• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1258-1264
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• 2009

The removal effects of two commonly used pesticides of Bifenthrin and Metalaxyl during preparation and fermentation of kimchi were studied. The two pesticides were applied to Baechu cabbages intentionally for 20 seconds; the applied amounts of Bifenthrin and Metalaxyl were 3.02$\pm$0.09 ppm and 6.79$\pm$0.17 ppm, respectively. The Baechu cabbages were washed by water 3 times. Then the residual amounts of the two pesticides of Bifenthrin and Metalaxyl were measured and the removal rates were 21.7% and 16.1%, respectively. When Baechu cabbages were brined with 10% salt solution for 12 hours after the application of the two pesticides, the removal rates significantly increased to 98.7% and 60.8%, and when brined and washed 3 times by water, the removal rates even more increased to 99.7% and 73.4% respectively. Then we made kimchi and investigated the quantities of the residual pesticides during the fermentation at $4^{\circ}C$ for 3 weeks. The residual amounts of the pesticides in kimchi decreased in a time dependent manner, finally the amounts of the pesticides to 0.35$\pm$0.04 ppm and 0.48$\pm$0.06 ppm while the removal rates of the two pesticides were 57.8% and 81.0%, respectively. When the kimchi was fermented at $4^{\circ}C$ and $10^{\circ}C$ for 3 weeks, the removal rates of Bifenthrin were 57.8% and 72.2% and those of Metalaxyl were 81.0% and 85.6%, respectively. Consequently, it appeared that the residual pesticides can be removed during preparation, especially brining; the fermentation process of kimchi also removed the residual pesticides effectively, especially at higher temperature and long period.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.314-321
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• 2007

This study was conducted to select leaf vegetables suitable for cultivation in apartment verandas and simple and easy fertigation method for home gardening. In order to develop the convenient fertigation method, hydroponics, wick irrigation, and overhead irrigation methods were compared. For the wick irrigation, two types of nutrient sources were used; one was slow release fertilizers mixed with medium and the other one was nutrient solution filled in container located under pots. The growth of leafy lettuce, leaf mustard, and leaf beet was better in both of the wick irrigation methods rather than in overhead irrigation and hydroponics. The wick irrigation method is very easy, so that it is expected to bring a good result from the cultivating and managing point of view, if it brings with commercialized system along with slow release fertilizer. As a result of investigation of environment such as temperature, relative humidity, and irradiance level in apartment verandas in autumn the highest irradiance level during a day was just 48% and 35% in verandas facing south and feeing southeast, respectively, comparing to that in greenhouse. The light environment was investigated as a limiting factor for vegetable growing in verandas. Therefore, to select the vegetables showing good growth under low irradiance environment, nine leaf vegetables such as romaine lettuce, lent lettuce, head lettuce, endive, pak-choi, leaf mustard, garland chrysanthemum, leaf beet, and Chinese chive were grown under 0%, 50%, 70%, 90% shading. Among them, Chinese chive showed the best growth under low irradiance levels. Endive showed line growth reduction according to shading degree, however, even under 90% shading condition, it showed good growth. And then leafy lettuce, garland chrysanthemum, and pak-choi followed. Therefore, these results will be of help in selecting vegetables for veranda gardening with different light levels.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.501-510
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• 2015

In this study, we investigated the onset and release of endo-dormancy under natural conditions by observing bud break characteristics in 'Fuji' apple trees using water cuttings. Through examinations of bud break rate and days to bud break, we found that the endo-dormancy of 'Fuji' apple tree continues for 70 d from 165 to 255 d after full bloom (DAFB), from late October to early January of the following year. In addition, within 20 d of first bud break, based on a final bud break rate of 60% or more, we able to identify the timing of the changeover from para-dormancy to endo-dormancy, and endo-dormancy to eco-dormancy. Analysis of the chilling requirement during the endo-dormancy period revealed that chilling accumulation up to 255 DAFB to release endo-dormancy amounted to 666 and 517 h based on the CH and Utah models, respectively. Observation of internal changes in the bud during endo-dormancy showed that flower bud differentiation begins from mid-July, and t ime of inflorescence o f the disk f lower is a vailable to f ind. The f lower buds subsequently developed slowly but steadily during endo-dormancy and in the following year in February, the developmental stage of each organ had progressed. Moreover, the flower buds of 'Fuji' apples were mostly healthy during the dormancy period, but some exhibited necrosis of flower primordium, due partial cell damage from the formation of ice crystals rather than a direct effect of the low temperature. Flower buds were formed in both the axillary buds of bourse shoots and terminal buds of spurs, but lower bud differentiation was observed for the terminal buds of spurs at rate of about 65% of total buds, which was directly related to the bud size and shoot diameter.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.210-219
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• 2017

This study was conducted to establish an efficient screening method for radish (Raphanus sativus) cultivars that are resistant to black spot, which is caused by Alternaria brassicicola. Seven A. brassicicola isolates were selected and investigated for their ability to produce spores and pathogenicity. Of these isolates, A. brassicicola KACC 40036 and 43923 produced abundant spores in V-8 juice agar medium and showed pathogenicity and strong virulence on radish seedlings. We examined the resistance of 61 commercial cultivars of radish to A. brassicicola KACC40036, and found that there are no highly resistant radish cultivars; however, some cultivars, such as 'Geumbong' and 'Searom', showed weak resistance to A. brassicicola. For further study, we selected four radish cultivars that showed different disease responses to A. brassicicola KACC40036. According to the growth stage of the radish seedlings, inoculum concentration, and incubation temperature of radish, development of black spot on four cultivars has been investigated. The results showed that younger seedlings were more sensitive to A. brassicicola than older seedlings, and the disease severity depended on the concentration of the spore suspension. The disease severity of plants incubated in humidity chamber at $25^{\circ}C$ was greater than that of plants grown at $20^{\circ}C$ or $30^{\circ}C$. Taken together, we suggest the following method for screening for radish plants that are resistant to A. brassicicola: 1) inoculate 16-day-old radish seedlings with an A. brassicicola spore suspension ($2.0{\times}10^5spores{\cdot}mL^{-1}$) using the spray method, 2) incubate the inoculated plants in a humidity chamber at $25^{\circ}C$ for 24 h and then transfer the plants to a growth chamber at $25^{\circ}C$ with 80% relative humidity under a 12 h light/dark cycle, and 3) assess the disease severity of the plants two days after inoculation.

• Journal of Aquaculture
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• v.3 no.1
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• pp.49-63
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• 1990

A population ecological study was carried out to estimate survival and growth rates, biomass, biological production and turnover ratio of cultured sea squirt, Halocynthia roretzi, by growth stages, using data from in situ culture experiment off Hansando in the southern part of Korea from February 1985 to July 1986. The squirt population followed an exponential decay function and the instantaneous coefficient of total mortality (Z) was estimated to be 0.0614 $month^{-1}$(Var (Z) = 0.000126). Growths in total weight and meat weight of squirts were expressed as linear functions during the period of culture experiment. The growth of squirts showed a negative correlation with the water temperature. The mean biomass per string ranged from 2.14 kg for March of the first year to 16.26 kg for March of the next year. The biological production per string was estimated to range from 3.28 kg for the first summer (June - July) to 6.46kg for the first late winter (February-March). The peak of turnover ratio occurred in the late winter (February-March) as 3.013 and the ratios sharply declined thereafter. Based on the results of this study, management implications for culturing sea squirts were also suggested. The optimum harvest time ($t_{mb}$) when the peak biomass in terms of total weight occurred was estimated to be late June of the second year, which corresponded to 16.7 months after the main hanging. However, the time when the peak biomass in terms of meat weight was occurred was early July of the second year. The maximum harvest biomass was 17.4 kg per string in terms of total weight and 6.3 kg per string in terms of meat weight. In conclusion, the process of culture should be conducted on the basis of the knowledge of population ecological theories as shown in this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.109-116
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• 1984

In order to assess the protein nutritional quality of salted and dried yellow corvenia, which was prepared using the different salting methods like dry and brine salting, the changes of trypsin indigestible substrate(TI) and in vitro apparent protein digestibility were studied during storage at room temperature($24{\pm}1^{\circ}C$). It was also examined the retention of available lysine and formation of nonenzymatic brown pigments under the same conditions of preparing and storage mentioned above and confirmed the relationship between in vitro digestibility and the antinutritional factors, such as nonenzymatic browning, unavailability of lysine and TI content, TI content was gradually increased during the storage and in showed $1.5{\sim}2$ times more after 57 days storage than at the initial stage which ranged from 0.11 to 0.17mg/g solid. Of all the products, $25\%$ brine salting product contained the least TI content in 0.21 mg/g solid, while $10\%$ dry salting products was the most abundant in 0.30 mg/g solid using Hamerstrand method(1981). In vitro protein digestibility of all dried products was decreased significantly up to 30 days as the contents of TI increased, except $25\%$ brine salted products. After storing for 57 days, the in vitro digestibility was only $4\%$ drip showed in $25\%$ brine salted products. The nonenzymatic brown pigments were also developed on the level of available lysine reduced as in vitro protein digestibility was decreased throughout storage. Of all the various salted and dried products of yellow corvenia, $25\%$ salting product showed the lowest rate of browning development and loss of available lysine. Therefore, it was revealed that unavailability of lysine and development of nonenzymatic brown pigments were major factors influencing the protein quality in salted and dried yellow corvenia.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.629-635
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• 2002

This study was performed to develop low-fat comminuted sausages (LFSs, < 3%) manufactured with 1% single (Konjac flour, KF; kappa-carrageenan, k-CN and Locust bean gum, LBG) or mixed hydrocolloids and to select the best combination which had similar textural characteristics to those with regular-fat (~25% fat) control. In experiment 1, LFSs were formulated with each 1% hydrocolloid, smoked and cooked to an internal temperature of 71.7$^{\circ}C$. The pH range of LFSs was 6.29 to 6.34 and approximately 23~24% of fat was removed in the final products, resulting in the higher moisture and protein contents (%) in LFSs, as compared to regular-fat control. No differences (p>0.05) in cooking loss (CL, %), expressible moisture (EM, %), and hunter color values (L, a, b) were observed with the addition of each 1% hydrocolloid. However, LFSs containing 1% k-CN had textural hardness values similar to those with low-/regular-fat controls, whereas LFSs having either KF or LBG had similar cohesiveness values to those with regular-fat counterpart. Tn experiment 2, two or three mixed hydrocolloids were added to the low-fat sausage formulation. The addition of mixed KF+LBG (KLL) and KF+CN+LBG(KCL) reduced EM and textural hardness values, as compared to low-fat control. Among the treatments, LFSs containing two or three combinations of CN with KF or/and LBG had similar textural characteristics to those with regular-fat control. These results suggested that multiple addition of CN with other hydrocolloids (KF or LBG) for the replacement of fats in LFSs would be recommended for the proper functional and textural properties.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.5
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• pp.103-115
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• 2016

This study aims to analyze the properties of cold air production and its flow of Nakdong-Jeongmaek(mountain ranges), and to suggest management strategies for Nakdong-Jeongmaek in order to enhance the green air conditioning functions of Jeongmaek. For this purpose, three study sites including Gudeoksan Mountain and the vicinity in Busan, Goheonsan Mountain and the vicinity in Ulsan, and Unjusan Mountain and the vicinity in Pohang were selected. The results found that cold air flow and its height of the three study sites were analyzed based on topographic properties and land use. Management strategies for preserving and enhancing their temperature reduction functions were suggested. The cold air produced in the vicinity of Gudeoksan was not fully developed and spread because of the high-density development at the border of Jeongmaek. Since high pressures of development are expected at the border, high conservation policies are required. In the vicinity of Goheonsan, where the agricultural complex and industrial park are located, cold air flows well throughout the entire study site thanks to fully developed cold air in the wide, flat valley. Hence, plans to maintain the current cold air flow are required, and conservation plans to mitigate future developments are also needed in the flat valley. The cold air in Unjusan and the vicinity with its complex and narrow mountain valleys gradually develops into valley bottoms. In order to take advantage of the terrain, the valley near the cold air production areas are preserved. In particular, special plans are required to prevent damage to the cold air layer near Youngcheonho Lake, where the highest height of cold air was recorded due to the closed and lower terrain feature. This study could support the establishment of systematic management plans of Nakdong-Jeongmaek to preserve and enhance its green air conditioning functions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1492-1503
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• 2015

This study evaluated the combination effect of various freezing and thawing techniques on the quality and nutritional aspects of onions. Onions were frozen by natural air convection freezing (NCF), air blast freezing (ABF), and liquid nitrogen freezing (LNF). Onions were frozen for 76 min by NCF, 9 min by ABF, and 9 min by LNF. The freezing treatment was stopped when the core temperature reached $-12^{\circ}C$ for NCF and ABF, and $-120^{\circ}C$ for LNF. Frozen samples were thawed through natural air convection thawing, running water thawing, sonication thawing (ST), or microwave thawing. The quality and nutritional aspects of frozen-thawed onions were evaluated by measuring thawing loss, pH, texture, water content, color, and SEM image. ST was found to cause the least loss in onion sample among the tested thawing methods, whereas the freezing methods did not cause any significant loss. In our experiment, thawing is found to be a more critical technique when compared to that of freezing. There were no clear quantifications or trends of pH and water content among different freezing and thawing techniques. The highest total color difference (${\Delta}E$) was observed in the NCF sample. For morphological observation, ABF gave the smallest ice crystal size, as well as minimum cell collapse. Loss of vitamin C, free sugar, and organic acid content was lower in the ABF and ST sample, when compared to other trials. In our study, we found that combination of ABF and ST could preserve the quality and nutritional aspects of frozen-thawed onions better than other methods.

• Journal of Korean Society of Forest Science
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• v.80 no.3
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• pp.257-264
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• 1991

Korea has accomplished the afforestation of its forest land in the early 1980's. To meet the increasing demand for forest products and forest recreation, a development of scientific forest management system is needed as a whole. For this purpose the development of efficient forestfire management system is essential. In this context, the purpose of this study is to develop a theoretical foundation of forestfire danger rating system. In this study, it is hypothesized that the degree of forestfire risk is affected by Weather Factor and Man-Caused Risk Factor. (1) To accommodate the Weather Factor, a statistical model was estimated in which weather variables such as humidity, temperature, precipitation, wind velocity, duration of sunshine were included as independent variables and the probability of forestfire occurrence as dependent variable. (2) To account man-caused risk, historical data of forestfire occurrence was investigated. The contribution of man's activities make to risk was evaluated from three inputs. The first, potential risk class is a semipermanent number which ranks the man-caused fire potential of the individual protection unit relative to that of the other protection units. The second, the risk sources ratio, is that portion of the potential man-caused fire problem which can be charged to a specific cause. The third, daily activity level is that the fire control officer's estimate of how active each of these sources is, For each risk sources, evaluate its daily activity level ; the resulting number is the partial risk factor. Sum up the partial risk factors, one for each source, to get the unnormalized Man-Caused Risk. To make up the Man-Caused Risk, the partial risk factor and the unit's potential risk class were considered together. (3) At last, Fire occurrence index was formed fire danger rating estimation by the Weather Factors and the Man-Caused Risk Index were integrated to form the final Fire Occurrence Index.