• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.2
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• pp.21-26
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• 2013

Conversion of fructose to 5-hydroxymethylfurfural (5-HMF) was investigated in dimethylsulfoxide (DMSO) solvent with increasing reaction temperatures and impact of residual water from dehydration reaction byproduct. To convert fructose to 5-HMF, increasing reaction temperature led more conversion to 5-HMF than lower temperature at the range of $120-150^{\circ}C$ in DMSO solvent. DMSO engaged in the acid-catalyzed dehydration and rearrangement reaction as acid and solvent. Increasing temperature led to more furanose structure than pyranose at the range of $30-80^{\circ}C$. Formed 5-HMF could be degraded to levulinic and formic acid at the presence of acid and water. Removal of water in reaction medium could prevent 5-HMF degradation.

• Preventive Nutrition and Food Science
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• v.13 no.1
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• pp.54-59
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• 2008

This study was conducted to investigate the effect of pH on the formation of furfural compounds from glucose and fructose reacting with amino acid enantiomers in the Maillard reaction. Hydroxymethylfurfural (HMF) content was highest at pH 4.0, and decreased with increasing pH. HMF was significantly higher in glucose-based systems than fructose-based systems. Furfuryl alcohol (FFA) and 5-methyl-2-furaldehyde (MF) were not increased with increasing pH, and only small amounts were formed. In addition, 2-furaldehyde (F) was found to increase in the systems, as pH increased. However, the content was small and variable. 2,5-Dimethyl-4-hydroxy-3(2H)-furanone (DMHF) was only found in Glc/D-Asn, Glc/L-Lys and Fru/D-Lys system, but the content was not increased with increasing pH. 2-acetylfuran (AF) was higher in Glc (or Fru)/L-Lys and Glc (or Fru)/D-Lys systems at pH 7.0. However, at pH 4.0, the content of AF was higher in the Glc (or Fru)/Gly and Glc (or Fru)/L-Asn systems. Therefore, this study aimed to observe the effect of pH, sugars and amino acid enantiomers on the production of furfural and related compounds by the Maillard reaction. A clear tendency was observed for some classes of compounds to be more easily formed at higher or lower pH. HMF was more readily formed at lower pH, while FFA, F, DMHF and MF were inhibited by acidic conditions. Particularly, compounds like FFA, F and MF were not affected by pH changes. In addition, DMHF and MF were only formed in L-Lys and D-Lys system.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.220.1-220
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• 2003

전분질원으로서 밀가루와 찹쌀을 단용 (A : 전량 밀가루 사용, D： 전량 찹쌀 사용) 또는 혼용(B: 밀가루 75%, 찹쌀 25%, C: 밀가루와 찹쌀을 각 50%사용)하여 담금한 고추장의 성분을 분석 한 결과는 다음과 같다. 숙성과정중 조단백질과 아미노태의 질소함량은 대체적으로 A,B,C,Drn의 순으로 높았고, ethyl alcohol은 D,C,B,A 구의 순으로 높았다. pH는 A 구에서 다소 높았으나 수분과 식염은 시험구간에 차이가 없었다. 90일 숙성 고추장중의 유리당은 glucose, fructose, maltose, rhamnose가 검출되었고, 이중 glucose는 양적으로 가장 많았다. 또한 glucose는 A 구에서, fructose는 B 구에서 각각 높았다. 숙성고추장의 알코올류로서 n-propyl, iso-buthyl, iso-amyl alcohol이 검출되었으며, 이들 함량은 3.2mg%이하로 시험구간에는 큰 차가 없었다.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.712-714
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• 1991

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.239-243
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• 2008

This study was conducted to investigate the effects of type of the sugar supplemented to the extender on the vigor, viability and intact acrosomal rates of frozen-thawed dog spermatozoa. The ejaculated semen was diluted with TRIS-citric acid extender containing 200mM TRIS, 73mM citric acid, 6% (v/v) glycerol, 20% (v/v) egg yolk, 1% (v/v) antibiotics (streptomycin/penicillin), 44 mM sugar, which was either glucose, fructose or glucose-fructose combination, and distilled water to make the final volume of 100ml. Extended semen samples were cooled at $4^{\circ}C$ for an hour, packaged in 0.25ml straws, equilibrated for 10 minutes in liquid nitrogen vapor, and frozen in liquid nitrogen. Samples were thawed by placing straws into $37^{\circ}C$ water for 120 seconds. After thawing, vigor, viability and intact acrosomal rates of frozen-thawed semen were compared according to type of sugar. No significant differences were observed between glucose and fructose groups. In addition, combination of the 2 sugars also did not show any significant differences in the vigor, viability and intact acrosomal rates. In conclusion, glucose and fructose were equally efficient as sugar supplements for freezing extender.

• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.182-189
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• 2008

In this study, the effect of pH on the antioxidative activities of melanoidins formed as a result of the reaction between sugars, glucose (Glc) or fructose (Fru), and amino acids, L-asparagine (L-Asn) and D-asparagine (D-Asn) are examined. For this purpose, antioxidative activities were evaluated on the basis of reducing power, including ferric reducing/antioxidant power (FRAP) and free radical scavenging activity includes 1,1-diphenyl-2-picryl- hydrazil (DPPH) and 2,2'-azinobis(3-ethylbenothiazoline-6-sulfonic acid) diammonium salt (ABTS) and ferrous ion chelating activity. Ethylene diamine tetraacetate (EDTA) and trolox, a water-soluble analog of tocopherol, were used as reference antioxidant compounds. The antioxidative activities of the melanoidins at a pH of 7.0 were greater than those with a pHs of 4.0 and pH 10.0. Especially, it was found that the melanoidins formed from D-isomers are more effective antioxidants in different in vitro assays. The reducing power and chelating activity of the melanoidins formed from the Fru systems were higher than those of the melanoidins formed from the Glc systems. However, the ABTS radical scavenging activity of the melanoidins formed from the Glc systems were higher than those of the melanoidins formed from the Fru systems. In particular, the DPPH radical scavenging activity and the FRAP of the melanoidins showed different antioxidative activities according to pH level.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.35-38
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• 1990

$\alpha$-D-Glucosidase inhibitor purified in a pure form was amorphous powder which gave a single spot at Rf value 0.12-0.71 with various developing solvent systems on silica gel thin layer chromatography, and melting point was 154.3-155.3$^{\circ}C$. It was disolved in water, formic acid and ethylene glycol monoethyl ether, and was very high hygroscopic substance. Biochemical reaction of the substance was positive to phenol sulfuric acid, ninhydrin, silver nitrate-sodium hydroxide, but negative to DNS reagent. Acid hydrolysis gave fructose and acid as sole sugar and amino acid constituents respectively. Moelcular weight of the inhibitor was estimated to be 1,050 by Shphadex G-25 column chromatography.

• YAKHAK HOEJI
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• v.31 no.4
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• pp.230-235
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• 1987

Antitumor and antimicrobial activities of water soluble fractions of Duchesnea indica (Andr.) and Focke (Rosaceae), have been studied. The contents of total polysaccharide were 22% and its composition was identified by G.C.: L-arabinose(Rt: 7.71), D-xylose (Rt. 9.91), D-glucuronic acid (Rt. 12.77), D-fructose (Rt. 13.63), D-galactose (Rt. 14.68), D-glucose (Rt. 15.42). The antimicrobial activity of Duchesnea indica against four bacterial species, S. aureus, S. paratyphi, S. dysenteriae and Ps. aeruginosa was observed.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.227-232
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• 2015

A microarray study has been employed to understand changes of gene expression in E. coli KD43162 resistant to ampicillin, ampicillin-sulbactam, piperacillin, piperacillin-tazobactam, cefazolin, cefepime, aztreonam, imipenem, meropenem, gentamicin, tobramycin, ciprofloxacin, levofloxacin, moxifloxacin, fosfomycin, and trimethoprim-sulfamethoxazole except for amikacin using disk diffusion assay. Using Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and MALDI-TOF MS analyses, 36 kDa of outer membrane proteins (OMPs) was found to be deleted in the multidrug resistant E. coli KD 43162. Microarray analysis was used to determine up- and down-regulated genes in relation to multidrug resistant E. coli KD43162. Among the up-regulated genes, these genes were corresponded to express the proteins as penicillin-binding proteins (PBPs), tartronate semialdehyde reductase, ethanolamine utilization protein, shikimate kinase I, allantoinase, predicted SAM-dependent methyltransferase, L-glutamine: D-fructose-6-phosphate aminotransferase (GFAT), phospho-glucosamine mutase, predicted N-acetylmannosamine kinase, and predicted N-acetylmannosamine-6-P epimerase. Up-regulation of PBPs, one of primary target sites of antibiotics, might be responsible for the multidrug resistance in E. coli with increasing amount of target sites. Up-regulation of GFAT enzyme may be related to the up-regulation of PBPs because GFAT produces N-acetylglucosamine, a precursor of peptidoglycans. One of GFAT inhibitors, azaserine, showed a potent inhibition on the growth of E. coli KD43162. In conclusion, up-regulation of PBPs and GFATs with the loss of 36 kDa OMP refers the multidrug resistance in E. coli KD 43162.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.28-32
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• 2003

As part of studies on the high quality dunggule tea, made of Polygonatum odoratum root with different growth year were analyzed for their flavor compounds. The quality attributes related to flavors were compared between raw and roasted samples which were treated at $130^{\circ}C$ for 15 min. Free sugars in the roots were mainly composed of fructose ($3.59{\sim}4.83%,\;d.b.$), sucrose ($1.78{\sim}2.49%$), and glucose ($1.60{\sim}1.80%$). Threonine ($1,239{\sim}1,444\;mg/100g,\;d.b.$), arginine ($589{\sim}689$), histidine ($289{\sim}370$) were three major free amino acids. The root grown for three years showed the highest content in total free sugar and amino acids (p<0.05). There was negligible difference in proximate composition and Hunter's color parameter depending on the growth year of the roots. However, sensory scores on color, taste and aroma were highest in 3 years' root, which is found most suitable for the preparation of dunggule tea. The roasting of 3 years old root significantly reduced the content of fructose and sucrose (p<0.01). It caused most apparent changes in the decreasing amount of threonine and in the decreasing rate of lysine, showing the significant decrease in total free amino acid content (p<0.01).