• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.994-998
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• 1999

To evaluate the effects of sucrose-fatty acid ester (SE) on bread-making characteristics, the dough mixing, gelatinization, baking properties with the addition of SE alone and together with other surfactants were investigated. SE increased the peak time and the peak height in mixogram, indicating that it contributed the elasticity of dough. In farinogram, SE increased the peak time and mechanical tolerance index, but reduced the dough stability. SE increased the peak viscosity and reduced the gelatinization temperature and maximum consistency temperature in amylogram. SE increased the specific volume of bread loaf and retarded the increase in hardness of bread during storage, showing its anti-staling effects. The maximum anti-staling effect of SE was observed at 0.5% level. The addition of SE (0.2%), SSL (0.15%) and ES-95 (0.15%) blend showed the maximum specific loaf volume, and that of SE (0.25%) and SSL (0.25%) did the maximum anti-staling effect.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.305-310
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• 1996

The degrees of retrogradation (DR) for 50% rice flour gels kept at $4^{\circ}C$ and $20^{\circ}C$ for the 6-day storage period at 0.5, 1.0 and 2.0% (w/w, on dry weight basis) levels of lipid additives (sucrose fatty acid ester, SE1670; soybean oil) were measured by ${\alpha}$-amylase-iodine method, differential scanning calorimetry (DSC) and X-ray diffractometry. The DRs were higher in rice flour gels stored at $4^{\circ}C$ than those stored at $20^{\circ}C$. The sucrose fatty acid ester and soybean oil reduced the retrogradation of rice flour gels, but the effect was higher in samples stored for 1 day. The DR decreased more effectively in the addition of SE1670 than that of soybean oil In case of SE1670, the change of enthalpy by DSC showed similar patterns with the degree of retrogradation by ${\alpha}$-amylase method; however, it was not the case for soybean oil. The intensity of peak at $2{\theta}=16.7^{\circ}$ in X-ray diffraction pattern was reduced with lipid additives but it was not clear.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.162-177
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• 2001

The hydrolysis rates of seven kinds of polyol ester base oils 〔POEs〕 of different branch shape were investigated by using a simple apparatus under mild acidic condition. Seven polyol ester base oils were made of poly hydric alcohols of two-four valence, normal or branched fatty acids of different carbon number. p-Toluene sulfonic acid was used as acid catalyst to accelerate the rate of hydrolysis. Partial esters and fatty acid produced by sequential hydrolysis of POEs were identified and their concentrations were determined by calibrated-internal standard method using Gas Chromatography. The rate constants of each step in sequential hydrolysis were determined by the least square method from rate equation and the concentration of each component, were compared with one another. It was shown that the rate of hydrolysis of POEs was strongly affected by whether molecular structure of fatty acid was straight chain or branch chain and which position was branched. The hydrolysis stability for all the POEs can be reasonably explained by using a steric hindrance effect anticipated fi:om their molecular structures affecting as water molecule makes an attack on the carbonyl carbon of POEs.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.951-956
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• 2001

A 28-kDa extracellular lipase (pI 8.7) was purified to homogeneity from the culture supernatant of Trichosporon sp. Y- 11 by mmonium sulfate precipitation, DEAE-Sephadex A-50, Bio-Gel P-30, CM- Sephadex C-50, and Bio-Gel P- 10 chromatographies. The purified enzyme exhibited a specific activity of $2,741{\;}{\mu}mol/min/mg$ based on the hydrolysis of triolein, and the optimal hydrolysis activity was dentified at pH 8.0 and $40^{\circ}C$. The enzyme activity was inhibited by $Ag^+$ and enhanced by $Fe^{2+}$, $Fe^{3+}$, $Mg^{2+}$, $Mn^{2+}$, and $Li^{+}$. The enzyme activity exhibited for the hydrolysis of both tributyrin and trilinolein. The ester synthesis of unsaturated fatty acids with various alcohols catalyzed by the purified lipase in a nonaqueous medium or microaqueous system was also investigated. The esterification activity of the lipase increased with an increase of the carbon chain length in the alcohol. The synthesis rate of linoleic acid and oleyl alcohol was the highest with an optimal temperature and pH of $40^{\circ}C$ and 8.0, respectively. The water content and agitation also affected the esterification activity of the lipase.

• Journal of the Korean Applied Science and Technology
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• v.19 no.2
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• pp.137-144
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• 2002

Methyl glycoside oleic acid polyester was successfully prepared from methyl glycosides and methyl oleate by emulsion interesterification in the presence of methyl fructoside oleic acid polyester as an emulsifier. Emulsion interesterification process was optimized to obtain 98% yield of methyl glycoside polyester within $3{\sim}5hr$ at temperatures as relatively low as $90{\sim}150^{\circ}C$ and $20{\sim}200mmHg$ pressure with a five-fold molar ratio of oleic acid methyl ester to methyl glycoside in the presence of 2(w/w)% potassium carbonate and 2O(v/v)% methyl fructoside polyester based on oleic acid methyl ester.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.12-18
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• 2006

The transesterification of vegetable oils into Biodiesel at $60^{\circ}C$ was performed on the rotary viscometer. The overall yield(%) of fatty acid methyl ester from canola oil at optimum conditions was 95%. The viscosities of fatty acid methyl esters were predicted by Orrick and Erbarr's model. The overall yield increased as the viscosities of fatty acid methyl esters decreased. The limiting molar ratio of methanol to oil appeared to be 1:5. The content of sodium hydroxide as the optimum catalyst appeared to be 0.5wt%.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.77-83
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• 2002

A bacterial consortium capable of utilizing a variety of polycyclic aromatic hydrocarbons has been isolated from a former manufactured gas plant site. The consortium consisted of four members including Arthrobacter sp., Burkholderia sp., Ochrobacterium sp., and Alcaligenes sp., which were identified and characterized by the patterns of fatty acid methyl esters (FAME analysis) and carbon source utilization (BIOLOG system). With the individual members, the biodegradation characteristics of aromatic hydrocarbons depending on different growth substrates were determined. FAME analyses demonstrated that microbial fatty acid profiles changed to significant extents in response to different carbon sources, and hence, such shift profiles may be informative to characterize the biodegradation potential of a bacterium or microbial community.

• Korean journal of food and cookery science
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• v.18 no.3
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• pp.333-339
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• 2002

This study was conducted to examine the effect of emulsifiers on the quality characteristics of Yackwa. Lecithin and various sucrose fatty acid esters (S-570, S-970, S-1570) were used as emulsifiers. The addition of emulsifiers to Yackwa decreased the hardness, cohesiveness, springiness and gumminess, but increased the brittleness. This tendency was most distinct by the addition of S-970. All sensory characteristics of Yackwa such as color, smooth surface, smell, internal layer formation, softness and overall quality, were improved greatly by the addition of emulsifiers. As a result, the mechanical and sensory characteristics of Yackwa were improved by the addition of the emulsifiers, and sucrose fatty acid esters showed better results than lecithin.

• BMB Reports
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• v.33 no.1
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• pp.54-58
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• 2000

Recent research results regarding the very long chain transmembrane ${\alpha},{\omega}-dicarboxylic$ components in the membrane of extremophilic eubacteria, such as Sarcina ventriculi, Thennotoga maritima, and Thermoanaerobacter ethanolicus have raised interesting questions concerning the physical and biochemical function on these components in the membrane. In order to understand the dynamic characteristics of these acids which reside in the bilayer membrane, 580 ps molecular dynamic simulations at 300 K were performed for two model systems. These systems were the bilayer with regular chain (C16:0 or C18:1) fatty acid methyl esters and the fatty acid bilayer containing very long chain transmembrane dicarboxylic acid methyl esters (${\alpha},{\omega}-15,16-dimethyltriacotane-dioate$ dimethyl ester; C32:0). Our analyses indicate that very long chain transmembrane dicarboxylic acids have a noticeable influence on the bilayer dynamics at a sub-nanosecond time scale. The center-ofmass mean-squared-displacement (MSD) of regular chain fatty acids adjacent to the very long chain transmembrane dicarboxylic acids decreased, the long-axis order parameter increased, and the reorientational motions of methylene groups were slowed along the hydrocarbon chains. These results indicate that the very long chain transmembrane dicarboxylic acids reduce the molecular order of the whole bilayer membrane.

• Korean Journal of Plant Resources
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• v.12 no.3
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• pp.192-197
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• 1999

The contents of total lipids and their components of brown rice grain were studied for 5 colored rice cultivars, 1 aromatic rice cultivar and 1 normal rice cultivar grown in Korea. The total lipid contents ranged 2.04 to 4.69% based on total dry weight. The Tohoku #149 showed the highest content which was followed by Hansanheukmi and Sanghaehyang-hyeolna. The lowest content were observed in three cultivars, Heuknambyeo, Hyangnambyo and Dongjinbyeo which showed no difference among cultivars. The main classes of the total lipid were triglyceride, diglyceride, free sterol, free fatty acid and sterol esters in all cultivars examined. The ratio of triglyceride in total lipid was high in colored rice and aromatic rice compared to Dongjinbyeo which is normal rice cultivars, but the ratio of diglyceride was high in Dongjinbyeo. The major fatty acid compositions in the cultivars examined were linoleic acid, oleic acid and palmitic acid. There was a varietal difference in fatty acid composition, for example, erucic acid was detected in aromatic and colored rices cultivars, while none of this compound was found in Dongjinbyeo.