• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.1
• /
• pp.499-505
• /
• 2013

Cr(VI)-4-(dimethylamino)pyridine[4-(dimethylamino)pyridinium chlorochromate] was synthesized by the reaction of 4-(dimethylamino)pyridine with chromium trioxide in 6M-HCl, and characterized by IR, ICP. The oxidation of benzyl alcohol using 4-(dimethylamino)pyridinium chlorochromate in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order: cyclohexene$H_2SO_4$ solution), 4-(dimethylamino)pyridinium chlorochromate oxidized benzyl alcohol and its derivatives(p-$OCH_3$, m-$CH_3$, H, m-$OCH_3$, m-Cl, m-$NO_2$) smoothly in DMF. Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.68(303K). The observed experimental data was used to rationalize the hydride ion transfer in the rate-determining step.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.1
• /
• pp.35-44
• /
• 2004

The water soluble fractions(WSF) from Japanese larch wood were isolated, purified by anion exchange resin and Sephadex gel filtration and identified its chemical structure by means of periodate oxidation and methylation reactions. Its major components are arabinose and galactose (1 : 3.4). Based on the results of periodate oxidation, methylation and gas chromatographic analysis of purified WSF, main chain is composed of β-1,3-glycosidic linkage among D-galactopyranoses, and two different side chains; β-1,6-glycosidic linkage among 2-3 units of D-galactopyranoses and β-1,6-glycosidic linkage between 1-2 units of D-galactopyranose and L-arabinopyranose. Addition of WSF to culture media of oak mushroom (Lentinula edodes) accelerated the mycelial growth. In the case of PDA cultures, 2 percent addition of WSF in Sanlim No. 6 strain and 4 percent of WSF in Mok-H strain mostly enhanced the mycelial growth of the mushroom. In the case of sawdust cultures, 4 percent addition of WSF in two strains showed the best mycelial growth. High percentages addition of WSF inhibited mycelial growth of the mushroom. Mushroom production was increased with addition of WSF. By the addition of WSF, ergosterol contents in the media were quite high at the colonized stage and rapidly increased at the fruiting stage. Therefore the ergosterol content could be utilized as an indicator to evaluate the culture maturity for the mushroom fruiting.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.8
• /
• pp.378-384
• /
• 2018

$C_9H_7NHCrO_3Cl$ was synthesized by reacting $C_9H_7NH$ with chromium (VI) trioxide. The structure of the product was characterized by FT-IR (Fourier transform infrared) spectroscopy and elemental analysis. The oxidation of benzyl alcohol by $C_9H_7NHCrO_3Cl$ in various solvents showed that the reactivity increased with increasing dielectric constant(${\varepsilon}$) in the following order: DMF (N,N'-dimethylformamide) > acetone > chloroform > cyclohexane. The oxidation of alcohols was examined by $C_9H_7NHCrO_3Cl$ in DMF. As a result, $C_9H_7NHCrO_3Cl$ was found to be an efficient oxidizing agent that converts benzyl alcohol, allyl alcohol, primary alcohols, and secondary alcohols to the corresponding aldehydes or ketones (75%-95%). The selective oxidation of alcohols was also examined by $C_9H_7NHCrO_3Cl$ in DMF. $C_9H_7NHCrO_3Cl$ was the selective oxidizing agent of benzyl, allyl and primary alcohol in the presence of secondary ones. In the presence of DMF with an acidic catalyst, such as $H_2SO_4$, $C_9H_7NHCrO_3Cl$ oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, and $m-NO_2$). Electron donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. The Hammett reaction constant (${\rho}$) was -0.69 (308K). The observed experimental data were used to rationalize hydride ion transfer in the rate-determining step.

• Food Science of Animal Resources
• /
• v.35 no.4
• /
• pp.557-563
• /
• 2015

The present study was carried out to investigate the effects of soy protein hydrolysates (SPHs) addition on the quality characteristics of pork patties. The SPHs was prepared by subcritical water process (SWP) at 180℃ without holding time and mixed with the pork patty components at varying concentrations (0-3%), and the patties were stored at 4℃ for 14 d. As quality parameters, instrumental color, thiobarbituric acid-reactive substances (TBARS), pH, water holding capacity (WHC) and shear force were measured at the end of storage. Regardless of SPHs concentration, the addition of SPHs significantly manifested low L* and high a* values compared to those of untreated control (p<0.05). For b* value, addition of SPHs in the 0.5-1.5% was unaffected, while >2.0% of SPHs caused significantly lower b* than control (p<0.05). The color changes in pork patties with and without SPHs were also identified in visual appearance where the pork patties containing 0.5-2.0% showed bright red color which was comparable to brownish color of control and patties containing >2.5% SPHs. Lipid oxidation was delayed by the addition of 0.5-1.5% SPHs, while it was accelerated by the addition of 3% SPHs. The pH of patties increased with increasing concentration of SPHs, whereas there were no significant differences in WHC and shear force of patties. Consequently, the results indicated that the addition of 0.5-1.5% SPHs had a potential advantage in suppressing oxidative deterioration of fat-containing meat products during chilled storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.16 no.4
• /
• pp.300-305
• /
• 1987

Changes in pigments of freeze dried grasshopper in refrigerator were determined to asses the storage stability. In storage at $5^{\circ}C$, chlorophyll contents were drastically decreased but pheopytins were increased. The degradation of chlorophylls get under controlled with vacuum package. The pigments extracted from 98 days stored samples were fractionated by silicic acid column and obtained 3 portions (3a, 3b and 3d). These portions were compared Rf values (0.75, 0.56, 0.50, respectively) and absorption spectra (408, 666nm; 419, 651nm; 433, 655nm, respectively) with that of standard and were identifed pheophytin a and b and 'changed' chlorophyll a. Especially, pheophytins a and b were great strength accelerated to lipid oxidation.

• Korean Journal of Food Science and Technology
• /
• v.26 no.6
• /
• pp.824-827
• /
• 1994

Sardine oil was vacuum-steam deodorized at $170^{\circ}C$ with acid (acetic and citric acid) and ethanol solution as steam sources. Glycerol was added to fish oil to remove volatile odorous constituents. The storage stability of deodorized fish oil was determined by totox value, secondary parameter obtained from peroxide and anisidine values. Both deodorization with acetic acid solution and addition of glycerol to the oil resulted in improved storage stability. The totox values of fish oil deodorized with water, glycerol+water and glycerol+acetic acid solution were 936, 611, and 443, respectively after 10 days at $30^{\circ}C$. The result showed that acetic acid seemed to destroy the odorous constituents and glycerol accelerated the removal of odorous constituents, such as amines in fish oil.

• Korean Journal of Food Science and Technology
• /
• v.37 no.3
• /
• pp.474-478
• /
• 2005

Antioxidative effects of several solvents extracts of cactus Cheonnyuncho (Opuntia humifusa) grown in Korea were investigated. Because 70% ethanol extract showed relatively high antioxidative activity and extraction yield, it was sequentially fractionated with hexane, chloroform, ethyl acetate, butanol, and water, Ethyl acetate fraction showed highest scavenging activity against free radical DPPH. Antioxidative activity of ethyl acetate fraction determined based on acid and peroxide values under accelerated oxidation condition of lard was similar to that of ${\alpha}$-tocopherol, but slightly lower than that of BHA. Similar results were observed using TBA method during peroxidation of linoleic acid.

• Korean Journal of Materials Research
• /
• v.23 no.9
• /
• pp.501-509
• /
• 2013

To evaluate the development of the microstructure and mechanical properties on surface modified and post-heattreated Inconel 718 alloy, this study was carried out. A friction stir process as a surface modification method was employed, and overlap welded Inconel 718 alloy as an experimental material was selected. The friction stir process was carried out at a tool rotation speed of 200 rpm and tool down force of 19.6-39.2 kN; post-heat-treatment with two steps was carried out at $720^{\circ}C$ for 8 h and $620^{\circ}C$ for 6 h in vacuum. To prevent the surface oxidation of the specimen, the method of using argon gas as shielding was utilized during the friction stir process. As a result, applying the friction stir process was effective to develop the grain refinement accompanied by dynamic recrystallization, which resulted in enhanced mechanical properties as compared to the overlap welded material. Furthermore, the post-heat-treatment after the friction stir process accelerated the formation of precipitates, such as gamma prime (${\gamma}^{\prime}$) and MC carbides, which led to the significant improvement of mechanical properties. Consequently, the microhardness, yield, and tensile strengths of the post-heat-treated material were increased more than 110%, 124% and 85 %, respectively, relative to the overlap welded material. This study systematically examined the relationship between precipitates and mechanical properties.

• Korean Journal of Materials Research
• /
• v.28 no.6
• /
• pp.324-329
• /
• 2018

Needle-like NiO protecting layers on NiCrAl alloy foam, used as support for hydrogen production, are introduced through electroplated Ni and subsequent microwave annealing. To improve the stability of the NiCrAl alloy foam, oxygen concentration of microwave annealing to form a needle-like NiO layer with good chemical stability and corrosion resistance is controlled in a range of 20 and 50 %. As the oxygen concentration increases to 50 %, needle-like NiO forms a dense coating layer on the NiCrAl alloy foam; this layer formation can be attributed to accelerated growth of the (200) plane. In addition, the increased oxygen concentration causes increased NiO/Ni ratio of the resultant coating layer on NiCrAl alloy foam due to improved rate of the oxidation reaction. As a result, the introduction of dense needle-like NiO layers formed at 50 % oxygen concentration improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the electrolyte and the foam. Thus, needle-like NiO can be proposed as a superb protecting layer to improve the chemical stability of NiCrAl alloy form.

• Microbiology and Biotechnology Letters
• /
• v.10 no.2
• /
• pp.109-115
• /
• 1982

A Corynebacterium sp. capable of utilizing diaminododecane (DAD) were isolated from the soil by enrichment culture. Among 9 different kinds of substituted alkanes containing CN, NH$_2$, Cl, and SH groups (monoteminally or diterminally substituted) tested as carbon source, the isolate, designated as DAD 2-2. utilized DAD, putrescine dihydrochloride, dodecanethiol, dodecane and lautylamine. Thioanisole, decanedithiol, dicyanooctane, laurylcyanide, and dichlorodecane were not utilized. When emulgen 950 was added to the medium, the growth of DAD 2-2 was greatly accelerated. Isolated DAD 2-2 grown in the medium with DAD as carbon source formed ethyl $\alpha$-ketoglutarate. Metabolic product of DAD 2-2 grown in a medium without nitrogen source was different from that of grown in a medium with NH$_4$NO$_3$. When glucose, putrescine, n-dodecane and other alkane derivatives were tested in place of DAD, isolate DAD 2-2 yielded products different from those they formed with DAD suggesting specificity of DAD as a carbon source.