• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.53-60
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• 1999

Possibility of utilization of fig as a source of vinegar was tested. Alcohol fermentation was conducted by inoculation of Saccharomyces bayanus into fig juice. After 5 days of fermentation at 27oC, fig wine with alcohol content of 13.6%. Then fig vinegar was produced by cultivation of Acetobacter sp. E which was isolated from fig vinegar. Optimum concentration of alcohol, starter content and fermentation temperature for the acid production were 8~9%, 5% and 27~30oC, respectively. More acetic acid was produced by adding 0.5% of yeast extract and 0.01% of Ca pantothenate. Adjustment pH of culture broth with acetic acid and shaking cultivation method were not effective in higher yield of acid production. Addition of sulfite up to 50 ppm did not inhibit for acetic acid fermentation. Addition of 1% bentonite or 1% kakishibu was more effective for the clarification of fig vinegar than any other clarifying agents tested. During aging and racking, acidity, absorbance and tannin content of fig vinegar decreased, while redness and yellowness increased. Aged and racked fig vinegar showed higher sensory score than non aged one in the aspects of color and overall acceptability.

• Journal of Mushroom
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• v.19 no.2
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• pp.81-87
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• 2021

Roridin E, produced by Podostroma cornu-damae, is a mycotoxin with anticancer activity. To increase the content of roridin E, submerged culture conditions were optimized using response surface methodology. Three factors, namely, medium initial pH, incubation time and agitation speed were optimized using a Box-Behnken design. The optimum submerged culture conditions to increase the content of roridin E included a medium with an initial pH of 4.0, an incubation time of 12.90 days, and an agitation speed of 63.03 rpm. The roridin E content in the submerged culture, under the aforementioned conditions, was 40.26 mg/L. The findings of this study can help lower the current price of roridin E and promote its related research.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.118-123
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• 2017

'Nunkeunheugchal' is a waxy black rice variety that has a large embryo. The quality of black rice depends on the anthocyanin content of the rice seed coat, which is mainly determined by cultivation environment. Factors that affect the anthocyanin content include nitrogen level, planting density, transplanting date and harvesting date. This study was carried out to investigate the optimum black rice cultivation conditions by examining the effects of different nitrogen levels and planting densities. An initial study was conducted to determine the optimum nitrogen level in which four levels of nitrogen were applied to the field (0, 4, 8 and 12 kg/10a). As the nitrogen contents were increased up to 8 kg/10a, there was a concomitant increase in rice yields. However, nitrogen levels greater than 8 kg/10a, the yield was maintained at the same level. Correlation analysis indicated that the optimum nitrogen level for maximum yield was 9.6 kg/10a. In addition, anthocyanin levels showed a trend similar to that of yield, with correlation analysis indicating that the optimum nitrogen level for maximum anthocyanin content is 10.6 kg/10a.On the basis of these results, a second study was conducted to determine the optimum combination of planting density and nitrogen level. The planting densities investigated were $30{\times}12$, $30{\times}14$, $30{\times}16$ and nitrogen levels were 7, 9 and 12 kg/10a. A high planting density ($30{\times}12cm$) was shown to produce higher numbers of tillers and yield. As calculated in the first study, a nitrogen level of 9 kg/10a shown to produce the highest anthocyanin content and yield. Collectively, the results of this study indicate that a planting density of $30{\times}12cm$ and a nitrogen level of 9 kg/10a is the optimal combination in terms of maximizing both rice yield and anthocyanin content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.79-84
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• 1994

Sweet corn hybrid GCB 70 and super sweet corn hybrid NES were cultivated at vinyl tunnel in 1991 to determine the physiologically optimum harvest time for higher eating quality and sugar contnent of kernel by eat parts after silking and stored in refrigerator of 4$^{\circ}C$ and in the air. The development of ear increased continuously from silking to 30th day after silking, and sugar content was the hightest on 15th day after silking. The physiologically optimum harvest time for GCB 70 and NES was about 15~20th day and 20~25th day after silking, respectively. The sugar content of kernel by ear parts for two hybrids were high in order of basal, middle and top parts of the ear and showed significant differences among the parts of the ear. Changes of total sugar content during the storing period at 4$^{\circ}C$ for NES was almost the same by 9th day, but for GCB 70 rapidly decreased from 3rd day. The content of sucrose, glucose and fructose in super sweet corn NES were much higher than those of sweet corn GCB 70, but the maltose content of NES was lower than that of GCB 70.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.1
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• pp.4575-4591
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• 1978

In order to investigate the effects of grain size distribution, cement content, and molding pressure on the strength and durability of soil-cement mixtures, a laboratory test of soil cement mixtures was performed at four levels of cement content, five levels of molding pressure, and four levels of normal curing periods. The results are summarized as follows: 1. Optimum moisture contents in loam soil and maximum dry density in sand soil increased with the increase of cement content, but in others, both optimum moisture contents and maximum dry density were changed ununiformly. 2. When the specimens were molded with molding pressure, 50kg/$\textrm{cm}^2$, strength of soil cement mixture with cement content, 2 and 4 per cent, was lower than the strength of soil cement mixture without cement content by more than 40 to 50 per cent. 3. The strength of soil-cement molded with molding pressure, 100kg/$\textrm{cm}^2$, was higher than the strength of soil-cement molded with M.D.D. obtained from standard compaction test more than 40 per cent in sand loam cement and 50 per cent in loamy cement. 4. There was highly significant positive correlation among molding pressure, cement content and unconfined compressive strentgh and so the following multiple regression equations were obtained. Loam: fc=1.9693C+0.197P-0.84 Sandy loam: fc=2.9065C+0.235P-0.77 5. When the specimens were molded with molding pressure, 20 to 100kg/$\textrm{cm}^2$, the regression equation between the 28-day and 7-day strenght was obtained as follows. Loam : q28=1.1050q7+7.59(r=0.9147) Sandy loam : q28=1.3905q7+3.17 (r=0.9801) 6. At the cement contents of above 50 per cent, the weight losses by freeeze-thaw test were negligible. At the cement content of below 8 per cent the weight losses were singnificantly high under low molding pressure and remarkably decreased with the increase of molding pressure up to 80kg/$\textrm{cm}^2$. 7. Resistance to damage from water and to absorption of water were not improved by molding pressure alone, but when the soil was mixtured with cement above 6 per cent, damage seldoms occurred and absorbed less than 5 per cent of water. 8. There was highly significant inverse-corelationship between the compressive strength of soil cement mixtures and their freeze-thaw loss as well as water absorption. By the regression equation methods, the relationships between them were expessed as followed fc=-7.3206Wa+115.6(r=0.9871) log fc=-0.0174L+1.59(r=0.7709) where fc=unconfined compressive stregth after 28-days curing. kg/$\textrm{cm}^2$ Wa=water absorption, % L : freeze-thaw loss rate, %

• Journal of Environmental Science International
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• v.26 no.3
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• pp.381-392
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• 2017

The present study aimed to investigate the effects of low temperature on the growth, yield, quality, and biologically active compounds of strawberry and obtain basic information for developing a technology for stable growth of strawberry in greenhouses. Growth of strawberry, including leaf number, area, and length, plant height, and dry weight was better at the optimum growth temperature of $20^{\circ}C$ than at a lower temperature of $15^{\circ}C$. At the low temperature of $15^{\circ}C$, the cultivar 'Maehyang' was more tolerant and displayed better growth rate than 'Seolhyang'. At $15^{\circ}C$, the fruit production per week and fruit weight was lower than that at $20^{\circ}C$. In contrast, fruit length and diameter were not significantly different between the two growth temperatures. Growth temperature also did not affect the fruit color index, Hunter L, a, b value, or fruit firmness. However, the sugar content of strawberries grown at $15^{\circ}C$ was higher by 0.8 and 1.5 Brix for 'Seolhyang' and 'Maehyang', respectively, than of those grown at $20^{\circ}C$. There was no difference in the content of fisetin, a biologically active compound, for 'Seolhyang' at both growth temperatures, however, the fisetin content of 'Maehyang' was higher at $20^{\circ}C$ than at $15^{\circ}C$. Cinchonine and ellagic acid content of 'Seolhyang' was higher at $20^{\circ}C$ than at $15^{\circ}C$, whereas that of 'Maehyang' was higher at $15^{\circ}C$ than at $20^{\circ}C$. Quercetin content showed no significant differences with respect to growth temperature, however, it tended to increase at $20^{\circ}C$. The cinnamic acid content of 'Seolhyang' was higher at $15^{\circ}C$ than at $20^{\circ}C$, whereas that of 'Maehyang' increased at $20^{\circ}C$. Collectively, the biologically active compounds of strawberry were affected by growth temperature. Moreover, the content of these compounds tended to increase at $20^{\circ}C$, the optimum growth temperature, rather than at the sub-optimal growth temperature of $15^{\circ}C$.

• Journal of the Korean GEO-environmental Society
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• v.9 no.1
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• pp.47-54
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• 2008

In this study, the effect of water content condition was investigated on the Mohr-Coulomb shear strength parameters which are commonly used as the input data in the soil slope analysis. For the purpose, a series of direct shear test was conducted in different water content conditions on the two types of weathered soils and a dam core material, obtained from the domestic slope construction sites and the dam construction site, respectively. The comparisons between the values of the Mohr-Coulomb ${\phi}_{peak}$ and $c_{peak}$, estimated from the relationships between the normal stress and the peak shear stress for the samples in the four different water content conditions (i.e., dry side, optimum, wet side, and saturated), showed that overall, the values of $c_{peak}$ decreased gradually while those of ${\phi}_{peak}$ did not vary much with increasing the water content. A rough estimate for the varying ratio of the values of ${\phi}_{peak}$ and $c_{peak}$ indicated that the values of $c_{peak}$ decreased by every 25% of the $c_{peak}$ values in dry side, while those of ${\phi}_{peak}$ were constant, as the water content condition changed from dry, optimum, and wet to saturated, respectively.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.1-7
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• 2002

Characteristics (salt concentration, weight loss, soluble solid content, moisture content, and textural properties) of radish cube $(2{\times}2{\times}2\;cm)$ were evaluated during salting. Three different summer radish cultivars harvested in high land were immersed into 15% brine solution (radish : brine solution = 1 : 2) at $15^{\circ}C$ for 4 h. The time required to reach the optimum salt concentration (3%) was different among cultivars; 3 h for 'Bakbong', 4 h for 'Kwandong' and '92343'. Similar weight loss (about 24-26%) of salted radish cubes was found among cultivars. While the highest value of weight loss of salted radish cubes was observed with '92343', the lowest, 'Bakbong'. Hardness decreased during salting; the highest value of hardness was observer with 'Kwandong', the lowest, 'Bankbong'. The sample of '92343' has the lowest moisture content but has the highest soluble solid content and hardness, while 'Bakbong' has the highest moisture content, but has the lowest soluble solid content and '92343'. In separate experiments, seasonal variations in characteristics of salted radish cubes at optimum salt concentration (3%) were observed: for 'Bakbong', salt concentration, weight loss, soluble solid content, and hardness, and for 'Bakwang', salt concentration, weight loss, and hardness were higher in autumn cultivars than in spring or summer one, while moisture contents of both cultivars were higher in spring or summer cultivars than in autumn one.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.401-408
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• 2012

The grain and agronomic characteristics of Korean barley cultivars were investigated with respect to ethanol yield. Test weight, grain yield, and starch yield showed noticeable variation among the cultivars. Grain yields were higher in covered barley and non-waxy barley. Starch yield was higher in non-waxy barley than waxy barley. Protein, ${\beta}$-glucan, and starch content of tested cultivars ranged in 10.0-12.9%, 4.4-7.5% and 49.7-65.3%, respectively. Naked barley cultivar had higher starch content than covered barley cultivar. However, covered barley had high starch yield because it has higher grain yield than naked barley. Covered barley cultivar had higher husk content, ranging 7.6-14.0%, than that of naked barley cultivar, ranging 5.3-8.0%. Starch content was positively correlated with amylose content, test weight, ethanol yield and negatively correlated with protein, husk, ${\beta}$-glucan content. Ethanol yield per ton was positively correlated with starch content, but negatively correlated with husk content. Ethanol yield per hectare was positively correlated with starch yield, grain yield, grain weight and negatively correlated with protein, test weight. From this research, the important characteristics of barley cultivar as a bioethanol producing material were starch content and grain yield. Optimum barley genotype was non-waxy naked barley that had low protein, ${\beta}$-glucan, husk content, and high starch content and grain yield.

• Particle and aerosol research
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• v.6 no.4
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• pp.151-164
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• 2010

Inorganic ions and water are major components of ambient fine particles. Water content in fine particles is mainly determined by ambient meteorological conditions and the concentrations of hygroscopic species such as inorganic ions. Thus, to reduce fine particle mass concentration, it is important to accurately estimate the relationship between water content and the concentration of ions in fine particles. Water content in fine particles in Seoul are estimated by using a gas/particle equilibrium model to understand the characteristics of fine particle mass concentration. In addition, sensitivity of fine particle mass concentration to the changes of particulate ionic species (sulfate, nitrate, and ammonium) is estimated. It was found that water content in Seoul is mostly determined by the concentrations of the hygroscopic ionic species, especially, sulfate and ammonium, and ambient relative humidity.