• Microbiology and Biotechnology Letters
• /
• v.13 no.3
• /
• pp.285-287
• /
• 1985

To investigate effective constituents of the many taste components in ordinary Korean soy sauce, we analyzed free amino acids, organic acids, free sugars and saline as taste components in ordinary Korean soy sauce, and determined sensory score of the ordinary Korean soy sauce taste with 45 persons of the trained pannels. The relationships between original data transformed with variables and sensory score of the ordinary Korean soy sauce were analyzed by stepwise multiple regression analysis. Eighty five percents of the ordinary Korean soy sauce taste is affected by twenty one kinds (Isoleucine, Leucine, Valine, NaCl, Lactic acid, Alanine, Phenylalanine, Tartaric acid, Sugar(\ulcorner), Proline, Malic acid, Glycine, Tryptophan, Arginine, Glutaric acid, Maltose, Histidine, Glucose, Fructose and Serine) of the taste components by stepwise multiple regression analysis of original data. Eighty one percents of the ordinary Korean soy sance taste is affected by sixteen kinds (Lactic acid, NaCl, Fumaric.Succinic acid, Tyrosine, Tartaric acid, Glycine, Malonic acid, Malic acid, Tryptophan, Glutaric acid, Methionine, Histidine, Cysteine, Maltose, Fructose and (Glutamic acid) of the taste components by stepwise multiple frgression analysis of original data transformed with square root. Eighty five percents of the ordinary Korean soy sauce taste is affected by nineteen kinds (Fumaric.Succinic acid, Lactic acid, Phenylalanine, NaCl, Tyrosine, Sugar(\ulcorner), Tartaric acid, Leucine, Glutaric acid, Methionine, Glycine, Tryptophan, Histidine, Proline, Cysteine, Glutamic acid, Maltose, Threonine and Oxalic acid) of the taste components by stepwise multiple regression analysis of original data transformed with logarithm.

• Analytical Science and Technology
• /
• v.14 no.1
• /
• pp.34-43
• /
• 2001

The present work is aimed to evaluate the conditions of the hydride generation (HG) for germanium analysis by inductively coupled plasma (ICP)-atomic emission spectrometry (AES). Twelve different kinds of acids were used such as phosphoric, hydrochloric, nitric, sulfuric, perchloric, boric, tartaric, malic, oxalic, tannic, citric, and acetic acid. It was found that phosphoric acid yielded the maximum efficiency of hydride generation. Also, efficient hydride generation was obtined with the buffer solutions containing phosphate ions over a wide range of pH. In addition, in the presence of phosphoric acid the interference caused by metals was suppressed in the hydride generation of germanium. As the concentrations of a reducing agent and a stabilizing increased the hydride generation efficiency and the acid concentration proviaing the maximum intensity were increased. By using an analytical method developed in this study, the contents of germanium in water and rock samples were determined. The detection limit of germanium in the presence of phosphoric acid was $0.03{\mu}g/L$.

• Microbiology and Biotechnology Letters
• /
• v.28 no.3
• /
• pp.185-187
• /
• 2000

Instead of using binary HPLC pump which is usually used for the generation of solvent gradient for the analysis of amino acid an isocratic HPLC pump and conventional gra-dient maker were demonstrated to perform such analysis withmuch lower expenses and similar efficiency.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.3
• /
• pp.320-324
• /
• 2003

The protein hydrolysis with 6 M formic acid containing 0.3% tryptamine was a superior method for amino acid analysis of standard amino acid and protein than 6 M HCI containing 0.3% tryptamine. The recoveries of standard amino acid after acid hydrolysis were more accurate in the 6 M formic acid hydrolysis than 6 M HCI hydrolysis, especially recovery of tryptophan showed higher values of 1.5 times than that of 6 M HCI hydrolysis. The results of analysis on the standard protein, bovine serum albumin, showed very similar values compared to the sequence analysis reported in the literature for the 6 M formic acid hydrolysis than 6 M HCI hydrolysis, especially in the tryptophan recovery as standard amino acid recovery. Butylthiocarbamyl - trimethylsilyl (BTC - TMS) derivatives of 22 standard amino acids were successfully resolved DB-17 capillary column. Excellent reproducibility of standard amino acid recovery and composition of bovine serum albumin were obtained with BTC-TMS derivatives.

• Polymer(Korea)
• /
• v.28 no.6
• /
• pp.519-523
• /
• 2004

Starch was grafted with maleic anhydride by melt process and then the grafted starch was blended with poly(lactic acid). The thermal properties of the poly(lactic acid), poly(lactic acid)/starch, and poly(lactic acid)/ modified starch were observed by DSC and TGA analysis. In the case of poly(lactic acid)/modified starch, an additional melting peak at 1$65^{\circ}C$ accompanying with 172$^{\circ}C$ assigned to pure poly(lactic acid) melting transition was clearly displayed in DSC analysis. Also, smooth decomposition pattern between starch and poly(lactic acid) was also monitored in poly(lactic acid)/modified starch blend by TGA analysis. The modulus of poly(lactic acid)/modified starch was 12％ higher than that of poly(lactic acid)/starch. The thermal and mechanical characteristics of poly(lactic acid)/modified starch might be due to the enhanced compatibilization between each components, which was also observed in SEM analysis.

• Korean Journal of Food Science and Technology
• /
• v.37 no.6
• /
• pp.912-917
• /
• 2005

Physicochemical components of dried green algae, Seaweed fulvescens (Capsosiphon fulvescens) with $96.02{\pm}0.02%$ moisture content, were investigated. Crude protein, crude lipid, ash and carbohydrate content of C. fulvescens were $31.76{\pm}0.26,\;1.01{\pm}0.21,\;13.58{\pm}0.62\;and\;53.65{\pm}0.73$, respectively. Predominant minerals were Na, Mg, Ca, K and P. Fe $(122.83{\pm}11.19mg/%)\;and\;Se\;(0.90{\pm}0.07mg%)$ contents in were higher than those of other seaweeds. Major free sugars were identified as fructose, glucose, sucrose, maltose and galactose. Organic acid including L-malic acid, citric acid, tartaric acid and d-malic acid were detected. Most abundant amino acids were glutamic acid, aspartic acid and alanine. Main fatty acids were palmitic acid, linolenic acid and stearidonic acid, with 58.37% polyenes.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.9 no.1
• /
• pp.23-40
• /
• 1999

The analysis of thiodiglycolic acid in urine has been used as an index of biological exposure to vinyl chloride. Unfortunately thiodiglycolic acid has a strong hydrophilic character, because it has two carboxylic groups, so that it can only be extracted with organic solvent with a great difficulty. Underivatized thiodiglycolic acid tends to tail because of non-specific interaction with the inert support. Therefore, esterification is the obvious first choice for derivatization of thiodiglycolic acid, particularly for gas chromatography. In this study, the focus of interest is to compare two method of esterifications (methylation and silylation). Methylation is to make the methyl ester of thiodiglycolic acid by reaction with diazomethane. Silylation is to make the trimethylsilyl ester of thiodiglycolic acid by reaction with N-trimethylsily-ldiethylamine. The results and conclusions are as the following: 1. The detection limit (sensitivity) of methylated thiodiglycolic acid was $5.00{\mu}g/m{\ell}$ and silylated thiodiglycolic acid was $3.07{\mu}g/m{\ell}$ by gas chromatography with flame ionization detector. 2. The optimal liquid-liquid extraction of thiodiglycolic acid was as following: To each of the tubes, $15m{\ell}$ of urine, concentrated sulfuric acid (pH 1 - 2) and 5 gsodium sulfate were added. The samples was extracted three times with $5m{\ell}$ ethylacetate each time. 3. The methylated thiodiglycolic acid was more stable than silylated thiodiglycolic acid in extractional solvent which contained humidity. 4. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.07324 in methylated thiodiglycolic acid with external standard calibration, and 0.07033 in methylated thiodiglycolic acid with internal standard calibration. 5. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.10914 in silylated thiodiglycolic acid with external standard calibration, and 0.13602 in silylated thiodiglycolic acid with internal standard calibration. From the above results, the analysis of methylated thiodiglycolic acid was more sensitive (limit of detection) than silylated thiodiglycolic acid by gas chromatography. However, the methylated thiodiglycolic acid was stable in the humidity and was separated sharply on chromatogram. Also, analysis of methylated thiodiglycolic acid was more precise (pooled coefficient of variation for 4 days) than silylated thiodiglycolic acid. In conclusion, it is established that the analysis of methylated thiodiglycolic acid is appropriate for biological monitoring of exposure to vinyl chloride.

• Microbiology and Biotechnology Letters
• /
• v.30 no.1
• /
• pp.21-25
• /
• 2002

Structural analysis was performed by the $^1$H-NMR, $^{13}$ C-NMR, amino acid composition analysis and FAB-mass. The instrumental analysis represented that the potential antifungal antibiotic belonged to the iturin E group antibiotic, consisting of 7 $\alpha$-amino acid residues and a collection of $\beta$-amino acid with aliphatic side chain. Compared to the Iturin E group, notably, the potent antifungal antibiotic from Bacillus sp. YJ-63 carried longer $\beta$-amino acid side chain. In conclusion, these findings identified a potential antibiotic, which contained a stable cyclopeptide structure with long $\beta$-amino acid side chain.

• Journal of the Korean Society of Tobacco Science
• /
• v.9 no.1
• /
• pp.57-64
• /
• 1987

The pyrolysis of geometrical isomers of 9-octadecenoic acid were conducted at $600^{\circ}C$ under nitrogen, and its pyrolytic behaviors were investigated. The pyrolytic products of both fatty acids, cis-9-octadecenoic acid(oleic acid) and trans-9-octadecenoic acid(elaidic acid), were analyzed using a gas chromatograph and GC/MS spectrometer. Twenty-seven different compounds were identified from these pyrolyzates, and the chief products of them were ketones, alcohols and aromatic hydrocarbons. And also, the pyrolytic mechanisms of two geometrical isomers of this fatty acid were discussed by a comparison of experimental results.

• Korean Journal of Plant Resources
• /
• v.11 no.2
• /
• pp.202-209
• /
• 1998

Through total fatty acid analysis by the Gas chromatography, 17 different fatty acids were identified from the sap extracted from bark of Korean Rhus(Anacardiaceae), six species. Linoleic acid(C18 :2) and oleic acid(C18 : 1) were identified as major fatty acids for the species investigated, but except in R. chinensis.In the fatty acid composition for the species, one or two specific-fatty acid was detected, and its could be utilized as a useful taxonomic character.The result of cluster analysis by the 22 reliable characters in the fatty acid composition suggested first group was R.trichocarpa and R. succedanea, the second group, R.verniciflua, R.ambgua and R. sylvestris, but R.chinensis was a greatly independent species. The possible chemotaxonomic application of the fatty acid composition of bark in the genus Rhus was discussed.