• 한국유가공학회:학술대회논문집
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• 2002.04a
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• pp.59-60
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• 2002

Edible films such as wax coatings, sugar and chocolate covers, and sausage casings, have been used in food applications for years$^{(1)}$ However, interest in edible films and biodegradable polymers has been renewed due to concerns about the environment, a need to reduce the quantity of disposable packaging, and demand by the consumer for higher quality food products. Edible films can function as secondary packaging materials to enhance food quality and reduce the amount of traditional packaging needed. For example, edible films can serve to enhance food quality by acting as moisture and gas barriers, thus, providing protection to a food product after the primary packaging is opened. Edible films are not meant to replace synthetic packaging materials; instead, they provide the potential as food packagings where traditional synthetic or biodegradable plastics cannot function. For instance, edible films can be used as convenient soluble pouches containing single-servings for products such as instant noodles and soup/seasoning combination. In the food industry, they can be used as ingredient delivery systems for delivering pre-measured ingredients during processing. Edible films also can provide the food processors with a variety of new opportunities for product development and processing. Depends on materials of edible films, they also can be sources of nutritional supplements. Especially, whey proteins have excellent amino acid balance while some edible films resources lack adequate amount of certain amino acids, for example, soy protein is low in methionine and wheat flour is low in lysine$^{(2)}$. Whey proteins have a surplus of the essential amino acid lysine, threonine, methionine and isoleucine. Thus, the idea of using whey protein-based films to individually pack cereal products, which often deficient in these amino acids, become very attractive$^{(3)}$. Whey is a by-product of cheese manufacturing and much of annual production is not utilized$^{(4)}$. Development of edible films from whey protein is one of the ways to recover whey from dairy industry waste. Whey proteins as raw materials of film production can be obtained at inexpensive cost. I hypothesize that it is possible to make whey protein-based edible films with improved moisture barrier properties without significantly altering other properties by producing whey protein/lipid emulsion films and these films will be suitable far food applications. The fellowing are the specific otjectives of this research: 1. Develop whey protein/lipid emulsion edible films and determine their microstructures, barrier (moisture and oxygen) and mechanical (tensile strength and elongation) properties. 2. Study the nature of interactions involved in the formation and stability of the films. 3. Investigate thermal properties, heat sealability, and sealing properties of the films. 4. Demonstrate suitability of their application in foods as packaging materials. Methodologies were developed to produce edible films from whey protein isolate (WPI) and concentrate (WPC), and film-forming procedure was optimized. Lipids, butter fat (BF) and candelilla wax (CW), were added into film-forming solutions to produce whey protein/lipid emulsion edible films. Significant reduction in water vapor and oxygen permeabilities of the films could be achieved upon addition of BF and CW. Mechanical properties were also influenced by the lipid type. Microstructures of the films accounted for the differences in their barrier and mechanical properties. Studies with bond-dissociating agents indicated that disulfide and hydrogen bonds, cooperatively, were the primary forces involved in the formation and stability of whey protein/lipid emulsion films. Contribution of hydrophobic interactions was secondary. Thermal properties of the films were studied using differential scanning calorimetry, and the results were used to optimize heat-sealing conditions for the films. Electron spectroscopy for chemical analysis (ESCA) was used to study the nature of the interfacial interaction of sealed films. All films were heat sealable and showed good seal strengths while the plasticizer type influenced optimum heat-sealing temperatures of the films, 130$^{\circ}$C for sorbitol-plasticized WPI films and 110$^{\circ}$C for glycerol-plasticized WPI films. ESCA spectra showed that the main interactions responsible for the heat-sealed joint of whey protein-based edible films were hydrogen bonds and covalent bonds involving C-0-H and N-C components. Finally, solubility in water, moisture contents, moisture sorption isotherms and sensory attributes (using a trained sensory panel) of the films were determined. Solubility was influenced primarily by the plasticizer in the films, and the higher the plasticizer content, the greater was the solubility of the films in water. Moisture contents of the films showed a strong relationship with moisture sorption isotherm properties of the films. Lower moisture content of the films resulted in lower equilibrium moisture contents at all aw levels. Sensory evaluation of the films revealed that no distinctive odor existed in WPI films. All films tested showed slight sweetness and adhesiveness. Films with lipids were scored as being opaque while films without lipids were scored to be clear. Whey protein/lipid emulsion edible films may be suitable for packaging of powder mix and should be suitable for packaging of non-hygroscopic foods$^{(5,6,7,8,)}$.

• Food Science and Preservation
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• v.20 no.5
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• pp.602-607
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• 2013

Correct packaging enables processors to pack fresh produce and extend its shelf life. This study was carried out to investigate the effect of different packaging materials on the weight loss, pH, $O_2$, $CO_2$ and sensory characteristics of soybean sprouts during their storage at $5^{\circ}C$ for seven days. Soybean sprouts ($320{\pm}20g$) were packaged with oriented polypropylene (OPP) and cast polypropylene (CPP) films, respectively. The $O_2$ transmission rate of the packaging materials was set to have a control of $10,000cc/m^2$.day.atm, and an OP15 and CP15 with $15,000cc/m^2$.day.atm through a pre-screening test. The average weight loss of the soybean sprouts during their storage was less than 10%, and that of the soybean sprouts with a CPP film was higher than that of the OPP film. The pH of the soybean sprouts increased during their storage regardless of their packaging materials; but compared to the pH of the soybean sprouts packaged with OPP, those packaged with CPP were higher. The $CO_2$ content of the packaging increased with a decrease in the $O_2$ content. The ratio of $CO_2$ to $O_2$ in the soybean sprouts with the OPP film was 3.5 times higher than in the soybean sprouts with the CPP film. The results of the overall sensory test showed that the marketability of the soybean sprouts packaged with OPP film and stored at $5^{\circ}C$ seemed to have been maintained effectively for six days (at a $15,000cc/m^2$.day.atm $O_2$ transmission rate). When the correlation coefficients of the control, OP15 and CP15 were analyzed, the highest correlation was shown between a control and OP15 (0.986; p<0.01).

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.11-18
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• 2011

The quantitative interfacial adhesion energy of the Cu-Cu direct bonding layers was evaluated in terms of the bonding temperature and Ar+$H_2$ plasma treatment on Cu surface by using a 4-point bending test. The interfacial adhesion energy and bonding quality depend on increased bonding temperature and post-annealing temperature. With increasing bonding temperature from $250^{\circ}C$ to $350^{\circ}C$, the interfacial adhesion energy increase from $1.38{\pm}1.06$ $J/m^2$ to $10.36{\pm}1.01$ $J/m^2$. The Ar+$H_2$ plasma treatment on Cu surface drastically increase the interfacial adhesion energy form $1.38{\pm}1.06$ $J/m^2$ to $6.59{\pm}0.03$ $J/m^2$. The plasma pre-treatment successfully reduces processing temperature of Cu to Cu direct bonding.

• Journal of Food Hygiene and Safety
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• v.3 no.3
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• pp.117-129
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• 1988

Packaged meal manufacturing establishments in Seoul city and Kyungkido province were assessed in terms of the sanitary conditions and practices, time and temperature, and microbiological quality. Sanitary check-lists were developed to evaluate the sanitary condition of sampled packaged meal manufacturing establishments. Microbiological tests on.food containers, equipments, and foods in various phases of product flow were done. The results of the study are summarized as follows; 1) Sanitary condition of kitchen.and sanitary practices of employees in.large and medium establishments were evaluated as the some improvement required in order to meet all standards. But sanitary practices of employees in small establishments were evaluated as the unsatisfactory state with negligence or ignorance of safe practice. 2) The microbiological quality of basic ingredients and food materials after pre-preparation were poor. 3) Time and temperature data indicated that phases of holding ingredients at room temperature after cooking, assembly and packaging before delivery were critical. 4) Microbiological test results for food containers, equipments indicated that sanitary conditions of stainless steel ware, knife, wiping clothes and cutting board should be improved promptly. 5) Critical control points identified were ingredients, pre-preparation, Holding, and assembly and packaging. 6) Guidelines were suggested for effective quality control of packaged meals production.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.688-697
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• 2014

In this study, electrode bonding technology needed for high density of rechargeable battery is studied, which is recently researched for electric vehicle, the small leisure vessel. For the alternative overcoming the limit of stacking amount able to be stacked by conventional ultrasonic welding, the low temperature bonding method, eligible for minimum of degeneration of chemical activator on the electrode surface which is generated by thermal effect as well as the increase of conductivity and tension strength caused by electrode bonding using filler metal, not using conventional direct heating on the electrode material method, is studied. Specifically to say, recently used more generally the ultrasonic welding and spot welding method are not usable for satisfying stable electric conductivity and bonding strength when much electrode is stacking bonded. If the electrical power is unreasonably increased for the welding, due to the effect of welding temperature, deformation of electrode and activating material degeneration are caused, and after the last packaging, decline of electrical output and generating heat cause to reduce stability of battery. Therefore, in this study, induction heating system bonding method using high frequency heating and differentiated electrode method using filler metal pre-treatment of hot dipping are introduced.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.95-103
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• 2005

The interfacial reaction between 42Sn-58Bi solder (in wt.$\%$ unless specified otherwise) and electroless Ni-P/immersion Au has been investigated before and after thermal aging, with a focus on formation and growth of an intermetallic compound (IMC) layer, consumption of under bump metallurgy (UBM), and bump shear strength. The immersion Au layer with thicknesses of 0 (bare Ni), 0.1, and $1{\mu}m$ was plated on the $5{\mu}m$ thick electroless Ni-P ($14{\~}15 at.\%$P) layer. Then, the 42Sn-58Bi solder balls were fabricated on three different UBM structures by screen-printing and pre-reflow. The $Ni_3Sn_4$ layer (IMC1) was formed at the joint interface after pre-reflow for all the three UBM structures. On aging at $125^{\circ}C$, a quaternary phase (IMC2) was observed above the $Ni_3Sn_4$ layer in the Au-containing UBM structures, which was identified as $Sn_{77}Ni{15}Bi_6Au_2$ (in at.$\%$). The thick $Sn_{77}Ni{15}Bi_6Au_2$ layer deteriorated the integrity of the solder joint and the shear strength of the solder bump was decreased by about $40\%$ compared with non-aged joints.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.47-53
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• 2012

Bonding strength of Sn-3.0Ag-0.5Cu solder joint due to degradation characteristic of OSP surface finish was investigated, compared with SnPb finish. The thickness variation and degradation mechanism of organic solderability preservative(OSP) coating were also analyzed with the number of reflow process. To analyze the degradation degree of solder joint strength, FR-4 PCB coated with OSP and SnPb were experienced preheat treatment as a function of reflow number from 1st to 6th pass, respectively. After 2012 chip resistors were soldered with Sn-3.0Ag-0.5Cu on the pre-heated PCB, the shear strength of solder joints was measured. The thickness of OSP increased with increase of the number of reflow pass by thermal degradation during the reflow process. It was also observed that the preservation effect of OSP decreased due to OSP degradation which led Cu pad oxidation. The mean shear strength of solder joints formed on the Cu pads finished with OSP and SnPb were 58.1 N and 62.2 N, respectively, through the pre-heating of 6 times. Although OSP was degraded with reflow process, the feasibility of its application was proven.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.31-37
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• 2009

Cu-Cu thermo-compression bonding process was successfully developed as functions of the $N_2+H_2$ forming gas annealing conditions before and after bonding step in order to find the low temperature bonding conditions of 3-D integrated technology where the quantitative interfacial adhesion energy was measured by 4-point bending test. While the pre-annealing with $N_2+H_2$ gas below $200^{\circ}C$ is not effective to improve the interfacial adhesion energy at bonding temperature of $300^{\circ}C$, the interfacial adhesion energy increased over 3 times due to post-annealing over $250^{\circ}C$ after bonding at $300^{\circ}C$, which is ascribed to the effective removal of native surface oxide after post-annealing treatment.

• Food Science and Preservation
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• v.10 no.1
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• pp.23-27
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• 2003

This study was conducted to develop the corrugated fiberboard box which is suitable to pre-cooling and low temperature distribution of chinese cabbage Consider from a cooling performance viewpoint, the folding type box with 5.4% vent hole ratio was most efficient for fast cooling and even temperature distribution in the packaging box. At the end of storage periods, the compressive strength of the folding type box was less than the bliss type box. However, the compressive strength of the folding type box after storage was higher than required safety compressive strength for long term storage. So the folding type box was considered to have no problems toy practical use. The shelf-life of the chinese cabbage packaged with the developed box was 6∼7 days which was 2∼3 days longer than usual packaging.

• 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.