• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.169-185
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• 2017

Physicochemical properties of water quality were analyzed to understand the long-term variations in Lake Youngrang from 1998 to 2015. Nonparametric statistical methods were applied to deduct correlation among water quality parameters and water quality trend. In total observations(N=64), the Secchi depth (SD) transparency showed significant positive correlation with salinity (r=0.458) and highly significant negative correlation with chlorophyll-a (r= -0.649) for p<0.0001 in two-tailed test of Spearman's rank correlation. Significant negative correlations of SD were observed with chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN). These correlation patterns were very similar in rainy (N=25) and non-rainy (N=39) periods too. Chlorophyll-a (Chl-a) had significant correlation with COD. Sen's slope test was performed along with Mann-Kendall trend test (significance ${\alpha}=0.05$, two-tailed) to find water quality trend. Positive trends were observed for SD and salinity with Sen's slopes 0.012 and 0.385, respectively (p<0.0001). Negative significant trends were observed for total nitrogen (TN) and Chl-a with Sen's slopes -0.02 (p<0.0001) and -0.346 (p=0.0010), respectively. Temperature, COD and phosphorus components had no trends. Carlson's trophic state index (TSI) for SD, TP and Chl-a were obtained in the ranges of 46~80, 37~82 and 39~82, respectively. Trophic index values suggest that Lake Youngrang was mesoeutrophic to eutrophic and there could be possibility of anoxia during the summer and dominance of blue-green algae. Excess nutrient inputs from external and internal sources were the causes of eutrophication in this lake. The findings of this study would be helpful to recognize water quality variables to manage the water body.

• Korean Journal of Microbiology
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• v.36 no.4
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• pp.285-291
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• 2000

To investigate the variations of physicochemical factors and microbial populations in seven stations at water region of Gangjin bay, nutritive salts, water temperature, transparency, suspended solid, salinity, COD, DO, pH, heterotrophic bacteria, fungi and fecal coliform were analysed four times from February to October, 1999. Total fecal coliform and heterotrophic bacterial population during investigation periods ranged 16.1~166.0 CFU/ml and $5.0{\times}10^3$~$13.1{\times}10^3$CFU/ml, respectively. Stational mean values of these bacterial population showed higher densities at the inlet of fresh water inflow than those of other stations. When the aspects of abiotic and biotic parameters measured were analyzed, ecosystem of Gangjin bay was regulated by factors such as inflow of fresh water, nutrient salts, salinity and variation of water temperature during four seasons.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.3
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• pp.230-236
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• 2016

The study was carried out to evaluate the quality of commercial pork and beef jerky at a market in Korea. The amount of food additives, place of origin, meat content, microbiological and physicochemical characteristics were investigated in 46 different jerky samples. Meat contents of pork and beef jerky were 75.2~94.0% and 80.0~95.6%, respectively. Food additives, including sodium nitrite, potassium sorbate, and sodium erythorbate were mainly used in jerky. Pork jerky was processed from domestic pork, and beef jerky was mostly processed from imported beef from the USA, Australia, or New Zealand. Pork jerky contained $23.82{\pm}5.74%$ moisture, $37.86{\pm}7.05%$ crude protein, $6.16{\pm}4.91%$ crude fat, and $4.6.87{\pm}1.76%$ crude ash. Beef jerky contained $26.64{\pm}5.21%$ moisture, $41.36{\pm}3.50%$ crude protein, $4.67{\pm}3.46%$ crude fat, and $7.21{\pm}1.91%$ crude ash. Water activity (Aw) of pork jerky was $0.73{\pm}0.09$ while that of beef jerky was $0.78{\pm}0.08$. Volatile basic nitrogen (VBN) content to jerky was 7.1~36.0 mg/100 g. There was no significant difference in the physicochemical composition of meat type (p<0.05). Coliform, Escherichia coli and Staphylococcus aureus were not detected in pork or beef jerky, whereas yeast and molds were detected below $1.2{\times}10^1CFU/g$ in beef jerky samples.

• Food Science and Preservation
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• v.10 no.4
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• pp.498-505
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• 2003

This was studied to evaluate the rheology properties of the Dumpling shell added chitosans(commercial and prepared from fungal), polyphosphate, guargum and tapioca. The physicochemical properties of fungal chitosans (FCs95 and FCs 40) were as follows respectively. The nitrogen was 6.71% and 6.9％, the solubility 99.05% and 99.13％, the viscosity 2.23cps and 2.21cps, the acetylation 12.0% and 12.7% and the molecular weight 3.12${\times}$10$\^$5/Dalton and 3.01${\times}$10$\^$5/Dalton. From the above facts, the components and physicochemical properties of two kinds of fungal chitosan had little difference. The addition of polyphosphate, guargum and tapioca showed effect on the texture parameters(hardness, cohesiveness, springiness and gumminess) of Dumpling shell dough and the optimum addition concentration wag 0.074%, 6.59% and 0.062%(w/w), respectively. In case of chiotsans addition, texture of the dough by added SCs, FCs95 and FCs40 showed effect.

• YAKHAK HOEJI
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• v.37 no.6
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• pp.638-646
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• 1993

A cepfialosporin with an aminothiazoiylmethoxyimino-type side chain at the 7 position and bicyclic quinolone dithicarbamate at the 3' position was synthesized. It has broad and potent antivacterial activity in vitro. The antibacterial spectrum reflects contributions of both the cephalosporin moiety and the quinolone moiety. Thus, this compound was named DACD implying a dualaction cephalosporin derivative. In this paper, the physicochemical proper-ties (lipid-water partition, pKa), stability and pharmacokinetics of DACD were determined and compared with cefotaxime 3'-norfloxacin dithiocarbamate (CENO). Stability tests were studied in pH 1.20, 6.80 and 8.00 buffers and in the presence of AB type human plasma, rat liver homogenate and its .betha.-lactamase. The pharmacokinetic parameters of DACD were evaluated in mice after a single intravenous dose of 40 mg/kg. The results are as follows. The lipid-water partition coefficient of DACD was higher than that of CENO. The calculated pKa values of CENO and DACD, were 6.82$\pm$0.03, 7.53$\pm$0.21, respectively. In the hydrolysis test, half-lives (t$^{1/2}$) of CENO and DACD was 66.0 hr and 80.0 hr in pH 6.80 buffer, 190 hr and 91.4 hr in pH 8.00 buffer. CENO and DACD were rapidly hydrolyzed in human plasma and in rat liver hornogenate. Half-lives (t$_{1/2}$ of CENO and DACD were 1.29 hr and 1.15 hr in hyman plasma, 0.62 hr and 0.71 hr rat liver homogenate. In $\beta$-lactamase stability test, CENO and DACD were very stable to the .betha.-lactamases obtained from three different strains. Half-life (t$_{1/2}$) and areas under the curve (AUC) in mice were 2.33 hr and 15.97 (mg.h/1), respectively.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.799-809
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• 2018

This study was performed to compare the physicochemical characteristics between imported dry-cured Hams from black and white pigs available in the domestic market. The black dry-cured hams contain higher moisture and ash contents than that of white hams, whereas the black dry-cured hams had lower fat contents than that of the black ones (p < 0.05). The hams from black ones had lower lightness ($L^*$) and yellowness ($b^*$) values than those from the white ones (p < 0.05). Moreover, the pH values and salt contents of the hams from the black ones were higher than those from the white ones (p < 0.05). Moreover, the black ones had a higher water holding capacity (WHC) than that of the white ones (p < 0.05). The thiobarbituric acid reactive substances (TBARS) values of the black ones were lower than those of the white ham samples (p < 0.05). For texture profile analysis, hardness, gumminess, chewiness, cohesiveness and shear force values were significantly lower in the black ones than in the white samples (p < 0.05). Saturated fatty acids in the white ones were higher than in the black ones, whereas unsaturated fatty acids in the black ones were higher (p < 0.05). Free amino acids such as aspartic acid and glutamic acid in the black ones were higher than in the white ones (p < 0.05). The shrinkage of muscle fiber was stronger in the white ones. Considering the meat quality parameters of ham, the black ones showed a superior meat quality. In general, this research can be used as fundamental information for the mass production of dry-cured hams in Korea.

• Food Science of Animal Resources
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• v.42 no.4
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• pp.639-654
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• 2022

The current study investigated the effects of the most suitable modified atmosphere packaging (MAP) on the physicochemical, microbiological, and sensory properties of fermented dry sausages during 45 days of refrigeration (4℃) storage period. Treatments were vacuum-packed (control), 25% CO₂/75% N₂ (MAP1), 50% CO₂/50% N₂ (MAP2), 70% CO₂/30% N₂ (MAP3), and 100% CO₂ (MAP4). All MAP samples regardless of their CO₂ composition significantly (p<0.05) decreased in pH, a_w, total plate count, and lactic acid bacteria count values as compared to the vacuum-package during storage. The Enterobacteriaceae count in all MAP packaging was significantly (p<0.05) lower than the vacuum-packed samples and counts in MAP3 and MAP4 samples were markedly (p<0.05) lower than all other treatments in prolonged storage of 15 and 45 days. Based on the thiobarbituric acid reactive substance content at day 15 and 30 storage time, treatments are ranked as follows: Vacuum-packed>MAP1>MAP2>MAP3>MAP4. The a^* of MAP4 was higher than all other treatments. In the final storage days, no variation was exhibited (p>0.05) among treatments in lactic acid aroma and sourness, and MAP2 samples had the lowest (p<0.05) overall acceptability. The use of MAPs with an increase in the CO₂ from MAP1 to MAP4 samples can help in better microbial inhibition than vacuum package, and 70% CO₂/30% N₂ (MAP3) and 100% CO₂ (MAP4) were effective to maintain several quality parameters (a_w, pH, microbial inhibition, stability against lipid oxidation, and instrumental color traits) and extend the shelf life of dry fermented sausage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.512-519
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• 2023

Pacific oysters Crassostrea gigas are a popular shellfish in the Republic of Korea. However, due to their abundant moisture and nutrient content, oysters are susceptible to microbiological growth and biochemical changes, which lead to quality degradation. Therefore, the present study aimed to investigate the effectiveness of modified atmosphere packaging (MAP) in maintaining the quality of raw oysters during storage. Microbiological and physicochemical parameters such as pH, glycogen content, soluble protein, turbidity, and volatile basic nitrogen (VBN) were analyzed for oysters stored under various gas compositions and storage periods. The results showed that there was no significant increase in viable cell count in MAP oysters after six days in MAP oysters. Moreover, the physicochemical quality of non-MAP oysters deteriorated rapidly, whereas the quality of MAP oysters were maintained during storage. This study suggests that MAP can be an effective technique for maintaining the freshness of raw oysters during distribution and storage, and may also be useful for extending the shelf-life and maintaining the quality of other seafood products.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.41.1-41.17
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• 2023

Objectives: This scientometric and bibliometric analysis explored scientific publications related to hydraulic calcium silicate-based (HCSB) sealers used in endodontology, aiming to describe basic bibliometric indicators and analyze current research trends. Materials and Methods: A comprehensive search was conducted in Web of Science and Scopus using specific HCSB sealer and general endodontic-related terms. Basic research parameters were collected, including publication year, authorship, countries, institutions, journals, level of evidence, study design and topic of interest, title terms, author keywords, citation counts, and density. Results: In total, 498 articles published in 136 journals were retrieved for the period 2008-2023. Brazil was the leading country, and the universities of Bologna in Italy and Sao Paolo in Brazil were represented equally as leading institutions. The most frequently occurring keywords were "calcium silicate," "root canal sealer MTA-Fillapex," and "biocompatibility," while title terms such as "calcium," "sealers," "root," "canal," "silicate based," and "endodontic" occurred most often. According to the thematic map analysis, "solubility" appeared as a basic theme of concentrated research interest, and "single-cone technique" was identified as an emerging, inadequately developed theme. The co-occurrence analysis revealed 4 major clusters centered on sealers' biological and physicochemical properties, obturation techniques, retreatability, and adhesion. Conclusions: This analysis presents bibliographic features and outlines changing trends in HCSB sealer research. The research output is dominated by basic science articles scrutinizing the biological and specific physicochemical properties of commonly used HCSB sealers. Future research needs to be guided by studies with a high level of evidence that utilize innovative, sophisticated technologies.

• Food Science of Animal Resources
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• v.40 no.1
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• pp.55-73
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• 2020

Poultry meat is generally exposed to quality deterioration due to lipid oxidation during storage. Oxidative stability of meat can be increased by feed supplementation. Aim of the current study was to investigate the effect of dietary supplementation of fish waste derived bioactive peptides on antioxidant potential of broiler breast meat and physico-chemical characteristics and quality parameters of nuggets prepared from breast meat. 180 broiler birds (six groups of 30 birds) were purchased. Each group was given different concentrations of bioactive peptides i.e. 0, 50, 100, 150, 200, and 250 mg/kg feed. After completion of six weeks birds were slaughtered and breast meat was stored at -18℃ for six months. Nuggets were prepared and stored at -18℃ for 45 days. Meat samples were analyzed for antioxidant activity [total phenolic contents (TPC), DPPH^· scavenging activity, and ferric reducing antioxidant power] and lipid oxidation assay at regular intervals of 1, 2, 3, 4, 5, and 6 months while nuggets were analyzed for quality (pH, color, texture and water holding capacity) parameters after regular interval of 15 days. A significant (p<0.05) effect of feed supplementation was observed on antioxidant status such as TPC, DPPH^· scavenging activity, and FRAP of broiler breast meat. Dietary interventions of bioactive peptides significantly (p<0.05) delayed lipid oxidation of breast meat than control. All the quality parameters were also significantly affected due to dietary bioactive peptides and storage duration. Thus, dietary interventions of bioactive peptides can increase the antioxidant and shelf stability of broiler breast meat and nuggets.