• Journal of Sensor Science and Technology
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• v.29 no.2
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• pp.93-99
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• 2020

A colorimetric paper sensor was used to detect volatile nitrogen-containing compounds emitted from spoiled salmon filets to determine their freshness. The sensing mechanism was based on acid-base reactions between acidic pH-indicating dyes and basic volatile ammonia and amines. A sensing layer was simply fabricated by drop-casting a dye solution of bromocresol green (BCG) on a polyvinylidene fluoride substrate, and its color-change response was enhanced by optimizing the amounts of additive chemicals, such as polyethylene glycol, p-toluene sulfonic acid, and graphene oxide in the dye solution. To avoid the adverse effects of water vapor, both faces of the sensing layer were enclosed by using a polyethylene terephthalate film and a gas-permeable microporous polytetrafluoroethylene sheet, respectively. When exposed to basic gas analytes, the paper-like sensor distinctly exhibited a color change from initially yellow, then to green, and finally to blue due to the deprotonation of BCG via the Brønsted acid-base reaction. The use of ammonia analyte as a test gas confirmed that the sensing performance of the optimized sensor was reversible and excellent (detection time of < 15 min, sensitive naked-eye detection at 0.25 ppm, good selectivity to common volatile organic gases, and good stability against thermal stress). Finally, the coloration intensity of the sensor was quantified as a function of the storage time of the salmon filet at 28℃ to evaluate its usefulness in monitoring of the food freshness with the measurement of the total viable count (TVC) of microorganisms in the food. The TVC value increased from 3.2 × 10⁵ to 3.1 × 10⁹ cfu/g in 28 h and then became stable, whereas the sensor response abruptly changed in the first 8 h and slightly increased thereafter. This result suggests that the colorimetric response could be used as an indicator for evaluating the degree of decay of salmon induced by microorganisms.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.722-726
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• 2009

The residue distribution ratio of pesticides among the flesh, stem and leaves of hot peppers were investigated to assure the safety of pepper powder and pepper leaves. Mixed solutions of chlorothalonil (wettable powder), kresoximmethyl (water dispersible granules) and procymidone (wettable powder) were applied once onto pepper plants in a plastic film house. After 7 days, the fruits and leaves were harvested and the fruits were divided into the flesh and stems. Pesticide residues in each pepper part were then analyzed by gas chromatography. The results showed that the concentration ratios of the chemicals in the flesh:stem and flesh:leaf ranged from 1:2-5 and 1:11-39, respectively, depending on the chemical evaluated. The observed flesh:stem ratio indicates that the pesticide content of the pepper powder product can increase by 20% if pepper stems are included in the powder product. The Korea Food and Drug Administration does not set a pesticide maximum residue level (MRL) for pepper leaves if a residue ratio in leaves over flesh is more than ten times. Results from this study support non-MRL status on the pepper leaves for the studied pesticides. Additionally, we recommend that the chlorothalonil product of a wettable powder type include the phrase "prohibition of distribution or sale for pepper leaves as food" because chlorothalonil highly resided in pepper leaves as more than twenty-four times that is a criterion level to determine an inclusion of the phrase in the label of pesticide product.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.469-473
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• 2001

Fuji apples were sliced and dipped in distilled water, 1% (w/v) ascorbic acid and 1% (w/v) oxalic acid. After minimal processing, the slices were packaged with three films which have different gas transmission rate and stored in cold room$(0-2^{\circ}C)$. The visual quality, gas composition, pH, texture, soluble solids content and titratable acidity were determined. The most deteriorative effects on quality were produced by browning of flesh. Ascorbic acid inhibited the development of browning and extended storage life from 7 days of control to 14 days at $0-2^{\circ}C$. Minimally processed Fuji apple treated with ascorbic acid and P640 film showed exhausting of oxygen in the packaging after 14 days. It showed only a slight reduction of pH from 3.73 to 3.72. The visual quality, gas composition, pH, texture, soluble solids content, titratable acidity were slightly changed, indicating that higher quality was maintained during storage. Ascorbic acid inhibited the development of browning and extended storage life of fresh-cut Fuji apple.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.1
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• pp.87-91
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• 2005

Dental plaque is a film of microorganisms on the tooth surface that plays an important part in the development of caries and periodontal diseases. Streptococcus mutans (S. mutans) is present in almost all types of dental plaque. Teeth and their supporting structure, the gums (gingiva) are subjected to infection by S. mutans that causes cavities and pyorrhea which, if left untreated, can eventually lead to gingivitis. Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. The present study was designed to investigate the effect of Aralia continentalis (Araliaceae) extracts on the growth, acid production, adhesion, and insoluble glucan synthesis of S. mutans. The methanol extract of A. continentalis showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.25, 0.5, 1, 2 and 4 mg/ml compared to the control group. The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 60% at the concentration of 0.25 mg/ml and complete inhibition was observed at the concentration of 4 mg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan from sucrose, methanol extract of A. continentalis showed more than 10% inhibition over the concentration of 0.25 mg/ml. The synthesis of insoluble glucan was decreased in the presence of 0.25 - 4 mg/ml of the methanol extract of A. continentalis. Hence, we conclude that A. continentalis might be a candidate of anticaries agent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.299-305
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• 1984

As one trials to utilize sea mussel and anchovy effectively, powdered instant soups were prepared and then their quality stability were examined during storage. Powdered instant soup was made by adding $3\%$ sugar, $20\%$ table salt, $5\%$ monosodium glutamate, $0.2\%$ black pepper and garlic powder to the pulverized dried sea mussel or anchovy. Powdered instant soup products, powderd products, and dried round state sea mussel or anchovy were packed with air in laminated film bag (cellophane/polyester/aluminium foil/polyester: $20{\mu}m/15{\mu}m/7{\mu}m/20{\mu}m,\;13{\times}14cm$). The contents of amino-nitrogen and volatile basic nitrogen of these products were showed little significant variations and also water activity and color value (L, a, b) of these products were little changed during storage. Thiobarbituric acid value increased up to 30 days of storage and then decreased slightly. Comparing the quality of powdered-seasoned products with that of dried round state products, there were no significant differences in stability during storage. Judging from the experimental results, the quality of powdered instant soup of sea mussel and anchovy were stable for 100 days at room temperature($25{\pm}3^{\circ}C$).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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• pp.574-577
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• 2011

In this study, we use the $2.5cm{\times}7.5cm$ soda lime glass as the substrate. We used the ultrasonicator. Glass was dipped in the acetone, methanol and DI water respectively for 10 minutes. Ar(99.99%)gas was used as the sputtering gas. We varied the RF power between 100~175 W with 25 W steps. Base pressure was kept by turbo molecular pump at $3.0{\times}10^{-6}$ torr. Working pressure was kept by injection of Ar gas. ZnS thin films were deposited with the radio frequency magnetron sputtering technique at various temperatures and sputtering powers. It is also clearly observed that, the intensity of the (111) XRD peak increases with increasing the RF power. Electrical properties were measured by hall effect methods at room temperature. The resistivity, carrier concentration, and hall mobility of ZnS deposited on glass substrate as a function of sputtering power. It can be seen that as the sputtering power increase from 100 to 175 W, the resistivity of the films on glass decreased significantly from $8.1{\times}10^{-2}$ to $1.2{\times}10^{-3}\;{\Omega}{\cdot}cm$. This behavior could be explained by the effect of the sputtering power on the mobility and carrier concentration. When the RF power increases, the carrier concentration increases slightly while the resistivity decreases significantly. These variation originate from improved crystallinity and enhanced substitutional doping as the sputtering power increases.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.409-414
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• 2008

Porous carbon electrode for electrosorption was prepared by a wet phase inversion method. Carbon slurry that was a mixture of activated carbon powder(ACP) and PVdF solution was cast directly upon a graphite sheet by means of a casting knife. Porous carbon electrodes were fabricated by immersing the cast film in pure water as a non solvent. Physical and electrochemical properties of carbon electrodes prepared with various ACP contents(50.0, 75.0, 83.3, 87.5, 90.0 wt %). From the SEM images we can verify that the electrode was porous. The average pore sizes determined for the electrodes fabricated with various ACP contents ranged from 72.7 to 86.4 nm and the size decreased as the ACP content increased. The electrochemical properties were characterized by cyclic voltammetry(CV) method. All of the voltammograms showed typical behavior of an electric double layer charging/discharging on the carbon surface. The capacitance increased with the ACP content and the values ranged from 2.18 F/cm$^2$ for 50 wt% ACP to 4.77 F/cm$^2$ for 90 wt% ACP.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.303-311
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• 1997

Proliposomal patch of clenbuterol, ${\beta}_2-agonist$ bronchodilator, was prepared and its feasibility as a novel transdermal drug delivery system was examined. Proliposomal granules containing clenbuterol was prepared by a standard method using sorbitol and lecithin with (Rx 2) or without cholesterol (Rx 1). The porous structure of sorbitol in the proliposomes was maintained allowing tree flowability of the granules. Following contact with water, the granules were converted probably to liposomes almost completely within several minutes. It indicates that proliposomes may be hydrated, when they are applied on the skin under occlusive condition in vivo, by the sweat to form liposomes. Clenbuterol release from Rx 1 and Rx 2 proliposomes to pH 7.4 isotonic phospate buffer (PBS) across cellulose membrane (mol. wt. cut-off of 12000-14000) was retarded significantly compared with that from the mixture of clenbuterol powder and blank proliposomes. Interestingly, proliposomes prepared with lecithin and cholesterol (i.e., Rx 2 proliposomes) showed much more retarded release of clenbuterol than proliposomes prepared only with lecithin (i.e.. Rx 1 proliposomes), indicating that clenbuterol release from proliposomes can be controlled by the addition of cholesterol to the proliposomes. Proliposomal patches were prepared using PVC film as an occlusive backing sheet, two sides adhesive tape (urethane, 1.45 mm thickness) as a reservoir for proliposome granules and Millipore MF-membrane (0.45 mm pore size) as a drug release-controlling membrane. Rx 1 or Rx 2 proliposomes containing 4.6 mg of clenbuterol were loaded into the reservoir of the patch. Clenbuterol release from the patches to pH 7.4 PBS was determined using USP paddle (50 rpm)-over-disc release method. Clenbuterol release from the proliposomal patches was much more retarded even than from a matrix type clenbuterol patch (Boehringer Ingelheim ltd). Being consistent with clenbuterol release from the proliposomal granules, the release from the patches was highly dependent on the presence of cholesterol in the proliposomes : Patches containing Rx 2 proliposomes showed several fold slower drug release than patches containing Rx 1 proliposomes. When the patch containing Rx 1 proliposomes was applied on to the back of a hair-removed rat, clenbuterol concentration in the rat blood was maintained during 6-72 hrs. Transdermal absorption of clenbuterol from the patch was accelerated when the patch was prehydrated with 50 ml of pH 7.4 PBS before topical application. Above results indicate that sustained transdermal delivery of clenbuterol is feasible using proliposomal patches if the cholesterol content and pore size of the release rate-controlling membrane of patches, for example, are appropriately controlled.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.05a
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• pp.91-115
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• 1996

In the recent years, protected horticultural facilities have been modernized and glasshouses are also propagating in Korea, even most vegetables production are conducted in the traditional plastic houses covered with, for example, PVC film for just temperature keeping. It would limit the productivity and competitivity of the vegetable production industry without automatization and high quality year round production. A plant factory, aimed to produce vegetables in the limited areas, was initiated in Christensen farm, Denmark in 1957, and widely propagated in some developed countries. As it has the automatized system which enables to keep optimized environment conditions, it will be the best facility for high quality products as well as year round planned production. However, we have not even started the plant factory production. Since the plant factory is requiring lots of resources, besides plant cultivation technologies, such as environment control, automatic engineering and robotics, our approach to the development of plant factories should be minded on Practical Plant Factories considering our current farming practices and least capital needs rather than blindly employing the advanced technologies from developed countries. Thus, Korean plant factory development can be initiated with year round leaf vegetables production in NFT or DFT cultivation system instead of the moval bed system, in which aerial environment factors such as light, temperature, humidity and CO$_2$ concentration and root environment ones such as solution concentration, temperature, pH and water soluble oxygen shall be automatically controlled. And the seeding, seedling and transplanting operations shall be accomplished in the house entrance, and the harvesting and grading opreations shall be conducted in the house exit. For practical plant factories, environment control technologies including artificial light source, illumination and air conditioning, automatic management for nutrient solution and automatic production line of moval bed system, transplanting and harvest should be developed along with researches on the cost reduction of factory building construction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.221-226
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• 1977

The quality changes of yellow sea bream, Branchiostegus japonicus japonicus, during frozen storage were mentioned from the view point of commercial value. The experiments were conducted to find out the effective storing method by varying the storage temperatures $(-5^{\circ}C,\;-35^{\circ}C)$ and pretreatment with chemicals $(0.l\%\;BHA,\;1\%\;sodium\;Polyphosphate)$. The samples were stored for 6 months at $-5^{\circ}C$ and $-35^{\circ}C$ after dipping in the chemical solutions and packing with polyethylens film. The extractibility of salt soluble protein of sample stored at $-35^{\circ}C$ was higher than that of samples stored at $-5^{\circ}C$, while the chemical treatments were not so much effective. Difference in the amount of free water released from samples was obvious between $-5^{\circ}C$ and $-35^{\circ}C$ storage, and that of samples treated with sodium Polyphosphate was much less than the BHA-treated ones. VBN content was differed by varying the storage temperature whereas no effect by the chemical treatments. TBA value of the sample storage at $-35^{\circ}C$ was lower than $-5^{\circ}C$ and the effect of chemicals on the development of oxidation was in order of sodium polyphosphate, BHA and control. Carotenoid content also changed by varying the storage temperature and the color was completely faded out with quality deterioration after 3 months storage at $-5^{\circ}C$.