• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2004.10a
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• pp.67-72
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml $h^{-1}\;m^{-2}\;atm^{-1}$ at $5^{\circ}C\;and\;99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%\;CO_2+1\;or\;20\%\;O_2,\;8\%\;CO_2+1\;or\;20\%\;O_2,\;or\;12\%\;CO_2+20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2+1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SSC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown using black polyethylene mulch under NF was over 7-fold that of slices from tomato fruit grown using hairy vetch under Tom-Cast. When stored at $20^{\circ}C$, slices from light-red tomato fruit grown with black polyethylene or hairy vetch mulches both showed a rapid increase in electrolyte leakage beginning 6 hours after slicing. However, slices from tomato fruit grown using the hairy vetch mulch tended to have lower electrolyte leakage than those grown with black polyethylene mulch. These results suggest that tomato fruit from plants grown using hairy vetch mulch may be more suitable for fresh-cut slices than those grown using black polyethylene mulch. Also, use of the disease forecasting model Tom-Cast, which can result in lower fungicide application than is currently used commercially, resulted in high quality fruit for fresh-cut processing. Experiments were conducted to determine if ethylene influences chilling injury, as measured by percentage of slices exhibiting water-soaked areas in fresh-cut tomato slices of 'Mountain Pride' and 'Sunbeam' tomato (Lycopersicon esculentum Mill.). Ethylene concentration in containers without ventilation significantly increased during storage at $5^{\circ}C$, whereas little or no accumulation of ethylene occurred in containers with one or six perforations. Chilling injury was greatest for slices in containers with six perforations, compared to slices in containers with one perforation, and was over 13-fold greater than that of slices in control containers with no perforations. An experiment was also performed to investigate the effectiveness of including an ethylene absorbent pad in containers on subsequent ethylene accumulation and chilling injury. While ethylene in the no-pad controls increased continually during storage of both 'Mountain Pride' and 'Sunbeam' tomatoes at $5^{\circ}C$ under modified atmosphere conditions, no increase in accumulation of ethylene was observed in containers containing ethylene absorbent pads throughout storage. The ethylene absorbent pad treatment resulted in a significantly higher percentage of chilling injury compared with the no-pad control. In studies aimed at inhibiting ethylene production using AVG during storage of slices, the concentration of ethylene in control containers (no AVG) remained at elevated levels throughout storage, compared to containers with slices treated with AVG. Chilling injury in slices treated with AVG was 5-fold greater than that of controls. Further, we tested the effect of ethylene pretreatment of slices on subsequent slice shelf-life and quality. In slices treated with ethylene (0, 0.1, 1, or $10\;{mu}L\;L^{-1}$) immediately after slicing, ethylene production in non-treated controls was greater than that of all other ethylene pre-treatments. However, pretreatment of slices 3 days after slicing resulted in a different pattern of ethylene production during storage. Ihe rate of ethylene production by slices treated with 1 L $L^{-1}$ ethylene 3 days after slicing was greater during storage than any of the other ethylene treatments. With slices pre-treated with ethylene, both immediately and 3 days after slicing, the rate of ethylene production tended to show an negative correlation with chilling injury. Chemical name used: 1-aminoethoxyvinylglycine (AVG).

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.78-84
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• 1993

This study was conducted to investigate the effect of various polyethylene (PE) film packaging on the quality of strawberry during storage at low temperature. Gas composition in film was changed rapidly at early stage of storage and then kept at the level of 5~10% $CO_2$and 1~3% $O_2$. Weight loss and decay rate were low at 0.08mm PE film packed strawberries. Titratable acidity, pH and soluble solids were changed slightly during storage but its large difference according to film thickness was not observed. Decrease of flesh firm-ness and a value was restrained by PE film packaging. Free sugar of strawberry was composed of glucose and fructose in similar content and it was decreased a little during storage but the difference according to film thickness was not observed. The organic acids in strawberry were citric acid, malic acid, succinic acid, ascorbir acid, oxalic acid, tartaric acid and pyruvic acid and the major organic acid was citric acid. The contents of citric acid, malic acid, succinir acid and ascorbic acid were decreased and oxalic acid and tartaric arid were not changed during storage but pyruvic acid was increased in early stage and then decreased. These changes of organic acid were slight in packaged with 0.08mm PE film strawberry.

• Journal of Mushroom
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• v.16 no.3
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• pp.131-139
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• 2018

The king oyster mushroom (Pleurotus eryngii) is widely consumed because of its flavor, texture, and its functional properties such as antioxidant activity and prebiotic effects. However, long-term product storage and transportation (e.g., export) are difficult because of its limited durability. The shelf-life of king oyster mushroom is affected by environmental factors such as temperature, humidity, gas composition, and ventilation, which may affect sensory characteristics including respiration rate, texture, moisture, flavor, color, and pH. The major problems regarding storage of mushrooms are browning, flavor changes, and softening. To address these problems, novel preservation techniques were developed, and more durable variants were bred. Different drying methods, gamma irradiation, chitosan coating, modified atmosphere (MA) packaging, and controlled atmosphere (CA) storage were evaluated in order to extend the shelf-life of king oyster mushrooms. Freeze drying showed better results for the preservation of mushrooms than other drying methods. Irradiation with 1 kGy was more effective for extending mushroom shelf-life than higher doses. The preservative performance of chitosan-based films was improved by combining the compound with other hydrocolloids, such as oil, protocatechuic acid, and wax. The CA storage conditions recommended for king oyster mushrooms are 5kPa $O_2$ and 10 to 15kPa $CO_2$ at temperatures below $10^{\circ}C$. Active MA packaging with microperforated PP film was also effective for maintaining quality during storage.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.75-82
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• 2011

Five different composition UV-cured poly(urethane acrylate-co-acrylic acid) (PU-co-AA) films have been prepared by reacting isophorone diisocyanate(IPDI), polycaprolactone triol(PCLT), 2-hydroxyethyl acrylate(HEA), and different weight ratio trimethylolpropane triacrylate(TMPTA) and acrylic acid(AA) as diluents, and characterized using a Fourier transform infrared spectroscopy(FT-IR). The adhesion properties onto the stainless steel, morphology, mechanical hardness, and electrical property of UV-cured PU-co-AA films were investigated as a function of acrylic acid(AA) content. All the PU-co-AA films are structure-less and the molecular ordering and packing density decreased with increasing content of AA due to the flexible structure and -COOH side chains in AA. The crosscut test showed that PU-co-AA films without AA and with low content of AA showed 0% adhesion(0B) and the adhesion of PU-co-AA films in the range of 40-50% AA increased dramatically as the content of AA increases. The pull-off measurements showed that the adhesion force of PU-co-AA films to stainless steel substrate varied from 6 to 31 kgf /$cm^2$ and increased linearly with increasing AA content. The mechanical hardness also decreased as the content of AA increases. This may come from relatively linear and flexible structure in AA and low crystallinity in PU-co-AA films with higher content of AA. The higher AA-containing PU-co-AA films showed higher dielectric constant due to the increase of polarization by introducing AA monomer. In conclusion, the physical properties of UV-cured PU-co-AA films are strongly dependent upon the content of AA and the incorporation of AA in polyurethane acrylate is very useful way to increase the adhesion strength of UV-curable polymers on the stainless steel substrate.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.91-96
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• 2016

In this study, effects of demolding temperature (DT) on the formability and optical properties were evaluated in order to optimize thermal nanoimprint lithography for anti-reflective film. Characterization on optical property showed that optical performance was gradually enhanced as the DT increased up to $70^{\circ}C$ while the transmittance and the reflectance was degraded as the DT increased further to $100^{\circ}C$. In addition, similar behavior was observed from formability analysis. It was contributed to the formation of free volume and viscose flow. Therefore, it was concluded that the formability and optical property are highly influenced by the formation of free volume and viscous flow of polymer depending on the DT.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.1
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• pp.55-61
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• 2006

'Bing' sweet cherries (P. avium L.) were coated with four different coating materials at 1% concentration ($Semperfresh^{(R)}$, calcium caseinate, chitosan, or TIC $Pretested^{(R)}$ colloid 911)and stored at $2.0^{\circ}C$ and 88% RH up to 35 days. The influence of different coating materials on the storability of fresh cherries was investigated. $Semperfresh^{(R)}$ coatings significantly improved overall quality of fresh cherries by decreasing weight loss and improving color stability, and chitosan-based coatings were effective in controlling mold incidence. However, colloid 911 and calcium caseinate coatings did not show significant benefit in preventing quality deterioration of fresh cherry during storage, probably due to their hydrophilic nature leads to exacerbated weight loss and shriveling with the possible interactions between coating materials and cherries epidermal layers.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.35-39
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• 2020

Nonwet (Head in Pillow) defect is one of the defects in SMT (surface mount technology) process, the defect is caused by several factors, such as solder paste misalignment, reflow condition, package warpage and package ball size. This paper focused on ① reflow condition ② package ball & solder paste misalignment ③ package ball size for nonwet experiment. The first, on the case of reflow condition, there would be high risk of nonwet defect when the soldering time was increased, but N₂ was adopted to reflow process, there could be no or low risk of nonwet defect because of oxidation barrier control. And when the contact depth between Solder ball and solder paste was below 20 ㎛, there could be high risk of nonwet defect. Also smaller package ball would have low risk of nonwet defect.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.2 s.39
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• pp.1-7
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• 2006

In this paper, warpage magnitude and shape of printed-circuit board in case that properties of core and thickness of solder resist are varied are investigated. The cause of warpage is coefficient of thermal expansion differences of stacked materials. Therefore, we need small difference of coefficient of thermal expansion that laminated material, and need to decrease asymmetric of top side and bottom side in structure shape. Also, we can control occurrence of warpage heightening hardness of core in laminated material. Composite material that make core are exploited in connection with the structural bending twisting coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. If we use such characteristic, we can control warpage with change of material properties. In this paper, warpage of two layer stacked chip scale package is investigated, and evaluate improvement result using an experiment and finite element method tool.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.69-74
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• 2017

Effect of post-annealing treatment times at $200^{\circ}C$ on the peel strength of screen-printed Ag film/polyimide substrate were systematically investigated by $180^{\circ}$ peel test for thermal reliability assessment of printed interconnect. Initial peel strength around 16.7 gf/mm increased up to 29.4 gf/mm after annealing for 24hours, and then sharply decreased to 22.3, 3.6, 0.6, and 0.1 gf/mm after 48, 100, 250, and 500 hours, respectively. Ag-O-C chemical bonding as well as binder organic bridges formations seemed to be responsible for interfacial adhesion improvement after the initial annealing treatment, while excessive Cu oxide formation at Cu/Ag interface seems to be closely related to sharp decrease in peel strength for longer annealing times.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.415-424
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• 2020

This study investigated the effects of an ethylene scrubber (ES) with a micro-perforated polypropylene (MP-PP, 30 ㎛) or a high density polyethylene (MP-HDPE, 30 ㎛) film liner for the export carton packaging box in 'Campbell Early' grapes. Rachis browning was highest in the untreated group, followed by MP-PP and MP-HDPE for 14 days of simulated marketing at 20℃. The combination treatment of ES with the film liners showed a partial inhibition of the rachis browning regardless of the film liners. The effects of an alcohol releaser (AR) sachet or chlorine dioxide (CD) diffuser co-packaging were also investigated in the 'Campbell Early' grapes packed with the MP-HDPE (40 × 99 pin hole·m^-2) film liner. The CD 1 g treatment showed a very limited weight loss of 1.1%, which was significantly lower than the 4.7% of the untreated control after 14 days of simulation marketing at 20℃. The berry shatter was 0.7% for the MP-HDPE + CD 1 g treatment and 1.8% for the MP-HDPE + CD 5 g treatment on the 10th day of the simulated marketing, which was significantly lower than the 8.9% of the control. The stem browning was significant suppressed until the 10th day of the simulated marketing. In particular, the CD 1 g treatment in combination with the MP-HDPE showed a low rachis and pedicel browning index of 2.0, which is 50% and 40% lower than that of the untreated control and the MP-HDPE single treatment, respectively. In addition, the CD 1 g treatment group showed a higher decay reduction effect than the CD 5 g treatment group, which caused high concentration damage.