• Journal of Environmental Health Sciences
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• v.30 no.1
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• pp.22-28
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• 2004

This study was performed to investigate the changes of amino nitrogen, total amino acids, free amino acids, and color of Korean traditional soy sauce (kan-jang) during the ripening and storage for 12 months and the characteristics of the changes. All of the preparation methods for soy sauce followed the recommendations of the Korea Food Research Institute. The components of soy sauce were analyzed at 0,6, and 12 months. The contents of amino nitrogen of soy sauce were significantly higher than that of soybeans or meju (soybean cakes) at the initial stage of storage (p<0.05), and decreased during the storage. The content of total amino acids of soybean sauce was significantly lower than that of soybeans, and the content of free amino acids was higher than that of soybeans (p<0.05). The contents of total and free amino acids decreased in soy sauce after 12 months of storage (p<0.05). The composition of total and free amino acids and their ratios of soy sauce were changed during the storage. The ratios of free to total amino acids of soybeans, meju, and soy sauce were 0.8％, 17.3％, and 53.1-59.8％, respectively. Glutamic acid, which represents the savory taste, was detected the most abundantly in soy sauce during the storage. The ratios of free to total amino acids of glutamic acid were 42.9-59.5％ in soy sauce. Lightness of Hunter color of soy sauce decreased over time (p<0.05). This study indicates that the ratios of free to total amino acids of soy sauce were much higher than those of soybeans, although its contents of total amino acids were much lower than those of soybeans. This study also indicates that this comes from the preparation and fermentation of meju. It was suspected that the organoleptic characteristics of soy sauce derived from the amino nitrogen, amino acids, and color might be inferior over 1 year of storage time. However, more detailed research should be conducted to interpretate this characteristics more accurately.

• Natural Product Sciences
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• v.1 no.1
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• pp.5-9
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• 1995

The metabolites of marine mollusk Mytilus edulis were isolated and characterized, revealing the presence of the rare free fatty acids and proteinogenic amino acids together with a non-proteinogenic free amino acid, taurine. The free fatty acids in this organism were particularly interesting for the presence of both unusual n-6 acid [20:4 (n-6)] and triple bond containing acid (2,5-octadecadiynoic acid). In addition to the proteinogenic amino acids commonly found in proteins, non-proteinogenic free amino acid taurine was isolated and the structure was determined by its physicochemical properties. Recently taurine has been given much interest in the molecular level because of diverse biological activities and the medicinal properties. Furthermore, the result of the analyses of analyses of free amino acids showed that glycine, glutamic acid, serine and alanine, which were considered to be related to the taste of this organism, are predominantly present.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.47-50
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• 1998

For the quantitiative determination of chemical and taste components in black omija(Schizandra nigra Max) and omija(S.chinensis), compositions of free sugars, free amino acids, total amino acids, and minerals were analyzed. Among the total free sugars in black omija and omija, glucose and frutose were major free sugars and sucrose was little amount. The most abundant free amino acid in black imija was histidine and that in imija was serine. The major free amino acid in black omija and omija were histidine, serine, glutamic acid and aspartic acid. The major total amino acids in black omija and omija were glutamic acid, arginine , leucine and histidine. The limiting amino acid of each omija was S-containing amino acids. The abuntdant minerals in black omija and omija were K and Ca.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.382-387
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• 2001

Characteristics of six commercial samjangs were analyzed such as proximate composition, free amino acids, organic acids and free sugars. Also color, taste and odor were evaluated by 36 panelists. They were composed of moisture content 41.4-48.4%, crude protein 9.2-10.4%, crude fat 2.2-3.4%, pH 5.3-5.7, amino nitrogen 194.0%-375.6 mg% and sodium chloride 7.7-9.1%. Total free amino acids of samjangs were 975.89-2304.98 mg%. Glutamic acid was the highest amino acid among free amino acids as 231.7-788.01 mg%. Proline, arginine, alanine and lysine were higher than other free amino acids while histidine, cystine and methionine were lower than other. Eleven free amino acids including glutamic acid were the highest in samjang (B) which contained more doenjang than any other makers did. Total organic acids were 401.01-640.27 mg%. 69.65-269.07 mg% of succinic acid was the highest among organic acids. Lactic acid was the highest in samjang (F) which was home made. Total free sugars was the highest in samjang (A) which contained more wheat flour than any other makers did it. Glucose was 9.30-23.99% and fructose was nd-2.69%. The result of proximate composition showed a different pattern comparing with that sensory evaluation. Samjang (A) which contained less salt showed the highest overall acceptability while samjang (F) which contained more dark color, more salt was the lowest one among the samples.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.35-40
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• 1972

The contents of free amino acids in deembryod brown rice of two varieties were investigated by amino acid autoanalizer in relation to specific gravity grade. The analytical methods of free amino acid were also discussed. 1) The lower the specific gravity of the unhulled rice the higher the content of total free amino acids in the deembryod brown rice, and the similar trend appears to hold on each amino acids. 2) Main free amino acids were serine+asparagine, glutamic acid, aspartic acid, alanine and valine, and maximum values of them were 7.3, 5.1, 4.0, 3.4, 0.9mg/100g rice, respectively. They consist about 85% of total free amino acids in most cases. 3) The contents of soluble nitrogen and free amino acids appear to be lower in high protein variety (IR 667) than in low protein variety (Jinhung). The percentage of free amino acid nitrogen to soluble nitrogen, however, appears to be higher in high protein variety (IR 667). 4) Alanine was much lower than aspartic acid in IR 667 having Indica blood while alanine appears to be higher than aspartic acid in Jinhung (Japonica rice) suggesting varietal difference in amino acid metabolism. 5) Threonine peak was overlaped with glutamine, and serine was with asparagine in this study.

• Korean Journal of Veterinary Research
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• v.13 no.1
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• pp.17-21
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• 1973

Free amino acid extracts of musculus brachiocephalicus and musculus glutaeus of cattle, swine, goats and rabbits are analyzed to see the composition and the contents of free amino acids by thin layer chromatography and automatic amino acid analyzer. The results obtained are summarized as follows: 1. Meats of cattle, swine, goats and rabbits analyzed by thin layer chromatography have 6 kinds of free amino acids such as glycine, histidine, methionine, lysine, alanine and leucine, and the spots of glycine in chromatogram of meats of cattle, swine and goats and the ones of methionine in chromatogram of meats of rabbits are the largest and the most denes of all other ones. 2. Distribution curves of free amino acids in meats of cattle, swine, goats and rabbits showed significant differences, but differences on distribution curves of free amino acids between musculus-brachiocephalicus and musculus glutaeus of the same tested animal are not significant. 3. Contents of free amino acids in meats of cattle, swine, goats and rabbits showed significant differences, but differences on contents of free amino acids between musculus brachiocephalicus and musculus glutaeus of the same tested animal are not significant.

• Archives of Pharmacal Research
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• v.2 no.2
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• pp.133-144
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• 1979

To investigate constituents of Strobilomyces floccopus (Fr.) Karst. and Coprinus comatus (Fr.) S. F. Gray, free and total amino acids of the two mushrooms were quantitatively analyzed by G. L. C. and an amino acid analyzer. Free amino acids were extracted from both mushrooms with ethanol. Fourtenn free amino acids were detected from the ethanol extract of S. floccopus and fifteen free amino acids from C. comatus by G. L. C. And the dry carphopores of both mushrooms were hydrolyzed with hydrochloric acid and then the total protein amino acids were analyzed by A. A. A. Seventeen total amino acids were detected from each acid-hydrolysate of S. floccopus and C. comatus. Lipids were extracted from the carpophores of S. floccopus and saponified with alcoholic potassium hydroxide. The isolated sterols were subjected to G. L. C. and two sterols were detected. The isolated free fatty acids were methylated with diazomethane and subjected to column chromatography and G. L. C. Eleven saturated and nine unsaturated free fatty acids were detected from the carpophores of S. floccopus. The presence of these nutrient components shows that the two mushrooms can be utilized as edible ones.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.103-113
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• 2014

Hydrophobicity is the key concept to understand the role of water in protein folding, protein self-assembly, and protein-ligand interaction. Conventionally, hydrophobicity of amino acids in a protein has been argued based on hydrophobicity scales determined for individual free amino acids, assuming that those scales are unaltered when amino acids are embedded in a protein. Here, we investigate how the hydrophobicity of constituent amino acids depends on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we compute and analyze the hydration free energy - free energy change upon hydration quantifying the hydrophobicity - of three short proteins based on the integral-equation theory of liquids. We find that the hydration free energy of charged amino acids is significantly affected by the protein total charge and exhibits contrasting behavior depending on the protein net charge being positive or negative. We also observe that amino acids in the central ${\beta}$-strand sandwiched by ${\beta}$-sheets display more enhanced hydrophobicity than free amino acids, whereas those in the ${\alpha}$-helix do not clearly show such a tendency. Our results provide novel insights into the hydrophobicity of amino acids, and will be valuable for rationalizing and predicting the strength of water-mediated interaction involved in the biological activity of proteins.

• Journal of the Korean Home Economics Association
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• v.20 no.4
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• pp.99-105
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• 1982

Changes of free amino acids as taste compunds during the fermentation of cod-roe, Gadus marcrocephlus, were analyzed by a amino acid autoanalyzer. Leucine, lysine, valine, isoleucine and arginine were dominent amino acids in fresh cod-roe extracts, and the amounts of leucine (797.3mg%, on moisture and salt free base), lysine (577.7mg%) and valine(487.4mg%0 were 54.9% of total free amino acids. The contents of methionine, histidine, tyrosine and phenylanine were lower, and aspartic acid, glycine, threonine, glutamic acid and serine were detected trace amount. The free amino acids analyzed in this experiment were not changed in composition but changed in the amounts during 80 days of the fermentation. Total free amino acids were increased until 59 days of fermentation and than decreased gradually.

• Journal of the Korean Society of Food Culture
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• v.4 no.2
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• pp.181-184
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• 1989

The compositions of total and free amino acids in parts of Omija were investigated. The most abundant amino acids in fruits, endocarps, and seeds were arginine (50.80%), lysine (14.37%), glutamic acid (14.22%), respectively. Since the amino acid scores of fruits, endocarps, and seeds were 9.4, 11.9, and 16.7, respectively, the limiting amino acid of each part were S-compound amino acids. In the composition of free amino acids, contents of lysine were highest one such as 51.78, 57.00 and 32.88% in fruits, endocarps and seeds, respectively. The contents of histidine from free amino acids were 23.62% in fruits, 22.37% in endocarps, and 26.41% in seeds.