• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.853-859
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• 2017

This study was conducted in an effort to investigate the effect of Maillard reaction products (MRPs) on enzymatic browning of burdock and their anti-oxidant activity. The MRPs were prepared by heating glucose and amino acids at $90^{\circ}C$, which served to produce a strong inhibitory effect on burdock polyphenol oxidase. As the reaction time of the solution containing glucose and amino acid increased at $90^{\circ}C$, the production of MRPs increased and intensity of the brown color deepened. When MRPs were prepared by heating at $90^{\circ}C$ for five hours, the absorbance of MRPs from glucose and lysine was 6.44, while those of glucose and glycine was 1.95. The MRPs synthesized from the glucose and lysine also reduced the pH of MRPs from 5.60 to 4.51, but those from glucose and glycine decreased slightly from 5.57 to 5.33. The Michealis-Menten constant value ($K_m$) of burdock PPO with pyrocatechol as a substrate was 16.0 mM, and MRPs were a non-competitive inhibitor against burdock PPO. The anti-oxidant activity of MRPs was measured by evaluating its radical scavenging activities of DPPH radicals, ABTS radicals and reducing power. The color intensity of MRPs produced by lysine and glucose were deeper than that produced by glucose and glycine. It was also found that MRPs produced from glucose and lysine exhibited stronger anti-oxidant properties than those produced by glucose and glycine.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.195-200
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• 2022

Sulfur is an essential element in plants, including amino acids, vitamin synthesis, and acting as an antioxidant. However, the interaction between endogenous sulfur and proline synthesis has not been yet fully documented. White clover (Trifolium repens L.) is known as a species highly sensitive to sulfate supply. Therefore, this study aimed to elucidate the role of sulfur in regulating proline metabolism in relation to ammonia detoxification and hydrogen peroxide (H₂O₂) accumulation in white clover. The detached leaves of white clover were immersed in solution containing different concentration of sulfate (0, 10, 100, and 1000 mM MgSO₄). As MgSO₄ concentrations were increased, the concentration of H₂O₂ increased up to 2.5-fold compared to control, accompanied with H₂O₂ detection in leaves. Amino acid concentrations significantly increased only at higher levels (100 and 1000 mM MgSO₄). No significant difference was observed in protein concentration. Proline and ∆^1-pyrroline-5-carboxylate (P5C) concentrations slightly decreased at 10 and 100 mM MgSO₄ treatments, whereas it rapidly increased over 1.9-fold at 1000 mM MgSO₄ treatment. Ammonia concentrations gradually increased up to 8.6-fold. These results indicate that exogenous sulfur levels are closely related to H₂O₂ and ammonia synthesis but affect proline biosynthesis only at a higher level.

• Corrosion Science and Technology
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• v.22 no.2
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• pp.73-89
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• 2023

Due to continuous promotion of green alternatives to toxic petrochemicals by government policies, research efforts towards the development of green corrosion inhibitors have intensified recently. The objective of the current work was to develop novel green and sustainable corrosion inhibitors derived from 4-aminoantipyrine to effectively prevent corrosion of mild steel in corrosive environments. Gravimetric methods were used to investigate corrosion inhibition of 4-((furan-2-ylmethylene)amino)antipyrine (FAP) and 4-((pyridin-2-ylmethylene)amino)antipyrine (PAP) for mild steel in 1 M HCl. FAP and PAP were subjected to quantum chemical calculations using density functional theory (DFT). DFT was used to determine the mechanism of mild steel corrosion inhibition using inhibitors tested in HCl. Results demonstrated that these tested inhibitors could effectively inhibit mild steel corrosion in 1.0 M HCl. At 0.0005 M, these inhibitors' efficiencies for FAP and PAP were 93.3% and 96.5%, respectively. The Langmuir adsorption isotherm was obeyed by these inhibitors on the mild steel surface. Values of adsorption free energies, ΔG^o_ads, revealed that FAP followed chemical and physical adsorptions.

• Food Science and Preservation
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• v.15 no.5
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• pp.719-724
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• 2008

The overall objectives of this study were to examine the potential of sturgeon as an intermediate moisture food (IMF) by measurement of nutritional components, such as minerals, fatty acids, amino acids, and water activity. Chemical compositions were as follows:moisture 73.2%, crude protein 19.9%, crude lipid 5.7%, ash 1.1%, and carbohydrate 0.1%. Minerals were K 317.70, P 259.88, and Mg 29.78 mg/100 g. Fatty acids detected were oleic acid (40.46% of total), palmitic acid (23.27%), and linoleic acid (15.35%). In addition, sturgeon was very rich in glutamic acid (1,189.71 mg/100 g) and deficient in serine (55.12 mg/100 g). Moisture content and water activity of sturgeon dried at $40^{\circ}C$ after soaking in different concentrationsof sugar and salt solutions were 15.12-16.24% and 0.68-0.79, respectively. Sensory evaluation of sturgeon soaked in different concentrations of sugar and salt solutions indicated that sturgeon soaked in 3.0% (w/v) sugar and salt solution scored highest.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.37-43
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• 1973

In this paper, non-enzymatic browning reactions as a factor of self stability of boiled and dried anchovy were studied to discuss the effect of water activity to the discoloring reaction and the preservative moisture content. The development of rancidity of the fish meat was also mentioned since the fish is fatty and the lipid oxidation is a functional deteriorative reaction. Fresh anchovies were boiled in $10\%$ salt solution immediately after the catch, sun dried, and stored at room temperature ($20^{\circ}C$) for two months in humidistat chambers maintaining different levels of water activity as described in Table 1. The pigments formed by non-enzymatic browning reations were extracted in two fractions, those were chloroform-methanol soluble and water dialyzed fraction, and analyzed spectrophotometrically at the wavelength of 460 nm. These two fractions were considered, respectively to be the brown pigments formed by lipid oxidation reactions for the formler and for the latter, to be the pigments developed by sugar-amino or Maillard reaction. The oxidation of lipid in anchovy meat during the storage was measured as the changes in Peroxide value and the color development of thiobarbituric acid reaction. It is summarized from the results that the rate of both reactions, lipid oxidation and browning, was affected by water activity levels. In regard to the changes in peroxide and TBA value during the storage, the propagation of lipid oxidation was obviously accelerated at lower humidities whereas the development of browning progressed at the higher. These two reactions occurring simultaneously and contrary in activity resulted in that the rate of deterioration occurring oxidatively or by browning, was the minimum at the water activity of 0.32-0.45 which were $7-9\%$ as moisture content and slightly higher value than that of monolayer (Aw=0.21, $5.11\%$ as moisture content). It is also noted that the lipid oxidative browning was presumed to dominate sugar-amino reactions so that the rate of browning of the meat was ultimately depended on the development of rancidity although sugar-amino reactions initiated earlier than the other at the first ten days of storage, particulary at higher humidity. At the lower humidity sugar-amino reactions were occurred gradually but lower levels in color development in contrast to the consistent increase in lipid oxidative browning.

• Molecules and Cells
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• v.24 no.3
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• pp.437-440
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• 2007

$OGL-20P^T$-358 is a novel 66 amino acid residue protein from the hyperthermophile Thermococcus thioreducens sp. nov., strain $OGL-20P^T$, which was collected from the wall of the hydrothermal black smoker in the Rainbow Vent along the mid-Atlantic ridge. This protein, which has no detectable sequence homology with proteins or domains of known function, has a calculated pI of 4.76 and a molecular mass of 8.2 kDa. We report here the backbone $^1H$, $^{15}N$, and $^{13}C$ resonance assignments of $OGL-20P^T$-358. Assignments are 97.5% (316/324) complete. Chemical shift index was used to determine the secondary structure of the protein, which appears to consist of primarily ${\alpha}$-helical regions. This work is the foundation for future studies to determine the three-dimensional solution structure of the protein.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.419-425
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• 1985

N-Methylamidinoglycine, an isomer of creatine which was postulated to be formed enzymatically in vitro, has been synthesized by coupling glycine with N, S-dimethylthiopseudouronium iodide in a yield of approxirnately 60%. On heating in acidic solution, it was converted to a cyclized form (isocreatinine) in analogy with the conversion of creatine to creatinine(anhydrous form). Structures were confirmed by an elemental analysis and proton NMR spectroscopy. Further studies on their characteristics were compared with those of creatine and creatinine in regard to isoelectric points(pI), retardation coefficients(Rf) on thin layer chromatography, and elution profiles on amino acid analyzer. In order to facilitate the comparison, $^{14}C$-labeled creatine, creatinine, isocreatine and isocreatinine were also synthesized.

• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.1
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• pp.55-67
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• 1998

The developing agent is the materials which first acts on silver grain and make it into metallic silver by reducing reaction. There are several types in developing agents, and according to Lumiere-Andresen principle, substitution product which has amino or hydroxyl group in benzen nucleus has a developing power, but all reducing substances are not in used .In the developing effect, not only the role of developing agent but also that of assistant materials are important. But In this work, we have studied effect, change by lith developing agent which require high contrast image. We made an developing experiment after having manufactured developing solution used hydroquinone and another developing agents like chlorohydroquinone, pyrocatcchol and pyrogallol as developing agent. And we added that did in addition of diethanolamine and ascorbic acid. and then we examined the possibility of use.

• BMB Reports
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• v.43 no.11
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• pp.726-731
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• 2010

We report the tissue-specific distribution of chitinolytic activity in Korean ginseng root and characterize two 31-kDa chitinolytic enzymes. These two enzymes (SBF1 and SBF2) were purified 70- and 81-fold with yields of 0.75 and 1.25%, respectively, and exhibited optimal pH and temperature ranges of 5.0-5.5 and 40-$50^{\circ}C$. With [$^3H$]-chitin as a substrate, $K_m$ and $V_{max}$ values of SBF1 were 4.6 mM and 220 mmol/mg-protein/h, respectively, while those of SBF2 were 7.14 mM and 287 mmol/mg-protein/h. The purified enzymes showed markedly less activity with p-nitrophenyl-N-acetylglucosaminide and fluorescent 4-methylumbelliferyl glycosides of D-N-acetylglucosamine oligomers than with [$^3H$]-chitin. End-product inhibition of both enzymes demonstrated that both are endochitinases with different N-acetylglucosaminidase activity. Furthermore, the $NH_2$-terminal sequence of SBF1 showed a high degree of homology with other plant chitinases whereas the $NH_2$-terminal amino acid of SBF2 was blocked.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.310-313
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• 2011

본 논문에서는 지구온난화의 주요원인 중의 하나인 이산화탄소를 포집하기 위한 새로운 흡수제를 연구하였다. 액상 흡수법에서 가장 중요한 핵심 기술요소는 성능과 경제성면에서 우수한 흡수제를 개발하는 것이다. 흡수평형장치인 VLE(Vapor-Liquid Equilibrium)장치를 사용하여 신규흡수제의 이산화탄소 흡수능을 평가하고 특성을 알아봄으로써 신 흡수제를 개발하고자 하였다. 기존 아민흡수제인 MEA(monoethanolamine), DEA(diethanolamine)와 비교한 결과 아미노산염 흡수제의 경우 MEA (1.108), DEA (1.105)의 이산화탄소 흡수능보다 0.15～0.2 (mol $CO_2$/mol absorbent) 더 높은 흡수능과 2.5～3배 더 빠른 겉보기 속도를 나타내는 것을 확인하였다. 본 연구를 통하여 개발된 아미노산염 흡수제가 경제적인 이산화탄소 포집공정을 구현할 수 있는 가능성을 확인하였다.