• The Korean Journal of Food And Nutrition
• /
• v.14 no.1
• /
• pp.40-45
• /
• 2001

This study was conducted to investigate the effects of various emulsifiers on the quality of the waxy rice cake. Falling numbers of the waxy rice flour with monoglyceride, lecithin and control were not significantly different, but with sugar esther 0.5% and 1% showed higher value as 88.4 and 81 than control Initial pasting temperature of the waxy rice flour was 66.78$\^{C}$ and others were 66.45 ∼ 67.05$\^{C}$ by adding 0.5%, 1% of emulsifiers such as monoglyceride, lecithin, sugar esther. Waxy rice flour with 1% sugar ester showed the highest peak viscosity as like as falling number. Waxy rice cake wish various emulsifiers showed tendency to be slowly firming rate as compared with control. In all case, waxy rice flour with sugar ester 1% was considered to be more effective to the decrease of firming rate. Waxy rice flour with lecithin showed worse visual color than others and sugar ester provided best visual and sensory quality. After 5 days cold storage, waxy rice flour with sugar ester 1%\`s Aw was 0.875 and control\`s 0.911. These results suggested that water holding capacity of sugar ester was the best during storage.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.504-507
• /
• 2002

A separation/purification process for enzymatic sugar ester production was investigated The crude reaction mixture contained sugar ester and unreacted fatty acid in acetone. The reaction mixture was mixed with KOH/phosphate buffer. Hexane was then added to enhance phase separation. Three phases formed: a lower aqueous phase containing nothing of interest, a polar organic solvent middle phase that contained mostly fatty acid soaps, and a hexane-rich upper phase that contained mostly sugar ester. Distribution coefficient of each component was measured.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.977-983
• /
• 1999

This study was conducted to investigate the effects of emulsifiers on the quality of steamed bread. initial pasting temperature of the flour was decreased from $63.8^{\circ}C$ to $59.40{\sim}62.95^{\circ}C$ by adding 1% of emulsifiers such as monoglyceride, lecithin, sugar ester and diacetyl tartaric acid esters of mono- and diglycerides (DATEM). But other rheological properties of the doughs were varied with different emulsifiers. Flour with 1% sugar ester showed the lowest value of final viscosity and set back, therefore sugar ester might be effective for retard the retrogradation of bread. By alveogram test, flour with 1% DATEM showed the highest value of P (tenacity) but the lowest value of L (extensibility), that means DATEM might be effective for strengthening tenacity of dough but it lowered extensibility. After 72 hours of storage test, the steamed bread based on the flour with 1% monoglyceride showed the best crumb softness and the highest score of sensory test.

• Korean Journal of Microbiology
• /
• v.33 no.3
• /
• pp.181-186
• /
• 1997

Sugar ester compounds were synthesized in organic solvent using lipase. Anhydrous pyridinc was selected as ;I solvent because of reasonable solubility of sugar. The synthesis of sugar ester compound was catalyzed by Pseudomonas sp. lipase in the reaction system containing anhydrous pyridine as .i solvent and vinyl butylate as an acyl donor. The analysis of the reaction product by TLC and GC showed thilt monobutyryl and dibutyryl fructose esters were synthesized by transesterification reaction between fructose and vinyl butyrate. Optimal conditions for the transesterification reaction were as follows: the ratio of fructoselvinyl butylate, I : lO(M : M): reaction temperature, 40^{\circ}C.$, velocity of shaking, 150 rprn: concentration of enzyme, 10 mglml. The longer the reaction period, the higher the conversion rate, and the conversion rate reached up to 90% after about 10 days of reaction. Monobutyryl fructose was mainly synthesized in the early stage of reaction, but the amount of dibutyryl fructose increased gradually as the rcdction progressed. When a small amount of water was added to the reaction mixture (micro-water system), the reaction rate decreased, while that of rnonobutyr~l fructosc increased. Only monobutyryl fructose was obtained when 1% water was added to the reaction mixture.

• Applied Chemistry for Engineering
• /
• v.16 no.5
• /
• pp.705-711
• /
• 2005

The reaction of lauric acid vinyl ester with n-butanol was established to give lauric acid butyl ester by subtilisin A-catalyzed transesterification in organic media containing nonionic surfactants. Pyridine has been used as an organic solvent since it provides higher yields than other organic solvents. However, because of stench of pyridine, compounds enzymatically synthesized in pyridine may be unsuitable as ingredients for foods and drugs. Hence, in order to select an organic solvent to replace pyridine, sugar esters were synthesized with the protease in various organic media. However, no solvent paralleled pyridine in yields. On the basis of this result, pyridine-based W/O microemulsions containing nonionic surfactants and water were used in enzymatic synthesis of the sugar ester, and when Tween 60, Brij 56, or 1-O-octyl-${\beta}$-D-glucopyranose was used for the W/O microemulsions, the yield was higher.

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.859-864
• /
• 1995

Mono- and oligosaccharides are derivatized with p-aminobenzoic ethyl ester (ABEE), strongly absorbs UV light at 254 nm, in the presence of sodium cyanoborohydride. C18-bonded silica column is used for the separation of sugar-ABEE derivatives in an isocratic mode. RP-HPLC conditions are optimized by using ternary mixture as mobile phase and $45^{\circ}C$ as a column temperature. Sugar-ABEE derivatives are separated well within a short run time (ca. 25 min) by reverse-phase partition chromatographic mode. The ($1{\rightarrow}6$) linkage type of dihexose-ABEE derivatives has shorter retention time than ($1{\rightarrow}4$)-linkage type. After acid hydrolysis of glycoproteins with 2M trifluoroacetic acid, monosaccharide composition and contents are determined. This procedure is very useful for the simultaneous analysis of neutral and amino sugars in a single chromatographic step using RP-HPLC without reacetylation of deacetylated amino sugars, which are produced by acid hydrolysis.

• Korean Journal of Food Science and Technology
• /
• v.42 no.1
• /
• pp.75-81
• /
• 2010

In order to investigate the effects of different milling degrees on the quality of glutinous rice wines, the physicochemical properties and volatile compounds of various wines were evaluated. Sample wines prepared from glutinous rice with 90, 80, and 70% milling yields were analyzed for ethanol, pH, total acids, amino acids, soluble solids, coloring degree, UV absorbance, reducing sugars, organic acids, free sugars and volatile compounds. After fermentation for 17 days, ethanol contents in the wines ranged from 15.2 to 15.85%, while total acid levels ranged from 0.31 to 0.35%. The amino acid contents in four samples ranged from 0.63 to 0.73%, while soluble solid contents ranged from 11.4 to $13.1^{\circ}Bx$. The wine prepared from glutinous rice with a 30% degree of milling showed the highest coloring degree, UV absorbance and reducing sugar content among four samples. Furthermore, this wine had the highest levels of malic acid and acetic acid, while the glutinous rice wine prepared from rice with a 0% degree of milling had the highest levels of succinic acid and lactic acid. In all the glutinous rice wines tested, the most abundant free sugar was glucose followed by maltose. With increasing degree of milling, the alcohol, amino acid and organic acid contents of the glutinous rice wines decreased, whereas soluble solids, coloring degree, UV absorbance, reducing sugar and free sugar contents increased. Volatile compounds were identified using GC-MSD, and thirty-nine esters, seven alcohols, six acids, one aldehyde, four alkanes, one alkene and two miscellaneous compounds were identified in the glutinous rice wines. Using relative peak area, it was determined that other than ethyl alcohol, hexadecanoic acid ethyl ester was the major component and was primarily found in the range of 11.566-18.437%. Succinic acid diethyl ester and isoamyl laurate decreased with an increasing degree of milling, whereas hexanoic acid ethyl ester and 2-octenoic acid ethyl ester increased. Overall, it was shown that different milling degrees greatly affected the physicochemical and volatile characteristics of the glutinous rice wines.

• 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.

• Korean Journal of Food Science and Technology
• /
• v.30 no.1
• /
• pp.54-61
• /
• 1998

Samjangs (Korean-style mixture of soybean paste) were prepared using magjang, traditional doenjang (Korean style soybean paste), and mixture of traditional doenjang and magjang (a kind of Korean style soybean paste) as a main composition. Charateristics including volatile compounds were investigated. Total sugar in samjang by using magjang was higher than that of other treatment while reducing sugar of the mixed treatment was high. Glutamic acid $(230.6{\sim}310.9\;mg/100\;g)$ was highest among free amino acids. Hunter color values of samjang with magjang was lower than those of others. Volatitle flavor components of smajang were identified with GC and GC-MSD. Fifty four components including 11 alcohols, 7 esters, 13 acids, 3 aldehydes, 4 alkanes, 4 phenols, 3 pyrazine and others were found in samjangs. Ethanol, acetic acid ethyl ester, 3-methyl butanoic acid, 2,4-hexadienoic acid and acetic acid might be major volatile components considering of high peak area. Pentanoic acid methyl ester and 4-methoxy-2-buten-1-ol were higher than other components in samjang with magjang while 2-methyl-1-propanol, butanoic acid and 3-methyl butanoic acid were in samjang with traditional doenjang and ethanol, acetic acid ethyl ester and 2,4-hexadienoic acid were in the mixed treatment.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.9
• /
• pp.1579-1585
• /
• 2016

Sugar esters are valuable compounds composed of various sugars and fatty acids that can be used as antibacterial agents and emulsifiers in toothpaste and canned foods. For example, fructose fatty acid esters suppress growth of Streptococcus mutans, a typical pathogenic bacterium causing dental caries. In this study, fructose laurate ester was chosen as a target material and was synthesized by a transesterification reaction using Candida antarctica lipase B. We performed a solvent screening experiment and found that a t-butanol/dimethyl sulfoxide mixture was the best solvent to dissolve fructose and methyl laurate. Fructose laurate was synthesized by transesterification of fructose (100 mM) with methyl laurate (30 mM) in t-butanol containing 20% dimethyl sulfoxide. The conversion yield was about 90%, which was calculated based on the quantity of methyl laurate using high-performance liquid chromatography. Fructose monolaurate (M_r 361) was detected in the reaction mixture by high-resolution mass spectrometry. The inhibitory effect of fructose laurate on growth of oral or food spoilage microorganisms, including S. mutans, Bacillus coagulans, and Geobacillus stearothermophilus, was evaluated.