• Membrane Journal
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• v.27 no.5
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• pp.415-424
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• 2017

Commonly cation exchange membranes have been used for vanadium redox flow batteries. However, a severe vanadium ion cross-over causes low energy efficiency. Thus in this study, we prepared 3 different anion exchange membranes to investigate the effect on the membrane properties such as vanadium ion cross-over and long term stability. The base membranes were prepared by an electrolyte pore filling technique using vinyl benzyl chloride (VBC), divinylbenzene (DVB) within a porous polyethylene (PE) substrate. Then 3 different functional amines were introduced into the base membranes, respectively. These resulting membranes were evaluated by physico-chemical properties such as ion exchange capacity, dimensional stability, vanadium ion cross-over and membrane area resistance. Conclusively, TEA-functionalized membrane showed longest term stability than other membranes although all the membranes are similar to coulombic efficiency.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.380-385
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• 2007

This study was basic research to improve the existing method far distributing just harvested and sail-clad fresh ginseng. The quality of surface-washed fresh ginseng was compared to that of muddy fresh ginseng during storage at 0, 5, 10, and $20^{\circ}C$. After 45 days of storage, there was no difference in weight loss between the washed ginseng and the control at $0^{\circ}C$, but the loss was 46% and 37% lower in the washed than the control at $5^{\circ}C$ and $10^{\circ}C$, respectively. The ginseng stored at $20^{\circ}C$ after washing had less deterioration than the control stored at $10^{\circ}C$ for the same period. The sensory characteristics of the washed ginseng showed better quality scores ranging from 6.8 to 8.2, while the control ranged from 5.7 to 6.9 after 45 days of storage at $10^{\circ}C$. The washed ginseng had less viable cells, mold and yeast, and coliforms at 0.87, 1.55, and 0.95 log units, respectively, compared to the control, and this trend was maintained in the washed ginseng throughout storage.

• Food Science and Preservation
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• v.21 no.5
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• pp.601-608
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• 2014

To determine the optimal shelf life for maintaining the high quality of kohlrabi, the changes in the physiological and secondary metabolites of kohlrabi stems during storage were investigated. The results showed that the kohlrabi maintained its marketable quality for two weeks at room temperature and for two months in cold storage ($4^{\circ}C$). Interestingly, the total phenol and flavonoid contents sharply declined along with the quality deterioration after two-week storage at room temperature. Moreover, insignificant changes in these compounds were observed for two months during the cold storage. The secondary metabolites of the kohlrabi were also influenced by its storage condition. The total phenol and total flavonoid contents of the kohlrabi significantly increased with the storage periods at low temperature, and significantly decreased with the storage periods at room temperature. In terms of the packaging, no significant difference in the total phenol content of the kohlrabi was found between the packaged and non-packaged types of storage. However, the flavonoid content of the packaged kohlrabi was higher than that of the non-packaged kohlrabi at the end of their storage. The content of glucosinolates, an anti-cancer ingredient was maintained during the storage, so the vegetables remained good sources of these compounds when stored in cold storage even for a long period. This study showed a close correlation between the secondary metabolites and the change in the quality of kohlrabi during storage. The results also suggested that secondary metabolites such as phenolics can be considered quality indicators of the shelf life of kohlrabi.

• Food Science and Preservation
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• v.20 no.2
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• pp.151-157
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• 2013

This study was conducted to investigate the effect of mature stages on quality of Rafito tomatoes (Lycopersicon esculentum Mill.) during storage at low temperature. Tomatoes grown in greenhouse were harvested at three different mature stages (turning, pink, and red), packaged with a 30-${\mu}m$-thick polyethylene film, and then stored at 5 and $10^{\circ}C$, respectively. The changes in firmness, soluble solids content (SSC), titratable acidity (TA), colour, lycopene content, decay, and chilling injury were measured on a weekly basis. After three weeks of storage, chilling injury and decay were found to have individually occurred at 5 and $10^{\circ}C$, respectively. As there was little change in quality at $5^{\circ}C$, it was concluded that red tomatoes could maintain their good quality for two weeks. The normal postharvest ripening was inhibited in the turning and pink tomatoes during storage at $5^{\circ}C$. The turning and pink tomatoes showed improved quality after two-week storage at $10^{\circ}C$. In particular, the turning fruits showed the highest firmness throughout the storage period. Furthermore, the red colour, SSC/TA, and lycopene content of the turning fruits reached the same levels as with the red fruits after two-week storage at $10^{\circ}C$. These results suggest that red tomatoes should be stored at $5^{\circ}C$ to inhibit decay, and that the optimum temperature for early-harvested tomato (turning and pink) is $10^{\circ}C$ for the ripening process after harvest.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.522-527
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• 2010

Onion has been reported to contain various organosulfur compounds which have antibiotic and anticarcinogenic properties and flavonoid like quercetin which is a valuable natural source of antioxidants. Carbohydrates in onion constitute about 80% of dry matter, and the major non-structural carbohydrate of onion bulb is fructo-oligosaccharides, well known as fructan, followed by glucose, fructose, and sucrose. The sugar concentration is associated with dormancy and storage life of onion, occurring as decrease in glucose, fructose and fructan, particularly towards the end of storage. Forced air pre-drying for 15-20 days at room temperature is an essential procedure to reduce freezing injury and sprouting, then onion bulbs can be stored at $0^{\circ}C$ for 6 months to control sprouting and decay. Bacterial soft rot caused by $Erwinia$ and $Pseudomonas$ is the main postharvest disease when the bulbs are infected with the bacteria and stored at room temperature. Browning in sliced onion is due to oxidation of phenolic compounds by polyphenol oxidase and it can be inhibited by citric acid treatment, packing with nitrogen gas, and polyethylene film.

• Food Science and Preservation
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• v.18 no.3
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• pp.288-293
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• 2011

This study investigated the changes in the quality of fresh-cut lotus roots that were treated with hot water. Lotus roots were purchased from Daegu, Korea. They were washed, peeled, and cut into lcm-thick slices with a ceramic knife. The peeled and sliced lotus roots were dipped for 45 sec in water at 30, 55, and $80^{\circ}C$. After they were air-dried at room temperature, the slices were packed in polyethylene films and stored at $4^{\circ}C$ for 12 d. Then the changes in the weight loss, color, total viable cell, and sensory characteristics were measured. Generally, the weight loss of the lotus roots that were treated with hot water slightly increased. The application of the heat treatment delayed the browning of the lotus roots, especially the treatment with $55^{\circ}C$ hot water. The L and a values of the lotus roots that were treated with $80^{\circ}C$ hot water significantly increased during their storage, though. The heat treatment effectively inhibited the growth of microorganisms. The organoleptic quality of the lotus roots that were treated with $55^{\circ}C$ hot water was the best.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.119-128
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• 2023

This study was examined for investigating the quality changes of spring kimchi cabbage under various treatments (pre-drying/pre-cooling, packaging types, and stacking and loading in container and pallete in the storage room) during cold storage. The results showed that control (upward stacking without pre-drying/pre-cooling and HDPE or PVC film cover) was increased significantly in weight loss and trimming loss, compared to other treatments such as DPDH (downard stacking + pre-drying + HDPE), DPDP (downard stacking + pre-drying + PVC), DPCH (downnard stacking + pre-cooling + HDPE), and UPCH (upward stacking + pre-cooling +HDPE) during storage for three months. In Sensory evaluation, judging from marketable properties, the desirable appearance of spring kimchi cabbage with the modified pallet-unit MA packed, PE, and PVC film wrapping could be maintained until 9 weeks after pre-drying/pre-cooling. Meanwhile, the control without any treatments after 6 weeks, the sensory score was declined, significantly. In general, the low temperature (10℃ and 2℃) of pre-treatment with combination of plastic film packaging in spring kimchi cabbage storage could inhibit the physiological activity and reduce the direct exposure of environmental cold air in the storage. Therefore, these two variables were the key points for extending the shelf-life of spring kimchi cabbage.

• Korean Journal of Organic Agriculture
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• v.15 no.1
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• pp.109-121
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• 2007

For developing standard method for diease, pest and weed control in environmental friendly 'Ssam' vegetable cultivation, this study was carried out to investigating agriculture material use in organic agriculture and no pesticide cultivation for lettuce, kale, leafy perilla and korean cabbage. The 28.6% of investigated farmer carried out seed sterilization by seed selection with salt solution and soaking in chitosan that not validated. For raising seedling periods, the 55.6% of farmer did not use environmental-friendly agriculture material for, diease control and the 50% of farmer used one time for. pest control. Therefore, the control of disease and pest could be achieved with one or two times use of environmental-friendly agriculture material. Seed sterilization was carried out by soil solar sterilization, one time per year in 71.4% of farmer. Weed was controled by black PE film for weed germination of furrow in many farmer, by man-power weeding for weed of ridge in 85% of farmer and by machine weeding and mulching in some farmer. During cultivation period, the major pest were Aphis gossypii in lettuce, Plutella xylostella in kale, Plutella xylostella and Phyllotreta striolata (Fabricius) in korean cabbage and Pyrausta panopealis (Walke) in feat perilla. The many farmers used environ-mental-friendly agriculture material for control of pest over 10 times for spring season, and more used sold materials in market than home-made materials. In result, it needs to develop standardized method and validate cultivation methods for control of disease and pest, and seed sterilization treatment environmental-friendly 'Ssam' vegetable.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.610-617
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• 2019

The effects of dippin treatments using Glycyrrhiza uralensis extract (0.5%, 1.0%, 2.0%) and calcium chloride (0.5%, 1.0%, 2.0%) on the quality of peeled chestnuts were investigated. Following dipping treatment, peeled chestnuts were vacuum-packed using a 75-㎛ polyethylene PE and nylon film, and stored in a 0 ℃ incubator for six weeks. The dipping treatments of the peeled chestnuts successfully achieved browning inhibition. The browning degree following 2.0% calcium chloride treatment was the lowest at 0.68 OD. The color change (ΔE) of the peeled chestnuts was the highest (6.0) in the control, and the lowest (3.5) for the 1.0% and 2.0% calcium chloride-treated samples. G. uralensis extract and calcium chloride treatments did not impact weight, moisture loss rate, firmness, or the soluble solid content of the peeled chestnuts following storage. The decay rate was 12.0% in the control group, and 11.0%, 11.5%, and 11.0% for G. uralensis treatment at 0.5%, 1.0%, and 2.0% calcium chloride treatment, respectively, and 13.0%, 9.5%, and 9.0% at 0.5%, 1.0%, and 2.0% calcium chloride treatment, respectively. Sensory evaluation (palatability, off-odor) showed that a 2.0% G. uralensis extract treatment presented excellent results during the storage period. Texture and color indicated no differences as a result of the browning inhibition treatments. Therefore, when considered comprehensively, a 2.0% G. uralensis extract treatment was shown to be effective for maintaining the quality and providing browning inhibition of peeled chestnuts. This result isexpected to solve the problem of quality deterioration in the form of sour taste, which is a problem in chemical processing.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.419-428
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• 2021

In order to develope a mobile-based greenhouse energy calculation program, firstly, the overall thermal transmittance of 10 types of major covers and 16 types of insulation materials were measured. In addition, to estimate the overall thermal transmittance when the cover and insulation materials were installed in double or triple layers, 24 combinations of double installations and 59 combinations of triple installations were measured using the hotbox. Also, the overall thermal transmittance value for a single material and the thermal resistance value were used to calculate the overall thermal transmittance value at the time of multi-layer installation of covering and insulating materials, and the linear regression equation was derived to correct the error with the measured values. As a result of developing the model for estimating thermal transmittance when installing multiple layers of coverings and insulating materials based on the value of overall thermal transmittance of a single-material, the model evaluation index was 0.90 (good when it is 0.5 or more), indicating that the estimated value was very close to the actual value. In addition, as a result of the on-site test, it was evaluated that the estimated heat saving rate was smaller than the actual value with a relative error of 2%. Based on these results, a mobile-based greenhouse energy calculation program was developed that was implemented as an HTML5 standard web-based mobile web application and was designed to work with various mobile device and PC browsers with N-Screen support. It had functions to provides the overall thermal transmittance(heating load coefficient) for each combination of greenhouse coverings and thermal insulation materials and to evaluate the energy consumption during a specific period of the target greenhouse. It was estimated that an energy-saving greenhouse design would be possible with the optimal selection of coverings and insulation materials according to the region and shape of the greenhouse.