• Bulletin of the Korean Chemical Society
• /
• v.22 no.12
• /
• pp.1380-1384
• /
• 2001

The chemoselective reactions of 1,n-dicarbonyl compounds with allyl halides using indium metal were investigated. $\alpha-Ketoesters$ such as ethyl pyruvate, ethyl 3-methyl-2-oxobutyrate and ethyl benzoylformate reacted with a variety of allyl halides i n the presence of indium to afford hydroxy unsaturated carbonyl compounds in good to excellent yields in MeOH/HCl at $25^{\circ}C.$ For the allyl bromide, the presence of various substituents at the $\alpha$ or $\gamma$ position exhibited little effects on both the reaction rates and yields. Ethyl acetoacetate or ethyl levulinate was treated with allylindium reagent to give hydroxy unsaturated carbonyl compounds in good yield. These results mean that both reactivity and selectivity are independent of the distance between carbonyl groups. 2,3-Butanedione or 1-phenyl-1,2-propanedione reacted with allylindium to produce monoallylation product as major compound.

• Journal of the Korean Chemical Society
• /
• v.51 no.3
• /
• pp.240-243
• /
• 2007

The eight coordinated yttrium(III) complex Y(tpb)3(H2O)2 (Htpb=4,4,4-Trifluoro-1-phenyl-1,3-butanedione) has been synthesized and structurally characterized by X-ray diffraction method. The coordination polyhedron of Y(tpb)3(H2O)2 has a dodecahedron. The angle between two trapezia, Y-O2-O1-O5-O6 and Y-O4-O3-O8-O7, is 89.59°. The O1-O5 and O3-O8 distances are 2.965 and 2.995 A whereas the O2-O6 and O4-O7 distances are 4.256 and 4.403 A.

• Korean journal of food and cookery science
• /
• v.18 no.4
• /
• pp.413-425
• /
• 2002

Quality characteristics of white bread added with lotus root powder(3, 6%) were investigated. Moisture content of white bread added with lotus root powder were higher than control. As the amount of added lotus root powder increased, the lightness, redness and yellowness of bread crust as well as the volume of the bread decreased, but the redness and yellowness of the crumb increased slightly. The content of free amino acids increased by the addition of lotus root powder and the major ones were L-glutamic acid, L-alanine, L-valine and threonine. The major flavor components were 2-methyl butanal and 3-methyl butanal, which were formed by the amino-carbonyl reaction in baking bread at high temperature. Aldehyde flavor components such as 2-ethylfuran, 2-butanedione and 3-butanedione were formed by yeast fermentation. Ethyl acetate and vinyl acetate also influenced the flavor of the bread. The addition of lotus root powder increased the hardness and fracturability, and decreased the gumminess, chewiness and cohesivenes of the bread. Sensory evaluation of white bread indicated that the addition of 3%, 6% lotus root bread enhanced the grain formation, color, mouth feeling, appearance, hardness, moistness, flavor and overall acceptability. Overall, the addition of 6% lotus root powder showed the best performance in the nutritional and functional aspects of the bread.

• Journal of Photoscience
• /
• v.11 no.3
• /
• pp.129-132
• /
• 2004

Photochemically stable dibenzoylmethane and curcumin were cleaved dramatically when they were irradiated in the presence of N,N-dimethylaniline in methanol with 300 nm UV light. Several products such as benzil, secondary product derived from 1,4-diphenyl-1,4-butanedione, and unidentified compound were observed from the photoreactions of dibenzoylmethane with N,N-dimethylaniline. It was also found that one of the primary fragments produced by irradiation of curcumin in methanol were coupled with N,N-dimethylaniline to give a new enone compound, i.e., 1-(4-dimethylaminophenyl)-4-(4-hydroxy-3-methoxyphenyl)-but-3-en-2-one, as the major product.

• Korean Journal of Food Science and Technology
• /
• v.52 no.5
• /
• pp.524-528
• /
• 2020

The aim of this study was to enhance the use of wheat bran in lactic acid bacteria (LAB) fermentation. LAB fermentation of wheat bran and the flavor components and amino acids of fermentation products were analyzed using gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC). The results showed that total flavor components increased by 93% and 73% in the animal-based LAB mixture (T2) and plant-based LAB mixture (T3), respectively, after fermentation. Among these components, 2,3-butanedione (diacetyl), known for its buttery flavor, was detected at concentrations of 18.44 ng/g (T2) and 16.95 ng/g (T3). Levels of hexanal and nonanal, which causes off-flavor components in wheat bran, dramatically decreased after T2 fermentation; similarly, levels of total free amino acids decreased by 37.6% (T2) and 36.7% (T3) after fermentation. This may explain why some components were bound to volatile compounds during LAB fermentation. These results suggest that LAB-fermented wheat bran is a potential value-added food material.

• The Korean Journal of Food And Nutrition
• /
• v.7 no.1
• /
• pp.1-7
• /
• 1994

To investigate the characteristics of active sites of the D-xylanase and $\beta$-xylosidase purified from Penicillium verruculosum, effects of various chemicals on the enzyme activity were analyzed. The D-xylanase was activated by Cua), however it was inhibited by metal ions, Hg2+ and Mna+, by chemicals, N-bromosuccinimide, iodine, diethylpyrocarbonate, and 2,3-butanedione. These results suggested that the D-xylanase from Penicillium verruculosum contained tyrosine, histidine, arginine and tryptophan at the active center. The $\beta$-xylosidase was inhibited by Hg2+, N-bromosuccinimide and sodium dodecyl sulfate, however it was not effected by Mn2+ and Cu2). It was suggested that the enzyme contained tryptophan at the active center.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.4
• /
• pp.566-571
• /
• 2002

Volatile flavor compounds in Alaska pollack sik-hae during fermentation at 5$^{\circ}C$ were analyzed by liquid-liquid continuous extraction (LLCE) and gas chromatography/mass spectrometry (GC/MS) methods. Sixty five volatile compounds were detected in Alaska pollack sik-hae during fermentation. These compounds were composed mainly of 11 S-containing compounds, 13 alcohols, 13 acids, 4 aldehydes, 4 ketones, 6 terpenes,4 aromatic compounds and 10 miscellaneous compounds. Among these, 9 S-containing compounds (3-(methylthio)-1-propene, dimethyl disulfide, diallyl sulfide, methylallyl disulfide, methyl-(E) -propenyl disulfide, dimethyl trisulfide, 2 diallyl disulfide isomers and diallyl trisulfide), 2 acids (acetic acid and butanoic acid), 2 ketones (2, 3-butanedione and 6-methyl-5-hepten-2-one) and 2 esters (ethyl formate and ethyl acetate) were significantly increased during fermentation (p<0.05), and these compounds were suspected to affect on the odor of Alaska pollack sik-hae.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.6
• /
• pp.460-465
• /
• 1994

New silicon-monosubstituted (${\eta}^4$-2,3,4,5-tetraphenyl-l-silacyclopentadiene)transi tion metal complexes are described. (7-Alkyl-7-silanorbornadienyl)MLn(Alkyl=Methyl: MLn=CpRu$(CO)_2$: Alkyl=Methyl: MLn=CpNi(CO): Alkyl=Ethyl: MLn=CpNi(CO)) complexes were prepared from the corresponding silole-transition metal complexes with dimethylacetylenedicarboxylate. Cycloaddition products were obtained with 2,3-dimethyl-1,3-butadiene, 2,3-butanedione, and 1,4-benzoquinone through the ruthenium-substituted silylene. We have determined the crystal structure of (1-methyl-2,3,4,5-tetraphenyl-l-silacyclopentadien yl)cyclopentadienyldicarbonylruthenium by using graphite monochromated Mo-Ka radiation. The compound was crystallized in the monoclinic space group $P2_{1/c}$ with a = 9.838(l), b = 15.972(3), c = 18.327(3) ${\AA}$, and ${\beta}= 94.28(l)^{circ}$. The ruthenium moiety CpRu$(CO)_2$ on silicon is in an axial position.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.2
• /
• pp.319-325
• /
• 1999

Volatile flavor compounds in Korean salt fermented shrimp on the market were analyzed by vacuum simultaneous distillation solvent extraction/gas chromatography/mass spectrometry/olfac tometry(V SDE/GC/MS/O) and aroma extract dilution anlaysis(AEDA). A total of 32 volatile com pounds were detected by GC/O analysis. Of these, 18 were positively identified, and composed of S containing compounds(5), aldehydes(4), ketones(3), N containing compounds(3), ester(1), alcohol(1) and aromatic hydrocarbon(1). Predominant odorants(Log3FD$\geq$4) in salt fermented shrimp were 2,3 butanedione(sour/buttery), 1 octen 3 one(earthy/mushroom like), dimethyl trisulfide(cooked cabbage /soy sauce like) and 2 acetylthiazole(grainy/nutty). Predominant free amino acids were aspartic acid, glutamic acid(sour and umami taste), arginine, methionine(bitter) and lysine(sweet and bitter) in evaluation of taste value.

• Korean Journal of Food Science and Technology
• /
• v.47 no.2
• /
• pp.176-183
• /
• 2015

To characterize the aroma properties of roasted bulgogi reaction flavor obtained by using a high-temperature reaction apparatus, the volatile flavor and aroma-active compounds were analyzed using simultaneous steam distillation and solvent extraction (SDE)-gas chromatography-mass spectrometry-olfactometry (GC-MS-O). One hundred five volatile compounds were detected in roasted bulgogi reaction flavor using GC-MS. Out of these compounds, furfural was the most abundant volatile compound, followed in order of abundance by 5-methyl furfural, phenylacetaldehyde, and nonanal. Of the volatile compounds identified in roasted bulgogi reaction flavor, 33 aroma-active compounds were detected using GC-O. 2,3-Butanedione and furfural were the most intense aroma-active compounds detected. Other relatively intense odorants included hexanal, octanal, nonanal, undecanal, phenylacetaldehyde, 5-methyl furfural, 2,6-dimethyl pyrazine, and dimethyl trisulfide. These were important aroma-active compounds that contributed to the aroma of roasted bulgogi reaction flavor because of their potency and aroma properties. The concentrations of the aroma-active compounds increased as the reaction temperature increased, whereas those of the sulfide compounds decreased.