• Horticultural Science & Technology
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• v.18 no.1
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• pp.22-27
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• 2000

National plant quarantine inspector of exporting country should inspect agricultural products according to the quarantine requisites of counterpart country when the commodities are shipped. Export of pear fruits was held because quarantine pests including Conogethes punctiferalis were found at the point of entry in Canada. In order to examine the problems in detail, the inspected pear fruits were stored at a low temperature for 43 days, almost the same period necessary for fruit sorting, quarantine procedures, and transportation by ship. Dead larvae of fruit moths, C. punctiferalis and Grapholita molesta were found during cold storage. Quarantine pathogens were not found, but non-quarantine ones such as Penicillium sp. was infected through wounds by bruises and stabs resulted from sorting procedures. Because of the wounding problem during export procedures, pear fruits with thin exocarp, such as fruits of P. pyrifolia Nakai cv. Whangkeumbae, are required more careful handling during fruit sorting and conveyance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.471-476
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• 1998

Microbiological spoilage of marine fish is complex process occurring by bacteria, yeasts and molds. There have been rare study for saprophytic yeasts although having enormous numbers of bacteriological studies on the spoilage of marine fish. The 14 genera of yeasts isolated from mackerel (Scomber japonicus) with high frequency of occurrence were Candida sp., Rhodotorula sp., Torulopsis sp., Cryptotoccus sp. and Tricosporon sp. Among these ones Candida lipolytica was identified as the strongest proteolytic yeast, then named Candida lipolytica FM5 (C. lipolytica FM5). C. lipolytica FM5 showed optimum growth at $25^{\circ}C$, pH 7.0 and could grow at $5^{\circ}C$ and in medium containing $10\%$ sodium chloride, To evaluate the saprophytic activity of the selected strain, C, lipolytica FM5 and Pseudomonas fluorescens ATCC 17571 which is one of representative spoilage bacteria were individually inoculated into the sterilized fish muscle homogenates, and then pH changes and volatile basic nitrogen (VBN) values were checked during the storage at various temperatures. According to the experimental results, the productions of VBN by C. lipolytica FM5 in the fish muscle homogenates were 50 mg-N/100 g at $5^{\circ}C$, 152 mg-N/100 g at $15^{\circ}C$ and 379 mg-N/100 g at $25^{\circ}C$ for 1 week storage, respectively. Above results were nearly same as in case of Ps. fluorescens ATCC 17571 inoculation. It suggest that sapyophytic yeasts also have important role in spoilage of marine fish.

• Horticultural Science & Technology
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• v.17 no.2
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• pp.118-122
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• 1999

Quality changes of fruit vegetables were investigated during simulated export and marketing to find out the optimum shipping temperature. Fruit vegetables were loaded into a small refrigerated-container and kept for four days at various temperatures, and fruit quality was assayed immediately after harvest, 4 days after storage and 4 days after marketing at ambient temperature. In 'Back Seong Ilho' cucumber fruits, fresh weight loss was further reduced at $13^{\circ}C$ and $11^{\circ}C$ than at $15^{\circ}C$ and room temperature. Soluble solid contents remained at relatively lower levels when cucumbers were stored at $13^{\circ}C$ and $11^{\circ}C$. In 'Chun Ryang' eggplant fruits, fresh weight loss was greatly increased at all the temperatures (room, $12^{\circ}C,\;9^{\circ}C,\;and\;6^{\circ}C$). However, flesh browning, a primary quality factor of eggplant fruit, was most effectively inhibited at $9^{\circ}C$, whereas chilling injury occurred in fruit flesh at $6^{\circ}C$. Water loss of 'Eals Seinu' melon fruits was most inhibited and soluble solid contents at harvest were maintained for the longest period at $4^{\circ}C$. In 'Pe Pe' cherry tomatoes, storage at $10^{\circ}C$ and $7^{\circ}C$ seemed to more effectively inhibit metabolic changes and the incidence of cracking, the severest disorder than room temperature. But the fruits stored at $10^{\circ}C$ contained higher level of soluble solids than those at $7^{\circ}C$. The overall results suggest that the optimum shipping temperature range is 11 to $13^{\circ}C$ for cucumbers, around $9^{\circ}C$ for eggplant fruit, $4^{\circ}C$ for melons, and $10^{\circ}C$ for cherry tomatoes.

• Food Science and Preservation
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• v.30 no.1
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• pp.88-97
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• 2023

As livestock consumption in Korea has been gradually increasing, the quality of the final products has been improved to meet this increased demand. In particular, maintaining the water holding capacity (WHC) and minimizing the drip loss during the thawing of frozen meat are of utmost importance. This study investigated the physicochemical properties of frozen pork subjected to thawing under different conditions: at room temperature (20℃, under air), at a low temperature (4℃ refrigerator, under air), under water (20℃, under water in a vacuum bag), under microwave (microwave-thawing, 260 W), and under low-pressure tumbling (20℃, 0.015 bar, tumbling). The shortest thawing time for frozen pork was recorded upon low-pressure tumbling thus indicating a fast heat transfer. The lowest drip loss (0.2%) and highest WHC (94.5%) were also recorded under this condition. A significantly higher drip loss was observed upon microwave- (1.0%) and water-thawing (1.2%), which resulted in the lowest WHC in microwave thawing (87.2%). The highest total count of aerobic bacteria and coliform group were observed upon room temp thawing while the low pressure tumbling and thawing resulted in the lowest aerobic bacteria (1.90 log CFU/g) and coliform (0.78 log CFU/g) count. Consequently, thawing by low pressure tumbling afforded the best food quality.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.3
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• pp.103-111
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• 2014

This study analyzed effects of packaging materials and storage temperature on the shelf-life of Korean grinded yam. For experimental measurement, experimental groups were used $PET(12{\mu}m)/Al(9{\mu}m)/LLDPE(60{\mu}m)$ as opaque barrier packaging material and $PET(12{\mu}m)/PE(20{\mu}m)/VM-PET(12{\mu}m)/PE(25{\mu}m$) and barrier $NY(15{\mu}m)/LLDPE(60{\mu}m$) as transparent barrier packaging material. Control group were used normal $NY(15{\mu}m)/LLDPE(65{\mu}m)$. The grinded yam stored at refrigeration temperature ($5^{\circ}C$) and room temperature ($20^{\circ}C$C) for 8 days. Changes in color, pH, viscosity, microorganisms and sensory characteristics were measured. In the grinded yam L and ${\Delta}E$ value were not changed rapidly at refrigeration temperature. However L and ${\Delta}E$ were rapidly changed in all of packaging materials at room temperature. In two temperature condition, pH and viscosity were decreased during storage but pH was increased at $5^{\circ}C$ after 4 days. PET/Al/LLDPE and PET/PE/VM-PET/PE inhibited the growth of microorganisms effectively. PET/AL/LLDPE which is a high barrier packaging material showed the best in two temperature condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.370-377
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• 1989

Jerusalem artichoke (Helianthus tuberosus L.) as a biomass potential crop has several distinct advantages such as vigorous growth on poor land and high yield of carbohydrate. In this crop, seed dormancy has hampered the efforts of seed-propagration and to use them in breeding programs for improving jerusalem artichoke. Several seed treatments were tested to determine their effectiveness in overcoming the seed dormancy found in five collected varietes of jerusalem artichoke. The first results showed that the seed fertilities of five collected varieties ranged from 2.4％ to 14.7％ and the number of seed produced by one plant ranged from 88 to 1058. Germinability of seeds stored for 3 months at room temperature after harvest was almost 0％ and it was not improved by addition to the treatments of temperature, light and GA3, while germinability of seeds stored for 27 months at room temperature after harvest increased to 47.5％ in germination rate. But the removal and pin-pricking of seedcoat were very effective in breaking the seed dormancy, giving germination of 96.8％ and 82.3％, respectively. These results showed that the seed dormancy of jerusalem artichoke was induced by the seedcoat. Besides the treatment of seedcoat removal and seedcoat-pinpricking, the treatment of low and wet stratification was also effective in breaking the seed dormancy of jerusalem artichoke. Whole dormant seeds incubated for 70 days in low and wet condition germinated over 85％.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.255-261
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• 2016

The present study was conducted to characterize physiological responses of aerial part according to soil water stresses in 'Mihong' peach trees. Discolorations, wilting and falling of leaves were observed in chronological order as response for waterlogging and no irrigation and the phenomena started from basal to end of shoots. Shoot growth in elongation and thickness decreased and fallen leaves were severe in waterlogged trees. Function of water uptake by roots and photosynthesis and leaf respiration decreased by waterlogging. Leaf chlorophyll contents decreased in both treatments. In waterlogging treatment, decrease of chlorophyll was observed in normal leaves with waterlogging using light microscopy. Starch content was lower in both treatment and carbohydrate content was lower in root with waterlogging. These results demonstrated that waterlogging weakened the function of soil water uptake and movement and decreased photosynthesis and fallen leaves. Finally the peach trees would wither or suffer low temperature damage through the shortage of reserve accumulations. We suggested that waterlogging damage in peach trees could be reduced to take notice of irrigation and install drainage facility to improve soil condition.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.65-74
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• 2003

Most of land reclamation projects are being implemented along the south and west coastal lines of the Korean Peninsula. The earth structures and in-ground LNG tank, and buildings can be constructed using artificial freezing method on the reclaimed land to control the uplift pressure caused by capillary forces. In this study, upon freezing a saturated soil in a closed-system from the top, a considerable frost heaving pressure was developed. Decomposed granite soils, silty soil, and sandy soil were used in the laboratory freeze test which is sometimes subjected to thermal gradients under closed-systems. A major concern has been the ability to predict the frost heaving pressure over the results of relatively short-term laboratory tests. The frost heaving pressure arising within the soil samples and the temperature of the samples inside were monitored with time elapse. The degree of saturation versus heaving pressure curve is presented for each soil sample and the maximum pressure is closely related to this curve. TDR apparatus was used to measure the volumetric water content by the measurement of unfrozen water contents of frozen soils. Unfrozen water increased in soils containing a high percentage of fine-grained particles. In fine-grained soils with strong attractive farces between soil grains and water molecules, additional water is attracted into the pores leading to further volume changes and ice segregation.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.421-429
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• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.751-758
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• 2020

SCR technology, which uses urea-water as a NO_x reducing agent, has been widely used to reduce NO_x in marine diesel engines. However, as an alternative NO_x reducing agent, solid-phase ammonium carbamate has several advantages, such as low-temperature NO_x reduction performance and NH₃ storage capacity. This study presents a method for evaluating the purity of ammonium carbamate using EA, FTIR, and XRD to investigate the change in the material characteristics of ammonium carbamate when it is exposed to various temperature and pressure conditions. In this study, it was found that the purity of ammonium carbamate can be effectively evaluated via EA analysis. The FTIR analysis results confirmed that the properties of ammonium carbamate did not change even after repeated heating and cooling under thermal decomposition temperature conditions, which may be applied to the SCR system of marine diesel engines. Additionally, it was found that when ammonium carbamate was exposed to the atmosphere for a long time, it transformed into ammonium carbonate.