• Journal of Species Research
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• v.10 no.1
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• pp.46-56
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• 2021

Diatoms have been used in examining water quality and environmental change in freshwater systems. Here, we analyzed molecular profiling of seasonal diatoms in the Han River, Korea, using the hypervariable region of 18S V1-V3 rRNA and pyrosequencing. Physicochemical data, such as temperature, DO, pH, and nutrients showed the typical seasonal pattern in a temperate region. In addition, cell counts and chlorophyll-a, were recorded at high levels in spring compared to other seasons, due to the diatom bloom. Metagenomic analysis showed a seasonal variation in the phytoplankton community composition, with diatoms as the most frequently detected in spring (83.8%) and winter (69.7%). Overall, diatom genera such as Stephanodiscus, Navicula, Cyclotella, and Discostella were the most frequent in the samples. However, a large number of unknown Thalassiosirales diatoms were found in spring (35.5%) and winter (36.3%). Our molecular profiling revealed a high number of diatom taxa compared to morphological observation. This is the first study of diatoms in the Han River using molecular approaches, providing a valuable reference for future study on diatoms-basis environmental molecular monitoring and ecology.

• Animal Bioscience
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• v.35 no.8
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• pp.1279-1288
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• 2022

Objective: The aim of this study was to investigate antioxidant activities of cinnamon (Cinnamomum cassia) extracts (extracted with different solvents) at various concentrations and to determine product quality of raw chicken patties added with different levels of cinnamon powder (CP) and oyster mushroon powder (OMP) during storage. Methods: After cinnamon was made into oven dried CP and extracted with water and different levels (50%, 80%, and 100%) of ethanol, antioxidant activities of these extracts were determined. CP and OMP were combined at different levels and added to raw chicken patties. Physicochemical properties and microbial counts were measured during refrigerated storage. Results: Cinnamon ethanol (80%) extract showed the highest (p<0.05) by 2,2-diphenyl-1picrylhydrazyl-radical scavenging activity and reducing power. Cinnamon water extract (CWE) had the highest iron chelating ability (p<0.05), while CP 100% ethanol extract had the highest content of total phenolic compound. Then, CP and OMP were applied to chicken patties at different levels (0.1% to 0.2%). After the addition of CPs, pH, L* (lightness), 2-thiobarbituric acid reactive substance, and volatile basic nitrogen values were decreased, whereas a* (redness) and b* (yellowness) values were increased. Microbial counts of total bacteria and Enterobacteriaceace were decreased with the addition of CP 0.2% regardless of the OMP level. Conclusion: The addition of CP in combination with OMP can increase the shelf-life of chicken patties during storage.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.334-341
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• 2010

The objective of this study was to examine the quality characteristics and antioxidant activity of yogurt containing hot water extract from maca. Four different levels (0, 4, 8, 12%) of maca extract were added to milk followed by fermentation with lactic acid bacteria at $37^{\circ}C$ for 12 hrs, and then the physicochemical properties of the samples were investigated. During 7 days of storage at $4{\pm}1^{\circ}C$, the acid production (pH and titratable acidity) of the yogurt increased with the addition of maca extract. The Hunter L value (lightness) decreased, while the b value (yellowness) increased as the maca extract level in the yogurt increased. Viable cell counts were not significantly different among the samples. The results of consumer acceptance tests showed that no significant differences in overall acceptability were observed between the yogurts containing 4% and 8% of maca extract and a control yogurt. The yogurt containing maca extract exhibited higher DPPH radical and superoxide anion radical scavenging activities than the control yogurt over the storage period.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.297-313
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• 2009

Long-term trends and distribution patterns of water quality were investigated in the Gunsan coastal areas of Yellow Sea, Korea from 1972 to 2006. Water samples were collected at 6 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids(SS), chemical oxygen demand(COD), dissolved oxygen(DO) and nutrients. Spatial distribution patterns of temperature, DO and SS were not clear among stations but the seasonal variations were distinct except COD and SS. The trend analysis by principal component analysis(PCA) during 24 years revealed the significant variations in water quality in the study area. Spatial water qualities were clearly classified into 3 clusters by PCA; station cluster 1, 2~4, and 5~6. Annual water qualities were clearly classified into 4 surface water clusters and 5 bottom water clusters by PCA. By this multi-variate analysis. The annual trends were summarized as follows; Salinity, pH and DO tended to increase since late 1970's, COD to increase since 1987, and SS to decrease and nutrients to increase in Gunsan coastal waters due to the input of fresh water from land same as in Kyoungin coastal area, Asan coastal area and Choensoo bay.

• Membrane Journal
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• v.17 no.3
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• pp.161-173
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• 2007

Membrane filtration processes are increasingly popular for drinking water treatment that requires high quality of water. Low pressure membrane(LPM) processes such as microfiltration(MF) and ultrafiltration(UF), however, are ineffective in the removal of dissolved organic matter and also membrane fouling is still an important issue to be resolved. High pressure membranes(HPMs) may guarantee better water quality, but at the high energy consumption. Thus, various approaches to combine LPM processes with other physicochemical methods have been recently made to achieve their efficiency to the level comparable to that of HPM processes. In this work, therefore, hybrid processes that coupled MF/UF with coagulation, adsorption, chemical reactions(e.g., chelation and oxidation) are reviewed regarding system design and performance and also membrane surface modifications conducted by grafting and polyelectrolyte multilayer formation were assessed.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.414-424
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• 2009

The research was to get a biological assessment on Bokha stream and Dal stream, using the physicochemical factors and the epilithic diatom from June, 2008 to March, 2009. As a result, Bokha stream showed high consistency of total phosphorus ($0.041{\sim}0.886\;mg{\cdot}L^{-1}$), and total nitrogen ($0.336{\sim}10.532\;mg{\cdot}L^{-1}$). Also, the concentration of BOD showed most of the sites polluted as $2{\sim}5\;mg\cdot}L^{-1}$ except for the upstream sites. However, excluding downstream sites and other few sites, Dal stream had very clean water quality having total phosphorus less than $0.06\;mg\cdot}L^{-1}$, and total nitrogen less than $2.0\;mg\cdot}L^{-1}$. Out of the 12 total sites, 98 taxa of epilithic diatoms appeared: 67 taxa from Bokha stream, and 78 taxa from Dal stream. The results of the water quality assessment showed that, Bokha stream, having TDI level over 80, was mostly $\alpha$-mesosaprobic, which indicates a severe pollution. On the other hand, Dal stream, having TDI level below 50, was examined to be xenosaprobic and $\alpha$-oligosaprobic, which indicates a clean water quality. The correlation between DAIpo and TDI measured to be high in correlation coefficent (0.83) from the result of correlation analysis. When the water quality is good, there is an inclination of getting high correlation between chemical and biological water quality assessment results. TDI, which uses numerous taxa of diatoms, showed more stability than DAIpo, which uses less amount of taxa of diatoms to get its result.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.212-220
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• 2009

In this study, we analyzed fish compositions and ecological characteristics such as trophic guilds and tolerance guilds in association with water quality characteristics in Masan Reservoir during November 2008. Total number of species were 12 species (6 families) and the dominant species were Zacco platypus, Hemiculter eigenmanni, and Pseudorasbora parva. We found three Korean endemic species and one exotic species, Carassius cuvieri. According to the analysis of ecological indicator characteristics, relative proportion of tolerant and omnivore species was 98% of the total indicating that probably, the fauna was influenced by physical habitat disturbance and physicochemical degradations. Fish distribution analysis along with littoral zone showed that the most fishes (${\sim}$95%) were observed in the littoral zone where emerged macrophytes were well developed. Also, substrate analysis indicated that the most species were found near silt area (11 species, 91.7%), so that the significant differences were found between the substrate types. Analysis of water quality indicated that concentrations of total phosphorus (TP) and chlorophyll-a (ChI-a) as a lake trophic indicator were judged as eutrophic states, respectively and COD as an indicator of organic matter pollution averaged 10.9 mg $L^{-1}$. Based on the water quality, this system were influenced by the nutrient enrichments and organic matter. The degradations of water quality in Masan Reservoir resulted in trophic compositions of fish (increase of omnivore species) and the dominance of tolerant fish. This Monitoring data may contribute changes of fish fauna and compositions in relation to habitat modifications and chemical water quality degradations in the future.

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.460-465
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• 2018

Deep sea water is deeper than 200 m in depth and maintains cool temperatures. It is clean seawater not contaminated by E. coli and other general bacteria. Because deep sea water is a recyclable resource with high industrial value, activities for commercial use are vigorously developing. We investigated safety, quality characteristics, and mineral contents of prototype products using deep sea water as a substitute for a curing agent and compared it with existing commercially processed products. This study examined the potential of deep sea water as an alternative to curing agent solution. As a result, safety and quality characteristics of processed meat products with deep sea water were not different from commercially processed meat products, but mineral contents were higher in processed meat products with deep sea water. Deep sea water could be widely used as purity salt and purity minerals that can replace chemical substances such as chemical salts. A new, active food market using deep sea water will emerge in the near future.

• Food Science of Animal Resources
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• v.36 no.5
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• pp.617-625
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• 2016

Pastırma, a dry-cured meat product, is produced from the whole muscle and/or muscles obtained from certain parts of beef and water buffalo carcasses. The purpose of this study was to determine the effects of different levels of sodium nitrite on changes in the physicochemical and microbial quality during the production of pastırma. The changes in residual nitrite, salt, pH, moisture, thiobarbutiric acid reactive substances (TBARS), colour (L*, a*, b*), total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), Micrococcus/Staphylococcus (M/S), mould-yeast (M-Y), and Enterobacteriaceae counts of pastırma with 0, 50, 100 and 150 ppm sodium nitrite were determined during the production. The nitrite levels and the production stages had significant effects (p<0.01) on residual nitrite, TBARS, pH, salt, and colour values. The TBARS values of the pastırma with nitrite were significantly lower (p<0.05) than the control. The final TAMB, LAB, M/S, and M-Y counts of pastırma with 150 ppm nitrite were significantly (p<0.05) lower than the control. Also, the a* (relative redness) values of control pastırma were significantly lower (p<0.05) than the pastırma with nitrite. The production stages had a significant effect (p<0.01) on the moisture.

• Food Science of Animal Resources
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• v.39 no.2
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• pp.345-353
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• 2019

Various commercial collagen mixtures aimed at improving the quality of meat products are available, but the optimal composition is unclear. This study aimed to compare the functional properties, including physicochemical characteristics and lipid oxidative stability, of loin ham marinated with three commercial collagen mixtures sold as food additives. The addition of collagen mixtures led to significant increases in the moisture content, water holding capacity (WHC), cooking yield, and instrumental tenderness, regardless of the type of collagen mixture. In particular, meat samples containing collagen mixture C showed the highest (p<0.05) WHC and tenderness among all groups. Furthermore, collagen mixture B induced increases (p<0.05) in pH values in both raw and cooked samples. The $a^*$ values of samples with collagen mixtures were lower (p<0.05) than those of samples without collagen mixtures. All collagen mixtures effectively improved oxidative stability during 7 days of storage at $4^{\circ}C$. The samples containing collagen mixture B had the lowest lipid oxidation (p<0.05) among groups. These results indicated that collagen mixture C could be used in injection brine to enhance the quality characteristics of meat products, particularly the WHC and tenderness. Collagen mixture A could be used for meat products with high fat contents based on its ability to improve lipid oxidative stability during long-term storage.