• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.604-607
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• 2004

Concrete structures in the marine environment often deteriorate in the early stage of their service life because of contact with various aggressive conditions. In recent years, the study on the concrete in the marine environment are carried out to increase their service life. In this experimental study, the concrete specimens were prepared with various adding contents of inorganic antifouling agent$(0\~3.0wt\%)$ composed to some fluosilicate solution. For evaluatin of the physical and chemical properties of concretes containing inorganic antifouling agent, various tests such as setting time, slump loss, compressive strength, water absorption rate, freezing and thawing resistance and SEM micrographs of concrete, were conducted. As the results, physical and chemical properties of concretes were improved with an adding of inorganic antifouling agent. From the results of various tests, the optimal adding contents of antifouling agent was $1.0wt\%$.

• Food Science and Preservation
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• v.4 no.2
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• pp.115-122
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• 1997

This experiment was hocused on the improvement of postharvest management of fresh shiitake to increase the marketing duration. the respiration rate of fresh shiitake at 2$0^{\circ}C$ was ranged from 395mg to 551mg CO2/kg/hr depending on the cultural condition. The rapid precooling is considered as one of the most important postharsvest management to remain shiitake quality. The optimum temperature for precooling and storage was -3$^{\circ}C$ because the occurrence of physical damage on frozen tissue at below -5$^{\circ}C$. Frozen storage at -3$^{\circ}C$ had benefits to minimize weight loss, browning induction at gill tissue and consumption of stored materials where as storage at $0^{\circ}C$ appeared not to be adequite for the extension of marking duration. Frozen shiitake was succesefully thawed when exposed to RH 40-50% at below 1$0^{\circ}C$.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.45-48
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• 2005

Self compacting concrete has the strong point in capability of concrete to be uniformly filled and compacted in every corners of formwork by its self-weight without vibration during placing. However, powder type self compacting concrete has the weak point in the heat of hydration, the drying shrinkage and the elastic property of concrete etc. Recently viscosity agent has been developed in order to overcome these weaknesses. In this study, self compacting concrete is made with viscosity agent based on polysaccharide derivative in order to develope the normal strength self compacting concrete. Slump flow, loss of slump flow and setting time are measured for comparison with normal concrete. Compressive strength, freezing and thawing test and carbonation test are conducted on normal and self compacting concrete using viscosity agent. In the experiment, we acquired good results in fresh and hardened self compacting concrete using viscosity agent based on polysaccharide derivative.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.196-202
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• 2005

This study was carried out to investigate the effect of dietary Rhus verniciflua Stokes on the quality of Hanwoo (Korean cattle) beef during cold storage $(4^{\circ}C)$ after thawing. After 4 groups (3 heads/group) of 22 months-Hanwoo (Korean cattle) steen were fed a common basal diet with 0, 2, 4 and $6\%$ Rhus verniciflua Stokes (RVS) powder for 4 months prior to slaughter, samples of M semimembranous from 12 carcasses were stored at $-20^{\circ}C$ for 9 months. Crude fat was significantly lower in 4 and $6\%$ RVS treatments than in control (p<0.05). pH value was significantly higher in4 and $6\%$ RVS treatments than in control from 2 and 5 days (p<0.05). Thawing loss was not significantly different among the treatments but drip loss was significantly lower in 4 and $6\%$ RVS treatments than in control during storage (p<0.05). CIE $L^{\ast}$ value was significantly lower in RVS treatments than in control during storage (p<0.05) and CIE $a^{\ast}$ value was significantly higher in 4 and $6\%$ RVS treatments than in control (p<0..05). CIE $b^{\ast}$ value was significantly higher in control than in $6\%$ RVS treatment in 0 days (p<0.05) but it was significantly higher in $4\%$ RVS treatment than in control in 7 days (p<0.05). CIE $C^{\ast}$ value was significantly higher in $4\%$ RVS treatment than in control during storage (p<0.05) and CIE $h^0$ value was significantly lower in $4\%$ RVS treatment than in control (p<0.05). TBARS value of 2 days was significantly lower in 4 and $6\%$ RVS treatments than in control (p<0.05) but it was significantly lower in $4\%$ RVS treatment than the other treatments from 5 days (p<0.05). Surface MetMb concentration was significantly lower in RVS treatment than in control during storage (p<0.05) and it was significantly lower in $4\%$ RVS treatment than in the other treatments in 7days (p<0.05) but surface $R_{6.30}/R_{580}$ value was opposite to this result.

• Food Science and Preservation
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• v.31 no.3
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• pp.423-432
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• 2024

In this study, a vacuum tumbler with 4 impellers (DVT) was designed and applied for thawing frozen pork (vacuum -60 kPa, jacket 35℃, 1 rpm). Quality characteristics of the thawed pork were compared with those of industrially thawed meat by natural air at room temperature (NAT) and imported vacuum tumbler (IVT). The thawing time for frozen pork (303.36 kg) using DVT (165 min) was much shorter than that of NAT (4,200 min). DVT-thawed pork had lower drip loss (0.85%) than NAT (2.08%). DVT-thawed pork showed a pH of 5.92, a total bacterial count of 1.96±0.02 log CFU/g and no coliforms. Deteriorations in fat (TBARS 0.31±0.01 MDA mg/kg) and protein (VBN 5.67±1.98 mg%) in DVT-thawed pork were significantly lower than those of NAT (p<0.05). DVT-thawed pork had a high water-holding capacity (WHC, 97.5%). The hardness (34.59±0.46 N) and chewiness (188.21±0.17) of cooked DVT-thawed pork were about 5-6 times lower than those of NTA. Microstructure (SEM) showed myofibrillar damage in NAT-thawed pork, whereas dense myofibrillar structure was observed in DVT-thawed pork. DVT was better or similar to IVT in all evaluation parameters. The designed DVT is expected to be used as an efficient thawing method in terms of processing time and yield and to produce thawed meat with high WHC, soft texture, and low spoilage by minimizing tissue damage.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.53-58
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• 2017

FRP Hybrid Bar, composed of an embedded steel and the coated composites with epoxy and glass fiber, is an effective construction material with tension-hardening performance and lightweight. The epoxy exposed to UV(Ultra Violet Rays) and FT(Freezing and Thawing) action easily shows a surface deterioration, which can cause degradation of bonding strength between inside-steel and outside-concrete. In the present work, surface inspection for 3 different samples of normal steel, FRP Hybrid Bar before UV, and FRP Hybrid Bar after UV test was performed, then concrete samples with 3 reinforcement types were prepared for accelerated FT test. Through visual inspection on 3 typed reinforcement, no significant deterioration like chalking was evaluated. The results from FT test to 120 and 180 cycles showed FRP Hybrid Bar exposed to UV test has higher bonding strength than normal steel by 106.3% due to enlarged bond area by silica coating. The 3 cases showed a similar bond strength tendency with increasing FT cycles, however a relatively big deviations of bond strength were evaluated in FRP Hybrid Bar after UV test due to loss of silica coating.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.710-715
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• 2014

To date, the quality and safety of frozen bokbunja have not been clearly assessed. To produce high-quality frozen bokbunja, the optimal freeze-thaw conditions need to be explored. The most popular cultivar (Rubus occidentalis) in Korea was selected for this study. To determine the changes in the quality of frozen R. occidentalis berries, different freezing temperatures were used. The berries were frozen at -20, -45, and $-70^{\circ}C$ immediately after harvest. The drip ratio, hardness, pH, sugar content, color, and anthocyanidin content of the frozen and thawed samples were analyzed. The drip ratio, sugar content, and hardness of the berries correlated significantly with the freezing temperatures. The color and pH of the berries were not significantly affected by the freezing conditions. Frozen leaks between cells reduced significantly with decreasing temperatures. The freeze-thawing process significantly reduced the total aerobic bacteria and inhibited the growth of yeast/mold in the berries to about 2 log scales.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.267-271
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• 2015

This study aimed to determine the optimal freezing temperature for preserving mulberries. Mulberries were frozen at -20, -45, and $-70^{\circ}C$ immediately after harvesting. After 24 h, frozen mulberries were stored at $-20^{\circ}C$ for two months and then thawed at $4^{\circ}C$ and room temperature. Frozen and thawed mulberries did not differ significantly in color and pH from fresh mulberries. However, the content of anthocyanidin and sugar, and the hardness of mulberry significantly decreased after feeze-thawing. Drip loss of the thawed berries increased as the freezing temperature decreased. A comparison among cross-section images of mulberries frozen at different temperatures did not show any significant differences. However, after thawing at $4^{\circ}C$ or room temperature, the total number of aerobic bacteria found in mulberry decreased more than ten times. Consequently, the freezing temperature showed no significant effect on the overall quality of the mulberry.

• Food Science of Animal Resources
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• v.27 no.1
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• pp.1-7
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• 2007

This study was carried out to compare the quality characteristics of korean native black pork (KNP) and modern genotype pork (MGP) during refrigerated storage after thawing. M. longissimus from 5 Korean native black barrows of 65.3 kg and 5 modern genotype barrows ($Landrace{\times}Yorkshire{\times}Duroc$) of 114.3 kg were frozen at $-80^{\circ}C$ for 1 month and stored at $2{\pm}0.3^{\circ}C$ for 7 days. The carcass weight and dressing percentage was significantly lower in pork from Korean native black pigs than modern genotype pigs (p<0.05). The crude fat and sensory quality were significantly higher in KNP than in MGP (p<0.05), and moisture, myristic acid, gamma-linolenic acid, linolenic acid, and cis-5,8,11,14,17-eicosapentaenoic acid levels were significantly lower in KNP (p<0.05). The pH value was significantly higher in KNP than in MGP after 5 days of storage (p<0.05). Drip loss was significantly lower in KNP than in MGP during storage (p<0.05). The TBARS value was significantly higher in KNP than in MGP after 5 days of storage (p<0.05). Overall, KNP had lower moisture and unsaturated fatty acid levels relative to MGP and showed less oxidative stability during storage, however it had higher crude fat content, water-holding capacity, sensory quality and color stability than MGP.

• Food Engineering Progress
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• v.22 no.4
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• pp.328-336
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• 2018

The aim of this study was to investigate the effect of pretreatments on quality of frozen peach. Pretreatments including steam blanching, water blanching, high pressure, and osmotic dehydration were applied to two varieties (Daeokgye and Hwangdo). Pretreated peaches were frozen and thawed at $-20^{\circ}C$ and $5^{\circ}C$, respectively. Steam blanching and osmotic dehydration with ascorbic acid reduced ${\Delta}E$ values without change of pH and acidity. Osmotic dehydration with sucrose decreased drip loss and increased brix. Freezing/thawing resulted in an increase of maximum force, while maximum force decreased with increasing time of steam and water blanching. Furthermore, osmotic dehydration with calcium chloride increased maximum force. High pressure decreased maximum force of Daeokgye and increased that of Hwangdo compared with non-treatment. Total polyphenol content, DPPH radical scavenging activity, and ABTS radical scavenging activity were improved by pretreatment including steam blanching, blanching, and osmotic dehydration with ascorbic acid.