufficiently by preventing membrane process in the system for advanced sewage treatment. In this study, ozone-coagulation-microfiltration membrane were used. The final removal efficiency of the pretreated water from the result of the ozone-coagulation were 50% of CODcr, 38% of TP and 11% of TOC respectively. Water quality treatment has decreased about 80% for TP. Ozone-coagulation-microfiltration membrane maintains the high flux while decreasing the number of organic matter and the membrane fouling, and reducing the TP. As a result, in order to reuse the water from the sewage, the ozone-coagulation-microfiltration membrane type must be considered in order to achieve the best efficiency.

• Journal of the Korean institute of surface engineering
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• v.38 no.3
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• pp.118-125
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• 2005

Low temperature plasma treatment with different gases and rf powers were performed to improve the adhesion strength between polytetrafluoroethylene(PTFE) and electroless deposited copper. According to the research, $H_2$ plasma having hydrogen radical was more effective in surface polarity modification than $O_2$ plasma due to the defluorination reaction. However, surface roughness of PTFE was more increased with $O_2$ than $H_2$ plasma. PTFE treated with $120W-O_2$ plasma and $250w-H_2$ plasma, consecutively showed rougher surface than single step $250w-H_2$ plasma treated one and more hydrophilic than single step $120W-O_2$ plasma treated one. And it showed 5B tape test grade, which is better adhesion property than 1B or 3B obtained by single step plasma treatment. In addition, adhesion strength between PTFE and Cu deposit is also deeply affected by residual water on its interface.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.563-572
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• 2000

The analysis of coal ash is very important to predict some factors, such as slagging and fouling in the boiler, and to determine optimum mixing ratios of the each coals used. In ASTM, the analysis of coal ash is clarified to use lithium metaborate (LiBO$_2$) as a fluxing agent and then to analyze the pre-treated samples using AAS. However, it takes too much time and efforts to analyze many samples by ASTM method, as a result, this method is not proper in our laboratory in charge of analyses of all power plants. So we tried to establish more convenient and accurate analytical method of coal ash by 3 different methods which are 2 different pre-treatment methods (fusion dissolution and microwave digestion) and XRF analysis method using a clear pellet. Although all 3 methods can be utilized to analyze the major elements of coal ash, each method has its own characteristics, therefore, each method should be chosen according to its own purpose.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.1-4
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• 2015

The current official perfluorochemicals (PFCs) analysis method is established with hydrophilic-lipophilic balance (HLB) solid phase extraction (SPE) clean-up method with LC-tandem mass spectrometry ($MS^n$). Herein the HLB clean-up method from the official method by Korean government was modified with Envi-Carb$^{TM}$ to improve the clean-up efficiency for agricultural water and the unexpected UV disturbance in the water was effectively removed by the adsorbent treatment without a significant disturbance of quantitation. And quadrupole time of flight mass spectrometry (qTOFMS) was suggested to the available $MS^n$ instruments for the residue analysis of PFCs based on the ng/L of quantitation limits in water as well.

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.347-355
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• 2007

The aim of this study was to evaluate the differences of salivary lead (Pb) and cadmium (Cd) concentrations, using ASV analysis, after various pre-treatment procedures. 10 unstimulated whole saliva samples of non-exposed subjects to Pb and Cd were collected. Each sample was divided into 6 aliquots and centrifugation was performed in only 3 aliquots. After centrifugation, 3 different types of pre-treatment procedures were carried out. Also, these pre-treatment procedures were carried out for another 3 aliquots, without centrifugation. Pre-treated aliquots were analyzed electrochemically, by ASV. The results are as follows: 1. Mean concentration of Pb in saliva after centrifugation was significantly higher than that of non-centrifugation. 2. In the detection sensitivity of Pb in saliva, those of simple dilution technique by HCl and acid digestion technique by nitric acid were significantly higher than that of simple dilution technique by electrolyte. 3. Mean concentration of Cd in saliva after centrifugation was significantly higher than that of non-centrifugation. 4. In the detection sensitivity of Cd in saliva, those of simple dilution technique by HCl and acid digestion technique by nitric acid were higher than that of simple dilution technique by electrolyte. But, there were no significant differences between them.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.45-51
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• 2014

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid (DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC$^{(R)}$ 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.