• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.811-821
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• 2018

This study focused on the improvement of blueberry delivery service using pre-cooled ice and $SO_2$ pads to prevent an increase in the fruit temperature as well as decay. To maintain the fruit quality during low temperature storage, the effect of a $SO_2$ pad and modified atmosphere packaging was also examined. Harvested blueberries were precooled at $15^{\circ}C$, sorted, and packaged. And the fruits were placed in a similar environment as that for the parcel service. Part of the fruits were stored at $0^{\circ}C$ for long term storage. The air temperature in the delivery box increased along with an increase in the simulated delivery time regardless of the treatment. However, the rate of temperature increase was lower in the ice pad treatment. No significant difference was not found after 48 h. The oxygen concentration in the box ranged between 10.5 - 14.5% in the ice pad treatment, which was higher than that of the untreated control (7.5 - 11.9%) whereas the $CO_2$ concentration was lower in the ice pad treatment. No differences were found in the occurrence of off-flavor, decay, and sensory quality loss during the 48 hours of the parcel service simulation. The combined treatment of the $SO_2$ pad and modified atmosphere packaging (MAP) using a perforated film increased the shelf-life of the blueberry fruits, the overall quality such as firmness, and the soluble solid content was not different between the treatments except for the decay incidence. No decayed fruit was found in the combined treatment. However, the percentage of decayed fruit in the control was 25% on day 15 of storage and 75% on day 33 of storage, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1141-1149
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• 2011

The objective of this study was to analyze quality changes during storage of fresh-cut produce (leafy vegetables and condiment vegetables) as a function of packaging and storage temperature. Fresh-cut produce was washed using a three step cleaning process and was packed in vacuum packaging (green onion, hot pepper, onion, baechu) and perforated film packaging (buchu and perilla leaf). The effects of packaging method and storage temperature on quality of fresh-cut produce were determined by analyzing total plate counts, E. coli, coliform groups, moisture content, pH, Aw, surface color, and exterior quality during storage at 4 and 10$^{\circ}C$. According to the results, surface color change and microbial growth were delayed during storage at 4$^{\circ}C$. Additionally, E. coli was not detected during storage. Generally, moisture content decreased in the perforated film packaging. Changes in surface quality such as skin browning, softening of tissue and chlorosis at 4$^{\circ}C$ were inhibited, whereas rapid vacuum annealing and changes in color and flavor were observed in the sample stored at 10$^{\circ}C$. The result indicated that overall quality of the fresh-cut produce at 4$^{\circ}C$ was well maintained. The perforation in packing materials did not significantly increase the number of microorganisms on buchu and perilla leaf. The proper packaging methods and temperature may beneficial effect on microbial safety, quality and thus result in longer shelf-life fresh-cut vegetables during distribution.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.559-567
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• 2012

The storage quality of ready-to-eat Campbell table grapes which were packaged under modified atmospheres was investigated in order to examine the effect of high $O_2$ and $CO_2$ on the fruit. Fresh table grapes with 10-15 berries were packed into polypropylene (PP) trays and were top-sealed with polythylene terephthalate/PP film. The initial gas compositions inside the packages were air, 20% $O_2$/10% $CO_2$/70% $N_2$, and 40% $O_2$/60% $N_2$. Sealed packages with low density polyethylene film bags and perforated PP trays were also used as a further treatment and control, respectively. The quality attributes were assessed during storage at $5^{\circ}C$ for 28 days. Fruit packaged in high $CO_2$ concentration showed the lowest viable cell counts of inherent microorganisms among all samples, although they suffered from severe off-flavors. High levels of $O_2$ significantly lowered flesh weight loss and maintained the flavor of grape. In an overall sensory aspect, the high $O_2$ and $CO_2$ packages exhibited greater scores than the air and control at the end of the storage period. Other quality attributes showed no significant differences among treatments. Results suggest that packaging with an appropriate combination of high $O_2$ and $CO_2$ can be used as an effective processing treatment for improvement of the storability of ready-to-eat table grapes.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2001.06a
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• pp.51-64
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• 2001

The qualities including taste of sweetpotato stored during the winter which can display in the spring market in Korea are affected by availability of storage for the roots. In order to make high storage availability of sweetpotato, the postharvest handlings should be done thoroughly from the moment of harvest until shipping them to the market. A lot of procedures that must be handled carefully for improving postharvest management are as follows; digging, trimming, gathering, putting in storage containers, carrying them from field to house, curing, storing, washing, drying, selecting marketable roots, packing and shipping to the market, etc.. Sweetpotatoes have a high moisture content, and a relatively thin and delicate skin, and are sensitive to chilling, so careless postharvest handling can lead to both quantitative and qualitative losses which may be extremely high in some circumstances. From now on research has concentrated on the improvement of postharvest conditions to increase yield and lower disease rates. Storage, which makes sweetpotatoes available through out the year, benefits both the producer and the consumer. Seven very important points must be needed in order to get the best quality marketable roots in the storing of sweetpotatos : $\circled1$The storage house must be clean and sanitary, $\circled2$The crop must be harvested before the first frost to avoid low-temperature injury, $\circled3$Particular care must be taken to avoid cutting, bruising, or other injuries of the sweetpotatoes during digging, picking up, grading, placing in containers, and moving to the storage house, $\circled4$Select sound, disease-free roots for storage $\circled5$Sweetpotatoes should be stored in properly stacked containers $\circled6$Cure immediately after harvest, preferably at 32∼33$^{\circ}C$ and 90 to 95 percent relative humidity for 4 to 7 days, After curing the temperature should be reduced to 13$^{\circ}C$ to 16$^{\circ}C$ by ventilating the storage with outside air. $\circled7$Store at 12$^{\circ}C$ to 14$^{\circ}C$ and a relative humidity of 80 to 85 percent. Storage houses should be located on suitable sites and should be tightly constructed and insulated so that temperature and humidity will be uniform. Sweetpotatoes are usually not washed and graded, and lately sometimes washed, graded, waxed, before being shipped to market. Consumer packaging of sweetpotatoes in paper boxes(10-15kg) or film bags is done mainly to aid marketing. The shelf life of washed roots in consumer packs in only 1 to 2 weeks. Weight loss of roots during marketing is much less in perforated film bags than in mesh and paper bags. Perforation of 0.8 to 1kg polyethylene bags with about six 6mm holes is essential ; to lower the internal relative humidity and avoid excessive sprouting, rooting, and dampness. Development and use of better postharvest handling with good storage facilities or marketing methods can minimize sweetpotate losses and has an effect of indirectly increasing productivity and farmer’s income.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.7-12
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• 2018

This study was conducted to determine effects of precooling and storage methods on asparagus spears' quality such as changes of fresh weight and color during simulated export distribution. Two types of precooling methods, air cooling and hydrocooling, were applied prior to packaging by comparing with no precooling as a control. Asparagus spears were packed with oxygen transmission rate (OTR) film for modified atmosphere packaging (MAP) and perforated (PF) film for a conventional packaging. All treatments were stored at $8^{\circ}C$ for 20 hours, and subsequently at $4^{\circ}C$ by final storage day, which is simulated distribution temperature condition from Yanggu, Korea to Shimonoseki, Japan. The half cooling time was 12 minutes for air cooling and 15 seconds for the hydrocooling, indicating precooling process of asparagus spears faster with the hydrocooling. Rates of respiration and ethylene production were lowest with hydrocooling. Fresh weight loss was higher, approximately 11%, at the control condition in conventional storage, compared with the MAP, less than 0.5%. Carbon dioxide and oxygen content in the MAP was in the permissible ranges for asparagus spears under recommended CA/MA conditions under both the air cooling and hydrocooling. Ethylene content in the film package was lower with the precooling treatment. Firmness of stems was lowest with the hydrocooling prior to the MAP. Visual quality, off-odor, and hue angle value were best with hydrocooling prior to the MAP. In conclusion, the combination of hydrocooling with the MAP is effective in preserving quality during the export distribution process.

• Progress in Medical Physics
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• v.21 no.1
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• pp.86-92
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• 2010

The purpose of this study was to measure curvature contour skin dose using radiochromic film and TLD for a conventional open field. We also attempted to quantify the degradation of skin sparing associated with use of immobilization devices for high energy photon beams and to calculate the skin dose with a help of Monte Carlo (MC) simulation. To simulate head-and-neck and shoulder treatment, a cylindrical solid water phantom 11 cm in diameter was irradiated with 6 MV x-rays using $40{\times}40\;cm^2$ field at 100 cm source axis distance (SAD) to the center of the phantom. Aquaplastic mesh mask was placed on the surface of the cylindrical phantom that mimicked relevant clinical situations. The skin dose profile was obtained by taking measurements from $0^{\circ}$ to $360^{\circ}$ around the circumference of the cylindrical phantom. The skin doses obtained from radiochromic film were found to be 47% of the maximum dose of $D_{max}$ at the $0^{\circ}$ beam entry position and 61% at the $90^{\circ}$ oblique beam position without the mask. Using the mask (1.5 mm), the skin dose received was 59% at $0^{\circ}$ incidence and 78% at $80^{\circ}$ incidence. Skin dose results were also gathered using thin thermoluminescent dosimeters (TLD). With the mask, the skin dose was 66% at $0^{\circ}$ incidence and 80% at $80^{\circ}$ incidence. This method with the mask revealed the similar pattern as film measurement. For the treatments of the head-and-neck and shoulder regions in which immobilization mask was used, skin doses at around tangential angle were nearly the same as the prescription dose. When a sloping skin contour is encountered, skin doses may be abated using thinner and more perforated immoblization devices which should still maintain immoblization.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.511-517
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• 2015

This research was conducted to evaluate the influence of root restriction materials and media on the growth of runner plantlets of 'Seolhyang' strawberry in a nursery field. To achieve this, the influence of three kinds of root media on the growth of runner plantlets was monitored when polyethylene film was used as the root restriction material. In addition, the influence of various root restriction materials (RRS) such as transparent polyethylene film (PE), non-woven fabric (NF), perforated polyethylene film (PP), and root proofing sheet (RPS) on the changes in volumetric water content (VWC) and temperature of root media as well as growth of runner plantlet were investigated when expanded rice hull (ERH) was used as the root medium. In the comparison of root media, growth parameters such as leaf area and crown thickness at 20 d after fixation as well as crown thickness and fresh weights of root and above-ground tissue at 40 d after runner plantlet fixation were higher in the ERH treatment than in sandy loam and loamy sand. When the influence of RRS was compared, the VWC of ERH was 55% just after irrigation, but decreased to 26% at just before irrigation. Ranges of the VWC as influenced by irrigation cycle were 16 to 10% in the PP and less than 10% in the NF and RPS. The soil temperature in the PE treatment was around $1^{\circ}C$ lower than in NF, PP, and RPS. The differences between day and night temperatures were also smaller in the PE treatment rather than those in NF, PP, and RPS. The growths of runner plantlet 50 d after fixation showed that plant heights as well as fresh weights of root and above-ground tissue were higher in the PE treatment than in NF, PP, and RPS. NF and PP did not effectively restrict roots inside the medium and the roots of runner plantlets penetrated through the root restriction materials resulting in the formation of root system below the restriction materials. The above results indicate that ERH is more effective than sandy loam or loamy sand as root medium. PE rather than NF, PP, or RPS as root restriction material resulted in better growth of runner plantlets in propagation of 'Seolhyang' strawberry. The results of this research will be used for production of high quality runner plantlets in strawberry propagation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.17 no.1
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• pp.13-17
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• 2011

There is a need in food industry to store minimally processed garlic for long time to have it be used just at the time of demand for final product processing. Optimal modified atmosphere packaging is expected to slow down the quality change extending its storage life. In order to find optimal packaging conditions, plastic films of different gas permeability properties (low density polyethylene (LDPE) $30{\mu}m$, polyolefin $50{\mu}m$ (PD 900), polyolefin $20{\mu}m$ (PD 941)) were used for packaging 400 g of minimally processed garlic. Perforated LDPE packages were prepared as control. The packaged products were stored at $1{\pm}1^{\circ}C$ for 52 days. Package treatments were compared in weight loss, decay, surface color, hardness and soluble solid content. While control package had normal atmosphere of air, LDPE, PD 900 and PD 941 packages attained internal concentration of $O_2$ 4.6% / $CO_2$ 12%, $O_2$ 0.9% / $CO_2$ 21% and $O_2$ 0.5% / $CO_2$ 13% after 45 days, respectively. Control packaging had rapid weight loss with high mold decay and great surface color change in 45 days. In PD 900 film packages of lowest gas permeability, the fresh-cut garlic could be stored without mold decay for 52 days. Except control packaging, there were no significant differences in surface color, hardness and soluble solid content among package treatments.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.221-221
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• 2014

The present work proposes an improved numerical simulator for design and modification of large area capacitively coupled plasma (CCP) processing chamber. CCP, as notoriously well-known, demands the tremendously huge computational cost for carrying out transient analyses in realistic multi-dimensional models, because electron dissociations take place in a much smaller time scale (${\Delta}t{\approx}10-8{\sim}10-10$) than time scale of those happened between neutrals (${\Delta}t{\approx}10-1{\sim}10-3$), due to the rf drive frequencies of external electric field. And also, for spatial discretization of electron flux (Je), exponential scheme such as Scharfetter-Gummel method needs to be used in order to alleviate the numerical stiffness and resolve exponential change of spatial distribution of electron temperature (Te) and electron number density (Ne) in the vicinity of electrodes. Due to such computational intractability, it is prohibited to simulate CCP deposition in a three-dimension within acceptable calculation runtimes (<24 h). Under the situation where process conditions require thickness non-uniformity below 5%, however, detailed flow features of reactive gases induced from three-dimensional geometric effects such as gas distribution through the perforated plates (showerhead) should be considered. Without considering plasma chemistry, we therefore simulated flow, temperature and species fields in three-dimensional geometry first, and then, based on that data, boundary conditions of two-dimensional plasma discharge model are set. In the particular case of SiH4-NH3-N2-He CCP discharge to produce deposition of SiNxHy thin film, a cylindrical showerhead electrode reactor was studied by numerical modeling of mass, momentum and energy transports for charged particles in an axi-symmetric geometry. By solving transport equations of electron and radicals simultaneously, we observed that the way how source gases are consumed in the non-isothermal flow field and such consequences on active species production were outlined as playing the leading parts in the processes. As an example of application of the model for the prediction of the deposited thickness uniformity in a 300 mm wafer plasma processing chamber, the results were compared with the experimentally measured deposition profiles along the radius of the wafer varying inter-electrode gap. The simulation results were in good agreement with experimental data.

• Food Science and Preservation
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• v.14 no.4
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• pp.345-350
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• 2007

Shelf-life and quality changes of four leaf lettuce cultivars packaged and stored at four different temperatures (0, 8, 16 and $24^{\circ}C$) were evaluated. Leaf lettuces were packaged in non-perforated polypropylene film (thickness 0.05 mm) bags. Weight loss, respiration rate, freshness degree, pigment content, and surface color were determined. At the storage temperature of $0^{\circ}C$, the weight loss, degree of freshness, pigment content, and change of surface color on packaged leaf lettuces showed no significant difference when compared with all other leaf lettuces. Meanwhile, an increase in storage temperature was observed with the quality changes of each flesh leaf lettuce. The leaf lettuces under storage conditions at $24^{\circ}C$ showed a difference in weight loss of the different types of leaf lettuces during a short storage period. However, there was no clear tendency in weight loss in different types of leaf lettuces as compared with each storage temperature. The rate of respiration and the contents of pigments in the four types of leaf lettuces also showed significant difference as the storage temperature increased.