• Journal of the Korean Geotechnical Society
• /
• v.37 no.12
• /
• pp.89-105
• /
• 2021

In this paper, feasibility study was carried out to evaluate necessity of seismic design of earth retaining structures in a deep excavation. Dynamic behavior of retaining system was analyzed using FLAC, a finite difference analysis program. It was shown that maximum bending moments of retaining walls and axial forces of supports were increased up to 98% and 87% during earthquake, respectively, compared to final excavation step, which indicates that dynamic earth pressure has a large effect on a retaining system. The stability of retaining system designed according to current design specifications was evaluated using structural forces obtained by numerical analysis, and effect of earthquake loading on structural design was analyzed.

• Korean Journal of Environmental Biology
• /
• v.36 no.3
• /
• pp.345-351
• /
• 2018

An efficient, quick and low-cost extraction and clean up method for the determination of 14 polycyclic aromatic hydrocarbons (PAHs) in the agricultural water samples was optimized using gas chromatography-tandem mass spectrometry (GC-MS/MS). The extraction of the target compounds in water sample was carried out with acetonitrile, followed by partitioning promoted by the addition of salt. As a clean-up procedure, dispersive solid phase extraction was employed to purify the analytes of interest for GC-MS/MS analysis. This method was successfully applied for the quantification of PAHs in real water samples collected for the purpose of monitoring from the waterways located in Chungbuk (15 sites) and Gyeongbuk (6 sites), S. Korea. Phenanthrene (0.54 to $2.53{\mu}gL^{-1}$) was detected in all the water samples collected from both the sites. Fluoranthene was detected in the water samples collected from the two sites in Gyeongbuk province, but other PAHs were not determined in these water sampling sites. Based on these results, the determined PAHs were conducted using an environmental risk assessment. The risk characterization ratios (RCRs) for phenanthrene ranged from 0.37 to 3.21. These RCR values referred to as risk was not controlled because RCR values of some sites were greater than 1. In conclusion, it is proposed that the optimized method in combination with GC-MS/MS could be successfully employed for the determination of PAHs in any environmental samples including water samples.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.8
• /
• pp.1144-1153
• /
• 2021

A released exopolysaccharide (rEPS)-producing strain (LM187) with good acid resistance, bile salt resistance, and cholesterol-lowering properties was isolated from Sichuan paocai and identified as Leuconostoc mesenteroides subsp. mesenteroides. The purified rEPS, designated as rEPS414, had a uniform molecular weight of 7.757 × 10⁵ Da. Analysis of the monosaccharide composition revealed that the molecule was mainly composed of glucose. The Fourier transform-infrared spectrum showed that rEPS414 contained both α-type and β-type glycosidic bonds. ¹H and ¹³C nuclear magnetic resonance spectra analysis showed that the purified rEPS contained arabinose, galactose, and rhamnose, but less uronic acid. Scanning electron microscopy demonstrated that the exopolysaccharide displayed a large number of scattered, fluffy, porous cellular network flake structures. In addition, rEPS414 exhibited strong in vitro antioxidant activity. These results showed that strain LM187 and its rEPS are promising probiotics with broad prospects in industry.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.5
• /
• pp.645-658
• /
• 2021

Porins are essential for the viability of Gram-negative bacteria. They ensure the uptake of nutrients, can be involved in the maintenance of outer membrane integrity and define the antibiotic or drug resistance of organisms. The function and structure of porins in proteobacteria is well described, while their function in photoautotrophic cyanobacteria has not been systematically explored. We compared the domain architecture of nine putative porins in the filamentous cyanobacterium Anabaena sp. PCC 7120 and analyzed the seven candidates with predicted OprB-domain. Single recombinant mutants of the seven genes were created and their growth capacity under different conditions was analyzed. Most of the putative porins seem to be involved in the transport of salt and copper, as respective mutants were resistant to elevated concentrations of these substances. In turn, only the mutant of alr2231 was less sensitive to elevated zinc concentrations, while mutants of alr0834, alr4741 and all4499 were resistant to high manganese concentrations. Notably the mutant of alr4550 shows a high sensitivity against harmful compounds, which is indicative for a function related to the maintenance of outer membrane integrity. Moreover, the mutant of all5191 exhibited a phenotype which suggests either a higher nitrate demand or an inefficient nitrogen fixation. The dependency of porin membrane insertion on Omp85 proteins was tested exemplarily for Alr4550, and an enhanced aggregation of Alr4550 was observed in two omp85 mutants. The comparative analysis of porin mutants suggests that the proteins in parts perform distinct functions related to envelope integrity and solute uptake.

• Nutrition Research and Practice
• /
• v.16 no.1
• /
• pp.132-146
• /
• 2022

BACKGROUND/OBJECTIVES: Various sodium reduction policies have been implemented. However, there are limitations in the aspect of actual field applicability and efficiency. For effective sodium reduction, cooperation with the field is required and consumer preference must be considered. Thus, this study aimed to develop a low-sodium burger considering field applicability and consumer preference. MATERIALS/METHODS: Focus group interviews and in-depth interviews on the sodium reduction measures were conducted with nine professionals in related fields to discuss practical methods for sodium reduction from September 7 to 21, 2018. By reflecting the interview results, a burger using a low-sodium sauce was developed, and preference analysis for sodium in the burger sauces and finished products was performed. The consumer preference for low-sodium burgers was evaluated on 51 college students on November 12, 2018. RESULTS: The results of the professional interview showed that it is desirable to practice sodium reduction gradually, and by reflecting this, the burger sauce was prepared by adjusting the ratio of refined salt to 15%, 30%, and 50%. The sodium content of the burger using low-sodium sauce was 399 mg/100 g in the control group, 362 mg/100 g in the H1 group, and 351.5 mg/100 g in the H2 group, showing a 9.3-11.9% decrease in sodium in the H1 and H2 groups. The preference evaluation on the low-sodium burgers showed a higher preference for burgers with 9.3-11.9% sodium reduction, which did not affect the overall taste. CONCLUSIONS: This study examined the potential for sodium reduction in the franchise foodservice industry. An approximate 10% sodium reduction resulted in an increase in consumer preference without affecting the strength of the taste. Thus, if applied gradually, sodium reduction at practical levels could increase the consumer preference without changing the taste or quality and could be applied in the franchise foodservice industry.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.32 no.2
• /
• pp.61-67
• /
• 2022

A metal salt solution was prepared from valuable metals (Ni, Co, Mn) recovered from a scrap of waste lithium secondary batteries, and an NCM811 precursor was synthesized from the solution. The effect on precursor formation according to reaction time was confirmed by SEM, PSA, and ICP analysis. Based on the analysis results, the electrochemical properties of the synthesized NCM811 precursor and the commercial NCM811 precursor were investigated. The Galvano charge-discharge cycle, rate performance, and Cycle performance were compared, and as a result, there was no significant difference from commercial precursors.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.4
• /
• pp.519-526
• /
• 2023

Panax ginseng is one of the most important herbal medicinal plants consumed as health functional food and can be fermented to achieve better efficacy. Lacticaseibacillus, one of the representative genera among lactic acid bacteria (LAB), has also been used as a probiotic material for health functional foods due to its beneficial effects on the human body. To achieve a synergistic effect by using these excellent dietary supplement ingredients together, a novel LAB strain was isolated from the root of 6-year-old ginseng. Through similarity analysis of 16S rRNAs and whole-genome sequences, the strain was confirmed as belonging to the genus Lacticaseibacillus and was named L. casei KGC1201. KGC1201 not only met all safety standards as food, but also showed excellent probiotic properties such as acid resistance, bile salt resistance, and intestinal adhesion. In particular, KGC1201 exhibited superior acid resistance through morphological observation identifying that the cell surface damage of KGC1201 was less than that of the L. casei type strain KCTC3109. Gene expression studies were conducted to elucidate the molecular mechanisms of KGC1201's acid resistance, and the expression of the glycosyltransferase gene was found to be significantly elevated under acidic conditions. Exopolysaccharides (EPSs) biosynthesized by glycosyltransferase were also increased in KGC1201 compared to KCTC3109, which may contribute to better protection of KGC1201 cells from strong acidity. Therefore, KGC1201, with its increased acid resistance through molecular mechanisms and excellent probiotic properties, can be used in health functional foods to provide greater benefit to overall human health and well-being.

• Analytical Science and Technology
• /
• v.21 no.2
• /
• pp.84-92
• /
• 2008

A method for the determination of trace amount of caffeine in urine and various drink samples using hollow fiber-liquid phase microextraction (HF-LPME) and capillary gas chromatograph/nitrogen phosphorus detector (GC/NPD) has been established. HF-LPME method has been optimized with respect to several experimental parameters including the effects of the hollow fiber length, extraction solvent, stirring mode, pH and salt concentration for the determination of caffeine from aqueous samples. The correlation coefficient of calibration curve for caffeine was 0.9994. The average recovery was 102%(n=3). The established method is feasible for the determination of trace amounts of caffeine in several aqueous sample. The limit of detection (LOD) and the limit of quantitation (LOQ) have been found to be 2.5 and 10 ng/mL, respectively. The established HF-LPME method for the analysis of caffeine from aqueous sample can be used for the determination of biological, food and environmental samples.

• Microbiology and Biotechnology Letters
• /
• v.51 no.2
• /
• pp.147-156
• /
• 2023

Tetragenococcus halophilus CY54, an isolate from jeotgal, grows best in media with 5% NaCl and can grow at 18% and higher salt concentration. Three different doenjang samples were prepared with multiple starters including T. halophilus CY54. TBZA doenjang was prepared with T. halophilus, Bacillus subtilis, Zygosaccharomyces rouxii and Aspergillus oryzae. BZA doenjang was prepared with the same 3 starters except T. halophilus. KACC doenjang was prepared with a single starter, B. subtilis KACC16750. During 16 weeks of fermentation at 25℃, the viable counts were maintained in the range of 7-8 log CFU/g in all 3 samples. As fermentation progressed, pH decreased and titratable acidity (TA) gradually increased. Crude protein contents decreased slightly. TBZA doenjang showed higher amino-type nitrogen (ANN) and volatile basic nitrogen (VBN) contents, and KACC doenjang showed higher ammonia-type nitrogen (AMN) content. TBZA doenjang showed higher fibrinolytic and protease activity than other doenjang samples. Metabolites analyses by GC/MS showed that doenjang samples were separated from each other by partial least squares-discriminant analysis (PLS-DA) analysis. Seventeen major metabolites involved in the differences between samples were identified and they included organic acids, amino acids, sugars, fatty acids and alcohols. TBZA doenjang showed higher contents for most metabolites responsible for flavor and taste of fermented foods including doenjang. These results showed that T. halophilus could be useful as a starter for doenjang and can improve the product quality by accelerating the fermentation processes.

• Journal of Nutrition and Health
• /
• v.57 no.2
• /
• pp.228-243
• /
• 2024

Purpose: This study aimed to identify the distinctions in dietary and health-related behaviors among Indonesian women who marry Koreans or into multicultural families (MF) and those who marry Indonesians living in Korea (IK) and in Indonesia (II). Methods: The study was performed with 192 subjects using an online questionnaire regarding food choice, dietary and health behavior, and nutrition quotient (NQ). The analysis used Pearson's chi-squared test, the Fisher's exact test, multinomial logistic regression, and the general linear model. Results: The MF group consumed Korean food more than once a day and Indonesian food 1-2 times monthly (p < 0.001). The main challenge for the IK and II groups in consuming Korean food was the presence of pork and the different food flavors (p < 0.001). The MF group tended to have normal body mass index, consumed more vitamin and mineral supplements (p = 0.014), and exercised regularly ≥150 min/week compared to the IK and II groups (p < 0.001). However, the MF group had the highest rate of skipping breakfast (p = 0.040). When evaluating the NQ of the participants, the MF group consumed more vegetables (p = 0.026), mixed grains (p = 0.031), and spicy and salt soups (p = 0.006). The II group consumed more fish (p = 0.005), beans (p = 0.009), and nuts (p = 0.003). The IK group checked the nutrition labels the most (p = 0.005), while their consumption of vegetables, fish, beans, and nuts was lowest. The MF group had a higher balance score, which resulted in a substantially more nutritious food intake compared to the other two groups (p = 0.037). Conclusion: The MF group consumed more vegetables and mixed grains, adequate fish, beans, and nuts, and engaged in longer daily physical activity. However, the IK group had a relatively low-quality diet and nutritional intake status compared to the other two groups, and this needs to be improved in the future.