• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.425-430
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• 2022

L-alanine (LA, as an amino acid residue) pentamer model was used to investigate changes in the dihedral angle, intramolecular hydrogen bonding and formation energies during structural optimization. LA pentamers having four conformation types [𝛽: 𝜑/𝜓=t-/t+, 𝛼: 𝜑/𝜓=g-/g-, PP_II: 𝜑/𝜓=g-/t+ and P-like: 𝜑/𝜓= g-/g+] were carried out by quantum chemical calculations (QCC) [B3LYP/6-31G(d,p)]. In LA, 𝛽, 𝛼, and P-like types did not change by optimization, having an intra-molecular hydrogen bond: NH⋯OC (H-bond), and PP_II types in the absence of H-bond were transformed into P-like at the designated 𝜓 of 140°, and to 𝛽 at that of 160° or 175°. P-like and 𝛼 were about 0.5 kcal/mol/mu more stable than 𝛽. In order to understand the processes of the transformations, the changes of 𝜑/𝜓, distances of NH-OC (d_NH/CO) and formation energies (𝜟E, kcal/mol/mu) were examined.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.3
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• pp.284-288
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• 1983

This experiment was carried out to investigate the stability of ascorbic acid (AsA) in the mixed solution of AsA and catechin according to the content changes of AsA and catechin under boiling, and for the respective concentration and pH. The loss of AsA was most for 10 minutes of boiling and accelerated by the mixture of catechin, but the loss was less in the high mixture rate than in the low the loss of catechin most for 10 minutes of boiling, also as the concentration of AsA becomes higher but that of cathchin lower, and as that of AsA lower but that of catechin higher, the loss of catechin becomes less moreover in the case of the low content ratio of catechin, the stability of AsA was better in order of the pH 4, pH 5, pH 6, namely as the pH increased, but in the case of the high better in order of the pH 6, pH 5, pH 4, that is as in decreased.

• Food Science of Animal Resources
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• v.18 no.2
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• pp.157-163
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• 1998

This study was carried out to examine that pepsin-hydrolyzed bovine lactoferrin has applicabilities which are market milk and dairy products. The stability of pepsin-hydrolyzed bovine apo-lactoferrin and the change of its antibacterial character has been studied under various method for pasteurization (LTLT; 65$^{\circ}C$ / 30min., HTST ; 75$^{\circ}C$ / 15sec., UHT ; 135$^{\circ}C$ / 3sec.) and pH Values (pH 2.0, pH 4.0, pH 6.8). The ehated samples were assayed for minimal bacteriocidal concentrations (MBCs) and bacteriocidal effect against E. coli. The results obtained were summarized as follows: After fractionation of pepsin-hydrolyzed bovine lactofeerin by gel filtration. several peptide fractions were found that had strong antibacterial activity. SDS-PAGE showed that the one of these fractions with strong antibacterial activity, which had a molecular mass a range of 30∼33KDa. The MBCs for pepsin-hydrolyzed bovine lactoferrin fraction No. 2 against E. coli required to cause complete inhibition of growth varied within the range of 200∼400 $\mu\textrm{g}$/ml, depending on heat treatments and pH conditions. The peptide fraction No. 2 showed strong bacteriocidal activity against E. coli at LTLT and HTST treatments under acidic pH conditions. and was reduced activity at UHT treatment under pH 6.8 condition.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.425-428
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• 2002

This study has been carried out to analized of long term changes of water quality with regard to main pollutant sources in agricultural reservoirs on the basis of data during 1996-2001. The major source was domestic wastewater(DWW) and water pollution by non-point sources(NPS) is increasing as time goes. It was determined that Seasonly average values of DWW were pH $7.6{\sim}8.7$, COD $7.0{\sim}9.4$, T-N $0.74{\sim}2.07$, T-P $0.05{\sim}0.62$, Live-stock wastewater(LWW) were pH $7.5{\sim}8.9$, COD $5.5{\sim}9.8$, T-N $0.57{\sim}1.91$, T-P $0.04{\sim}0.13$, NPS were pH $7.1{\sim}8.3$, COD $3.1{\sim}5.2$, T-N $0.29{\sim}1.44$, T-P $0.02{\sim}0.07$. Fluctuation of DWW and LWW were very wide and variable long term patterns of them were similar. Trophic states by Carlson Index of DWW and LWW was classified as eutrophic to hypretrophic from chl-a, T-P concentration.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.382-386
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• 1987

Changes of proteins of whole soybean and soy flour stored under different conditions of humidity (RH 65% and 85%) and packing material (HDPE and OPP/Al/PE film) for 90 days and their influence on formation of soybean curd were investigated. The water holding capacity, total nitrogen, soluble nitrogen, pH and Amylograph viscosity of whole soybean and soy flour were rapidly decreased during storage at high relative humidity. Furthermore, such quality changes were accompanied by considerable differences in final quality of soybean curds; lower volumes of soybean curds. Under the conditions of HDPE and OPP/Al/PE film packing, smaller changes were observed in protein qualify than those without packing.

• Korean Journal of Oriental Medicine
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• v.1 no.1
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• pp.441-459
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• 1995

To study stability of distilled herbal medicine, we chose changes in UV spectrum, pH, conductivity, and HPLC chromatogram. Aconiti Lateralis preparata Radix and Scutellariae Radix were selected and studied. There ws no consistancy in UV spectrums of preparatons and in duration. The changes in pH and conductivity were not correlated to those in UV spectrums. HPLC chromatograms were also compared each other depending on the preparations. One interesting peak of distilled Aconiti solution was appeared at 40 min retention time which was not identified yet. Ingeneral, UV spectrum, pH, conductivity measurements are pretty poor tool to study stability of herbal medicine although HPLC analysis should be studied further.

• Polymer(Korea)
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• v.32 no.5
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• pp.421-426
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• 2008

pH-responsive P(MAA-co-EGMA) hydrogel microparticles were synthesized via dispersion photo polymerization and the feasibility of the particles as the cosmetic formulation was investigated. Rh-B and the functional materials for the cosmetic application such as ascorbic acid, adenosine, EGCG, and arbutin were loaded in the P (MAA-co-EGMA) hydrogel microparticles in order to examine the interaction between the hydrogel and the loaded materials. In the loading experiments, Rh-B showed the highest loading efficiency to the P(MAA-co-EGMA) hydrogels due to the electrostatic attraction between the negative charge of the hydrogels and the positive charge of Rh-B at the ionized states. However, the functional materials showed relatively low loading efficiencies because of the electrostatic repulsions between the negative charges of both the hydrogels and the materials at the ionized states. In addition, P(MAA-co-EGMA) hydrogel microparticles showed pH-responsive release behavior of Rh-B according to the external pH changes.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.737-750
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• 2018

Effects of acid soaking (AS) and thermal sterilization (TS) on the shape and quality characteristics of Tteokbokki rice cake (TRC) were investigated. The F-value of a sequential process (SP) of the combination of AS and TS was quantitatively determined with a reference microorganism of Bacillus cereus. F-values were evaluated according to the minimum and the maximum D-value of B. cereus and the reduction exponent (m=12). The heat penetration curves at cold point (CP) of TRC (400 g) were used to estimate the TS time at 121, 100, and $95^{\circ}C$. F-values of the SP were revised according to the adjusted m values after AS at different pH. The non-uniformity parameters (NUP) of TRC had no significant changes during AS but it dramatically increased after applying TS at a low pH by AS. The result of solubilized starch contents (SSC) demonstrated that the shape changes during SP are related to SSC. The texture characteristics and the whiteness were significantly influenced by a low pH condition (3.5) (p<0.05). Sensory analysis showed that a lower pH and a longer thermal processing time influenced negatively on the acceptability. This study showed that pH 4.0 and $95^{\circ}C$ was an optimum condition for the SP.

• IMMUNE NETWORK
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• v.16 no.2
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• pp.109-115
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• 2016

To find the relation between exercise and cytokines, we examined the effect of the training intensity on the levels of cytokines, including interferon-gamma (IFN-γ), interlukine-4 (IL-4) and interlukine-4/interferon-gamma ratio (IL-4/IFN-γ ratio) in female Futsal players. Twelve well-trained female college Futsal players aged 19~22 participated in this study. The athletes completed 30-min of running at 60~65% maximal heart rate [moderate-intensity exercise], and 30-min of running at 75~80% maximal heart rate [high-intensity exercise]. peripheral blood samples were collected 24 h before and 24 h and 48 h after each of the exercise bouts. finding showed that The 30-min bout of moderate-intensity exercise induced a significant increase in IFN-γ (p=0.01) and significant decreases in IL-4 (p=0.001) and IL-4/IFN-γ ratio (p=0.003). And also, 30-min of running at 75~80% maximal heart rate induced increase in IFN-γ (p=0.07) and decreased in IL-4 (p=0.01) and IL-4/IFN-γ ratio (p=0.06) that these changes not significantly. In summary, exercise intensity can effect on the magnitude of changes in cytokines. It seems that moderate intensity exercise enhances cytokine pattern in female college Futsal players.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.702-709
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• 1995

Degradation Of $\kappa $-carrageenan-based film by microorganisms screened from carrageenan source and activated sludge of a carrageenan producing factory was investigated by measuring changes of pH, viscosity, total sugar and total organic carbon (TOC) of the medium containing $\kappa $-carrageenan as a carbon source. Initially fifteen strains of microorganism were isolated from carrageenan source and activated sludge and then three organisms among them were selected based on the ability of growing in the medium including 0.3% $\kappa $-carrageenan as a sole carbon source. They were identified as Escherichia coli, Saccharomyces cerevisiae and Aspergillus niger. As indices of biodegradability Of $\kappa $-carrageenan based film, the changes of pH, viscosity, total sugar, and TOC of the carrageenan film-based medium were tested by the cultivation of single or mixed strains of the identified organisms. Mixed culture showed the highest biodegradability, which resulted in the changes of pH from 6.5 to 3.0, viscosity from 164 cps to 15.6 cps, total sugar content from 2.35 g/l to 0.53 g/l and TOC from 5721 ppm to 232 ppm after 30 days of cultivation. The biodegradability determined as the reduction rate of TOC by pure cultures of Asp. niger, E. coli, Sacch. cerevisiae and mixed culture of the three organisms were 94%, 86%, 80% and 96%, respectively.