• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.60-66
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• 2003

The purpose of this study was to investigate the effective pretreatment of foodwaste for the anaerobic digestion. Considering the foodwaste generation and the anaerobic digester for municipal wastewater sludges, the some pretreatment processes were performed such as the grinding of foodwastes with the addition of water, the mixing with sludges, and the hydrolysis with the addition of NaOH. The results were as followings ; 1. As the stage of feasibility test in laboratory scale, the foodwaste grinding using a household garbage disposer was performed with three different water mixing ratios of 1:1, 1:5 and 1:9 as weight base. The physicochemical characteristics of grinded foodwaste were analyzed and the effective conditions was recommended as the 1 :5mixing ratio of foodwaste and water and the below 8mm particle size. 2. And the mixing of foodwaste and municipal wastewater sludge was studied with three different mixing ratios of 1:9, 3:7 and 5:5 as weight base. The physicochemical characteristics of the mixed foodwaste and sludges were analyzed and the effective mixing ratio was recommended as 3:7 of foodwaste and sludge.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.74-81
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• 1992

To develop the beverage from Schizandra chinensis Baillon, extraction condition was optimized, using the fractional factorial design with 3 variables and 3 levels, by a RSM computer program. The optimum extraction time, extraction temperature and alcohol concentration levels were 3 hrs, $80{\sim}85^{\circ}C$ and 0%(water) for a desired yield, color and non-volatile organic acid. And to obtain the optimum recipe, amounts of extract, sugar and citric acid were optimized, using the fractional factorial design with 3 variables and 3 levels, by a RSM program. The optimum extract, sugar and citric acid levels were 4%, 9.6%n and 0.06%, respectively, for a disired flavor and overall acceptance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.331-337
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• 1995

Seaweed Jellys(Muks) were prepared with sea mustard and sea tangle. Optimum storage condition was also investigated in terms of bacterial counts, pH, titratable acidity, gel strength and total volatile nitrogen(TVN) as soaking temperature and time in distilled water. Gel strength of Muk decreased, and TVN and baterial counts increased during storage in water. Seaweed Muk has a shelf life of 3 days at $32^{\circ}C$ in water and 15 days at $18^{\circ}C$. Shelf life of seaweed Muk with soy milk was 3 days at 18's and shorter than that of seaweed Muk without soy milk.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.9-13
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• 2000

Wood demand is increasing more and more, but world has been confronted with decreasing forest resources. Korea has to depend upon foreign wood and wood-based products for more than 95 percent of total domestic demand per year. In order to heighten self-sufficiency for wood supply and demand, we have to develop wood substitutes. Rice hull is the cheapest agricultural by-product we can get in Korea, more over the production of rice hull amounts to 1 million tons per year. This study was carried out to utilize rice hull and to decide the optimum condition of rice hull pretreatment for manufacture of rice hull board. Steam explosion method gave the best result, and the next boiling treatment of 1 hour, the last 1 hour treatment with 1% NaOH solution. Optimum conditions of explosion method were 20kgf/$cm^2-1$ minute and 25kgf/$cm^2-1$ minute. Rice hull board made with exploded rice hull met the KS standard(KS F 3104, 1997) and showed the same strength as a control, PB. And also the 1 hour boiling treatment was more effective than the 1 hour treatment with 1% NaOH solution.

• Journal of the Korean Chemical Society
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• v.50 no.2
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• pp.99-106
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• 2006

The electronic absorption spectra of [3-(2-thenoyl) 3-(p-NO2-phenylhydrazone) ethyl pyruvate] (I), p-Br (II) and p-CH3 (III) were studied in ethanol and the spectra comprise four absorption bands which assigned to the corresponding electronic transition. The pK values of these compounds have been determined spectrophotometrically and pH-metrically, the results shown that the interval range for color change of compound (I) is (8-10) similar to that of phenolphethalin indicator, indicating that this compound can be used as acid-base indicator. The successive stability constants of the compounds under study with some transition elements (Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO2(II), La(III) and Zr(IV) have been determined pH- metrically. Stoichiometric complexes with ratios 1:1 and 1:2 (M: L) were formed for all metals. The pK of the three derivatives and the values of the stability constant (logK) of the complexes have the order; III > II > I. Also conductometric titrations have been carried out and the results show that this titration can be used for determination of both the metal ion and the ligand concentrations by each others.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.208-208
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• 2023

북한강 유역은 대한민국을 대표하는 한강의 제1지류로 상류에 북한산이 위치하여 풍부한 자연환경과 생태계를 보유하고 있다. 해당 유역은 수력 및 다목적댐이 위치하여 수력발전과 수도권 물공급에 있어 중요한 역할을 하고 있다. 더욱이, 상수원보호구역으로 지정되어 있어 수질오염 예방을 위한 수질 관리가 필요하다. 기존 연구의 경우 북한강 유역 내 1개 다목적댐(소양강댐) 지점에 대한 수량 및 수질 매개변수 검·보정을 수행한 사례가 있으나 다목적댐 및 수력댐을 모두 고려한 사례는 없어 관련 연구가 요구되는 실정이다. 본 연구에서는 SWAT 모형을 활용한 북한강 유역 내 수량·수질을 분석 및 평가하고자 한다. 대상유역은 북한강 유역이며 저류를 하지 않는 평화의 댐을 제외한 5개 댐(화천댐, 춘천댐, 소양강댐, 의암댐, 청평댐)에 대해 모형에서 고려하였다. 자료평가기간은 1983년부터 2021년이며 기상 및 지형자료, 저수지 자료, 점오염원 자료를 입력자료로 활용하였다. Penman/Monteith 방법, SCS 방법, Muskingum 방법, 저수지 운영 방법(일 단위 관측 방류량 입력 및 목표 저수량 유지)을 활용하여 모형 모의를 수행하였다. 매개변수 검·보정은 수량(댐 유입량 및 방류량, 저류량) 및 수질(유사량, 총질소, 총인) 자료를 활용하여 수량 9개 지점과 수질 6개 지점, 댐 저수지 5개 지점을 중심으로 수행하였다. 수량 및 수질에 대한 도시적 및 통계적 평가를 통해 관측 및 모의 간의 정확도를 평가하였다. 평가결과, 수량은 임남댐의 영향을 받는 일부 댐을 제외한 대부분의 댐 유역에서 관측 및 모의 유량 간의 적합도가 우수하게 나타났다. 수질은 수량의 영향을 직접적으로 받아 일부 지점을 제외한 대부분 지점에서 관측 및 모의값 간의 적합도가 높게 나타났다. 검·보정 적절성 판단을 위한 정량적 평가결과, 수량의 경우 결정계수(R²) 0.64~0.94, 용적오차(PBIAS) 0.09%~15.77%로 적정한 것으로 나타났다. 수질의 경우 용적오차 0.00%~29.14% 사이로 적정범위 안에 포함된 것으로 나타났다. 본 연구결과는 기후변화와 연계하여 미래 기간의 수량 및 수질 분석 연구에 기여할 것으로 기대된다.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.353-360
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• 1992

This study was carried out to investigate the changes of quality in yogurt during delivery and storage. To do this, microbiological, physico-chemical and sensory properties in stirred yogurt were studied at different temperatures $(10^{\circ}C$ & $20^{\circ}C)$ and shakings (100 rpm & 200 rpm for 30 min). Titratable acidity and TCA soluble nitrogen in yogurt were increased in accordance with increase of temperature and time, while pH, lactose and lactic acid bacteria tended to be decreased. Interestingly enough, shaking conditions almost did not influence these studies. In sensory evaluation it showed that acidity was strong and sweetness was weak as increasing the storage temperature and time, but there were no significant differences until 10 days at $10^{\circ}C$ and 3 days at $20^{\circ}C$. Off-flavor was developed after 12 days at $10^{\circ}C$ with only 200 rpm shaking and after 6 days at $20^{\circ}C$ in both shaking conditions. These yogurts were not suitable for consumer. Viscosity in the yogurt became high as the temperature and time were increased. Viscosity was lower in yogurt shaked at 200 rpm than in non-shaked yogurt. Finally, this study indicates that temperature and shaking during delivery of yogurt may be critical in keeping quality of yogurt.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.236-240
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• 1993

This study was conducted to investigate the chemical properties of soils under plastic house cultivation in northern Gyeonggi province(Yangju gun and Paju gun) in 1992. The results are summarized as follows: 1. Distributions of soil texture were in the order of sand loam(65%), silt loam(25%) and loam(5%). 2. Content of soil nutrient varied with difference with soil management practices and years of cultivation and chemical properties of soils. 3. Soil pH, Ca/Mg ratio and Mg/K ratio tended to be low, while other parameters high. 4. The average application rates of poultry dropping, cow dung and piggery waste were 6.0, 4.5, and 2.0ton/10a, respectively.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.151-157
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• 2011

This study was to examine the quality characteristics and biological activities of the yogurt containing dual fermentation MFCY (Monascus-Fermented Chinese Yam) powder. Six different contents (0, 0.1, 0.3, 0.5, 1.0, and 2.0%, w/v) of MFCY powder were added to raw milk and 5% skim milk followed by fermentation with lactic acid bacteria at $37^{\circ}C$ for 12 h, and then the biological activities of the samples were investigated. Biological activities of the prepared yogurt were evaluated for acid production (pH, titratable acidity), number of viable cells, total polyphenol contents, DPPH radical scavenging activity, reducing power, angiotensin converting enzyme inhibitory effects and GABA contents. In this study, the results show that after fermentation in raw milk and 5% skim milk added with MFCY powder. The yogurt can produced pH, titratable acidity, number of viable cells, total polyphenol contents, DPPH radical scavenging activity and reducing power at 4.12-4.25 (pH), 0.94-0.97% (TA), $7.50{\times}10^9-1.14{\times}10^{10}$ CFU/ml, 161.4-329.9 (TP, mg/L), 54-94% (DPPH), and 1.13-1.53 (R.P), respectively. In addition, the showed ACE inhibitory activity and GABA contents was 67.1-87.7% and 304.6-685.4 (mg/L).

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.391-396
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• 1998

To inhibit the import of hot sauce, the manufacturing process of the Korean type hot sauce was developed. Chemical analysis of the imported hot sauce showed as follows; moisture 95.66% (w/w), salt 2.79% (w/w), titratable acidity 3.62% (w/w), crude fiber 0.42% (w/w), reducing sugar 0.03% (w/w), capsanthin 0.89% (w/w), capsaicin 4.28 mg% and pH 3.26. Korean type hot sauce prepared with red pepper, salt and vinegar was aged in oak barrel for 12 months at $10^{\circ}C$. Chemical analysis of the Korean type hot sauce showed as follows; moisture 92.05% (w/w), salt 8.82% (w/w), titratable acidity 3.88% (w/w), crude fiber 3.14% (w/w), reducing sugar 1.78% (w/w), capsanthin 0.13% (w/w), capsaicin 2.32 mg% and pH 3.29. Among chemical components, the contents of reducing sugar, salt and crude fiber except capsaicin and capsanthin were more than those of imported one. Chemical components of the Korean type hot sauce were changed slightly during aging for 12 months. The cell counts of yeast were increased from $3.2{\times}10^2\;to\;5.2{\times}10^6$ till the second month and those of lactic acid bacteria were increased from $3.{\times}10^1\;to\;1.5{\times}10^7$ till the third month, those of yeast and lactic acid bacteria decreased from the eighth month showed $6.6{\times}10^4$ and not detectable on the twelfth month, respectively. As the results of sensory evaluation on the Korean type hot sauce were evaluated to be superior to the imported to be superior to the imported one.