• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.216-223
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• 2012

Dextran was produced by $Leuconostoc$ $mesenteroides$ SM with various contents of yeast extract and its rheological properties were modulated, via an addition of hydroxypropyl methylcellulose (HPMC) of different viscosities. The conversion yield reached 90% after adding 3% yeast extract, which remained constant, thereafter. The acidity of the cultures was approximately 1.4 and 0.9% after fermentation for 24 h at 25 and $30^{\circ}C$, respectively. The total dextran content (107.3 g/kg) was the highest in the presence of the 3% yeast extract. Under the same conditions, the consistency, viscous modulus (G"), and elastic modulus (G') of the cultures were $37.6\;Pa{\cdot}s^n$, 38 Pa, and 50 Pa, respectively. The rheological properties of the culture were changed drastically by the fortification with HPMC of higher concentration and viscosity. The addition of 10% HPMC (4,000 cp) resulted in a significant increase in G" to 1,950 Pa. Furthermore, adding HPMC to a viscous culture resulted in a remarkable increase in both hardness and firmness.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.367-372
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• 2012

Antioxidant and anti-hyperglycemic activities of fermented red ginseng added with 5 kinds of medicinal herbs (FRGM) were investigated in vitro. Total polyphenol and total flavonoid contents in FRGM extracts were $22.41{\pm}3.51$ and $16.80{\pm}4.22{\mu}g/mg$, respectively. FRGM extracts were capable of directly scavenging DPPH free radicals ($RC_{50}=95.57{\pm}7.40{\mu}g/mL$), and then showed higher inhibitory activities for ${\alpha}$-glucosidase. This study was also conducted to evaluate the effects of FRGM extracts in streptozotocin (STZ)-induced diabetic (DM) rats. The activities with regards to serum aspartate aminotransferase and alanine aminotransferase were significantly decreased by FRGM extracts compared to those from the STZ group. The hepatic glutathione content depleted by STZ was significantly increased by FRGM extracts, but elevation of lipid peroxide content induced by STZ was significantly decreased by FRGM extracts. The decreased activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase after STZ-treatment were increased through the treatment of FRGM extracts. These results indicated that fermented red ginseng added with medicinal herbs can protect against STZ-induced diabetic rats through its antioxidant properties.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.165-172
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• 2014

Mixed fermentation of cow milk was performed by sequential co-cultures with Bacillus subtilis and Lactococcus lactis. After a first fermentation step with B. subtilis for 6 h, the number of viable cells increased to $2.5{\times}10^8$ CFU/mL. The second fermentation step with L. lactis resulted in increased viable cells $1.09{\times}10^{10}$ CFU/mL for 3 days and increased acidity. However, the number of viable B. subtilis cells was decreased greatly to $5{\times}10^1$ CFU/mL following fermentation with L. lactis. Milk proteins were markedly hydrolyzed by the first fermentation after 2 h, and the second fermentation induced curd formation in milk. However, after 4 h, the first fermentation resulted in higher whey separation and 80 mg% tyrosine content. Gamma-aminobutyric acid (GABA) production was dependent upon the degree of protein hydrolysis by first fermentation. Second fermentation resulted in 0.14% GABA. The milk fermented by B. subtilis indicated the rough surface of yogurt depended upon the degree of protein hydrolysis. In conclusion, set-type yogurt was efficiently produced by co-culturing of milk, and fortifying with peptides, GABA, and probiotics.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.434-440
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• 2013

Functional properties of Cheonnyuncho fruit paste (CFP) were enhanced by fermentation, using Leuconostoc mesenteroides SM. The stability of CFP pigment was maintained and microorganisms in crude CFP were sterilized by heating at $80^{\circ}C$ for 30 min. The production of dextran in CFP was increased by increasing the fermentation time and sugar content, resulting in an increase of consistency. The CFP fermented with 20% sucrose contained 4.8% mucilage after fermentation for 2 days. In particular, the production of mucilage was greatly enhanced by fortification with 3% sodium citrate in CFP, resulting in mucilage production of 7%. In addition, the viscous modulus of fermented CFP showed a greater increase than that of the elastic modulus. Thus, it was concluded that CFP fermented by L. mesenteroides SM can be fortified with functional ingredients, such as mucilage and probiotics, with enhanced rheological properties. Therefore fermented CFP can be utilized as the functional ingredients for functional foods.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.580-585
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• 2008

The principal objective of this study was to determine the effects of defatted soybean grits (DSG) on body lipidmetabolism with 4 weeks of feeding on a high-fat diet. The rats were divided into the following 4 groups: control group (Con), control group treated with 20% DSG (C20D), high-fat group (HF), and high-fat group treated with 20% DSG (HF20D). The plasma total cholesterol and LDL-cholesterol concentrations were significantly lower in the HF20D group than in the HF group. On the other hand, the DSG supplement resulted in a significant increase in plasma HDL-cholesterol levels. The DSG supplement reduced the hepatic total lipid, total cholesterol, and triglyceride contents as compared to what was observed in the HF diet groups. In addition, the fecal total cholesterol and triglyceride contents increased in the DSG treatment groups. The hepatic HMG-CoA reductase activities were demonstrated to be significantly lower in the HF20D group than in the HF group. These results showed that the DSG powder lowered plasma cholesterol levels, tissue lipid contents, and cholesterol accumulation in the rats.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.438-445
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• 2015

The production of GABA was optimized by co-cultivation of immobilized Lactobacillus plantarum K154 (ILK) with Ceriporia lacerata cultures. The mycelial culture of C. lacerata was performed in a defined medium containing 3% glucose, 3% soybean flour, and 0.15% $MgSO_4$ in a submerged condition for 7 days at $25^{\circ}C$, resulting in the production of 29.7 g/L mycelia, 3.1 g/L exopolysaccharides, 2% (w/w) ${\beta}$-glucan, 68.96 unit/mL protease, and 10.37 unit/mL ${\alpha}$-amylase. ILK in C. lacerata culture showed viable cell counts of $3.13{\time}10^9CFU/mL$ for immobilized cells and $1.48{\time}10^8CFU/mL$ for free cells after 1 day. GABA production in the free and immobilized cells was 9.96 mg/mL and 6.30 mg/mL, respectively, after 7 days. A recycling test of ILK in the co-fermentation was consequently performed five times at $30^{\circ}C$ for 15 days, resulting in the highest production of GABA. GABA could also be efficiently overproduced by co-cultivation with the produced polysaccharides, ${\beta}$-glucan, peptides, and probiotics.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.507-512
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• 2017

The physicochemical properties of maize starch sonicated at various amplitudes (100, 200, and 300 W) and times (10, 30, and 50 min) were examined. The amount of enzyme-susceptible starch increased marginally after sonication. Sonication increased the amount of oil absorbed in the starch although the degree of oil absorption decreased with an extension of the sonication time, implied that different types and extent of damages occurred. Scanning electron microscopy revealed that ultrasound sonication did not form pores on the surfaces, but caused damages such as depression and erosion. Pasting viscosity of starch decreased with an increase in the severity of sonication conditions because of the weakened polymer network. X-ray diffraction suggested that the crystalline domains in starch were not susceptible to sonication and were more resistance to degradation. Sonicated starch formed more pin-holes on the surfaces in the initial glucoamylase reaction; subsequently, as the reaction proceeded, porous starch with enlarged pores was formed and finally, disrupted granular fragments were observed.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.53-61
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• 2020

Cell migration is a central process for recovering from wounds triggered by physical distress besides embryogenesis and cancer metastasis. Wound healing assay is widely used as a fundamental research technique for investigation of two-dimensional cell migration in vitro. The most common approach for imitating physical wound in vitro is mechanical scratching on the surface of the confluent monolayer by using sharp materials. The iron metal pin with a suspension spring for fine adjustment of the orthogonal contact surface between the scratching point and the individual bottom of multi-well plate with planar curvatures were adopted for the creative invention of a 96-well plate wound maker. While classic tips drew diverse and zigzag scratching patterns on the confluent monolayer, our wound maker displayed synchronized linear wounds in the middle of each well of a 96-well plate that was seeded with several cell lines. Given that several types of multi-well plates commercially available are compatible with our lab-made wound maker for creating uniform scratches on the confluent monolayer for the collective cell migration in wound healing assay, it is certain that the application of this wound maker to the real-time wound healing assay in high content screening (HCS) is superior than utilization of typical polypropylene pipette tips.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.107-113
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• 2003

This study was carried out to improve the performance of pre-developed heat recovery devices attached to exhaust-gas flue connected to combustion chamber of greenhouse heating system. Four different units were compared in the aspect of heat recovery performance; A-, B-, and C-types are exactly the same with the old ones reported in previous studies. D-type newly developed in this experiment is mainly different with the old ones in its heat exchange area and tube thickness. But airflow direction(U-turn) and pipe arrangement are similar with previous three types. The results are summarized as follows; 1. System performances in the aspect of heat recovery efficiency were estimated as 42.2% for A-type, 40.6% for B-type, 54.4% for C-type, and 69.2% for D-type. 2. There was not significant improvement of heat recovering efficiency between two different airflow directions inside the heat exchange system. But considering current technical conditions, straight air flow pattern has more advantage than hair-pin How pattern (U-turn f1ow). 3. The main factors influencing on heat recovery efficiency were presumably verified to be the total area of heat exchange surface, the thickness of ail-flow pipes, and the convective heat transfer coefficient influenced by airflow velocity under the conditions of allowable pipe durability and safety. 4. Desirable blower capacity for each type of heat recovery units were significantly different to each other. Therefore, the optimum airflow capacity should be determined by considering in economic aspect of electricity required together with the optimum heat recovery performance of given heat recovery systems.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.53-59
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• 2005

In this study, the supercritical electroplating was investigated by forming macroemulsion of electroplating solution using surfactant in supercritical $CO_2$. The fluorinated analogous AOT surfactant, sodium salt of bis (2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate which has both '$CO_2$ philic' chains and 'hydrophilic' head group was used as a surfactant, and Ni plate and Cu plate were used as the anode and the cathode, respectively. Electroplating was carried out in the conventional method and the supercritical macroemulsion and both results were compared. The supercritical electroplating was carried out in various concentration of surfactant such as 2, 4, 7 wt%, the volume ratio of Ni-plating solution to $CO_2$ was varied in the range of 10-70 vol%, and propane was used as a supercritical fluid instead of $CO_2$. According to the experimental results, the plated surface of Ni on Cu plate performed in supercritical macroemulsion was better than that, in conventional state. In the image of Ni surface plated on Cu plate in supercritical state, there were fewer pin-holes and pits comparing with that in the conventional process. The current and conductivity was increased as the volume ratio of Ni-plating solution to $CO_2$ was increased and the current and the amount of Ni plated on Cu plate were decreased as the concentration of surfactant become higher. In addition, in case of the continuous phase, using $CO_2$ was more effective than using $CO_2$.