• Fisheries and Aquatic Sciences
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• 제27권6호
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• pp.379-391
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• 2024

Tocopherol, carotenoids, and chlorophyll are the primary components of the antioxidative response in microalgae. Conditions of stress, such salt stress, can trigger the processes responsible for the accumulation of tocopherol and carotene. It has been found that the most difficult part of culturing microalgae is keeping it affordable. This study investigated the effects of different salt types and concentrations on the amount of α-tocopherol, carotenoid derivatives, and flocculation efficiency of Euglena sp. Cultures of Euglena sp. was developed under salt stress conditions of NaCl 200 mM and KCl 200 mM. UV-VIS spectrophotometry was used to confirm the presence of α-tocopherol and carotenoid derivatives under thirteen days of salt stress testing. Increasing salinity has a significant effect on Euglena sp., causing spherical cell morphologies with aspect ratio 1.385 ± 0.031 for NaCl 200 mM and 1.414 ± 0.040 for KCl 200 mM. Increasing salinity also slowing down development with specific growth rate value of 0.171 ± 0.006 per day and 0.122 ± 0.029 per day for NaCl and KCl 200 mM, respectively. Nevertheless, the amount of α-tocopherol in Euglena sp. increases with a high salt concentration; algal cells flocculated more successfully when increasing the salt concentrations (NaCl 200 mM and KCl 200 mM) was added. Due to the inhibition of photosynthetic activity in salt-stressed cells, the control group exhibited higher levels of carotenoid derivatives (ranging from 0.5-1 ㎍/mL) and pheophytin a and b (0.0062 ± 0.001 ㎍/mL and 0.0064 ± 0.001 ㎍/mL) than the group treated with salt stress. In conclusion, salt stress was an effective way to raises the concentration of α-tocopherol and significantly reduce the expense of harvesting Euglena sp.

• 한국농공학회논문집
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• 제51권6호
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• pp.53-62
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• 2009

The EFDC (Environmental Fluid Dynamics Code), a numerical model for simulating three-dimensional (3D) flow, transport, and biogeochemical processes in surface water systems including rivers, reservoirs, and estuaries, was applied to assess the effect of sea water and fresh water exchange rates ($Q_e$) on the mixing characteristics of a conservative pollutant (tracer) induced from upstreams and salinity in Saemangeum Lake, Korea. The lake has been closed by a 33 km estuary embankment since last April of 2006, and now seawater enters the lake partially through two sluice gates (Sinsi and Garyuk), which is driving the changes of hydrodynamic and water quality properties of the lake. The EFDC was constructed and calibrated with surveyed bathymetry data and field data including water level, temperature, and salinity in 2008. The model showed good agreement with the field data and adequately replicated the spatial and temporal variations of the variables. The validated model was applied to simulated the tracer and salinity with two different gate operation scenarios: RUN-1 and RUN-2. RUN-1 is the case of real operation condition ($Q_e=25,000,000\;m^3$) of 2008, while RUN-2 assumed full open of Sinsi gate to increase $Q_e$ by $120,000,000\;m^3$. Statistical analysis of the simulation results indicate that mixing characteristics of pollutants from upstream can be significantly affected by the amount of $Q_e$.

• 한국식생활문화학회지
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• 제26권4호
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• pp.394-399
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• 2011

This study was conducted to investigate the effect of Nelumbo nucifera G. (NN) powder on cookie quality characteristics. The cookies were made with various NN powder levels (1, 3, and 5%). Crude fiber, crude ash, and the Mg contents of cookies with added NN powder were higher in concentration than those of the control group. Salinity of NN-powder added groups was not significantly different when it was compared with the control group's salinity. No significant difference among the groups were observed for specific volume, but the width determined by water content in the dough decreased as the amount of added NN powder increased. The L-value of the cookies was significantly larger than that of the control group. The a- and b-values were the highest for the 5% substituted NN flour. According to the sensory evaluation of the cookies, scores for color, flavor, and texture increased with increasing amounts of added NN powder. The overall acceptance of the 3% NN added cookies was greater than that of the 1 and 5% cookies.

• 한국가스학회지
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• 제22권5호
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• pp.53-61
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• 2018

저염수 기반 폴리머공법은 기존의 폴리머공법과 저염수주입공법의 시너지 효과를 통해 오일회수율을 더욱 증진시킬 수 있는 기술로서, 공법의 효율성을 극대화하기 위해서는 폴리머의 특성을 고려한 저염수 설계가 필수적이다. 이에 본 연구에서는 탄산염암 오일 저류층에 저염수 기반 폴리머공법 적용 시, 주입수의 pH와 주입수 내 PDI(Potential Determining Ion) 이온 중 $SO_4{^{2-}}$ 이온이 오일 생산량에 미치는 영향을 규명하고자 하였다. 우선, 주입수의 pH와 주입수 내 $SO_4{^{2-}}$의 농도에 따른 폴리머 분자의 안정성 및 흡착 현상을 분석하였다. 그 결과, 주입수의 pH와 주입수 내 $SO_4{^{2-}}$의 농도에 상관없이, 주입수 내 $SO_4{^{2-}}$가 함유되어 있는 경우 폴리머 용액의 안정성이 확보되었다. 그러나, 폴리머 용액의 정체 현상 분석 결과, 주입수의 pH가 중성인 7일 때에는 $SO_4{^{2-}}$ 이온이 폴리머의 흡착을 방해하여 $SO_4{^{2-}}$의 농도가 높을수록 폴리머 흡착층의 두께가 더 얇은 것으로 나타난 반면에, 주입수가 pH 4로 산성인 경우에는 폴리머 용액을 주입함에 따라 폴리머의 흡착량이 증가하여 폴리머 용액의 유동성이 크게 낮아졌다. 다음으로, 저염수 효과에 의한 습윤도 변환을 살펴본 결과, 주입수가 중성일 때에는 $SO_4{^{2-}}$의 농도가 높을수록 탄산염암 표면에 흡착되어 있던 오일의 탈착이 증가하여 암석의 습윤도가 친유성에서 친수성으로 크게 변환되었다. 반면에, 주입수가 산성일 때에는 용해와 폴리머 흡착의 복합적 작용으로 인해 전체 코어 시스템의 습윤도는 중성일 때에 비해 비교적 덜 변환되는 것으로 나타났다. 이에 따라 $SO_4{^{2-}}$ 농도가 높은 중성의 저염수 기반 폴리머 용액을 주입할 경우 오일 생산량은 저염수주입공법에 비해 최대 12.3% 증진되어 보다 양호한 EOR(Enhanced Oil Recovery) 효과를 얻을 수 있는 것으로 평가되었다.

• 한국식품조리과학회지
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• 제27권5호
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• pp.531-543
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• 2011

In this study, Bokbunja (Rubus coreanus Miquel) was used with a Demi-glace sauce to compare and analyze the effect of different amounts of Bokbunja (0, 10, 20, 30, and 40%) on the physico-chemical qualities of the Demi-glace sauce. The moisture content of Demi-glace sauce increased but crude protein, crude lipid, and crude ash decreased as the amount of added Bokbunja increased. DPPH radical scavenging activity of the control group was 43.33%, whereas Bokbunja Demi-glace sauces ranged from 83.13~86.40%. As the amount of added Bokbunja increase, pH decreased, and acidity of the Demi-glace sauces increased. Sauce sweetness was significantly different between each sample (p<0.01). Salinity decreased, but viscosity increased as the amount of added Bokbunja increased. Color L, a and b values decreased significantly, as storage period increased. The sensory property results showed that the 20% and 30% Bokbunja sauces were higher than the others. The 20% Bokbunja sauce was the most preferred with regards to the balance of a steak containing this sauce with a score 5.34 points.

• 한국식생활문화학회지
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• 제29권2호
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• pp.187-194
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• 2014

The physicochemical and sensory properties of barley Kochujang added with germinated barley powder were periodically examined during storage at 20 for 40 days. The pH of barley Kochujang added with germinated barley powder increased gradually according to the level of added germinated barley powder, whereas it decreased gradually during storage. On the other hand, acidity showed the opposite relationship with addition level. Salinity of the samples decreased gradually according to the amount of added germinated barley powder. Amino nitrogen content of barley Kochujang increased gradually according to the amount of added germinated barley powder, whereas it increased gradually during storage. L-, a-, and b-values of samples increased gradually according to the amount of added germinated barley powder, whereas they decreased gradually during storage. As a result of the sensory evaluation, barley Kochujang added with 5% germinated barley powder was found to be superior in taste, viscosity, and overall preference. Sensory evaluation revealed that addition of 5% germinated barley powder was optimum for improving Kochujang quality.

• 한국식품조리과학회지
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• 제27권4호
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• pp.89-98
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• 2011

The physicochemical and sensory properties of kochujang added defatted rice bran powder were periodically examined during storage at 30$^{\circ}C$ for 45 days. The pH of kochujang added defatted rice bran powder increased gradually according to the added level, whereas pH decreased gradually during storage. But the acidity to be appeared opposite of pH. The L-, a and b-values of samples increased gradually according to the amount of added defatted rice bran powder, whereas they decreased gradually during storage. The salinity of samples decreased gradually according to the amount of added defatted rice bran powder and storage. Amino nitrogen content of kochujang added defatted rice bran powder was higher than that of the control during storage. Electron donating activities of kochujang added defatted rice bran powder increased gradually according to the amount added. As a result of the sensory evaluation, the 3% treatment was superior in color, aroma, and overall preference. The sensory evaluation revealed that adding 3% defatted rice bran powder was optimum for improving kochujang quality.

• 한국토양비료학회지
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• 제48권3호
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• pp.205-212
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• 2015

Farmers with forage barley (Hordeum vulgare L.)-rice (Oryza sativa L.) cropping system at reclaimed tidal lands burn crop residues to facilitate seedbed preparation or remove them for feed stock. This study was conducted to investigate the effect of rice straw amendment and N fertilization on soil properties and N uptake of rice under forage barely-rice cropping system at reclaimed tidal paddy field. Rice straw was applied at the rates of 0, 2.5 and $5.0ton\;ha^{-1}$ and N was fertilized at 0, 100, 200 and $400kg\;ha^{-1}$. Although there was no significant difference in the growth and yield of rice, fresh and dry weight of forage barely increased with increasing the amount of rice straw. The amount of N uptake of rice at harvesting stage was $65.8-69.2kg\;ha^{-1}$ by the amount of rice straw amendment, but there were no significant differences among rice straw amendment levels. After harvesting the rice, the soil salinity decreased with rice straw amendment compared to the control. After forage barely and rice cultivation, soil organic matter contents increased to $2.6-2.8g\;kg^{-1}$ and $3.2-3.5g\;kg^{-1}$, respectively. The amount of N uptake of rice at harvesting stage increased up to $82kg\;ha^{-1}$ in $400kg\;ha^{-1}$ N applied plots which were $37.8kg\;ha^{-1}$ higher than the control. Nitrogen fertilization decreased N recovery efficiency. The highest yield of rice was observed at $244kg\;ha^{-1}$ N fertilization level, but the optimum N level was estimated at $168kg\;ha^{-1}$ in order to keep the protein content of rice under 6.5%. Further researches on N uptake and application of organic matter according to soil salinity will be necessary to increase N use efficiency at reclaimed tidal paddy field.

• 한국양식학회지
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• 제11권2호
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• pp.231-240
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• 1998

온도와 염분에 대하여 내성이 강하고 대량배양이 쉬워서 조개류의 인공종묘생산시 먹이로서 많이 사용하고 있는 5종의 Tetraselmis (T. tetrathele, T. suecica, T. subcordiformis, T. sp. (Haeundae), T. sp (China)) 중 우리나라 기후 환경에 대향배양이 가장 적합한 종을 선택하기 위핵서 최적 배양환경 (온도, 염분)을 조사하고 이때의 세포크기와 영양성분을 조사하였다. 5종의 Tetraselmis의 세포크기 및 체적은 T. sp. (Haeundea)가 장경 $17.6{\pm}1.87$${\mu}$m, 체적 727${\mu}$$m^3$로 가장 대형종이었으며 중국산 T. sp.가 장경14.6+- 1.46${\mu}$m, 체적 625${\mu}$$m^3$으로 가장 소형종이였다. Tetraselmis는 광염성, 광온성이나 최적성장을 위한 수온과 염분 구간은 각각 24~$30^{\circ}C.$와 27~30%.였다. 5종의 Tetraselmis에서 고수온에 대한 내성은 중국산 Tetraselmis, 저수온데 대한 내성은 T. tetrathele가 높은 것으로 나타났다. 5종의 Tetraselmis중 배양밀도가 가장 높았던 종은 T. suecica였으며, 이 종은 배양 7일째 $24^{\circ}C.$, 30%.에서 세포수가 $141{\times}10^4$cells/ml (s.g.r., 0.3906)로 성장이 가장 좋았다. 5종의 Tetraselmis의 화학성분중 조단백질 함량은 T. suecica가 44.50%로 가장 높게 나타났고 조지방은 해운대산 T. sp.가 7.13%로 높게 나타났다. 필수아미노산은 해운대산 .T.sp.에서 50.40%로 가장 높게 나타났고, 불포화지방산은 중국산 T.sp.에서 11.7%로 가장 높게 나타났다. 5종의 Tetraselmis의 성장과 영양성분 결과로 보아 우리나라에서 대량배양이 가장 적합한 종은 T. seucica임을 알수 있었다.

• 한국산학기술학회논문지
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• 제21권8호
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• pp.298-303
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• 2020

본 연구는 고품질의 천일염을 생산하기 위한 세정조건을 구명하기 위해서 수행되었다. 세정시 수율의 감소를 방지하기 위해서 세정수의 염도는 5 %로 설정하였고, 온도조건은 5, 10, 17.5, 20 ℃로 총 4가지 수준이었다. 세정 실험 후 수분, 염도, 불용분, 사분의 함량을 측정하였다. Color 특성으로는 L*[lightness], a*[redness], b*[yellowness]값을 측정하였고, 최종적으로 수율을 측정하였다. 세정 후 천일염의 수분은 세정수의 온도가 10 ℃이상의 범위에서 증가하는 경향을 나타내었다. 염도와 수율은 세정수의 온도가 높을수록 감소하였고, 불용분의 함량은 세정수의 온도가 낮을수록 감소하는 것으로 나타났다. 사분의 함량은 세정수의 온도가 5 ℃인 경우 0.67 %이었고, 더 높은 온도에서는 0.57 %로 감소하였다. 색도중 b*값의 경우에는 세정수의 온도가 높을수록 높게 나타났으며, 이는 표면품질 저하의 원인으로 판단되었다. 따라서, 품질 저하와 수율의 감소를 최소화하는 세정수의 온도는 10 ℃이상이 적합한 것으로 나타났다. 향후 세정 후 건조조건 구명을 위한 실험을 수행하여 최적의 고품질 생산 공정의 설계인자를 도출할 수 있을 것으로 기대된다.