• Bulletin of the Korean Chemical Society
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• v.6 no.2
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• pp.74-79
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• 1985

The stabilities of the charge transfer complexes of pentamethyl benzene with iodine in n-hexane have been investigated by UV-spectrophotometric measurements at 25, 40 and 60$^{\circ}C$ up to 1600 bars. The equilibrium constant of the complex formation was increased with pressure while being decreased with temperature raising. Changes of volume, enthalpy, free energy and entropy for the formation of the complexes were obtained from the equilibrium constants. The red-shift at higher pressure, the blue-shift at higher temperature, and the relation between pressure and oscillator strength have been discussed by means of thermodynamic functions. In comparison with the results in the previous studies, the absolute values of ${\Delta}$V at each temperature were increased with the number of methyl groups of polymethyl benzene. However, it can be seen that both ${\Delta}$H and ${\Delta}$S show extreme behaviors in durene near atmospheric pressure but they are negatively increased with the number of methyl groups near 1600 bar. This order of the thermodynamic parameters may be a measure of the relative basicities of polymethyl benzenes toward iodine under each pressure, and these phenomena are explained in terms of a positive inductive effect and a steric hindrance effect of the polymethyl benzene molecule.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.31-36
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• 1989

Optimal conditions of producing red pigment by Monascus anka, Nakazawa, et Sato, IFO 4478 and 6540 were found to be at pH 6.0 and $30^{\circ}C$ for 10 days. When 3.0% steamed rice and 1.0% defatted sesame exfracts were used as substrates, the highest production of red pigment was yielded. Furthermore, mutants such as Monascus anka 4475-27 and 6540-185 induced by N -methyl-N-nitro-N-nitrosoguanidine (MNNG) treatment were found to produce pigment much more than parent strains.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.182-186
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• 2013

In this study, we examined the chemical properties and microbial community characteristics in 25 controlled horticultural soils (CHS) sampled from Gyeongnam Province by fatty acid methyl ester (FAME) method. The electrical conductivity of watermelon CHS was significantly (p < 0.05) higher than those of red pepper CHS, pumpkin CHS, and strawberry CHS. The amounts of total FAMEs, total bacteria, gram-negative bacteria, gram-positive bacteria, and fungi were significantly (p < 0.05) higher in red pepper CHS than those in strawberry CHS and pumpkin CHS. In addition, higher (p < 0.05) ratios of cy19:0 to $18:1{\omega}7c$ were detected in tomato CHS than those in watermelon CHS, pumpkin CHS, and red pepper CHS. This implied that microbial communities of tomato CHS were stressed more than other species of cultivation soils. Actinomycetes community in red pepper CHS was significantly (p < 0.05) higher than those in tomato CHS, strawberry CHS, and watermelon CHS. Differences in soil microbial community composition were highly associated with cultivated crop species which might result from the management inputs such as fertilizer, herbicide, and irrigation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.219-227
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• 1995

Natto is a Japanese tradiational food made from whole soybeans by the fermentation of Bacillus natto. This study was attempted to improve the taste of Natto, garlic(2%) and red pepper oleoresin(0.2%) were added. Conventional Natto(N-1), garlic Natto(N-2), red pepper oleoresin Natto(N-3), garlic and red pepper oleoresin Natto(N-4) were prepared. Volatile flavor components, fatty acid, organic acid, pH and titratable acdity in all samples were investigated. The experimental results revealed the presence of 62 volatile components in conventional Natto. Among there, the major flavor compounds were identified to be 2, 5-dimethylpyrazine, trimethyl-pyrazine, 2, 6-bis91, 1-dimethylethyl) phenol. Seventy-one volatile compounds were detected in N-2, and major compounds were identified to be methyl-2-propenyl disulfide, 2, 6-bis(1, 1-dimethylethyl)phenol and 2, 5-dimethylpyrazine. The amounts of volatile compounds, 2-methyoxyphenol and 1, 2-benzenedicarboxylic acid increased by addition of garlic, where as, 1,2 -propanediol, 1-hexanol and 2, 5-dimethylpyrazine decreased. The compounds, 4, 5-dihydroxy-5-propyl-1H-pyrazole, 1, 1, 3-trimethylcyclopentane were identified in N-3. The compounds, such as trimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine increased by addition of red pepper oleoresin, whereas 1,2-propanediol, 1-hexanol and 2,5-dimethylpyrazine decreased. Fatty acid compositions were mainly consisted of linoleic acid(43.66~55.89%) and followed by oleic, palmitic, linolenic, stearic, arachidic, myristic acid. The organic acids we4re identified to be citric(28.2~30.6), acetic(50.0~73.3) and pyroglutamic acid(2.1~3.7).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.280-287
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• 2000

Three antimicrobial compounds (SL-l, SL-2 and SL-3) were isolated and identified from the marine red alga, Symphyocladia latiuscula. In addition, their biological functionalities such as cytotoxicity and desmutagenic activity were investigated. From the cryophyllized S. JatiuscuJa, SL-l, SL-2 and SL-3 were purified by solvent extractions and HPLC.SL-2 was crystallized in benzene-diethyl ether solvent. On the EI-MS spectra, it was found that they had three bromines in their structure which showed typical signal strength ratios at $M^+, [M+2]^+, [M+4]^+, [M+6]^+ (13: 38: 37: 12)$. $SL-l$ was identified as 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol ($C_8H_7Br_3O_3, MW=374$) by NMR and MS spectra. SL-2 was assigned as 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether ($C_8H_7Br_3O_3, MW=388$) and confirmed by X-ray crystallographic analysis. SL-3 was presumed as an isomer of SL-2. Methanol extract of the S. latiuscula showed antimicrobial activities against all strains tested (bacteria, 15 strains; yeasts, 17 strains; fungi, 4 strains), much or less. The strongest inhibition activity of the methanol extract was to the Vibrio mimicus ($50 {\mu}g/ml$) and V. vulnificus ($50 {\mu}g/ml$). The mice injected intraperitoneally with 3 mg of SL-l and 5 mg of 5L-2 showed no acute toxicity response. SL-2 showed higher desmutagenic activity than SL-l against PhIP and MeIQx.

• Journal of Information Display
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• v.3 no.1
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• pp.6-10
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• 2002

We have synthesized a new green Ir(III) complex fac-tris-(3-methyl-2-phenyl pyridine)iridium(III) $Ir(mpp)_3$ and fabricated phosphorescent polymer light-emitting device using it as a triplet emissive dopant in PVK. $Ir(mpp)_3$ showed absorption centered at 388 nm corresponding to the $^1MLCT$ transition as .evidenced by its extinction coefficient of the order of $10^3{\cdot}$ From the PL and EL spectra of the $Ir(mpp)_3$ doped PVK film, the emission maximum was observed at 523 nm, due to the radiative decay from the $^3MLCT$ state to the ground state, confirming a complete energy transfer from PVK to $Ir(mpp)_3$. The methyl substitution has probably caused a red shift in the absorption and emission spectrum compared to $Ir(mpp)_3$. The device consisting of a 2 % doped PVK furnished 4.5 % external quantum efficiency at 72 $cd/m^2$ (current density of 0.45 $mA/cm^2$ and drive voltage of 13.9 V) and a peak luminance of 25,000 $cd/m^2$ at 23.4 V (494 $mA/cm^2$). This work demonstrates the impact of the presence of a methyl substituent at the 3-position of the pyridyl ring of 2-phenylpyridine on the photophysical and electroluminescence properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.1
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• pp.1-5
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• 1988

Kochujang (Red pepper paste) is one of a traditional fermented seasoning foods having peculia. flavor. In present paper, the effects of microorganisms on the formation of volatile components of Kochujang during fermentation were observed. The volatiles of Kochujang were extracted by a steam-distillation under the reduced pressure and determined by gas chromatography and gas chromatography-mass spectrometry (CC-MS), respectively. During fermentation of Kochujang, Saccharomyces sp. and three strains of Bacillus sp. were isolated as main microorganisms participating in the formation of volatile components. According to the analytical results, tetrahydro geroniol, furfuryl alcohol, methoxy acecoptenone and myrtanal in Kochujang inoculated with Saccharomyces spl, 2-methyl-propan-2-ol, furfuryl alcohol an furfuryl-n-butyrate in Kochujang inoculated with Bacillus sp. B-1, 2-methyl-propan-2-ol, furfuryl alcohol and furfuryl-n-butyrate in Kochujang inoculated with Bacillus sp. B-2, and 2-methyl-propan-2-ol, furfuryl alcohol and n-propylbenzene in Kochujang inculated with Bacillus sp. B-3, were identified as major components, respectively.

• Advances in nano research
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• v.15 no.1
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• pp.35-48
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• 2023

Nanoparticles are known for their outstanding properties such as particle size, surface area, optical and electrical properties. These properties have significantly boasted their applications in various surface phenomena. In this work, calcium oxide nanoparticles were synthesized from periwinkle shells as an approach towards waste management through resource recovery. The sol gel method was used for the synthesis. The nanoparticles were characterized using X-Ray diffractometer (XRD), Fourier Transformed Infra-Red Spectrophotometer (FTIR), Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultra violet visible spectrophotometer (UV-visible). While DLS and SEM underestimate the particle diameter, the BET analysis reveals surface area of 138.998 m²/g, pore volume = 0.167 m³/g and pore diameter of 2.47 nm. The nanoparticles were also employed as an adsorbent for the purification of dye (methyl orange) contaminated water. The adsorbent showed excellent removal efficiency (up to 97 %) for the dye through the mechanism of physical adsorption. The adsorption of the dye fitted the Langmuir and Temkin models. Analysis of FTIR spectrum after adsorption complemented with computational chemistry modelling to reveal the imine nitrogen group as the site for the adsorption of the dye unto the nanomaterials. The synthesized nanomaterials have an average particle size of 24 nm, showed a unique XRD peak and is thermally and mechanically stable within the investigated temperature range (30 to 70 ℃).

• Food Science and Preservation
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• v.30 no.6
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• pp.944-959
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• 2023

This study investigated the essential oil composition of fresh Panax ginseng root and identified novel compounds from ginseng oil. The oil was divided into five fractions (neutral, basic, phenolic, acidic, and aldehydic). In total, 149 constituents, including 29, 19, and 38 compounds in the basic, phenolic, and aldehydic fractions, respectively, were identified by gas chromatography (GC) and GC-mass spectrometry (MS). The primary constituents of the total ginseng volatile oil were α-humulene (13.91% as a peak area), bicyclogermacrene (13.59%), β-caryophyllene (8.24%), α-neoclovene (7.78%), and α- and β-panasinsenes (5.14% and 7.53%). The primary constituents of the basic fraction were 2-isopropyl-3-methoxypyrazine (35.51%), 3-sec-butyl-2-methoxy-5-methylpyrazine (31.54%), 2-isobutyl-3-methoxypyrazine (8.64%), and 2-methoxy-3-methylpyrazine (8.40%), whereas in the phenolic fraction, these were benzoic (25.40%), octanoic (11.57%), nonanoic (9.16%), propionic (6.35%), and decanoic acids (6.16%). The primary constituents of the aldehydic fraction were 4-(2-furyl)-3-buten-2-one (23.41%), benzaldehyde (10.18%), cis-2-heptanal (9.42%), 3-(α-furyl)-propenal (8.51%), and 2-phenyl-2-butenal (7.28%). Among these, the phenylalkenal compounds, including 2-phenyl-2-butenal, 2-methyl-3-phenyl-2-propenal, 5-methyl-2-phenyl-2-pentenal, 5-methyl-2-phenyl-2-hexenals, 2-phenyl-2-octenal, and 2-phenyl-2-nonenal, were newly identified in this study as ginseng volatile constituents. Furthermore, 2-phenyl-2-nonenal was identified as a plant-based volatile constituent for the first time in this study.

• ALGAE
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• v.32 no.4
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• pp.359-377
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• 2017

Pyropia haitanensis (T. J. Chang et B. F. Zheng) N. Kikuchi et M. Miyata is one of the most commercially useful macroalgae cultivated in southeastern China. In red algae, the biosynthesis of terpenoids through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway can produce a direct influence on the synthesis of many biologically important metabolites. In this study, two genes of cDNAs, 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-D-xylulose-5-phosphate reductase (DXR), which encoding the first two rate-limiting enzymes among MEP pathway were cloned from P. haitanensis. The cDNAs of P. haitanensis DXS (PhDXS) and DXR (PhDXR) both contained complete open reading frames encoding polypeptides of 764 and 426 amino acids residues, separately. The expression analysis showed that PhDXS was significant differently expressed between leafy thallus and conchocelis as PhDXR been non-significant. Additionally, expression of PhDXR and its downstream gene geranylgeranyl diphosphate synthase were both inhibited by fosmidomycin significantly. Meanwhile, we constructed types of phylogenetic trees through different algae and higher plants DXS and DXR encoding amino acid sequences, as a result we found tree clustering consequences basically in line with the "Cavalier-Smith endosymbiotic theory." Whereupon, we speculated that in red algae, there existed only complete MEP pathway to meet needs of terpenoids synthesis for themselves; Terpenoids synthesis of red algae derivatives through mevalonate pathway came from two or more times endosymbiosis of heterotrophic eukaryotic parasitifer. This study demonstrated that PhDXS and PhDXR could play significant roles in terpenoids biosynthesis at molecular levels. Meanwhile, as nuclear genes among MEP pathway, PhDXS and PhDXR could provide a new way of thinking to research the problem of chromalveolata biological evolution.