• Natural Product Sciences
• /
• v.14 no.4
• /
• pp.281-288
• /
• 2008

From the MeOH extract of the whole plants of Lathyrus davidii (Fabaceae), thirteen constituents were isolated and identified as the flavonoids astragalin, isoquercitrin, nicotiflorin, and rutin, as the saponins soyasapogenol B 3-O-${\beta}$-D-glucuronopyranoside, azukisaponins II and V, soyasaponins II and V and as 4-O-${\beta}$-Dglucopyranosyl syringic acid, uracil and n-hexacosanol. Five saponins and 4-O-${\beta}$-D-glucopyranosyl syringic acid were isolated from the BuOH fraction as their methyl esters. Ombuoside (rutin 7,4'-di-O-methyl ether) was also isolated from the methylated BuOH-soluble fraction. However, no ombuoside was detected in the HPLC analysis of the nonmethylated BuOH fraction. Therefore, ombuoside is an artifact derived from methylation of rutin. All of these compounds were isolated for the first time from this plant.

• Korean Journal of Food Science and Technology
• /
• v.28 no.3
• /
• pp.446-450
• /
• 1996

To investigate the effect of heating conditions on the polymerization of methyl linoleate, the esters were heated at $60^{\circ}C,\;90^{\circ}C,\;120^{\circ}C$ and $150^{\circ}C$, respectively, with sparging oxygen for different periods of time. On the basis of the peroxide curve obtained at each of the four temperatures, four heating times were chosen for the analysis of the polymers and total oxidation products. Significant linear relationships were found between polymer contents and total oxidation product contents. The contents of polymers and their linkage types were analyzed by High Performance Size Exclusion Chromatography. The polymers formed at four temperatures were qualitatively identified as dimers. The dimers with peroxide linkages were detected from methyl linoleate oxidized at $60^{\circ}C\;and\;90^{\circ}C$ but they were not detected from methyl linoleate oxidized at $120^{\circ}C\;and\;150^{\circ}C$. Therefore, all dimers formed at $120^{\circ}C\;and\;150^{\circ}C$ seemed to be the ones with ether linkage or carbon to carbon linkage. The degradation rate of the dimers with peroxide linkages at $90^{\circ}C$ was faster than at $60^{\circ}C$.

• Polymer(Korea)
• /
• v.39 no.3
• /
• pp.487-492
• /
• 2015

The effects of chemical structure of alkyl groups of norbornene carboxylic alkyl esters(methyl, octyl, 4-chlorobenzyl) and endo/exo ratios of norbornene monomers on activity of palladium catalyst and polymerization behavior were investigated. Norbornene ester monomers were synthesized from the reaction of 5-norborene-2-carboxylic acid and various alcohols. Polymerization catalyst, di-${\mu}$-chloro-bis(-methoxybicyclo[2,2,1]-hept-2-ene)palladium(II) (DCBMP), was synthesized according to the literature procedure and silver hexafluoroantimonate ($AgSbF_6$) was used as a conjugate anion source. Gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) were the principal techniques for polymer characterization and $^1H$ NMR spectroscopy was used for chemical structures determination of monomers and polymers. For all of the norbonene alkyl esters GPC data showed that when the amounts of endo isomers exceeded those of exo isomers decreased molecular weight polymers were obtained probably due to the decreased catalyst activity. Polymerizations were conducted by varying the monomer/catalyst mole ratios (100:1, 200:1, 300:1). When 300:1 monomer/catalyst ratio was employed it was possible to synthesize high molecular weight ($M_n=27500g/mol$), film forming polymer from exo-norbornene carboxylic acid octyl ester.

• Journal of the East Asian Society of Dietary Life
• /
• v.11 no.6
• /
• pp.472-478
• /
• 2001

This study was conducted to investigate the change in volatile flavor components of persimmon leaves during growth. The flavor components of persimmon leaves were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry(GC/MS). The flavor compounds were collected by simultaneous steam distillation and extraction(SDE) method, and were separated and identified resulting in 126 components, including 23 alcohols, 18 aldehydes, 4 esters. 15 acids, 37 hydrocarbons, 14 ketones, 6 phenols. and 9 others in persimmon leaves. The most abundant components of persimmon leaf were alcohols including iinalool. cis-3-hexanal. 1-$\alpha$ -terpineol. 3.7.11.15-tetramethyl-2-hexadecen-1-ol and aldehydes including trans-2-hexanal. nonanal, 2-decenal and hydrocarbons including 1.1-dimethylethyl cyclohexane, 1-methyl-4-(2-methylpropyl) -benzene. During growth, many other components were formed and dissipated after the 20th of June.

• Journal of the Korean Applied Science and Technology
• /
• v.28 no.4
• /
• pp.472-481
• /
• 2011

It is known that the content of saturated fatty acids methyl ester (SFAME) affect the pour point of biodiesel at low temperature. In this study, biodiesel (BD) was produced from beef tallow (TAL) by alkali catalyst. To reduce the saturation in BD, acetone fractionation was applied. Besides, TAL was also solvent-fractionated to reduce the saturated fatty acid (SFA) content for further producing BD. With acetone, TAL or TAL methyl ester (5:1 v/w) were fractionated at 10, 0, -10, and $-15^{\circ}C$, respectively. At $-10^{\circ}C$, 17.35% of SFA was observed in fractionated TAL (liquid part, -10TAL) when 5:1 solvent ratio was used for 24 hr. Under the same condition, fractionated BD (liquid part, -10BD) showed SFA (33.14%) with 78wt % yield. Also, fractionation of BD with different concentration of crystallizer 209 (0.1, 0.5, and 1%) along with different time (2, 6, 12, and 24 hr.) was observed. The best condition for reducing the SFA was 0.5% of crystallizer 209 addition for 12 hr of fractionation time at $-10^{\circ}C$, in which 30.14% of SFA content was observed in BD (liquid part). Among different crystallizer, ps 66 showed the least content of SFA content (23.28%) in BD after fractionation ($-10^{\circ}C$ and 24 hr) with 0.5wt% addition.

• KSBB Journal
• /
• v.22 no.4
• /
• pp.222-227
• /
• 2007

Biodiesel (fatty acid methyl esters) have used to as substitutes for petro-diesel by mixed-form with petro-diesel. In several processes of biodiesel production, alkali-catalyst transesterification produced to biodiesel of high contents with short reaction time. In this study, we investigate the optimal condition of alkali-catalyst transesterification of rapeseed oil produced at Jeju island in Korea using response surface methodology. The optimal condition of biodiesel production is reaction temperature 59.7$^{\circ}C$, catalyst amount 1.18%, oil to methanol molar ratio 1:8.75, and reaction time 5.18 min. At that reaction condition, the fatty acid methyl ester contents of product are above 97%. Our results may provide useful information with regard to the development of more economic and efficient biodiesel production system.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.4
• /
• pp.1013-1030
• /
• 2018

Biodiesel is a fuel produced in the form of a fatty acid methyl ester by using raw materials such as animal fat, vegetable oil and its by-products, and is being seen as a biofuel that can replace petroleum energy. However unsaturated fatty acid methyl esters in biodiesel causes to oxidize during storage and distribution, resulting in poor fuel quality and corrosion of vehicle engine components. In this study, the influence of quality and oxidation characteristics of biodiesel on the oxidation stability is investigated and the evaluation method related it is described. We also propose a method to improve the drawback of oxidation stability in biodiesel.

• Microbiology and Biotechnology Letters
• /
• v.50 no.2
• /
• pp.202-210
• /
• 2022

Aflatoxin contamination in rice has been documented in a number of studies, and has a high incidence in Asian countries, and as such, there has been a growing interest in alternative biocontrol strategies to address this issue. In this study, 147 strains of yeasts and yeast-like fungi were screened for their potential to produce volatile organic compounds (VOCs) active against Aspergillus flavus strains that produce aflatoxin B₁ (AFB₁). Five strains within four different genera showed greater than 50% growth inhibition of some strains of A. flavus. These were Anthracocystis sp. DMKU-PAL124, Aureobasidium sp. DMKU-PAL120, Aureobasidium sp. DMKU-PAL144, Rhodotorula sp. DMKU-PAL99, and Solicococcus keelungensis DMKU-PAL84. VOCs produced by these microorganisms ranged from 4 to 14 compounds and included alcohols, alkenes, aromatics, esters and furans. The major VOCs produced by the closely related Aureobasidium strains were found to bedistinct. Moreover, 2-phenylethanol was the most abundant compound generated by Aureobasidium sp. DMKU-PAL120, while methyl benzeneacetate was the major compound emitted from Aureobasidium sp. DMKU-PAL144. On the other hand, 2-methyl-1-butanol and 3-methyl-1-butanol were significant compounds produced by the other three genera. These antagonists apparently inhibited A. flavus sporulation and mycelial development. Additionally, the reduction of the AFB1 in the fungal-contaminated rice grains was observed after co-incubation with these VOC-producing strains and ranged from 37.7 ± 8.3% to 60.3 ± 3.4%. Our findings suggest that these same microorganisms are promising biological control agents for use against aflatoxin-producing fungi in rice and other agricultural products.

• Korean Journal of Food Science and Technology
• /
• v.31 no.1
• /
• pp.36-44
• /
• 1999

Samjangs which were prepared using magjang, traditional doenjang, and mixture of traditional doenjang and magjang were stored. Characteristics of the stored samjangs were investigated. Maximum titratable acidity was shown in traditional doenjang after 30 day of storage. Total sugar in samjangs decreased while reducing sugar increased to $11.45{\sim}12.35%$ from $8.44{\sim}9.29%$ after 40 days. Amino type nitrogen predominantly increased to $337.3{\sim}381.1\;mg%$ after 40 days from $48{\sim}53\;mg%$ of initial period of preparation. Among the free amino acids the content of glutamic acid $(202.6{\sim}464.6\;mg/100g)$ was highest and others were not too much changed. Forty two components including 7 alcohols, 4 esters, 13 acids, 6 aldehydes, 5 phenols, 3 pyrazines and others were found in samjangs. Ethanol, acetic acid ethyl ester and 2-phenylethanol were found in all treatments and ethanol, acetic acid ethyl ester, phenylacetaldehyde, butanoic acid, acetic acid, 3-methyl butanoic acid and 2,4-hexadienoic acid might be major volatile components considering of high peak area. 2-Phenylethanol, butandioic acid ethyl ester, butanoic acid and 2-methyl-2-butenoic acid were higher than other components in samjang with magjang while ethanol, acetic acid, 2,4-hexadienoic acid were in samjang with traditional doenjang and 3-methyl butanoic acid, acetic acid ethyl ester and methyl pentanoic acid were in the mixed treatment.

• Archives of Pharmacal Research
• /
• v.21 no.6
• /
• pp.738-743
• /
• 1998

Thirty six 5,8-dimethoxy-1,4-naphthoquinone derivatives, which bear unsaturated alkyl side chain with ester bond, were synthesized and tested cytotoxic activity on L1210 cells a nd antitumor activity against ICR mice bearing S-180 cells. It could be recognized that the cytotoxicities of naphthoquinones with R1, being methyl and propyl (IV1~24) were not enhanced by replacing the alkanoyls with alkenoyls. In contrast, the introduction of the alkenoyl moieties on the compounds with $R_1$=hexyl (IV25~36) resulted in the enhancement of their cytotoxicities. Replacement of alkanoyl group with an alkenoyl group generally increased the T/C value of the mice bearing S-180 cells.