• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.246-249
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• 2007

DL-phenylalanine (DLPA) is known as an essential amino acid exhibiting opiate capacities by inhibiting the degradation of enkephalins. From the viewpoint of developing a drink containing DLPA, its solubility and stability in aqueous solutions were investigated at some processing conditions such as temperature and pH. When the solubility was analyzed by transmittance at 600 nm, the solutions containing DLPA of 0.1% to 2% showed transmittance over 98% above $60^{\circ}C$ and over 99% at wide range of pH (3.0, 7.0, and 10.0). The valuable stability was also recognized through HPLC analysis for DLPA content, that is, 61-71% DLPA was still remained even after processing at high temperature and wide pH range, indicating the possibility of de-velopment of drink containing DLPA. Among flavors considered for the improvement of consumers' acceptability on drink, orange and amino acid flavors were superior to others. Microbial growth was not detected during 6-week storage after drink preparation.

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.805-813
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• 2018

Vanda is an aerial tropical orchid native to Thailand and nitrogen (N) fertilizer is mainly used to promote its growth and quality. However, little is known about the characteristics of N absorption and assimilation in Vanda. The objective of this study was to determine the appropriate source of N for Vanda cultivation. In this experiment, shoots and roots of Vanda 'Ratchaburi Fuchs-Katsura' were sprayed weekly with 100 ml of $^{15}N$ tracer solution (1) 10 mM of $^{15}NO_3{^-}$, (2) 5 mM of $^{15}NO_3{^-}$ plus 5 mM of $NH_4{^+}$, (3) 5 mM of $NO_3{^-}$ plus 5 mM of $^{15}NH_4{^+}$ and (4) 10 mM of $^{15}NH_4{^+}$. The results indicated that plants fed with a combined N fertilizer gave the highest of $^{15}N$ use efficiency ( $^{15}NUE$) of about 21.8%, 30 days after the first feeding (DAF), compared with those fed sole sources of $^{15}NO_3{^-}$ (21.0%) and $^{15}NH_4{^+}$ (16.6%). However, a sole nitrate fertilizer or combination fertilizer did not significantly affect the total N and labelled N content. Alanine was a major amino acid found in leaves and roots at 7 DAF, whereas glutamine was mainly found in stems. At 30 DAF, tyrosine and alanine became major components in the leaves, and glutamine decreased in stems when plants were fed with a single $^{15}NH_4{^+}$ source.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.104-111
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• 2002

The peptidyl prolyl sis-trans isomerase (PPIase, EC 5.2.1.8) from bacillus stearothermophilus was extracted from the cells treated with by lysozyme. PPIase was purified from the cell extracts by heat treatment, ammonium sulfate precipitation, ion exchange chromatography and finally gel filtration, sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE). The molecular weight of the purified PPIase was estimated as 18kDa by SDS-PAGE. The 39 amino acid residues from the N-terminus were determined by the protein sequencer. The enzyme showed the optimum pH at 8.0 and was stable at the range of pH 7.0∼8.0. The enzyme was considerably stable after heat treatment at 60$\^{C}$ for 30minutes, and the enzyme was quite stable up to 65$\^{C}$. The presence of the PPIase in the refolding solution accelerated the isomerization rate of the assay peptide. PPIase gene of Bacillus stearothermophilus was screened from a genomic library by plaque hybridization using the A-l primer as a probe. A PPIase positive plaque contained a 3.0kb insert of the chromosomal DNA. A 3.0kb fragment was subcloned into pUC18, resulting pPI-40. A DNA fragment encoding the N-terminal portion of the PPIase in pPI-40 was amplified by polymerase chain reaction(PCR) method using the A-1 and B-2 primers. The amplified fragment was cloned into the Sma I site of pUC18 and recombinant plasmid was designated as pSN-18. The nucleotide sequence of 167bp fragment was determined. The deduced amino acid sequence of PPIase was completely matched with the determined N-terminal amino acid sequence of PPIase B. stearothermophilus.

• Korean Journal of Food Science and Technology
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• v.47 no.6
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• pp.772-778
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• 2015

Hydrolysis of isolate soybean protein (ISP) using subcritical water (SCW) was conducted to study the feasibility for producing protein hydrolyzate. SCW hydrolysis of SPI suspension (5-15%) was conducted in an electrically heated batch reactor (2 L). The effects of temperature (230 to $270^{\circ}C$) and holding time (10 to 50 min) on the degree of hydrolysis (DH) and the production of amino acids were studied by surface response method. The DH was determined by derivatizing the hydrolyzates with ortho-phthalaldehyde (OPA) solution. It was confirmed that reaction temperature and holding time affected the hydrothermolysis of soybean protein. However, the holding time was less effective on amino acid yield when the temperature was higher than $230^{\circ}C$. In order to achieve optimal yields of amino acids exceeding 43%, the temperature should be within the range between 256 and $268^{\circ}C$ with holding time from 29 to 41 min, respectively. A maximum estimated amino acid yield of 43.5% was obtained at $268^{\circ}C$ for 35 min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.862-868
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• 2005

Korean mountain ginseng roots were freeze-dried at $-70^{\circ}C$ and extracted by different extracting solution conditions to investigate chemical compositions of extracts. The soluble solid content of the extract from $7.04\~13.45\%\;and\;50\%$ EtOH and MeOH extracts were higher than those of other extracts. $100\%\;water\;and\;90\%$ EtOH extracts gave the highest Brix with $19.98\%$\;and\;19.65\%$, respectively. pH of the extracts were ranged from $5.82\~6.60$. Browning color at 470 nm of the extract were high value in 50$\%$ EtOH extract. In case of Hunter's color value, L value of extract was higher in $100\%$ water extract (21.28) than EtOH extract $(17.18\~21.02)$, a and b values of extract were the highest in $100\%$ water (-0.12) and $90\%$ MeOH extract (1.34). The contents of free sugars in the EtOH extract were increased with the ethanol concentration. Sucrose contents of $90\%$ EtOH and MeOH extracts were 6,159 mg/100 g and 5,238 mg/100 g. Major organic acids of the extract were citric and malic acids. Major free amino acids of the extract were L-arginine, L-proline, $\gamma$ -amino-n-butyric acid, alanine and aspartic acid. The highest ginsenoside content was shown to be about $10.50\%\;in\;90\%$ MeOH extract. Major minerals of extract were P, K, Na, Mg and Ca.

• Journal of the Korean Chemical Society
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• v.16 no.2
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• pp.80-83
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• 1972

The activity change of lysozyme resulted from its exposure to $Ti-H_2O_2$system in aqueous liquid at room temperature and to ${\gamma}$-irradiation in ice at $195^{\circ}K$ has been measured at room temperature with a Cary-14 spectrophotometer. The enzymatic activity of lysozyme which had been added to a previously flow-mixed solution of $TiCl_3$ and $H_2O_2$ (System I) was compared with the activity of a lysozyme-$H_2O_2$ solution after flow-mixing with $TiCl_3$ (System II), considering the differences between these two activity changes as the extent of the enzymatic inactivation by the involvement of OH radical reaction. The fraction of lysozyme inactivated by OH radical in the system containing 0.0025 M $TiCl_3-0.1M$ $H_2O_2$ (ph 3.5) was 13%, When the $TiCl_3$ concentration is double (pH 3.0), the fraction of enzyme inactivated increases to 36%. The activity of the system containing 0.025 M $TiCl_3-0.1$ M $H_2O_2$ (pH 1.5) was essentially zero. The results seem to support the previos view that the production of OH radical should be proportional to $TiCl_3$ concentration when $H_2O_2$ is present in excess. Increase in the extent of inactivation found in system I with increasing $TiCl_3$ concentration may be due to a pH effect. $H_2O_2$ seems to be less effective than $TiCl_3$ in the inactivation. 1% lysozyme solution, when ${\gamma}$-irradiated with a total dose of 3M rads, loses about 20% of its activity. Lowering of temperature also was found to yield a reduction in enzymatic activity.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.277-281
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• 2000

Agar, one of the most abundant marine products has not been utilized extensively because of low level of processing technology in Korea. This research was carried out to improve the utilization of agar and consequent increase in profit. Antibacterial activity of agarooligosaccharides were evaluated against bacteria causing putrefaction and flood poisoning. Addition of 0.4% agarooligosaccharides showed antibacterial activity toward Staphylococcus aureus and Escherichia coli O157:H7; furthermore, autoclave treatment of agarooligosaccharides solution enhanced the antibacterial activity. Agarooligosaccharides showed high stability against the pH change. Addition of amino acid(alanine, lysine, glycine, phenylalanine) in agarooligosaccharides solution enhanced antibacterial activity in E. coli O157:H7, Streptococcus mutans and Staphylococcus aureus.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.451-460
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• 2015

An enantioselective recognition of D- and L-tryptophan (Trp)-b-cyclodextrin (CD) inclusion complex was performed using electrochemical and FT-Raman spectroscopic analysis. From the electrochemical analysis, the selectivity coefficient ($K_{DL}$) of b-CD inclusion complexes was found higher than that of the D- and L-Trp in phosphate buffered saline (PBS, pH=7.0) solution. The percentage of enantioselectivity ($I_{%{ee}}$) for peak current of D-Trp-b-CD inclusion complexes was observed higher than that of L-Trp-b-CD inclusion complexes in PBS solution. From Raman spectroscopy, chemical shift difference (D, $cm^{-1}$) for the C=C stretch, ring vibration, and ring breathing of D-Try-b-CD inclusion complex were observed higher than that of L-Trp-b-CD inclusion complex. The electrochemical and Raman spectroscopic analyses were found very useful for chiral detection of racemic amino acid in the presence of b-CD.

• Polymer(Korea)
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• v.28 no.4
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• pp.352-359
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• 2004

Membrane technology was used for the optical resolution of the various racemic compounds such as tryptophan, tyrosine and phenylalanine, using enantioselective membranes prepared from sodium alginate (SA) and glutaraldehyde as a membrane material and crosslinking agent, respectively, The chemical structure of the membranes was characterized with FT-IR spectrophotometry and 3D molecular structure modeling study was done to figure out the optical resolution mechanism through the membrane. Effects of degree of crosslinking, feed concentration, operating pressure and different kinds of feed solution on the membrane performances were studied. As results, it was found that with increasing degree of crosslinking and membrane thickness, and decrease in the concentration of the feed solution and smaller size of solutes, the enantinselectivity of the membrane was improved. When the sodium alginate membranes with 80% of swelling index and 79${\mu}{\textrm}{m}$ of thickness were used, 77% of enantiomeric excess was obtained.

• Journal of Chest Surgery
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• v.25 no.5
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• pp.458-468
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• 1992

With the aid of extracorporeal circulation, nine dogs underwent orthotopic cardiopulmonary transplantation after preservation of the donor heart in a hypothermic amino acid[glutamate, aspartate] enriched high potassium extracellular solution, and preservation of the donor lung with hypothermic low potassium dextran solution from June 1990 to May 1991. The mean body weights of dogs were 20kg and the recipients` preoperative hematologic and hemodynamic pictures were within normal range except slightly decreased level of albumin and total protein, which was supposed to be due to malnutrition. The following modifications of the original Stanford technique were emphasized: [1] the posterior mediastinum is dissected as little as possible with meticulous hemostasis; [2] the surgical procedure is kept away from the phrenic and vagus nerves; [3] the tracheal anastomosis may be wrapped with recipient`s pulmonary artery flap or surrouding soft tissues. A combination of Cyclosporine, Azathioprine, corticosteroid was used as perioperative immunosuppressive therapy. Postoperatively all recipients could be weaned from extracorporeal circulation, showing favorable vital signs, but within 24 hours, irreversible congetive heart failure, ascites, arrhythmias developed with a mean survival time 13.6$\pm$6.6[n=9, range=6~26] hours. Hemoglobin and platelet counts were significantly[p<0.05] decreased postoperatively, which is thought to be attributed to blood damage by cardiopulmonary bypass and hemodilution. Postmortem finding included multiple subendocardial patch hemorrhage in both atrial and ventricular cavities, pulmonary and liver congestion, and all tracheal anastomoses were intact. Further consideration about quality control of the animal, infection, rejection, the effect of cardiopulmonary bypass on the experimental animal is required to improve the results.