• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.293-302
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• 1988

This study was performed to identify detailed informations on the nonvolatile flavor of Chinese quince fruits, Chaenomeles sinensis koehne. About 72% of the free amino acids were shown to be valine, asparagine, ${\gamma}-aminobutyric\;acid$, aspartic acid and serine. Arginine, tyrosine, methionine and tryptophan were not present. Glutamic acid and glutamine as a amino acid for peptides were the major components, whereas cysteic acid, methionine sulfone and tryptophan were not detected. The nucleotides attained were composed of cytosine, uridine-5'-monophosphate and cytidine-5'-monophosphate, and these were proved to be a very small quantity. Guanosine-5'-monophosphate, inosine-5'-monophosphate and adenosine-5'-monophosphate were not present. The major sugars were shown to be glucose, sorbose, sucrose and fructose. Fructose was the most abundant one among them. A total of 11 organic acids were identified by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The major components identified were tartaric acid and α-ketoglutaric acid. The total content of vitamin C determined was 386.6mg%, and those of ascorbic, dehydroascorbic, and 2, 3-diketo-L-gulonic acid were 28.8mg%, 154.5mg% and 197.3mg%, respectively. Calcium and phosphorus were the major components, while heavy metals such as cadmium, copper and lead were determined to be a small amount. In the result of organoleptic test on the natural and synthetic extract of Chinese quince fruits, the principal taste components consisted of free amino acids, sugars, organic acids, vitamin C and minerals. Five groups mentioned would have a favorable influence upon the taste of fresh Chinese quince fruits.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.255-258
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• 1986

This study was carried out to determine the shelf-life and quality changes of perilla leaves (Perilla ocimoides L.) in relation to changes in the concentration of biochemical components during storage. The shelf-life of perilla leaves was 2 to 3 days at room temperature and 6 days at $3^{\circ}C$. This was extended to 12 days at room temperature and 20 days at $3^{\circ}C$ by packaging in a 0.01 mm thick polyethylene film sack (PEFS). The ascorbic acid concentration of fresh perilla leaves was 23 mg per 100 g fresh weight. This declined to 16 mg per 100 g fresh weight on the 4th day of storage in all treatments. Ascorbic acid concentrations decreased further to 7 mg on the 8th day at room temperature and 8 mg per 100 g on the 16th day at $3^{\circ}C$ in PEFS. Total and reducing sugar concentrations in the controls were higher than those in the PEFS storage at room temperature. Protein and free amino acid concentrations gradually increased during storage. A higher protein level was maintained in the control than in the PEFS treatment. Changes in nucleic acid concentration and peroxidase and polyphenoloxidase activities during storage were also measured in relation to the changes in quality of perilla leaves.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.254-259
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• 1992

The processing conditions and food components of meaty textured sardine burgers were studied to develope a new form of burger, The separated sardine meat was chopped, mixed with 14.1% emulsion curd, 1.5% table salt, 2.0% sugar, 0.4% sodium bicarbonate, 0.2% polyphosphate, 0.1% monosodium glutamate, 8.0% bread powder, 0.4% onion powder, 0.1% garlic powder, 0.1% ginger powder and 3.0% soybean protein by remodeled stone mortar. This seasoned sardine meat was fried in soybean oil $(165{\pm}2^{\circ}C,\;3min)$. The main fatty acids of sardine burger were palmitic acid, oletic, acid, linoleic acid, eicosapentaenoic acid and docosahexaenoic acid. Amino acid composition of sardine burger were mainly consisted of histidine, glutamic acid, leucine and lysine. The major taste compounds in the product were revealed nucleotides and their related compounds $(11.19{\sim}11.96\;{\mu}mole/g)$ such as IMP and free amino acids (1824.8 mg/100g) such as histidine, glutamic acid, leucine and lysine. Total creatinine, betaine and trimethylamine oxide were seemed to act an auxiliary role in taste of product.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.207-215
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• 2003

Gene structure prediction, which is to predict protein coding regions in a given nucleotide sequence, is the most important process in annotating genes and greatly affects gene analysis and genome annotation. As eukaryotic genes have more complicated stuructures in DNA sequences than those of prokaryotic genes, analysis programs for eukaryotic gene structure prediction have more diverse and more complicated computational models. We have developed EGSP, a eukaryotic gene structure program, using duration hidden markov model. The program consists of two major processes, one of which is a training process to produce parameter values from training data sets and the other of which is to predict protein coding regions based on the parameter values. The program predicts multiple genes rather than a single gene from a DNA sequence. A few computational models were implemented to detect signal pattern and their scanning efficiency was tested. Prediction performance was calculated and was compared with those of a few commonly used programs, GenScan, GeneID and Morgan based on a few criteria. The results show that the program can be practically used as a stand-alone program and a module in a system. For gene prediction of eukaryotic microbial genomes, training and prediction analysis was done with Saccharomyces chromosomes and the result shows the program is currently practically applicable to real eukaryotic microbial genomes.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.93-97
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• 2008

RraA is a recently discovered protein inhibitor that regulates the enzymatic activity of RNase E, which plays a major role in the decay and processing of RNAs in Escherichia coli. It has also been shown to regulate the activity of RNase ES, a functional Streptomyces coelicolor ortholog of RNase E, which has 36% identity to the amino-terminal region of RNase E. There are two open reading frames in S. coelicolor genome that can potentially encode proteins having more than 35.4% similarity to the amino acid sequence of RraA. DNA fragment encoding one of these RraA orthologs, designated as RraAS2 here, was amplified and cloned in to E. coli vector to test whether it has ability to regulate RNase E activity in E. coli cells. Co-expression of RraAS2 partially rescued E. coli cells over-producing RNase E from growth arrest, although not as efficiently as RraA, induced by the increased ribonucleolytic activity in the cells. The copy number of ColEl-type plasmid in these cells was also decreased by 14% compared to that in cells over-producing RNase E only, indicating the ability of RraAS2 to inhibit RNase E action on RNA I. We observed that the expression level of RraAS2 was lower than that of RraA by 4.2 folds under the same culture condition, suggesting that because of inefficient expression of RraAS2 in E. coli cells, co-expression of RraAS2 was not efficiently able to inhibit RNase E activity to the level for proper processing and decay of all RNA species that is required to restore normal cellular growth to the cells over-producing RNase E.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.243-248
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• 2016

RNase E (Rne) is an essential enzyme involved in the processing and degradation of a large portion of RNAs in Escherichia coli. The enzymatic activity of RNase E is controlled by regulators of ribonuclease activity, namely, RraA and RraB. Gram-positive bacterium Streptomyces coelicolor also contains homologs of Rne and RraA, designated as RNase ES (Rns), RraAS1, and RraAS2. In the present study, we investigated the effect of S. coelicolor RraAS1 on the ribonucleolytic activity of RNase E in E. coli. Coexpression of RraAS1 with Rne resulted in the decreased levels of rpsO, ftsZ, and rnhB mRNAs, which are RNase E substrates, and augmented the toxic effect of Rne overexpression on cell growth. These in vivo effects appeared to be induced by the binding of RraAS1 to Rne, as indicated by the results of co-immunoprecipitation analysis. These results suggested that RraAS1 induces ribonucleolytic activity of RNase E in E. coli.

• Applied Biological Chemistry
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• v.15 no.2
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• pp.163-168
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• 1972

Previously identified female pupae were X-irradiated with a dose of 1000r one day prior to moth transformation. Female mothes from irradiated and non-irradiated pupae were copulated with normal male ones and allowed to lay eggs. Fertilized eggs were collected at 6 intervals such as 5, 15, 45, 90 minutes, 12 and 40 hours after laying, and deep-freezed immediately after each collection until measurements. RNase activity and nucleic acid content were determined with each sample and following results were obtained. 1) It was proved to exist two RNases in silk worm eggs as in mammalian tissues, one active maximally at pH 5.8 and the other at pH 8.0, and the acid RNase activity was much higher than that of alkaline RNase. 2) The activity of acid and alkaline RNases increased remarkably during early development of the embryo of silk worm eggs, reaching the maximum activity at 45 minutes from laying time in non-irradiated group. There was no appreciable difference in two RNase activities for 45 minutes after laying in both control and irradiated groups, but the activity of acid and alkaline RNases in latter group was three times as much as that in former group, at 90 minutes from laying time and it was also found the acid RNase activity was 1.8 times higher than alkaline one in irradiated group. 3) The RNA-P content of control group increased considerably for initial 45 minutes, followed by a decline 45 minutes later with sight but steady increase thereafter. The RNA-P content of irradiated group, however, increased at initial 5 minutes, followed by a marked fall 90 minutes after laying, with no change thereafter. The DNA-P of control group showed a sharp increase for initial 45 minutes, followed by a decline 45 minutes later with no appreciable change thereafter, whereas that of irradiated group showed an increase at initial 15 minutes, followed by a sharp decline for following 45 minutes with a gradual increase thereafter. It was thus proved that the synthesis of nucleic acid in silk worm eggs was much suppressed by X-irradiation during early development of embryo. 4) The RNase activity varied in parallel with the RNA-P content in control group, but the RNA-P content in irradiated group was shown to be minimum value in concidence with the maximum activity of both RNases.

• The Korean Journal of Food And Nutrition
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• v.19 no.3
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• pp.318-326
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• 2006

Soy sauce was prepared with the addition of Gorosoe and Kojesu saps instead of tap water to make ordinary soy sauce, respectively. The changes of free sugar, organic acid, mineral, amino acid and nucleotides and other compounds during the fermentation of soy sauce were assessed. The free sugar were found to be fructose, glucose, galactose and sucrose in soy sauce of saps but sucrose was not detected in ordinary soy sauce. Galactose contents were dominant free sugar in all samples. The contents of butyric acid were dominant among 7 kinds of organic acid while fumaric acid was trace amount during the fermentation of soy sauce. The contents of potassium and phosphorus among 13 kinds of minerals were dominant during the fermentation of soy sauce. In the amino acid composition of soy sauce, dominant amino acid was glutamic acid(185.6${\pm}$1.0 mg/100 ml above), but proline and arginine were not detected. AMP detected above 7.5${\pm}$O.2 ${\mu}$mol/100 ml was dominant while inosine was not detected during the fermentation of soy sauce. The results of sensory evaluation in the fermented soy sauce of Gorosoe was 'liked more' than that of soy sauce of Kojesu and control.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.498-504
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• 1989

Processing conditions and food components of frozen seasoned anchovy meat products were investigated. The separated anchovy meat was chopped, mixed with 12.8% emulsion curd, 0.5% table salt, 2.0% sugar, 0.4% sodium bicarbonate, 0.2% polyphosphate, 0.2% monosodium glutamate, 0.3% onion powder, 0.1% garlic powder, 0.1% ginger powder, 3.0% soybean protein, and 0.2% sodium erythorbate by remodeled stone mortar. This seasoned anchovy meat was frozen with contact freezer, Packed in a carton box and then stored at $-25{\pm}2^{\circ}C$. The major fat acids of product were linoleic, oleic, palmitic, docosahexaenoic, linolenic, palmitoleic, eicosapentaenoic acid. Amino acid composition of product were mainly consisted of Glu, Asp, Leu, Lys and Ala. The taste compounds of product were IMP 160.0 mg/100g ; free amino acids such as Glu, His, Ala, Leu 503.7 mg/100g ; total creatinine 158.3 mg/100g and small amounts of betaine, TMAO.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.614-618
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• 2007

The effect of irradiation on the quality characteristics of lyophilized kimchi powder was investigated in order to develop a commercial kimchi seasoning. Fresh and fermented kimchi powders were irradiated at 0, 1.5, 5, 10 and 30 kGy using a Linear Accelerator. By increasing the irradiation dose level, $a^*$ (redness) and $b^*$ (yellowness) values of the kimchi powders were decreased, while $L^*$ (lightness) value remained relatively unchanged as compared to the control. As the main volatile compounds, butanal, 2-butanone and acetic acid were produced in both of the kimchi powders at 30 kGy and dipropyl disulfide was detected only in the fermented kimchi. The viable counts of aerobic bacteria, yeasts, molds, and lactic acid bacteria in the kimchi powder were significantly reduced by all irradiation doses. However, aerobic and lactic acid bacteria were still observed in both of the kimchi powders at 30 kGy. No significant off-odors or off-tastes were produced in either of the kimchi powders by irradiation, while pungency decreased after irradiation. These results suggest that irradiated kimchi powder could be used as a kimchi seasoning.