• 한국식품저장유통학회지
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• 제7권2호
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• pp.145-149
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• 2000

Strawberry and cucumber were dipped with Korean medical herb extracts such as Rheum palmatum L. and Coptis chinensis Franch. to maintain the keeping quality during storage at 5$^{\circ}$C and 10$^{\circ}$C, respectively. Treatment with 500 ppm solutions gor strawberry retarded weight loss, microbial load increase, and decay during storage. Decay ratio was shown 68.8% for control, 45.0% for Rheum palmatum L. and 42.5% for Coptis chinensis Franch. at 10 days. Strawberry treated with Coptis chinensis Franch. showed a higher hardness and soluble solid content than others. Cucumber treated with 1,000 ppm solutions revealed a different O$_2$ and CO$_2$ concentrations after 16 days. Korean medical herb extracts showed an antimicrobial activity for the quality retention of cucumber during storage. Ascorbic acid content was generally increased till 8 days, but decreased thereafter.

• 한국식품저장유통학회지
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• 제1권1호
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• pp.1-7
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• 1994

To investigate the effect of several bactericides and fungicides against fruit & vegetable decay grapefruit seed extract(GFSE) was tested in a dilution solution. GFSE was shown to be effective against decay and rind breakdown and to extend the shelf-life of fruits and vegetables during storage and tiansport. Antimicrobial efficiency of GFSE on a wide spectra of gram + & - bacteria, moulds and yeasts was demonstrated by the measurement of minimal inhibitory concentrations performed (Bacteria 10-500ppm, Fungi:250-1,000ppm, Yeasts:100-250ppm). GFSE was separated and extracted into water-soluble fraction, water-insoluble and non-dialyzed fraction to isolate the antimicrobial substances. The water-soluble fraction showed the most active antimicrobial effect. The antimicrobial substances were isolated by gas chromatography. As the result of the isolation using GC, Peak-D was found to be the antimicrobial compound in GFSE. The identification of the most antimicrobial substance was carried out by using GC-MS.

• 한국작물학회지
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• 제53권3호
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• pp.303-307
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• 2008

Cotyledon Black Decay (CBD) on soybean sprout mimics the black spot due to microbial infection. CBD, not visible or predictable at seedlot state, for some reason, shows up exclusively on cotyledon of soybean sprout during sprouting process. Such an incidence rate fluctuated from 0.8 to 19.5% over three years from 2004. We suspected some pod-infecting anthracnose fungi and/or pod-blight pathogen, or pod-sucking bean bug, one of the major pests of soybean, might have involved, of which we ruled out fungal pathogen because it was preventable through heat treatment, a proven method for seedlot disinfestation. The healthy seeds artificially fed by bean bug for one to seven days were sprouted, and 6 to 41% of the soybean sprout revealed the CBD mimic to those occurred in soybean sprout from previous commercial seedlot screening experiments. This finding is the first report to confirm that bean bug damage to pod at $R_8$ stage is directly responsible for the CBD, which did not concur with any other deleterious effects on sprouting such as reduction in hypocotyls elongation and rooting except unsightly sprout quality. However, earlier feeding either at green pod or greenish yellow pod stage ($R_6$ -early $R_7$ stage) resulted in rather severe damages, which strikingly reduced hypocotyls growth to about one forth to about two third, as well as the reduction in rates of seed germination.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.126-130
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• 2002

저장실험용 과채류인 오이와 단감을 서부 경남 진주시 지역의 재배농가에서 저장실험 시작당일 직접 구입하여 사용하였다. 구입즉시, 과채류를 습도가 70%(저장온도 $25^{\circ}C$), 80%(저장온도 1$0^{\circ}C$) 및 90%(저장온도: 단감 5$^{\circ}C$, 오이 1$0^{\circ}C$)의 저장조건에 보관하면서 처리기간별로 채취하여 품질변화를 측정하였다. 실험결과, 5$^{\circ}C$ 또는 1$0^{\circ}C$에서 습도 90%조건하에 오이와 단감을 저장할 경우, 중량손실율이 최소가 되었으며, ascorbic acid의 감소율을 크게 줄일 수 있었고, 오염 미생물의 생육이 억제되어 과일의 변패현상을 방지할 수 있었으며, 저장중 표면색도의 변화를 최소화할 수 있어 소비자의 기호도를 만족시킬 수 있었다. 부패율 또한, 저온에서 90% 저장습도에 저장하였을 때, 변패 곰팡이의 오염도 및 오이와 단감의 조직연화현상이 크게 억제되었다. 이상의 연구결과를 토대로 하여 볼 때, 오이와 단감을 저장할 때, 모든 처리시험구에서 저장습도 90%를 유지하는 조건에서 저온 저장하는 경우, 선도유지기간을 최대한 연장할 수 있음을 확인할 수 있었다.

• Animal cells and systems
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• 제7권4호
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• pp.289-294
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• 2003

To quantify nutrient loading from emergent macrophytes through leaching in the littoral zones of Paldang Reservoir, we conducted incubation experiments using leaf litter of the emergent macrophyte, Zizaniz latifolia. To separate the leaching process from microbial decay, we used $HgCl_2$ to suppress microbial activity during the experiment. We measured electric conductivity, absorbance at 280nm, total nitrogen and dissolved inorganic nitrogen, total phosphorus and soluble reactive phosphorus, Na, K, Mg and Ca amounts in leaf litter and in water. In addition, we examined the effects of water temperature and ion concentrations of ambient water on the leaching process. A total of 6% of the initial ash-free dry mass of leaf litter was lost due to leaching during incubation (four days). Electric conductivity and A280 continued to increase and saturate during the incubation. To compare reaching rates of different nutrients, we fitted leaching dynamics with a hyperbolic saturation function [Y=AㆍX/(B+X)]. From these fittings, we found that ratios of leaching amounts to nutrient concentration in the litter were in the order of K > Na > Mg > P > Ca > N. Leaching from leaf litter of Z. latifolia was dependent on water temperature while it was not related with ion concentrations in the ambient water. Our results suggest that the leaching process of nutrients, especially phosphorus, from aquatic macrophytes provides considerable contribution to the eutrophication of the Paldang Reservoir ecosystem.

• 한국식품저장유통학회지
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• 제7권1호
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• pp.1-7
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• 2000

To develop natural antimicrobial agents for keeping qualities of postharvested greenhouse produce the antimiocrobial actions of Polygonum cuspidatum Sieb. et Zucc. extract , which showed remarkable antimicrobial effects against microorganism causing the postharvest decay of greenhouse produce, were investigate. In the inhibitory experiment of enzymes related to energy production metabolism hexokinase activities decreased to 73% and 68% by treating with Polygonum cuspidatum Sieb. et.Zucc. extract and Eugenia caryophyllata Thumnberg extract in comparison with control, respectively. Direct visualization of microbial cells by using both transmission electron microscope and scanning electron microscope showed that microbial cell membrane was destroyed by treating with the dilute extract solution. this change of celluloar membrane permeability could be identified in the experiment that 0-nitrophenyl-${\beta}$-D-galactopyrano-side(ONPG), the artificial substrate of ${\beta}$-galactosidase, was hydrolyzed in the presence of the extract, indicating that the membrane was perturbed. The separation and identification of the most antimicrobialo substances isolated from Polygonum cuspidatum Sieb et. Zucc. extract and Eugenia caryophyllata Thunberg extract were carried out by using gas chromatography and mass spectrometry 9GC/MSD), which were identified as eugenol. As a result, the functionality of Polygonum cuspidatum Sieb. et Zucc. extract and Eugenia caryophyllata Thunberg extract as antimicrobial agents for keeping qualities of postharvested greenhouse produce may be recommended.

• 전기학회논문지P
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• 제59권4호
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• pp.411-416
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• 2010

Interest in application of ultraviolet light technology for primary disinfection of potable water in drinking water treatment plants has increased significantly in recent years. The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics(CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. In this paper, It describe the how to design optimal UV disinfection device for ground water, BWT and rainwater. Spring shape instrument silver coated located in inner side of disinfection chamber. It make lead the active flowing movement target water and maximize disinfection performance. To search the optimal design method, it was performed computer simulation with 3D-CFD discrete ordinates model and manufactured prototype. Using proposed design method, performed simulation and proved satisfied performance.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.65-66
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• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.121-125
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• 2002

방울토마토의 포장에 적합한 필름을 선택하기 위하여 기체 투과도가 다른 여러 가지 필름으로 방울토마토를 포장하고 저장하면서 포장내 기체 농도, 총균수, 효모 및 곰팡이 수, 중량 감소율, 부패율 등을 조사한 결과는 다음과 같았다. CPP와 PD961로 포장한 시험 구는 저장 기간 동안 계속 적으로 산소와 이산화탄소 농도가 계속적으로 변화하였으나 다른 포장재로 포장한 시험구는 저장 10일 경에 대체적으로 평형에 도달하였다. 저장 기간 중 중량 감소율은 PY85로 포장한 시험구가 가장 현저하였으며 다른 포장재로 포장한 시험구는 저장 20일까지도 1% 부근이었다. 포장 직후의 총 균 수는 $10^4$ CFU/g 부근이었으며, 이들은 대부분 곰팡이나 효모인 것으로 나타났다. 또한 저장 기간이 경과함에 따라서 대체적으로 미생물의 수는 증가하였다. CPP로 포장한 시험구는 저장 5일에는 총균수, 효모 및 곰팡이 수가 가장 적었으나 10일 이후에는 가장 많았으며, 저장 20일에는 총균수가 $10^{8}$ CFU/g이었으며, 효모 및 곰팡이 수는 $10^{7.97}$ CFU/g 이었다. 저장 기간 중 pH는 대체적으로 증가하였으며, 총산 및 가용성 고형물은 큰 변화가 없으나 대체적으로 감소하였다. 단지 PY85로 포장한 시험구는 저장 기간동안 지속적으로 총산과 가용성 고형물이 증가하였다. 저장 5일 이후에는MPD와 PY85를 제외한 시험구에서 부패가 발생하기 시작하였으며, CPP와 PD961로 포장한 시험구의 부패율이 대체적으로 높았다. MPD는 저장 20일에도 5.3%의 가장 낮은 부패율을 보였다.다.

• 멤브레인
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• 제12권1호
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• pp.21-27
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• 2002

본 연구에서는 회분여과방식을 이용하여 부하율에 따라 생성되는 생물대사성분의 특성 및 분포를 관찰하였다. 실험에 사용된 기질은 단일 탄소인 phenol을 사용하였으며, 분자량 분포실험을 위하여 분자량이 각각 30K, 100K Dalton 및 $0.45{\mu}$ membrane filter를 이용하여 구하였다. 페놀농도가 120, 230 및 440 mg/L 일 때 비기질이용율(q)은 각각 0.639, 1.281, 1.744 (mgTOC/mg MLSS/day)로 나타났으며 Run C일 때 가장 높은 이용율을 나타냈다 . 내생단계에서 미생물의 사멸율($K_d$)는 각각 0.0536, 0.0661, 0.0749($day^1$)이며 생성계수 ($SMP_e$) 는 각각 0.006, 0.0058, 0.0057($day^1$)로 나타났다. 초기 유입된 기질이 기질분해에 의해 생성된 $SMP_s$로 분해되어지며, 시간경과에 따라 $SMP_{nd}$ 로 진행됨을 알수 있었다. 기질분해 완료 후 미생물의 내생단계에 접어들면서 $SMP_e$성분으로 전환되었다. 유입부하율에 따른 분자량 분포 측정결과는 운전시간이 경고함에 따라 점차 저분자 물질이 고분자의 난분해성 물질로 전환되었다.