• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.70-77
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• 2014

In this paper, the development of unique model of the 2.75 inch rocket propulsion system is described. Recently developed korean 2.75 inch rocket propulsion system shows the improvement of a flame stability resulted from a change in the configuration of propellant grain, and of an incidental ignition protection function using the EMI(electromagnetic interference) filter on ignition system. Moreover it is shown that a directional flight stability is improved by increasing the number of fins and changing the nozzle configuration. Static firing test and thermal shock test were conducted for the validation before flight, and flight test of 210 rounds of rockets was conducted to verify the trajectory uniformity. In addition, intellectual property issues can be overcome with the unique korean 2.75 inch rocket motor as well as the performance improvement.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.381-387
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• 1991

Andong Sickhae is a traditional Korean fermented rice product which is made from glutionous rice, male, radish, ginger and red pepper. The changes in chemical composition, pH, amino nitrogen, amino acid, enzyme activity and free sugar of a traditional Andong Sickhae were monitored during the fermentation and storage at $4^{\circ}C$. The changes in ash, crude fat and moisture the contents during Andong Sickhae fermentation and storage were negligible. The pH of the product tended to decrease in the course of fermentation and storage and it showed the minimum value of 3.90 after 20th day of storage. On the other hand the maltose continued to increase up from 6.35g to 9.85g/100ml by 15th day of storage. The content of amino nitrogen in Andong Sickhae gradualy increase up to 22.40mg% by 3th day of fermentation. Glutamic aicd and aspartic acid were the major amino acid in water and salt soluble protein in Andong Sickhae.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1388-1393
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• 1998

Traditional Andong sikhe was produced by fermenting L. bulgaricus LBS 47 and S. cerevisiae SCS 5. The changes of nitrogen compound and amino acid during fermentation and storage were investigated. Crude protein was increased until 4days, the main fermentation period. Amino form nitrogen increased up to 37.50 mg% at the 2nd day of fermentation and the product tasted best at this time. Water soluble and salt soluble protein decreased during fermentation. Proline and aspartic acid were the two major free amino acids. The free methionine increased while the free lysine decreased in the process of fermentation. The amino acids of water soluble protein and salt soluble protin were totally 17 kinds. The major amino acids of water soluble and salt soluble protein were glutamic acid and aspartic acid. The arginine content of salt soluble protein increased as the fermentation proceeded.

• Journal of the Korean Society of Food Culture
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• v.7 no.3
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• pp.259-270
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• 1992

The changes in life style today appear many ways. Many housewives turn away from home preparation of the time consuming traditional foods, such as 'Andong sikhe'. The importance, however, of succeeding the traditional cuisines is getting appreciated widely nowadays. This study aimed to investigate the preparation of Andong sikhe by use of pure culture inoculation and the improvement of storage stability by the addition of stabilizers to the product. Lactobacillus delbreuckii was selected for the pure culture inoculation in the fermentation. The changes in chemical composition such as total acidity, sugar content, amino acid and various forms of nitrogen during fermentation were determined. The changes in pH of the product, the enzyme activities and the population of lactic acid bacteria were also followed in the process of fermentation. The Lactobacillus dominated in the beginning of the fermentation but the Streptococcus out numbered the former as the fermentation proceeded. The crude protein content increased up to the 4th day of fermentation but slowly decreased there after. The pH of the product rapidly decreased to 4.2 by the 2nd day of fermentation. The total acidity reached to the 0.38% by the 2nd day of fermentation and kept on increasing slowly during the fermentation. The free sugar consisted of 6 kinds including maltose and one unknown sugar. The amino form nitrogen increased up to 38.5mg% at the 2nd day of fermentation and the product tasted best at this time. The ammonia form nitrogen, water soluble and salt soluble protein decreased during fermentation. Proline and aspartic acid were the two major free amino acids. The free methionine increased while the free lysine decreased in the process of fermentation. The major amino acids of water soluble and salt soluble protein were glutamic acid and aspartic acid. The arginine content of salt soluble protein increased as the fermentation proceeded. Linoleic, palmitic and oleic acid were the three major fatty acids and occupy 90% or more of the total fatty acids. The activities of acid protease and liquefying amylase reached to the maximum at the 4th day of fermentation while those of saccharogenic amylase and lipase reached to the peak at the 2nd day of fermentation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.550-556
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• 1985

In order to evaluate the marine mollusc muscle as foodstuff not only from the biochemical aspect but also from the view point of food science, we have analyzed the protein and amino acid compositions of the echiurid (Urechis unicinctus) and sea hare (Aplysia kurodai) muscle. The protein quality of the muscles was also investigated using in vitro methods based on in vitro digestibility, predicted digestibility, computed PER (C-PER) and discriminant computed PER(DC-PER). The remarkable feature of the protein compositions of the both muscles was that water soluble protein occupied a large amount of the muscle protein with fairly lower contents of the salt soluble protein. From the analysis of SDS-PAG electrophoresis, the sarcoplasmic proteins in the echiurid and the sea hare muscles were composed of 15 and 10 subunits, respectively. The free amino acid compositions of the total amino acids in the echiurid and sea hare muscle were characterized with $75\%$ of glycine and alanine, and with $78\%$ of taurine, respectively. The amino acid anaylsis of both muscle proteins showed that the echiurid muscle was rich in glycine, aspartic acid, glutamic acid, arginine and lysine, but was poor in cysteine, while the sea hare muscle was rich in glycine, glutamic acid, aspartic acid and arginine, but was negligible in cysteine and tryptophan. In the total amino acid profiles of the freeze dried muscles in echiurid and sea hare, there was not found a significant difference compared to the amino acid compositions of the muscle proteins. Predicting the protein quality of the echiurid and sea hare muscles using the in vitro method, it was apparently low compared to the muscle protein of fishes.

• Korean Journal of Agricultural Science
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• v.8 no.2
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• pp.231-237
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• 1981

In order to obtain the basical data for utilization of protein in hazel nut, protein was extracted from defatted hazel nut meal with salt solutions and alkaline solutions, and precipitated by adjusting pH of extract to 5.5 or addition of organic solvents. Amino acid composition of the isolated protein and defatted hazel nut meal were analyzed, protein isolates were identified by polyacrylamide gel electrophoresis. The results summarized were as follows. 1. Defatted hazel nut showed highly nutritional value as the content of 'protein was 53.6%. 2. Extractabilities of salt-soluble protein treated with 2.5M $MgCl_2$, and 1M NaCl(pH 11.0) were 53.0%, 31.5%, respectively 3. Protein in hazel nut were contained 53% of salt-soluble globulin, 14% of water-soluble albumin, 29.5% of glutelin based on solubility. 4. At pH 5.5, 85% of the extracted protein was precipitated, and about 90% of the extracted protein was separated by addition of organic solvents such as acetone and ethanol at 60-70% concentration. 5. Proteins extracted from defatted hazel nut with water and 0.027N NaOH showed 3 and 6 hands by polyacrylamide gel electrophoresis, respectively. 6. Amino acids of defatted hazel nut and protein isolate were chiefly composed of glutamic acid, arginine and aspartic acid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.335-343
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• 1994

To determine the optimal level of cryoprotectant on the denaturation of pollock surimi produced in Korea, the relative cryoprotective effects of crystalline sorbitol alone and in combination with sucrose were assessed. Freeze induced protein denaturation was also studied as affected by polyphosphates and maltodextrin during frozen storage at $-25^{\circ}C$ for 16 weeks. Variables evaluated included salt extractable protein, drip loss and in vitro protein quality. The best cryoprotective effect was achieved from sucrose/sorbitol 1:1(w/w) mixture at $8\%$ with $0.2\%$ sodiumpyrophosphate and sodiumtriphosphate(1:1, w/w) in surimi by measurement of salt extractable protein and drip loss. Those cryoprotectants had little effect on surimi protein quality during frozen storage as measured by trypsin inhibitor(TI), protein digestibility and computed protein efficiency ratio(C-PER). Protein digestibility of surimi was not changed significantly by polyphosphate and maltodextrin at various levels(p<0.05), with the exception of 4 or $6\%$ sorbitol and $10\%$ sucrose alone which resulted in a higher digestibility. $8\%$ sorbitol/sucrose (5:3, w/w) treatment without polyphosphates showed the highest cryoprotective effectiveness from digestibility assay.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.230-237
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• 1990

Studies were carried out to examine seasonal occurrence and emergence pattern of the onion fly, Delia antiqua (Meigen), in the field of Chinju city in Gyeongnam province from 1984 to 1987. Trap catch revealed that the onion fly had three generations in a year, the second flight being partial; the peaks of adult occurrence were at mid April for the overwintered generation (1st flight), at early June for the first generation (2nd flight), and at the period from late September to early October for the autumn generation (3rd flight). It was shown that parts of the pupae in the first and almost all of the pupae in the second (or autumn) generation underwent summer diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapaused pupae were form 8.5 to 145 days in the first generation in he filed, being shorter for the pupae pupated later. This resutled in synchronization on the emergence of these diapaused pupae at late September, with the adults from the second generation pupae. The ratio of diapausing pupae increased among the later pupated ones in the first generation ; the pupae which had been pupated in early May included 43.8% of diapausing pupae, while more than 86.7% of the pupae were under diapausing state for the pupae pupated in late May and thereafter. More than 93.3% of the pupae went into diapause, regardless of pupation time for the second generation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.29-38
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• 1972

The protein composition of abalone muscle was estimated with the following result: on a series of samples analyzed, water-soluble protein, $19\~22\%$, salt-soluble protein, $27\~39\%$: alkali-soluble protein, $20\~26\%$ : and stroma $20\~28\%$ : respectively. It was demonstrated by ultracentrifugal analysis that approximately $65\%$ of the salt-soluble protein is accounted for by paramyosin, $30\%$ by actomyosin, and $5\%$ by myosin, respectively. The ultracentrifugally homogenous paramyosin was prepared by BAILEY's ethanol-dried method. It showed a $S^{\circ}\;_{20,\;{\omega}$ of 3.14s, and was completely salted in with KCl beyond $0.35{\mu}$. The intrinsic viscosity at $25^{\circ}C$ was estimated at 3.1. The paramyosin is rich in several amino acids such as arginine, aspartic acid, glutamic acid, etc., and lacking of both proline and tryptophane, in rough accord with other paramyosins reported. The abalone paramyosin did not show ATPase activity over a pH range of 5 to 9,5 even in the presence of Ca++ or Mg++. So was the case with the paramyosin specimen prepared by BAILEY's wet-extraction method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.999-1004
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• 2002

In this study, pork loin was cured for 20 days in the 2$^{\circ}C$ curing solution with the salt concentration of 3, 5, 7 and 9% respectively, and the effects of salt concentration and curing time on myofibrillar protein extractability (MPE), myofibrillar fragmentation index (MFI), water holding capacity (WHC), salt content, and palatability of pork loin were investigated. The pork loin cured in the 3, 5 and 7% curing solution showed the increased level of MPE and WHC up to 20 days of curing time, and the increased level of MFI up to 16 days of curing time. Also those values increased with the increasing salt concentration, regardless of the curing time. The pork loin cured in the 9% curing solution did not show any consistency in the results. The boiled cured pork loin showed better color up to 16 days of curing time, as the salt concentration of curing solution increased. The color of pork loin cured in the 3% curing solution was not uniform. The pork loin cured in the 9% curing solution showed good color, but its flavor and palatability were unacceptable. The palatability of pork loin could be improved significantly by curing it in the 5% curing solution for 16 days, and in the 7% curing solution for 12 days.