• Applied Biological Chemistry
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• v.35 no.6
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• pp.490-494
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• 1992

The effect of heat treatments (boiling or microwave heating) on packaged Tofu was investigated by microbial and physicochemical changes during its storage in order to improve the shelf-life. The shelf-life of the packaged Tofu prepared by acetic acid was found better than that prepared by calcium chloride. As the spoilage of Tofu developed, titratable acidity, amino and ammonia nitrogen contents, and optical density of packaged Tofu suspension were increased. Heat treatment of fresh Tofu in package was effective in lowering the bacterial counts, and extending shelf-life, but there was no significant difference between heating methods. Packaged Tofu prepared from acetic acid and pretreated by heating for 3 minutes kept the shelf-life of 4 days at $30^{\circ}C$, but that without heat treatment spoiled at one day.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.303-304
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• 2005

In this paper, we report a fluxless eutectic die bonding process which uses 80Au-20Sn eutectic alloy. The chip LEDs are picked and placed on silicon substrate wafers. The bonding process temperatures and force are $305\sim345^{\circ}C$ and 10$\sim$100gf, respectively. The bonding process was performed on graphite heater with nitrogen atmosphere. The quality of bonding are evaluated by shear test and thermal resistance. Results of fluxless eutectic die bonding show that shear strength is Max. 3.85kgf at 345$^{\circ}C$ /100gf and thermal resistance of junction to die bonding is Min. 3.09K/W at 325$^{\circ}C$/100gf.

• Food Science of Animal Resources
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• v.33 no.4
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• pp.448-455
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• 2013

Proper storage of left-over meat in a household refrigerator is important for extending its shelf-life and assuring its safety until it is next used. Various fresh meat packaging methods were examined to determine their effects on the quality characteristics of pork loins during household storage at $5^{\circ}C$. The packaging methods include 1) wrapping in a polyethylene pouch (WP), 2) keeping in an air-tight plastic container (CP), and 3) using a household vacuum packaging machine (VP). The fastest increase in total aerobic bacteria during storage occurred in the WP samples, followed by the CP and VP samples. The count of Pseudomonas spp. was found to be lowest in the VP, and then the CP and WP samples. Enterobacteriaceae grew fastest in the WP samples, followed by the CP and VP samples. The WP samples also incurred the most significant increase in thiobarbituric acids and volatile basic nitrogen values over the storage period, as compared to the CP and VP samples. Off-odour at 30 min after opening the package, was first notable at day 11 in WP samples, but only at day 15 in the CP and VP samples. The colour also deteriorated earlier in the WP samples than in the CP and VP samples.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.317-322
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• 2000

This study examined the effect of nitrogen$(N_2)$ gas packing and ${\gamma}-oryzanol$ treatment on the shelf life of Yukwa(Korean traditional snack). Yukwa were stored with $N_2$ gas packing(AN), $N_2$ gas packing with ${\gamma}-oryzanol$ treatment(ANA), and PE film packing with air(PE) for 20 days at $60^{\circ}C$. They were evaluated by POV, AV, conjugated diene, hexanal, color and sensory characteristics. The POV, AV and conjugated diene content increased abruptly in PE and AN, but increased slowly in ANA with prolonged storage. Higher sensory scores for Yukwa were found in ANA as compared to those in PE and AN. Hexanal content, yellowness and redness in AN were higher than those in ANA and PE. The moisture content, which is supposed to be related with browning of Yukwa, was 3 times higher in AN than that in PE. Oxygen content of each Yukwa pack, even in $N_2$ gas packing, increased remarkably as storage period increased because their highly porous, fragile and syrup-coated structure resulted in incomplete degassing before $N_2$ gas was flushed into package. Consequently, $N_2$ gas packing was inefficient, but $N_2$ gas packing combined with antioxidant(such as ${\gamma}-oryzanol$) treatment was effective for the extension of shelf life of Yukwa.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.279-288
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• 2016

Stable Isotope Analysis(SIA) of carbon and nitrogen is useful tool for the understanding functional roles of target organisms in biological interactions in the food web. Recently, mixing model based on SIA is frequently used to determine which of the potential food sources predominantly assimilated by consumers, however, application of model is often limited and difficult for non-expert users of software. In the present study, we suggest easy manual of R software and package SIAR with example data regarding selective feeding of crustaceans dominated freshwater zooplankton community. We collected SIA data from the experimental mesocosms set up at the littoral area of eutrophic Chodae Reservoir, and analyzed the dominant crustacean species main food sources among small sized particulate organic matters (POM, <$50{\mu}m$), large sized POM (>$50{\mu}m$), and attached POM using mixing model. From the results obtained by SIAR model, Daphnia galeata and Ostracoda mainly consumed small sized POM while Simocephalus vetulus consumed both small and large sized POM simultaneously. Copepods collected from the reservoir showed no preferences on various food items, but in the mesocosm tanks, main food sources for the copepods was attached POM rather than planktonic preys including rotifers. The results have suggested that their roles as grazers in food web of eutrophicated reservoirs are different, and S. vetulus is more efficient grazer on wide range of food items such as large colony of phytoplankton and cyanobacteria during water bloom period.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.145-151
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• 2023

In order to extend shelf life for rockfish fillets by modified atmosphere packaging (MAP), different package atmospheres were compared in the product quality preservation. Firstly, CO₂ solubility was measured at 0, 5, 10, and 15℃ to be incorporated into the mathematical model to predict the volume and CO₂ concentration of the package at expected storage temperature. The CO₂ solubility given in Henry's constant decreased with temperature to be fitted with a linear equation. Then air packaging as control and four MAP conditions of 100 g fillets were prepared and stored for duration of 5 days at 10℃ to compare them in the quality preservation effect. Four MAP conditions employed were CO₂(60):O₂(30):N₂(10), CO₂(60):O₂(0):N₂(40), CO₂(30):O₂(30):N₂(40) andCO₂(30):O₂(0):N₂(70). MAP conditions with high CO₂ concentration inhibited total aerobic bacteria, and the conditions containing O₂ led to low TVB-N. MAP of CO₂(60):O₂(30):N₂(10) was found to be the best condition for rockfish fillet preservation considering total aerobic bacteria growth and nitrogenous volatiles production.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.21-26
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• 2002

The behavior of the biological water treatment process on start-up operation was evaluated in the integrated recirculating aquaculture system consisting of a double drain type rearing tank ($2.5 m^3$), a sedimentation tank, a floating bead filter, a foam separator and a rotating biological contactor. A system was stocked with nile tilapia (Oreochromis niloticus) at an initial rearing density of $2\%$ for 2 weeks for acclimated rotating biological contactor. The total ammonia nitrogen (TAN) level increased to $13.6 g/m^3$ on day 4 after adding feed and was decreased to $0.3 g/m^3$ on day 7. The total suspended solid was completely removed during overall experimental period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1104-1111
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• 2014

To investigate major characteristics affecting the consumer acceptability of Cheonggukjang, the physicochemical characteristics and consumer perception of 16 Cheonggukjang samples (seven commercial samples and nine samples prepared in the laboratory) were analyzed. Overall, consumer acceptability of Cheonggukjang increased with higher contents of amino nitrogen and volatile basic nitrogen, as well as at lower moisture contents. Cheonggukjang samples with higher consumer acceptability showed higher purchase intent (%) and willingness to pay (won/200 gram package), implying consistency in consumer evaluation. Ideal characteristics of Cheonggukjang were lighter color, less water in the soup, stronger characteristic Cheonggukjang taste, sweetness and nutty taste, as well as less off odors, saltiness, and bitterness. The result of this study demonstrates the needs to improve sensory quality by considering the relatively low consumer acceptability of Cheonggukjang samples.

• Food Science of Animal Resources
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• v.24 no.2
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• pp.121-127
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• 2004

This study was conducted to investigate the effect of dietary mugwort pelleted on the storage stability of pork. barrow (T1) and boar (T2) were alloted into six treatments: 1) control (commercial feed) 2) T1-1 and T2-1(commercial feed supplemented with 3.0％ mugwort pelleted) 3) T1-2 and T2-2 (commercial feed supplemented with 5.0％ mugwort pelleted). They were fed with the experimental diets for 60 days and slaughtered. Meat samples were in wrap package and stored at 4${\pm}$1$^{\circ}C$ for 10 days. pH, WHC and cooking loss were not siginificanly different in all treatment. But these values were tended to increase during storage for all treatment groups (p＜0.05). Thiobarbituric acid reactive substances (TBARS) and Volatile Basic Nitrogen (VBN) values were low for pork samples prepared from pigs supplemented mugwort pelleted diet and the values were increased as storage period increased for all treatment groups (p＜0.05). But L value was highest for pork samples prepared from pigs supplemented of 3.0％ mugwort pelleted diet among treatments group.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.06a
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• pp.95-112
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• 1998

Water quality in the public water course has been polluted more seriously than ever before due to the increase of the number and aremount of pollution sources such as domestic and industrial wastewater. For water quality conservation, the Korean government has been trying to construct sewage treatment facilities continually, of which treatment capacity reached to 11,452,400m$^{3}$/day in 1996. Night soil treatment facilites of m nationwide have the treatment capacity of 24,038m$^{3}$/day. But water quality has not been improved because the sewer systems were insufficient and the treatment efficiencies of sewage were not high, enough. For renovation of water quality, miscellaneous domestic wastewater must be treated because 27g BOD/day out of total 40g BOD/person-day come from miscellaneous wastewater, comparing to 13g BOD/day from night soil. However, sole treatment purifier treat only night soil from the flushing toilet. Therefore, it may be desirable to treat the miscellaneous domestic wastewater and the night soil from flushing toilet together by joint treatment purifier system as on-site domestic wastewater treatment technology. In Korea, the joint treatment purifier system, introduced in 1997, have the benefit as follows; i) good water poiluion control effect, ii ) good effect on river water flow, iii) water pollution control with sewage treatment facility, and iv) rapid pollution control effect, etc. In order to achieve a good effect as stated before, i ) strengthening effluent guideline including BOD, nitrogen and phosphorus, ii ) specializing operation to maintain high performance, and iii) supporting its construction and maintenance costs by the governmental level may be necessary: In addition, automation system of joint treatment purifier, technology for its package and compactness, and a new bio-media bio-filter with higher capacity should be further developed in agreement with a more stringent effluent guideline.