• Food Science and Preservation
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• v.22 no.4
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• pp.545-552
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• 2015

This study investigated the quality characteristics of popped rice Doenjang prepared with different Bacillus strains (Bacillus subtilis KACC 15935, and Bacillus subtilis HJ18-9). The changes in the enzyme activity (protease, cellulase, and ${\alpha}$-amylase), amino-type nitrogen and ammonia-type nitrogen contents, and the reducing sugar were investigated during the fermentation period. Enzymes such as protease, cellulase, and a-amylase plays an important role in the changes in composition of nutrients, and in flavor and taste of popped rice Doenjang. Protease activities of the popped rice deonjang fermented with different Bacillus strains (control, B. subtilis KACC 15935, and B. subtilis HJ18-9) was in the range of 171.77-185.97 unit/g at the beginning of fermentation, and there were no significant differences among the samples. On the other hand, the protease activity in popped rice Doenjang fermented with B. subtilis HJ18-9 increased significantly up to $248.77{\pm}4.53unit/g$ at the end of fermentation (p<0.05). Cellulase activity and a-amylase activity of popped rice Doenjang in HJ18-9 was higher than these of other samples. After 56 days of fermentation, amino-type nitrogen in popped rice deonjang fermented with control, B. subtilis KACC 15935, and B. subtilis HJ18-9 increased significantly up to $174.99{\pm}3.70$, $166.59{\pm}1.40$, $225.39{\pm}3.70mg%$, respectively (p<0.05). These results suggested that B. subtilis HJ18-9 was a suitable starter for the preparation of soybean paste.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1462-1466
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• 2014

In this study, an attempt was made to produce oat protein concentrates from defatted oat groat by alkali extraction. Independent variables formulated by D-optimal design were NaOH concentration (X1, 0.005~0.06 N) for extraction and precipitation pH (X2, pH 4.0~6.0), and the dependent variable was extraction yield (Y1, %). Experimental results were analyzed by response surface methodology to determine optimized extraction conditions. Extraction yield increased both with an increase in NaOH concentration of the extraction solution and when approaching a precipitation pH of 4.9, and NaOH concentrations were a major influencing parameter. Solubility of oat protein concentrates showed a minimum value (i.e., 0.1%) at pH 5 and increased substantially at pH values in the range of ${\leq}$ pH 3 or ${\geq}$ pH 7, reaching a maximum value at pH 11 (i.e., 76%). Regression equation coincided well with the results of the experiment. Optimized extraction conditions to maximize extraction yield were 0.06 N NaOH (X1) for extraction and pH 4.7 (X2) for precipitation.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.64-71
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• 1983

This experiment was carried out to investigate the effect of lime and phosphorus on soil and yield of rice plants in acid sulfate soil. 1. Lime requirement plus phosphorus (20Kg/10a) plot showed 60% increased in yield. 2. The effect of increase was 36% in lime and 15% in phosphorus. 3. pH and Eh were reversed each other by lime application, and lime and phosphorus increased soil reduction. 4. Sixty two percent of root was distributed in top soil (0-5cm) of control plot while it spreaed in sub soil (5-10cm) with high level of lime and phosphorus plot. 5. Soil pH reached maximum at maximum tillering stage and decreased there after approching near to original pH. But lime requirement was about half of original one. 6. There was significant positive correlation between yield silica or phosphorus in soil, which were high with increase of pH. 7. The application of lime and phosphorus increased nitrogen content in plants. When contents of phosphorus in rice plants were high the yield of rice was increased.

• Korean journal of food and cookery science
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• v.6 no.4 s.13
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• pp.1-8
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• 1990

For the purpose of supplying the imformation to improve the acceptability of soy paste as the condiment, the changes of enzyme activity, general component and flavor compounds (Free amino acid, Nucleic acid related compounds, and peptide) during improved soy paste fermentation were determined. The results were as follows; 1. The protease activity during fermentation were increased continuously, but amylase activity were decreased in 45 day fermentation. Cellulase activity were slowly increased until 45 day, and then slowly decreased. 2. Total nitrogen contents were almost constant during fermentation, but amino nitrogem were increased rapidly. Reducing sugar were not constant, but increased in the end of fermentation. PH were decreased to pH 4.97. 3. Total contents of free amino acid as flavor compound were rapidly increased in 10 day fermentation, but were constant in $30{\sim}60$ day. Aspartic acid contents were increased continuously, but glutamic acid were increased slowly until 30 day fermentation and were almost constant. IMP and GMP contents showed increasing pattern during fermentation.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.9-15
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• 2000

The effects of clearcutting on soil chemical ingredients and stream water quality have been investigated at a natural deciduous forest catchment within the Seoul National University Research Forest in Mt. Paekun, Chunnam province during the periods of 1993 to 1998. Soil chemical ingredients and stream water qualities were monitored at a 13 ha clearcutting site and a non-treatment site nearby. During the first and second years after harvesting, the levels of total-N, and exchangeable ions (K/sup ＋/, Na/sup ＋/, Ca/sup 2＋/, Mg/sup 2＋/) decreased compared to the values of before harvesting. During the fifth years after harvesting, these levels were significantly higher than those during the first and second years after harvesting. But the chemical characteristics of soil were not changed at all. pH of water in the harvesting area was 6.5 in stream water. Among the nutrients, Cd, Pb, Cu, and phosphate were not found, and the level of BOD reached at the level of the domestic use suitable for drinking. Turbidity, odor, taste, NH/sub 4//sup ＋/ -N, NO/sub 3//sup -/-N, standard plate count, and coliform were also low enough to be used as the domestic use for drinking by the near villagers. During the first and second years after harvesting, BOD increased to about 1 ppm. For that reason, the harvesting planning should be built in the harvesting area in consideration of the control of water quality in the stream.

• Membrane Journal
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• v.24 no.1
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• pp.63-68
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• 2014

Manufacturing facility for non-alcoholic drink, the parts of the food industry, disposes wastewater which includes high organic concentration and low nitrogen, phosphorus concentration. For this kind of wastewater, the treatment plant consists mainly of aerobic reactor and chemical coagulation process. And sand-filter or activated carbon process is normally installed further. However, aerobic reactor must have long HRT to treat high concentration of organic contaminant included in this wastewater, so the large site area is required. And settling tank which is normally applied for wastewater treatment facility has some problems such as water quality degradation caused by the sludge spill. To solve these problems, we applied MBR system for the wastewater. And the MBR pilot plant was installed nearby the wastewater treatment facility of W food factory and operated during long term to evaluate treatment efficiency. This plant was operated about 3 months and than the result was 97% of organic removal rate on conditions of flow rate $20m^3/day$, HRT 29 hr, recycle 4Q. However, contaminant removal ratio of bio-reactor decreased and TMP of membrane increased rapidly on more conditions.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.12
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• pp.657-667
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• 2015

Cyanobacteria frequently dominate the freshwater phytoplankton community in eutrophic waters. Cyanotoxins can be classified according to toxicity as neurotoxin (Anatoxin-a, Anatoxin-a(s), Saxitoxins) or hepatotoxin (microcystins, nodularin, cylindrospermopsin). Microcystins are present within cyanobacterial cells generally, and they are extracted by the damage of cell membrane. It has been reported that cyanotoxins caused adverse effects and they are acculmulated in aquatic oganisms of lake, river and ocean. In natural, microcystins are removed by biodegradation of microorganisms and/or feeding of predators. However, in process of water treatment, the use of copper sulfate to remove algal cells caused extraction of a mess of microcystins. Microcysitns are removed by physical, chemical and biological methods according to reports. The reduction of nutrients (N and P) inflow is basic method of prevention of cyanobacteria bloom formation. However, it is less effective than investigation because nutrients already present in the eutrophic lake. In natural lake, cyanobacteria bloom are not formed because macrophytes invade from coastal lake by eutrophication. Therefore, a coastal lake has to recover to prevent of cyanobacteria bloom formation.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.6
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• pp.311-317
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• 2017

The aim of this study is to investigate the environmental properties of paddy soils depending on farming methods and seasonal variation. The paddy soils in 11 plots of conventional paddy and 24 plots of organic paddy were sampled and analyzed in four season of March, May, August, and October. The obtained data of soil properties were used for statistical analysis. Analysis of variance showed that only $NH_4-N$ and $P_2O_5$ were significantly different depending on farming methods. However, the differences of all soil properties depending on seasonal variation were strongly significant. Principal component analysis also presented that nitrogen and phosphorus concentration in soils were more significantly influenced by seasonal variation than farming method. Electric conductivity in soil was decreased from March to October. Amounts of soil organic matter in August and October were higher than that in March and May. T-N was decreased from March to October. $NH_4-N$ and $NO_3-N$ in the soil of both conventional and organic paddy were higher in May than other seasons. T-P concentration was found to be highest in August, but $P_2O_5$ concentration was lowest in August. It can be concluded that seasonal variation should be considered for analysis and comparison of soil environmental properties.

• Journal of Korean Society of Disaster and Security
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• v.13 no.2
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• pp.65-75
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• 2020

The efficiency of sewage treatment was ananlyzed selecting a sewage treatment plant in Gyeonggi-do where A₂O process was applied. Statistical techniques based on the operation data of the sewage treatment were used. The main factors directly affecting the efficiency of the treatment process were analyzed using a GPS-X model. The correlation analysis and one-way ANOVA were performed. The T-N and NH₄⁺-N values of the effluent did not generate statistically significant level (p-value:>0.05) when compared with C/N ration values. Removel of nitrogen components form sewage treatment plants were affected by temperature, HRT, SRT and DO. In the case of BOD, all operating factors were affected, while COD was affecte by factors of HRT, STR and DO. In simulations using GPS-X, the parameters that greatly influence was included the maximum sedimentation rate, the dependent nutrient microbial yield (anoxic), the phosphorus saturation coefficient, the dependent nutrient microbial killing rate, the dependent nutrient microbial maximum growth rate, and the independent trophic microorganisms. The maximum growth rate and the maximum setting rate were identified.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.27-34
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• 1999

In order to obtain necessary data for the use of hydrophytes to improve water quality of artificial lakes, production and nutrients absorption by some macrohydrophytes were investigated in a small water course at Woongcheon, Chungnam Province. The maximum above-ground standing biomass of Phragmites communis, Typha angustifolia and Zizania latifolia stand were 3,504 g/m$x^2$, 2,834 g/m$x^2$ and 3,125 g/m$x^2$, respectively. Estimated below-ground standing biomass of each stand were 9,671 g/m$x^2$,5,158 g/m$x^2$ and 5,813 g/m$x^2$, respectively. Concentration of nutrients in each organ was different among plant species. Maximum amount of standing nitrogen was the highest in the reed stand and that of standing phosphorus was the highest in the cattail stand. Amount of maximum standing nutrients are 2795.6 kgN/ha and 42.5 kgP/ha for the reed stand, 1,413 kg N/ha and 24.8 kgP/ha for the cattail stand and 1.901.1 kgN/ha and 38.4 kgP/ha for the wild rice stand, respectively. According to our investigation, it is concluded that reed, cattail and wild rice are suitable for water quality improvement of artificial lakes through nutrients absorption.