• Membrane Journal
• /
• v.33 no.6
• /
• pp.439-446
• /
• 2023

Ceramic membranes are generally used for various industrial processes operating under extreme conditions because of its high thermal and chemical stability. However, due to the trade-off phenomenon of permeability and mechanical strength, preparation of high permeability-high strength membrane is necessary. In this study, the change in characteristics and performances of ceramic membranes was analyzed depending on the type of polymer binder and its mixing ratio. Because the solubility between solvent and polymer binder was higher in PSf (polysulfone) than in PES (polyethersulfone), the viscosity and discharge pressure of the PSf-based dope solution were higher than those of PES-based dope solution. When PSf was used as a polymer binder, ceramic membrane showed high mechanical strength and low water permeability due to the dense structure. On the other hand, in case of PES, the mechanical strength was slightly reduced and the water permeability was increased. It was confirmed that the optimum mixing ratio of the PSf and PES with high water permeability and mechanical strength was 9:1.

• Food Science and Preservation
• /
• v.30 no.6
• /
• pp.999-1011
• /
• 2023

This study investigated the anti-inflammatory, trypsin activity, and antioxidant effects of 11 kinds of plant extracts to discover materials for developing optimal mixtures that improve inflammation and help digestion. Ziziphus jujuba Mill. (ZJ), Leonurus japonicus Houtt. (LJ), Scutellaria baicalensis (SB), Platycodon grandiflorum, and Aster scaber extracts had excellent anti-inflammatory effects by reducing excessive nitric oxide (NO) and tumor necrosis factor-α content in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The malt (MA), Pyrus pyrifolia Nakai (PP), Raphanus sativus L., Platycodon grandiflorum extracts among the 11 kinds of plant extracts had high trypsin activity. The antioxidant activity of the plant extracts was examined by the DPPH radical scavenging activity, and the SB, PE, JU, and MA extracts had high antioxidant activity. Therefore, PP, MA, ZJ, LJ, and SB were selected to develop optimal mixtures that improve inflammation and help digestion. The extract of plant mixture containing PP, MA, ZJ, LJ, and SB in the ratio 1:1:2:1:2 (w/w) significantly inhibited NO production than the extract of PP, MA, ZJ, LJ, and SB, respectively, in LPS-stimulated RAW 264.7 macrophages. The DPPH radical scavenging activity of the mixture extract was significantly higher than the extract of PP, MA, ZJ, and LJ, respectively.

• Journal of Ginseng Culture
• /
• v.6
• /
• pp.51-79
• /
• 2024

In the 1970s and 1980s, during the nascent phase of ginseng disease research, efforts concentrated on isolating and identifying pathogens. Subsequently, their physiological ecology and pathogenesis characteristics were scrutinized. This led to the establishment of a comprehensive control approach for safeguarding major aerial part diseases like Alternaria blight, anthracnose, and Phytophthora blight, along with underground part diseases such as Rhizoctonia seedling damping-off, Pythium seedling damping-off, and Sclerotinia white rot. In the 1980s, the sunshade was changed from traditional rice straw to polyethylene (PE) net. From 1987 to 1989, focused research aimed at enhancing disease control methods. Notably, the introduction of a four-layer woven P.E. light-shading net minimized rainwater leakage, curbing Alternaria blight occurrence. Since 1990, identification of the bacterial soft stem rot pathogen facilitated the establishment of a flower stem removal method to mitigate outbreaks. Concurrently, efforts were directed towards identifying root rot pathogens causing continuous crop failure, employing soil fumigation and filling methods for sustainable crop land use. In 2000, adapting to rapid climate changes became imperative, prompting modifications and supplements to control methods. New approaches were devised, including a crop protection agent method for Alternaria stem blight triggered by excessive rainfall during sprouting and a control method for gray mold disease. A comprehensive plan to enhance control methods for Rhizoctonia seedling damping-off and Rhizoctonia damping-off was also devised. Over the past 50 years, the initial emphasis was on understanding the causes and control of ginseng diseases, followed by refining established control methods. Drawing on these findings, future ginseng cultivation and disease control methods should be innovatively developed to proactively address evolving factors such as climate fluctuations, diminishing cultivation areas, escalating labor costs, and heightened consumer safety awareness.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.4
• /
• pp.333-343
• /
• 1984

This study was designed to elucidate the lipid and its fatty acid composition in various tissues of fresh water fishes. The free and bound lipids in meat, skin and viscera of crucian carp (Carassius carassius) were extracted with ethyl ether and the mixed solvent of chloroform-methanol-water (10/9/1, v/v). The free and bound lipids were fractionated into neutral lipid, glycolipid and phospholipid by a silicic acid column chromatography using chloroform, acetone and methanol, respectively, and quantitatively analyzed by thin layer chromatography (TLC) and TLC scanner. The fatty acid compositions of polar ana nonpolar lipids in meat, and these of neutral lipid in various tissues were analyzed by gas liquid chromatography(GLC). The free lipid content in meat, skin and viscera was $6.22\%,\;9.95\%\;and\;9.76\%$, whereas the bound lipid content in those tissues was $10.01\%,\;3.56\%\;and\;7.36\%$, respectively. The neutral lipid contents in free lipid were ranged from $71.7\%$ to $89.4\%$, and $3{\sim}9$ times higher than those in bound lipid, while the phospholipid contents in bound lipid were ranged from $42.3\%$ to $63.2\%$, and $5{\sim}10$ times higher than those in free lipid. The neutral lipid was mainly consisted of triglyceride ($81.91{\sim}88.34\%$) in free lipid, and esterified sterol & hydrocarbon ($41.00{\sim}59.43\%$) in bound lipid. The phospholipid was mainly consisted of phosphatidyl ethanolamine($54.56{\sim}66.79\%$) and phosphatidyl choline ($21.88{\sim}34.28\%$) in free lipid, and phosphatidyl choline ($50.49{\sim}70.57\%$) and phosphatidyl ethanolamine ($15.74{\sim}24.92\%$) in bound lipid. The major fatty acids of polar lipid in free and bound lipids were $C_{16:0}\;(17.53\%,\;19.29\%)$, $C_{18:1}\;(24.57\%,\;16.08\%)$, $C_{18:2}\;(8.39\%,\;4.03\%)$, $C_{22:5}\;(1.68\%,\;8.08\%)$, and $C_{22:6}\;(6.22\%,\;13.60\%)$ and these of neutral lipid in free and bound lipids were $C_{16:0}\;(17.67\%,\;24.15\%)$, $C_{16:1}\;(12.81\%,\;5.52\%)$, $C_{18:1}\;(24.13\%,\;13.02\%)$, $C_{18:2}\;(15.47\%,\;8.68\%)$, $C_{22:5}\;(0.88\%,\;4.14\%)$ and $C_{22:6}\;(1.17\%,\;5.04\%)$, respectively. The unsaturations (TUFA/TSFA) of polar lipid in free and bound lipids were 2.02 and 2.74, and $1.5{\sim}2.0$ times higher than 1.51 and 1.23 of nonpolar lipid. In both polar and nonpolar lipids, w3 highly unsaturated fatty acid (w3HUFA) content of bound lipid was $2{\sim}5$ times higher than that of free lipid. The polyenoic acid contents such as $C_{20:5},\;C_{22:5}\;and\;C_{22:6}$ in bound lipid were $2{\sim}5$ times higher than these in free lipid. Consequently, there were significant difference between the lipid and its fatty acid composition in free and bound lipids and/or in various tissues.

• Korean Journal of Agricultural Science
• /
• v.4 no.2
• /
• pp.283-316
• /
• 1977

In an attempt to obtain a basic information to develop an effective integrated system of controlling sheath blight of rice in Korea, the transition of this disease, the variation of cultural characters and pathogenicity of the pathogen, environmental conditions affecting the disease outbreak and varietal resistance have been investigated. 1. Rice sheath blight which has been minor disease in the past was widely spread, especially since 1971. This disease has promptly spread all over the country and infected 65.2% of total rice growing area in 1976. Various factors are considered to be related to such transition of this disease. Above all, increace of application of nitrogenous fertilizer, early season and earlier cultivation of rice, introduction of more susceptible "Tongil" varieties etc. must be important factors influencing the outbreak of this disease. 2. Great variations in cultural characteristics-such as mycelial growth rate, color of the medium, amount of the aerial mycelium, shape and color of the sclerotia- and in the pathogenicity of isolates of the pathogen, Thanatephorus cucumeris Dank were observed. The optimum temperature for mycelial growth also varied with isolates, from $25^{\circ}C$ to $30^{\circ}C$. There were not necessarily any correlation between curtural characteristics and pathogenicity of isolates of Thanatephorus cucumens. 3. Mycelial grow th of isolates of Thanatephorus cucumens on the PDA medium were correlated with the air temperatures of the region where the isolates were collected. The isolates from the regions with high temperature grew well on PDA medium at $35^{\circ}C$ than those from the region with low temperature, on the other hand, the isolates from the regions with the low temperature grew well on the same medium at $12^{\circ}C$ than those from the regions with high temperature. 4. Pectin polygalacturonase (PG) and cellulase (Cx) were most active on the 3rd day after inoculation on the leaves of rice plant with Thanatephorus cucumeris, whereas pectin methylestrase (PE) was most active on the 4th day after inoculation. Relationship between the activities of PE of isolates and the strength of pathogenicity of isolates was obtained, but PG and cellulase activities were not correlated with pathogenicity of isolates. 5. The tolerence of sclerotia from in-vitro culture to low temperature varied with their water content, the dried cultural sclerotia were more tolerent than wet ones, Dried cultural sclerotia maintained almost 100% germinability for 45 days at $-20^{\circ}C$, whereas wet sclerotia lost viability at $-5^{\circ}C$. The germination ratio of the sclerotia after overwintering changed from 18% to 70% according to the water content of the test paddy fields and the ratio was low in wet paddy condition. 6. To investigate the host range of this fungi in and near paddy field, 17 weeds were inoculated with fungi. The lesions of sheath blight disease was obserbed on Sagittaria trifolia L., Echinochloa crusgalli P. Beauv., Monochoria vaginal is Presl, Polygonum Hydropiper L., Eclipta prostrata L., Digitaria sanguinalis Scapoli. 7. When the level of nitrogen applied was doubled over standard level, total nitrogen content in rice sheath increased, ami when silicate was applied, starch content in rice sheath decreased, inducing the rice plants more susceptible to sheath blight disease. Increased dressing of potash ferilizer reduced the incidence of sheat blight disease. 8. The percentage of infected stems in the early period increased more in the narrow hill plot than in the wide hill plot, but in the late period this tendency was inversed; the percentage of infected stems as well as severity in the wide hill plot increased more compared to the narrow hill plot, and the disease severity in the one plant per hill plot was also low. The number of stems in the wide hill plot was more than the number of stems in the narrow hill plot. This indicates that the microclimate, such as the relative humidity, in the narrow hill plot was more favorable for the development of this disease. 9. There was a high negative correlation between the disease severity of varieties to the sheath blight and the maturity of the varieties, that is, the early varieties were more susceptible than the late ones, and much-tillering varieties usually showed more infection than less tillering varieties. 10. No relationship was obtained between the percentage of infected stems in the early period and the severity after heading, whereas a distinct relationship was obtained between former and latter after Aug. 10.

• Horticultural Science & Technology
• /
• v.19 no.4
• /
• pp.521-525
• /
• 2001

This study investigated the effects of conventional predrying and modified atmosphere (MA) on the head quality and storability of Chinese cabbage 'Norang' cultivar. Immediately after harvest, heads were predried for 2 days and MA stored in $50{\mu}m$ PE film packages at $4^{\circ}C$. MA packaging restrained Hunter L and b values of Chinese cabbage more effectively than non-packaging during storage at $4^{\circ}C$. But there was little change between the two treatments. Fresh weight decreased less in heads treated with predrying and MA than non-treatment during storage. Predried Chinese cabbage heads kept a high level of soluble solids in 4 weeks of storage, while non-packaging maintained high contents of soluble solids for 6 weeks of storage period. Chinese cabbage heads contained 7.0 mg/gFW glucose, 6.3 mg/gFW fructose, and 0.6 mg/gFW sucrose as major soluble sugars at harvest. The content of sugars decreased immediately after predrying and increased steadily after 2 weeks storage. It was found inappropriate to assess head quality of Chinese cabbage by investigating was investigated by Hunter a, firmness, dry matters content, pH, and soluble sugars after predrying and MA package. Marketability of Chinese cabbage was lost when heads were stored at room temperature in 2 weeks. It showed poor appearance of heads stored at $4^{\circ}C$ in 7 weeks. Decay occurred in Chinese cabbage stored in MA under excessive relative humidity. Predried head showed good appearance during storage at $4^{\circ}C$ for 7 weeks. As a result, Chinese cabbage heads can be successfully stored for at least 7 weeks with predrying and MA storage.

• Korean Journal of Agricultural Science
• /
• v.41 no.4
• /
• pp.415-424
• /
• 2014

This study was carried out to determine the effect of storage condition, such as temperature or relative humidity (RH) in home-style refrigerator, on the change of quality traits and storage characteristics of Hanwoo M. longissimus to find out the condition for prolongation of shelf-life with maintaining the meat quality for consumers. Samples were sliced in $1{\pm}0.2cm$ thickness, and packed in foamed polystyrene tray with linear low-density polyethylene (LLD-PE) film to simulate the pre-packed Hanwoo loin sold in retail market, then stored in home-style refrigerator ($5^{\circ}C$/17% RH, Control), and chambers of $5^{\circ}C$/55% RH (T1), $5^{\circ}C$/85% RH (T2), and $-1^{\circ}C$/99% RH (T3), respectively. Quality traits (color, pH, water holding capacity, shear force and grilling loss) and storage characteristics (thiobarbituric acid reactive substances, volatile basic nitrogen and total microbes) were measured at 1, 4, 7, 14 and 21 days after storage. Lightness of Hanwoo loin stored in T1, T2 and T3 were higher than that of control until 14 days of storage, however at the end of storage (21 days) control showed significantly higher than other treatments (p<0.05). Redness and Yellowness of Hanwoo loin samples stored in T1 and T3 were significantly higher than others during all storage period (p<0.05). The water holding capacity (WHC) of control was significantly higher than others until 14 days of storage (p<0.05), however, Hanwoo loin stored in T2 was the highest ($63.64{\pm}7.62kg/cm^2$) at 21 days of storage. Hanwoo loin stored in T1 showed significantly lower shear force than others during all storage period (p<0.05). There was no consistent tendency in pH and grilling loss during storage in all treatments. Hanwoo loin stored in T1 showed lower TBARS value than others during storage period, however there was a rapid increase to $0.34{\pm}0.27mg$ malonaldehyde/kg meat at 21 days of storage. And, all the treated samples (from T1 to T3) showed significantly lower VBN values at 21 days of storage (p<0.05). The population of total aerobic microbes were significantly increased in all treatments as storage period increasing, and the population of T3 ($2.28{\pm}0.57logCFU/g$) was the lowest at 21 days of storage (p<0.05). From those results, it could be predicted the better storage condition to maintain the meat quality and prolong the shelf-life of Hanwoo loin by lowering the temperature and adjusting the humidity about 55%.

• Food Science and Preservation
• /
• v.11 no.3
• /
• pp.394-399
• /
• 2004

The effects of gamma irradiation to improve the hygienic quality and microbiological shelf stability of whole baked egg were investigated by comparison with autoclaving process. The contamination levels of coliform, total aerobic bacteria and fungal group in a fresh egg were 10$^{5}$ CFU/g, 10$^{2}$ CFU/g and 10$^{1}$ CFU/g, respectively. After baking process, total aerobic bacteria and fungi were not exceeded to 10$^{1}$ CFU/g. Also, coliform was not detected under the aseptic process. However, cell counts of the baked egg after packaging reached to 10$^{4}$ CFU/g of total aerobic bacteria, 10$^{1}$ CFU/g of coliform, and 10$^{2}$ CFU/g of fungi. Therefore, it was assumed that microbial contamination of baked and packaged egg was mainly originated from an environmental uptake during packaging process. Microbiological shelf stability of the non sterilized control was about a week. Whereas, the baked eggs irradiated at more than 5 kGy were stable over 12 weeks at ambient condition as like those being autoclaved. Analytical texture profIle was stable within 10 kGy, but it became hardened in the sample treated with autoclaving. About 67$\%$ of panelists identified a sensory difference between non-irradiated and 10 kGy-irradiated sample. The baked egg irradiated at 10 kGy and autoclaved had lower acceptability than the control or samples irradiated lower than 5 kGy. Therefore, it was considered that optimal irradiation dose for radiation sterilization of baked and packaged egg was 5 kGy. At that point, it was recommended that appropriate microbiological shelf-life was 12 weeks at ambient condition.

• Korean Journal of Ecology and Environment
• /
• v.40 no.1
• /
• pp.163-172
• /
• 2007

In this study, fish fauna and stream characteristics were surveyed during October-November 2003 in 31 small streams, which are small sub-tributaries of Geum River. The small streams were classified into 4 types of steep mountainous (SM), mountainous-flatland (MF), flat land (FL), and agricultural watercourse (AW) streams, and their types were categorized by features of stream width, water depth, bottom substrate, riparian vegetation, and landuse patterns. The fishes collected during this survey were identified 4 families and 8 species. Dominant family was Cyprinidae, and the most dominant species was Rhynchocypris oxycephalus with 73% (419 individuals) of the total. Only one species of R. oxycephalus was observed in the all five steep mountainous streams, which was surrounded by 100% forest area and had no point-and non-point pollution sources. The observed frequency of R. oxycephalus (as a relative proportion of species) showed a significant positive correlation (r=0.754, p<0.001, n=31) with the substrate composition of bedrock and boulder, indicating that the species prefer the bedrock and boulder rather than the sand or small pebble. Evidently, all five steep mountainous streams were judged as excellent condition (1st rank) according to the criteria of biological water quality, the Ministry of Environment, Korea. This result was accord with a general tendency of the species in most upper stream of the Koreas streams. One family and one species were found at the steep mountainous types and 4 families 6 species were at the mountainous-flatland. Four families 8 species were found at the flat land, which showed most diverse habitat, and 2 families 2 species were collected agricultural watercourse. These study results of 1st-order streams suggest that R. oxycephalus was considered as one of 1st rank ecological indicator species, and that the dominant area should be protected from various pollutions and disturbances.

• Korean Journal of Weed Science
• /
• v.11 no.1
• /
• pp.50-59
• /
• 1991

Residual period and carry-over effect of some herbicides were determined using a bioassay method in six summer crops(potato, carrot, corn, water melon, soybean, and sesame). The effects were measured at regular time intervals after applying different rates of the herbicides. There were no great differences in residual period and carry-over injury between the soils and kinds of crops used. However, the residual period varied with the herbicides studied and the carry-over injury was dependent upon season and rate of the herbicide application, sampling depth of soil, and kind and seeding date of the test plant. When the residual herbicides were applied, the carry-over injury could be minimized by selecting tolernet crops, delaying seeding of the crops after application of the herbicides, and regulating the cultivation depth. Herbicides which showed no residual effect by the end of the cropping period(100-120 days for summer crops) and no carry-over effect were alachlor, trifluralin, ethalfluralin, metribuzin, and prometryn. When pendimethalin, metolachlor, linuron, methabenzthiazuron, and simazine were applied at the recommended rate or less, there was no carry -over injury at harvesting time. With doubling the recommended rate, however, the carry-over effect was found in sensitive crops. Napropamide applied at the rate of 300 g a.i./10 a brought about carry-over injury for Italian ryegrass and barley at 140 days in summer crops, whereas the injury was not found in Cruciferae (radish, Chinese cabbage). Nitralin applied at the rate of 150-300 g a.i./10a caused the carry-over injury for Italian ryegrass and barley at 140 days in summer crops. However, there was no injury for Cruciferae.