• Tunnel and Underground Space
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• v.28 no.1
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• pp.97-110
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• 2018

The application of sprayed waterproofing membrane with high adhesion and ductility is considered to be promising as a measure for repair and reinforcement of a tunnel structure. Therefore, a powder-type and one-component membrane prototype with high tensile and bond strengths was made in this study. Then, its reinforcement effect on a shield segment was evaluated by carrying out a series of full-scale loading tests of segment specimens on which the membrane was sprayed. From the tests, it was confirmed that the initial cracking loads increased by approximately 34% due to cracking retardation by membrane coating. Even though the increase of failure loads were not so high as cracking loads, the strain-softening behaviors were observed from specimens coated by the membrane. Therefore, it is expected that the membrane coated on the inner surface of a lining might be effective in preventing its brittle failure.

• Journal of Mushroom
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• v.10 no.4
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• pp.191-197
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• 2012

This study was carried out to investigate proper modified atmosphere condition of king oyster mushroom (Pleurotus eryngii) during cold storage and distribution. King oyster mushrooms were divided into two treatments: $1{\mu}L/L$ 1-methylcyclopropene for 20 hours at $0^{\circ}C$ (1-MCP), while the other treatment was left at $0^{\circ}C$ (control). They were packaged with $30{\mu}m$ oriented polypropylene (OPP, $1238.0cc/m^2{\cdot}day{\cdot}atm\;O_2$), and microperforated (MP3, $3179.9cc/m^2{\cdot}day{\cdot}atm\;O_2$) film. Quality and sensory evaluation parameters of weight loss, stem firmness, skin color, off-flavor, overall quality were monitored after 3, and 4 weeks storage at $0^{\circ}C$ and plus 3 days on the shelf at room temperature. 1-MCP treated mushroom packaged with MP3 film kept 3.6~10.9% $O_2$ and 9.0~13.3% $CO_2$ concentration in the bag during storage, and showed high overall quality at 4 weeks storage at $0^{\circ}C$ + 3 days on the shelf at room temperature because of the lowest development of off-flavor, stem discoloration, and cap softening among the treatments.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.869-875
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• 1989

For the evaluation of storage stability of kiwifruit, the conditions of CA storage were based on the following gas compositions; 2% oxygen and 2, 4, 6% carbon dioxide, respectively. The results obtained from the experiment were as follows; The flesh softening was considerably reduced at the storage atmospheres of 4% $CO_2$ plus 2% $O_2$, and fruit firmness of 3.0kg was marked in this CA condition after storage for 180 days. The concentration of $CO_2$ affected clearly on the respiration rate and organic acid compositions of kiwifruit during CA storage. The respiration rate at the storage condition of 6% $CO_2$ was lower than those at 2 and 4% $CO_2$. Quinic and succinic acid contents were obviously increased in the kiwifruit stored at all the CA conditions studied. In comparision of the developed amounts of off-flavor substances, ethanol and acetaldehyde, depended upon the concentration of $CO_2$ in the CA conditions, the larger amount were produced in the storage condition of higher concentration of $CO_3$. From the results mentioned above, it could be concluded that the optimum atmosphere combination for CA storage of kiwifruit was 4% $CO_2$ plus 2% $O_2$.

• Food Science and Preservation
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• v.23 no.1
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• pp.27-33
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• 2016

This study investigated the effect of heat treatments on the quality characteristics of fresh-cut 'Romaine' lettuce by treating in hot water (45, 50, and $55^{\circ}C$) for 2 minutes. Sensory properties, respiration rate, ethylene production, microbial growth, browning index, total phenolics (TP), vitamin C, and antioxidant properties (DPPH, ABTS, and FRAP assays) of samples were evaluated after 5 days at $5^{\circ}C$. All heat treatment conditions tested in this study did not affect the change in TP after storage. Treatment at $45^{\circ}C$ enhanced respiration rate and ethylene production wheres decreased vitamin C content and antioxidant activities. There was no significant difference in browning index at $45^{\circ}C$ treatment. The rapid tissue softening occurred when treated with $55^{\circ}C$ hot water for 2 minutes. The $50^{\circ}C$ heat treatments exhibited the best quality index including texture and color, and inhibited microbial growth and browning after storage. In addition, the $50^{\circ}C$ heat treatment showed the highest vitamin C content and antioxidant activities (DPPH, ABTS, FRAP assay) after storage. Therefore, the $50^{\circ}C$ heat treatment can be used to maintain quality and antioxidant property of fresh-cut 'Romain' lettuce.

• Korean Journal of Medicinal Crop Science
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• v.28 no.2
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• pp.152-166
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• 2020

Background: Ginsenosides, which have various physiological activities, are known to be abundant in the leaves and roots of ginseng. Ginseng sprouts can be used as a fresh vegetable and roots, stems, and leaves of ginseng can be consumed. This study aimed to investigate the effect of carbon dioxide treatment and the modified atmosphere (MA) packaging method in suppressing quality deterioration during the distribution of ginseng sprouts. Methods and Results: Ginseng sprouts were packed using Styrofoam, barrier film + non gas treatment, barrier film + gas treatment, 15 ㎛ polyamide (PA) double film + non gas treatment, 15 ㎛ PA double film + gas treatment, 25 ㎛ PA film + non gas treatment, or 25 ㎛ PA film + gas treatment. Quality parameters including gas composition, relative humidity, chlorophyll SPAD (Soil Plant Analysis Development) value, firmness, and rate of quality loss in ginseng sprouts were monitored at the following temperatures: 20℃, and 10℃. Ginseng sprouts packaged with 25 ㎛ PA film showed loss in quality because of wilting owing to low relative humidity within the film. Chlorophyll and firmness did not differ between film and gas treatments. The time point at which the combined loss from softening and decay owing to fungal, and bacterial infection and wilt reached 20% was considered the limit of distribution. At 20℃, the packaging not included in the 20% distribution loss rate limit or up to 7 days was 15 ㎛ PA double film + gas treatment. At 10℃, the packaging not included in the 20% distribution loss rate limit for up to 18 days were barrier film + gas treatment and 15 ㎛ PA double film + gas treatment. Conclusions: The film packaging suitable for the distribution of ginseng sprouts was found to be the barrier film and PA film with low gas permeability and maintaining hygroscopicity at 95% relative humidity. To prevent the loss in quality of ginseng sprouts, gas treatment (8% of O₂ and 18% of CO₂) in the film was found to be more suitable than no gas treatment for inhibition of decay.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.209-216
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• 2010

In order to understand the effects of a single or combined treatments of 1-MCP($1{\mu}L/L$) and $CO_2$(100%) on the firmness of melting type peach fruit(cv. Chunjungdo), fruit were harvested at commercial maturity and examined physiological changes including flesh firmness during 10 days of shelf-life. Firmness loss of fruit was delayed by both single and combined treatments of 1-MCP and $CO_2$. The treatment of 1-MCP was more effective than $CO_2$ treatment but no additive effective on firmness retention was found in the combined treatment. The upsurge of ethylene evolution occurred 5 days of shelf-life in air treated control but ethylene evolution gradually increased in fruit treated by 1-MCP and 1-MCP+$CO_2$. The suppression of ethylene evolution seemed stronger in $CO_2$ treatment. The respiration of fruit significantly inhibited up to 10 days except control where climacteric increase of respiration was found at 10 days of shelf-life. A molecular shift of pectic polymers(an increase of chelator soluble pectins and decrease of water soluble pectins) was induced by both 1-MCP and $CO_2$ treatments. An increase of water soluble pectins was coincident with firmness loss. The delay of firmness loss seemed to be associated with the migration of calcium to wall matrix, especially pectins, resulting in the increase of wall bound calcium. The polygalacturonase activity was significantly reduced by 1-MCP alone 1 day after treatment and increased to similar level of activity 5 days after treatment compared to other treatment except air treated control whereas pectin methylesterase activity seemed not to be affected by both 1-MCP and $CO_2$ treatments. Thus, the molecular shift of pectic polymers appeared not to be related with pectin methylesterase. Further study is required to clarify the softening mechanism associated with molecular shift of pectic polymers and the inter- or intra-cellular movement of calcium ions induced by postharvest treatments of 1-MCP and $CO_2$.

• Food Science and Preservation
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• v.16 no.5
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• pp.623-628
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• 2009

Fresh ginger rhizomes were heat-treated for 10 min, 30 min, or 60 min using hot air ($40^{\circ}C$, $50^{\circ}C$, or $60^{\circ}C$), and stored in low-density polyethylene (0.04 mm thickness) bags for 2 months at $12{\pm}1^{\circ}C$. We studied the effects of heat pretreatment on changes in gas levels after packaging, and quality characteristics of the rhizomes. Oxygen and carbon dioxide levels progressively fell and rose, respectively, as the temperature of heat treatment rose and the duration of such treatment was extended. The sprouting rate of ginger rhizomes treated at $40^{\circ}C$ was higher than that of other samples. Rotting, softening, and increasing pH of rhizomes were accelerated by treatment at higher temperature for a longer time. Weight loss and soluble solid levels were not affected by heat treatment. Sensory qualities such as appearance, odor, and overall acceptability of rhizomes fell with treatment at a higher temperature for a longer time. These results suggest that heat pretreatment has a detrimental effect on the quality of fresh ginger rhizomes.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.669-675
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• 1989

Fresh mushroom (Agaricus bisporus L.) was irradiated (0, 1, 2, 3kGy) and kept for 20 days at 9{\pm}1^{\circ}C\;and\;80{\pm}7%$ RH. Parameters of qualities were investigated on the physical and physiological characteristics. The pileus and stipe on nonirradiated mushroom were expanded and elongated from the 3rd day of storage, there by losing the acceptability as edible samples. After 5 days of storage, 2 to 3kGy of gamma irradiation were especially effective for controllong natural maturation and senescence of fresh mushrooms and so irradiated mushrooms were acceptable more than 20days storage. The texture of irradiated samples was superior to that of nonirradiated samples, even though softening of the tissue occurred during storage. Weight loss was greatest in the nonirradiated sample due to evaporation from an increased surface area resulting from expansion and ripending, which were retarded in the 2 to 3kGy irradiated samples after 5days of storage. These results suggest that the irradiation dose of 2 to 3kGy is apparently effective to extend the shelf life of fresh mushrooms stored at the above-mentioned condition.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.57-62
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• 2010

In this study, the effect of different silt contents on the shear characteristics of silty sands was evaluated. Two series of triaxial compression tests were performed on the cylindrical specimens of compacted Nakdong river sand with 10% and 30% silt contents under unconsolidated undrained condition. All identical specimens were prepared to compact with same initial water content for five layers and saturated using control panel and then sheared under initial effective confining pressure, 100 to 400kPa. All specimens exhibited a strain softening tendency after failure in stress-strain curves and deviator stresses of specimens with 10% silt content were greater than those of specimens with 30% silt content. Pore water pressures of specimens with 10% silt content were observed negative(i.e. swelling) due to increasing void ratio after failure but those of specimens with 30% silt content were shown only positive. The behavior of compacted cylindrical specimens with low silt content was more dilative than that of high silt content. Peak deviator stresses decreased as increasing silt content and peak pore water pressures increased as increasing silt content.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1247-1260
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• 2009

This dissertation aims to study the five tastes in the Yellow Emperor's Canon of Internal Medicine. Medicinals as well as Foods are classified by the five tastes: sweet, sour, bitter, salty and pungent, which can be tasted by the tongue. With the development of the theory dealing with the medicinal properties, some flavors are summarized out of clinical actions of medicinals, therefore, there is a little difference between the flavors of medicinal herbs and the tastes got by tongue. Each taste acts on or has direct influence on a specific vital organ, and each of which has different physiologic actions. Taste also has a long-term or post digestive effect on the body and its metabolism. When each taste is consumed in moderation, it benefits the corresponding organ. Over-indulgence in any taste harms the organ and creates imbalance among the five vital organ systems. The Korean medicinal herbs with same flavor mostly possess similar actions while the medicinal herbs with different flavors show different actions in the treatment, which are shown as follows. Sour has absorbing, consolidating and astringent actions and acts on the liver. Bitter has the actions of drying or resolving dampness, purging and lowering and acts on the heart. Sweet has the nourishing, harmonizing and moistening actions and acts on the spleen. Pungent has an action of dispersing and promoting circulation of gi and blood and acts on the lungs. Salty has the effects of softening hard nodes or masses and promoting defecation, etc and acts on the kidneys. The five organ systems control and support each other. Proper coordination only exists when there is no one organ stronger or weaker than the rest. Since the five tastes have direct influences on the five organs, the diet we take should have a good combination of the five tastes in order to promote internal balance and harmony. They control our well-being and create dietary balance. Excessive consumption of any of these could result in adverse effects. In a word, when the properties of the five tastes respectively are distinguished, their natures and flavors cannot be separately considered. I think the harmonization of food and medicinals should be stressed on good nutritional diet to maintain good health. The traditional belief that food and medicine share the same origin is a part of Korean medicine tradition.