• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.502-506
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• 2017

To improve the storage and firmness of Tteokbokki tteok Korean-style rice cakes with spicy sauce, steaming of the rice dough, soaking of the rice cake in acidic solution, and heat sterilization were conducted sequentially. The untreated control could be stored for 1 month under cold conditions, but this was extended to 10 months at room temperature ($15-30^{\circ}C$) after immersion in lactic acid solution (pH 4.0) for 20 min and heating to $100^{\circ}C$ for 30 min. The mechanical strength, which was related to firmness, was significantly increased to $11.4kgm/s^2$ compared with the untreated rice cakes ($8.8kgm/s^2$, p<0.05) and the overall descriptions of the sensory evaluation, including texture, was significantly higher than the control (p<0.05). The average size of the pores in the treated rice cakes was smaller than that of the conventional sample and the texture was improved as a result of decreased starch elution from smaller pores.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.865-870
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• 1990

Four different fermentation methods of Korean cucumber pickles were compared with conventional method, pickling in 10% NaCl solution at $25^{\circ}C$, in order to improve the storage stability. The methods studied were brining the cucumbers in hot($90^{\circ}C$) 10% NaCl solution(method A), addition of KCl and $CaCl_2$ into the hot salt solution(method B) addition of a sodium salts mixture of phosphates, nitrite and citrate into half fermented pickles prepared by method B(method C), substituted nitrite and citrate with KCl in method C(method D). It was found from results that the method C and D reduced the decreasing rate of pH very significantly by more than 3 fold and method B also showed the reducing effect. However, higher total acidity was measured for method C and D, which was opposite to pH results. Changes in hardness of cucumber showed little difference to control while color of brining solution exhibited some difference in their Hunter values. Organoleptic comparison showed a clear effect of salts mixtures by receiving the significant higher scores in fresh cucumber flavor and lower values in yeast moldy and sour flavor for method C and D when those were compared to control.

• Clean Technology
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• v.21 no.4
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• pp.224-228
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• 2015

Phospholipase D (PLD) was immobilized on a submicro-porous membrane through covalent immobilization. The immobilization was conducted on the porous membrane surface with the treatment of polyethyleneimine, glutaraldehyde, and the anhydrase, in sequence. The immobilization was confirmed using X-ray photon spectrometer. The pH values of phosphatidylcholine (PC) dispersion solution with buffer were monitored with respect to time to calculate the catalytic activities of PC for free and immobilized PLD. The catalytic rate constant values for free PLD, immobilized PLD on polystyrene nanoparticles, and immobilized PLD on a porous cellulose acetate membrane were 0.75, 0.64, and 0.52 s^-1, respectively. Reusability was studied up to 10 cycles of PC hydrolysis. The activity for the PLD immobilized on the membrane was kept to 95% after 10 cycles, and comparable to the PLD on the nanoparticles. The stabilities for heat and storage were also investigated for the three cases. The results suggested that the PLD immobilized on the membrane had the least loss rate of the activity compared to the others. From these studies, the porous membrane was feasible as a carrier for the PLD immobilization in the production of phosphatidic acid.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.167-178
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• 2011

Garlic (Allium sativum L.) has long history of reputed value and actual use for its medicinal, antimicrobial and pesticidal properties. This study was conducted to find possible developments to natural food preservatives and natural antimicrobials from garlic extracts. The antimicrobial activities of raw garlic extract, heat, pH, temperature against pathogenic bacteria were investigated. E. coli, S. Enteritidis, L. monocytogenes, and S. aureus exhibited antimicrobial activities at 20% garlic extract, but no antimicrobial activity was seen in E. faecium. Raw garlic extract and garlic extract heated for 2 min at $95^{\circ}C$ showed strong antimicrobial activities, but the antimicrobial activity of garlic extract heated for 10 min at $95^{\circ}C$ was much less. The antimicrobial activities of 50% garlic extract adjusted pH 4.0~7.0 showed much the same, but the antimicrobial activities decreased at pH 8.0 or higher. The antimicrobial activities by storage $-18^{\circ}C$ of garlic extract showed much the same. When five strains were cultured for 72 hr at $35^{\circ}C$ in the TSB containing 1~10% garlic extract, viable cell number of five strains were decreased to $10^0{\sim}10^4$ CFU/ml even at 1% or 2.5% (E. faecium) after 24 hr, but later increased to $10^4{\sim}10^9$ CFU/ml after 72 hr. When five strains were cultured for 21 day at $4^{\circ}C$ in the TSB containing 1%, 2.5%, 5%, and 10% garlic extract, viable cell number of E. coli, S. Enteritidis, and S. aureus were decreased to $10^3$, $10^0{\sim}10^2$, $10^1{\sim}10^4$ CFU/ml after 21 day, respectively, but L. monocytogenes and E. faecium increased to $10^8$ and $10^6$ CFU/ml after 21 day.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.270-277
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• 2010

In order to manufacture Bacillus cereus-free fermented soybean products, an antimicrobial agentproducing isolate against B. cereus was obtained from 150 traditionally fermented soybean products. The morphological and biochemical tests and the phylogenetic relationship among 16S rRNA gene sequences indicated that the isolate named as the strain SCK 121057 was most closely related to Bacillus licheniformis. The B. licheniformis isolate began to produce the antimicrobial agent after 48 h of incubation. The agent was nonproteinaceous and insensitive to heat, long term storage and protease K. Electron microscopic observation indicated that the agent attacked the membrane of B. cereus, leaving the ghost cell. The isolate inhibited growth of B. subtilis, Lactobacillus brevis and various types of pathogenic strains including Escherichia coli, E. faecalis, Micrococcus luteus, Staphylococcus aureus, Aspergillus flavus, A. ochraceus, and A. parasiticus as well as B. cereus. After coinoculation of B. licheniformis SCK 121057 and B. cereus in the ratio (as the basis of CFU/g sample) of 10 to 1 on the surface of cooked soybeans, cell numbers of B. cereus had been dramatically reduced after 31 days of incubation compared to those of single inoculation of B. cereus.

• Fire Science and Engineering
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• v.25 no.6
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• pp.32-38
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• 2011

As the using rate of an explosive gas has been increased in the industrial site, the regional residents adjacent to the site as well as the site workers have frequently fallen into a dangerous situation. Damage caused by accident in the process using hydrogen gas is not confined only to the relevant process, but also is linked to a large scale of fire or explosion and it bring about heavy casualties. Therefore, personnel in charge should investigate the kinds and causes of the accident, forecast the scale of damage and also, shall establish and manage safety countermeasures. We, in Anti-Calamity Research Center, forecasted the scope of danger if break out a fire or/and explosion in hydrogen gas facilities of MLCC firing process. We selected piping leak accident, which is the most frequent accident case based on an actual analysis of accident data occurred. We select and apply piping leak accident which is the most frequent case based on an actual accident data as a model of damage forecasting scenario caused by accident. A jet fire breaks out if hydrogen gas leaks through pipe size of 10 mm ${\Phi}$ under pressure of 120 bar, and in case of $4kw/m^2$ of radiation level, the radiation heat can produce an effect on up to distance of maximum 12.45 meter. Herein, we are going to recommend safety security and countermeasures for improvement through forecasting of accident damages.

• Applied Biological Chemistry
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• v.18 no.2
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• pp.98-101
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• 1975

The components of Gardenia pigment in rind, flesh, fresh fruit and stored fruit, its heat resistance and stability in pH, its dilution and colour-degree were studied. The results are summarized as follows; 1. The components of CROCIN in fresh fruit and stored fruit were 0.0157% and 0.0136% respectively. One year storage of stored fruit resulted in the decrease of 15% of CROCIN. 2. The components of Gardenia pigment in flesh were contained nearly twice as much as in rind. 3. There were traces of ${\beta}-carotene$ and some unknown carotenoid pigments. 4. Gardenia pigment was stable at $100^{\circ}C$ for 60 minutes, but, at $150^{\circ}C$ for 30 minutes, nearly half of them was destructed. 5. Gardenia pigment turned to colurless but was stable in neutral or alkali condition after 10 days. 6. Supercially, dark Gardenia pigment looked yellowish red and thin Gardenia pigment looked yellow: however, each ${\lambda}_{max}$. was all the same.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.29-34
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• 2003

In development of the processed food, it is important not only to make the food delicious but to enhance its storage span and thermal stability without change in color, which greatly affects the tastes. Protopectinase (PPase) from Bacillus subtilis EK11 hydrolyses or dissolves protopectin in the middle lamella of plant tissues with the resultant separation of plant cells from each other, called enzymatic maceration. With the PPase, persimmon was enzymatically macerated to separate cells to primary cell wall without damage. Recovery rates of persimmon treated with PPase and mechanical maceration were 95% and 85%, respectively. Total and reducing sugars, crude protein and fat in the enzymatic maceration were well preserved as in the mechanical maceration. Importantly, over 50% of vitamin C, which is the most unstable component during the mechanical maceration, remained with an intact form for one day after the enzymatic treatment. When the suspensions of persimmon macerated with both treatments were stored at 4$^{\circ}C$ for 9 days, the mechanically macerated persimmon suspension was decolorized, whereas decolorization, was not found in the enzymatically macerated persimmon suspension. Moreover the mechanically macerated persimmon was greatly deteriorated after heat treatment at 10$0^{\circ}C$ for 60 min, whereas cells of the enzymatically separated persimmon suspension appeared to be stable, indicating increased thermal stability Thus, the PPase treatment of persimmon could be a better choice for preparation of highly valuable and functional processed food as well as for increase in preservation period.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.95-101
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• 2020

The wind turbine blades should be designed to possess a high stiffness and should be fabricated with a light and high strength material because they serve under extreme combination of lift and drag forces, converting kinetic energy of wind into shaft work. The goal of this study is to understand the basic knowledge required to curtail the process time consumed during the construction of small wind turbine blades using carbon fiber reinforced polymer (CFRP) prepeg composites. The configuration of turbine rotor was determined using the QBlade freeware program. The fluid dynamics module simulated the loads exerted by the wind of a specific speed, and the stress analysis module predicted the distributions of equivalent von Mises stress for representing the blade structures. It was suggested to modify the shape of test specimen from ASTM D638 to decrease the variance in measured tensile strengths. Then, a series of experiments were performed to confirm that the bladder compression molded CFRP prepreg can provide sufficient strength to small wind turbine blades and decrease the cure time simultaneously.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.564-572
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• 2002

본 연구에서는 크기가 서로 다른 자갈로 이루어진 3종류의 축열 매체에 대한 현열축열 특성을 조사하였으며, 그 연구 결과를 요약하면 다음과 같다. (1) 제 1 종 자갈: 축열조로 공급되는 공기의 온도가 5$0^{\circ}C$와 62$^{\circ}C$ 일 때, 축열조 출구의 공기온도가 33$^{\circ}C$에 도달될 때까지 가열되는 축열시간은 각각 170분과 130분이었으며, 방열시간은 각각 210분 및 250분으로 나타났다. 또한, 방열시 출열조 출구의 최고 공기 온도는 공급공기의 온도가 5$0^{\circ}C$와 62$^{\circ}C$ 일 때 각각 34.5$^{\circ}C$ 및 36.5$^{\circ}C$였으며, 출구 공기온도 33$^{\circ}C$이상을 기준으로 한 열 회수 시간은 각각 100분 및 115분으로 나타났다. (2) 제 2종 자갈: 축열조에 공급되는 공기의 온도가 52$^{\circ}C$와 64$^{\circ}C$ 일 때, 축열조 출구의 공기온도가 33$^{\circ}C$에 도달될 때까지 가열되는데 소요된 시간은 각각 175분과 140분이었고, 방열에 소요된 시간은 각각 215분 및 250분으로 나타났다. 방열과정 동안 축열조 출구의 최고 공기온도는 공급공기의 온도가 52$^{\circ}C$와 $65^{\circ}C$ 일 때 각각 35$^{\circ}C$ 및 38$^{\circ}C$였다. 축열조 출구의 공기온도 33$^{\circ}C$를 기준으로 한 열 회수 시간은 유입공기 온도가 52$^{\circ}C$ 및 64$^{\circ}C$ 일 각각 120분 및 140분으로 나타났다. (3) 제 3종 자갈: 축열조로 공급되는 공기의 온도가 52$^{\circ}C$와 64$^{\circ}C$ 일 때, 축열조 출구의 공기온도가 33$^{\circ}C$에 도달될 때까지 가열되는데 소요된 시간은 가열공기의 온도가 52$^{\circ}C$와 64$^{\circ}C$ 일 때 각각 180분과 150분이었고, 방열에 소요된 시간은 각각 240분 및 270분으로 나타났다. 방열과정 동안 축열조 출구의 최고 공기온도는 가열 공급공기의 온도가 52$^{\circ}C$ 와 $65^{\circ}C$일 때 각각 35.5$^{\circ}C$ 및 39.5$^{\circ}C$였다. 출구 공기온도 33$^{\circ}C$이상을 기준으로 한 에너지 회수시간은 유입공기 온도가 52$^{\circ}C$ 및 64$^{\circ}C$일 때 각각 140분 및 160분으로 나타났다. 이와 같이 자갈이 작을수록 축열조 출구의 공기온도가 기준온도 33$^{\circ}C$에 도달되는 시간이 길었으며, 이것은 축열조내의 공극이 작고 비중량이 커 자갈층을 가열시키는 축열시간이 길어지기 때문인 것으로 사료된다. 또한 작은 자갈일수록 방열시간도 다소 길어져 회수 가능 열에너지가 큰 것으로 나타났다.