• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.487-498
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• 1992

To study the effects of different nursing methods and transplanting on the growth of rice plant (Oriza sativa L.) in southern region of Korea, Kumo-byeo, Palgong-byeo and Dongjinbyeo were transplanted from April 20 to July 20 at an interval of 15 days with 8 days old seedling (infant seedling) and 25 days old box-seedling for machine transplanting, and 45 days old conventional seedling. Threshold transplanting date in southern region of Korea were June 26 for 8 days old seedling, July 1 for 25 days old seedling and] July 11 for 45 days old seedling for Kumo-byeo, and June 21, June 30, July 10 for Palgong-byeo, June 10, June 24, July 5 for Dongjin-byeo, respectively. Yield has no uniform tendency according to the transplanting date. However, yield were greater in the order of 8 days old seedling >25 days old seedling> 45 days old seedling in Kuma-byeo and 25 days old seedling (equation omitted)8 days old seedling (equation omitted)45 days old seedling in Palgong-byeo, 45 days old seedling(equation omitted)25 days old seedling(equation omitted) 8 days old seedling in Dongjin-byeo. The optimum accumulated air temperature during yield productive stage around heading (40 days from 10 days before heading to 30 days after heading) for high yield were 1,003$^{\circ}C$ for 8 days old seedling, 1,014$^{\circ}C$ for 25 days old seedling and 1,027$^{\circ}C$ for 45 days old seedling in Kumo-byeo. And they were 1,018$^{\circ}C$, 1,015$^{\circ}C$, 1,086$^{\circ}C$ in Palgong-byeo and 998$^{\circ}C$, 984$^{\circ}C$, 949$^{\circ}C$ in Dongjin-byeo, respectively. Earlier transplanting with 8 days old seedling showed higher ratio of broken rice and green kerneled rice in Kuma-byeo, and late transplanting after July 5 showed significant high rate of green kerneled rice. Palgong-byeo and Dongjin-byeo also showed high rate of green kerneled rice at transplanting after July 5.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.69-79
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• 1982

The objective of this study is to contribute to drainage planning in the most realistic and economical way by establishing the relationship between rice yield reduction and overhead flooding by muddy water of each growth stage of paddy, which is the most important factor in determining optimum drainage facilities. This study was based on the data mainly from the experimental reports of the Office of Rural Development of Korea, Reduction Rate Estimation for Summer Crops, published by Ministry of Agriculture and Forestry of Japan and other related research documenta- tion. The results of this study are summarized as follows 1. Damages by overhead flooding are highest in heading stage and have the tendency of decrease in the order of booting stage, panicle formation stage, tillering stage, and stage just after transplanting. Damages by overhead flooding of each growing stage are as follows: a) It is considered that overhead flooding just after transplanting gives a little influence on plant growth and yield because the paddy has sufficient growth period from floo ding to harvest time. b) Jt is analyzed that according to the equation y=11 12x 0.908 which is derived from this study, damages by overhead flooding during tillering stage for 1, 2, 3 successive days are 11.1 %, 20.9%, and 30.2% respectively. c) Damages by overhead flooding after panicle formation stage are very serious because recovering period is very short after damage and ineffective tillering is much. Acc- ording to the equation y=9. 58x+10. Ol derived from this study, damages by overhead flooding fal 1,2,3,5 successive days are 19.6%, 29.2%, 38.8%, 57.9% respectively. d) Booting stage is the very important period in which young panicle has grown up almost completely and the number of glumous flower is fixed since reduction division takes place in the microspore mother cell and enbryo mother cell. According to the equation y=39. 66x 0.558 derived from this study, damages by overhead floodingfor 0.5, 1, 3, 5 successive days are 26.9%, 39.7%, 72. 2% and 97.4%, respectively. Therefore, damages by overhead flooding is very serious during the hooting stage. e) When ear of paddy emerges, flowering begins on that day or the next day; when paddy flowers, fertilization will be completed 2-3 hours after flowering. Therefore overhead flooding during heading stage impedes flowering and increases sterilizing percentage. From this reason damages of heading stage are larger than that of booting stage. According to the equation y-41 94x 0.589 derived from this study, damages by overhead flooding for 0.5, 1, 3, 5, successive days are 27.9%, 63.1 %, 80.1%, and 100% 2. Considering that temperature of booting stage is higher than that of beading stage and plant height of booting stage is ten centimeters shorter than that of heading stage, booting stage should be taken as a critical period for drainage planning because possi- bility of damage occurrence in booting stage is larger than that of heading stage. There-fore, it is considered that booting stage should be taken as critical period of paddy growth for drainage planning. 3. Overhead flooding depth is different depending on the stage of growth. In case, booting stage is adopted as design stage of growth for drainage planning, it is conside red that the allowable flooding depth for new varieties and general varieties are 70cm and 80cm respectively. 4. Reduction Rate Estimation by Wind and Flood for Rice Planting of the present design criteria for drainage planning shows damage by overhead flooding for 1 to 2, 3 to 4, 5 to 7 consecutive days; damages by overhead flooding varies considerably over several hours and experimental condition of soil, variety of paddy, and climate differs with real situation. From these reasons, damage by flooding could not be estimated properly in the past. This study has derived the equation which shows damages by flooding of each growth stage on an hourly basis. Therefore, it has become possible to compute the exact damages in case duration of overhead flooding is known.

• Applied Biological Chemistry
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• v.39 no.6
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• pp.437-442
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• 1996

Two strains of Lactobacillus(L.) casfi and one strain of L. Pentosus, which were isolated from pickles, were used to investigate in studing their characteristics of ${\beta}-galactosidase$. The preferable carbon sources and pH of the MRS media for enzyme production from L. casei No.10 was found to be 1.0% lactose and pH 7.5, from L. Pentosus No.63 was 1.0% galactose and pH 7.5, and from L. casei No.36 was 1.0% lactose and pH 6.5, respectively. The maximum enzyme production from each strain was found after 48 hours culture at $30^{\circ}C$ in a medium with preferable carbon source. The optimum reaction temperature with substrate for ${\beta}-galactosidase$ activity was found at $60^{\circ}C$ for all three strains . The stability of enzyme from L. casei No.36 was found to be at $45^{\circ}C$, from L. Pentosus No.63 was found at $55^{\circ}C$. This stability from L. casei No.36 was found at $40^{\circ}C$, but it was reduced to 60% at $55^{\circ}C$. These stabilities of enzymes remained about 90% at $40^{\circ}C$ for all three strains. The optimal pH for enzyme activities was found to be pH 6.5 for all three strains. Enzyme activity remained over 90% for L. casei No.10 at $pH\;5.0{\sim}6.0$, for L. casei No.36 at $pH\;5.0{\sim}8.0$, and for L. pentosus No.63 at $pH\;6.0{\sim}7.0$.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.345-351
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• 1996

Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.630-637
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• 1998

Enzymatic properties of immobilized transglucosidase (TG) from Aspergillus niger was characterized and compared with soluble TG. Michaelis-Menten constant $(K_m)$ and maximum velocity $(V_{max})$ of immobilized TG were $122\;mM,\;3.9{\times}10^{-2}\;mM/min$ and in case of soluble TG, 21 mM, 0.4 mM/min. The optimum pH of immobilized TG was pH 5.0 like soluble TG but immobilized TG showed 16% and 45% higher activity than soluble TG at pH 5.0 and pH 6.0. Both of immobilized TG and soluble TG were stable from pH 2.0 to pH 9.0, and therefore their activities in these pH ranges were remained more than 90%. The temperature was optimal at $60{\sim}70^{\circ}C\;and\;70{\sim}80^{\circ}C$ for soluble TG and immobilized TG, respectively. The thermal stability of immobilized TG was significantly improved than that of soluble TG, and immobilized TG retained $32{\sim}40%$ higher activity than soluble TG. D-values from thermal inactivation of immobilized TG were 7690 sec at $65^{\circ}C$, 83 sec at $75^{\circ}C$, 7.2 sec at $80^{\circ}C$. Z-values of soluble and immobilized TG were $6.4^{\circ}C\;and\;5.3^{\circ}C$, respectively. The little difference of activation energies of soluble TG and immobilized TG supposed that there was little difference in mass transfer limitation during the reaction of soluble TG and immobilized TG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.3
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• pp.198-204
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• 1988

This study was aimed at obtaining elementary data on enzymatic browning of potato and potato products and examining the inhibitory method of browning. Therefore, we extracted polyphenol oxidase from potatoes(Solanum tubersum L.), and investigates its general properties and inhibiting effects of its activity with the different concentrations of sulfites($Na_2S_2O_4,\;Na_2SO_3{\cdot}7H_2O,\;NaHSO_3$). The optimum pH and temperature of polyphenol oxidase were observed to be 6.5 and $37^{\circ}C$ respectively. The polyphenol oxidase at PH5 was very stable, and the activity of polyphenol oxidase between pH $5.0{\sim}9.0$ was estimated to be relatively high, showing $72{\sim}75%$ of its activity at pH5. The polyphenol oxidase was very stable when heated at $40^{\circ}C$ for one hour, and almost 50% of enzyme activity was decreased when heated at $70^{\circ}C$ for twelve minutes. At 0.1mM concentrating of sulfites the relative activity of polyphenol oxidase was 98% in all the three cases of sulfites. Thus sulfites at 0.1mM concentration was found to have little inhibiting effect on polyphenol oxidase activity. At 1mM concentration of sulfites $NaHSO_3$ showed the lowest 36% relative activity among the three. At 5mM concentration of sulfites, the relative activity of $Na_2SO_3{\cdot}7H_2O$ was the lowest 14%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.4
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• pp.259-269
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• 2013

In this work, licorice extracts were prepared using various extraction conditions such as extraction solvent, temperature, and time from Glycyrrhiza uralensis (G. uralensis) produced in Korea and China and Glycyrrhiza glabra (G. glabra) in Uzbekistan. The optimum extraction condition was selected from the extraction yields and antioxidative activities of extracts. Korea licorice extracts showed the highest free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity (46.05%) under the extraction condition of 85% ethanol at $60^{\circ}C$ for 6 hours. The prominent ROS (reactive oxygen species) scavenging activity using luminol-dependent chemiluminescence assay and the cellular protective effect against $^1O_2$ induced cellular membrane damage were also shown from the extracts obtained from the same condition. Especially, Korea G. uralensis extracts exhibited the higher prominent protective effect (${\tau}_{50}$ = 116.4 min) than (+)-(+)-${\alpha}$-tocopherol (${\tau}_{50}$ = 28.5 min) and the extraction yield of Korea licorice extract was 18.75%, which is 1.2 times and 2.5 times higher than that of Uzbekistan and China, respectively. These results indicate that the extraction condition of 85% ethanol at $60^{\circ}C$ for 6 hours is optimal to prepare licorice extracts, which can be applicable as anti-oxidative cosmetic materials.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.1
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• pp.88-98
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• 2016

The pharmacological effects of ginseng berry have been known to improve psychological function, immune activities, cardiovascular conditions, and certain cancers. It is also known that fermentation improves the bioavailability of human beneficial natural materials. Accordingly, we investigated the optimal fermentation conditions of ginseng berry extract with strain isolated from conventional foods. We also analyzed the fermentation product and its antioxidant activity. The bacterium isolated from fermented kimchi was identified as Lactobacillus sp. strain KYH. To optimize the process, fermentation was performed in a 5 L fermenter containing 3 L of ginseng berry extract at 200 rpm for 72 hr. Under optimized conditions, batch and fed-batch fermentations were performed. After fermentation, organic acids, amino acids, sugars, ginsenosides, and antioxidant activity were evaluated. The optimum fermentation conditions were determined as pH 7.0 and a temperature of $30^{\circ}C$, respectively. After fermentation, the amounts and compositions of organic acids, amino acids, sugars, ginsenosides, and antioxidant activity were altered. In comparing the distribution of ginsenosides with that before fermentation, the ginsenoside Re was a major product. However, amounts of ginsenosides Rb1, Rc, and Rd were reduced, whereas amounts of ginsenosides Rh1 and Rh2 increased. Total phenol content increased to 43.8%, whereas flavonoid content decreased to 19.8%. The DPPH radical scavenging activity and total antioxidant activity increased to 27.2 and 19.4%, respectively.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.363-370
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• 2018

The succulent plants of Echeveria genus are in increasing demand worldwide, but it is difficult to supply good quality young plants throughout the year because propagation efficiencies are depend on cultivar and environmental factors. This study was carried out to investigate the propagation efficiencies of leaf cutting in Echeveria cultivars at different LED light qualities in a closed-type plant factory system. Leaf cuttings cut from stock plants of six difficult-to-propagated cultivars 'Afterglow (AG)', 'Berkeley Light (BL)', 'Mason (MS)', 'Subsessilis Light (SL)', 'Cream Tea (CT)', and 'Ben Badis (BB)' were put into cutting media in the plant factory system maintained at a temperature of $24{\pm}2^{\circ}C$ and relative humidity of $60{\pm}10%$, and watered with over-head irrigation twice a week. Cuttings were irradiated with sole or mixed red (R, 660 nm), blue (B, 450 nm), green (G, 530 nm), and far-red (FR, 730 nm) LEDs as follows: R10, R8+B2, R5+B5, R7+B2+FR1, and R7+B2+G1. PPFD just above the cuttings was $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and photoperiod was 16/8 (light/dark) hours. As a result, propagation efficiencies were dependent on cultivar. Rooting and shooting were relatively easy in 'SL' but shoot formation in 'AG' was very difficult. Light qualities from LEDs also affected plant regeneration. Light conditions with a higher ratio of B, R5+B5, R7+B2+FR1, and R7+B2+G1, promoted shoot formation and growth but inhibited rooting and root growth. R10 and R8+B2 with a higher ratio of R promoted rooting and root growth and inhibited shoot formation and growth of cuttings. In addition, the treatment with FR increased leaf size and biomass of the all plants. Therefore, further studies are needed to investigate the optimum compositions of LED light quality for the improvement of leaf cutting efficiency in difficultto-propagated Echeveria cultivars.

• The Korean Journal of Malacology
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• v.31 no.2
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• pp.93-101
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• 2015

The effects of different stocking densities on the growth and survival rate of the 3-year-old pacific abalone, Haliotis dicus hannai were investigated in marine net cage for a year. Stocking densities in net cage ($2.4{\times}1.2m$) was set 15, 30, 45 and 60 percentage (= per)/sq m (square meter, $m^2$) with share to cross-sectional area per shelter. The water temperature during the testing period was $8.2^{\circ}C-22.1^{\circ}C$, and salinity is $33.5{\pm}0.6psu$, and dissolved oxygen is $7.87{\pm}0.86mg/L$. In the shell length (initial size : $71.50{\pm}2.28mm$) growth and shell breadth (initial size : $46.43{\pm}2.28mm$) of the test abalones, the absolute growth rate (ARG), daily growth rate (DGR) and specific growth rates (SGR) of the 15 per/sq m and 30 per/sq m were higher than those of 45 per/sq m and 60 per/sq m density group (P < 0.05). Also in the weight (initial weight : $35.7{\pm}8.1g$), it showed the same results. In survival rates, it were that 15 per/sq m and 30 per/sq m is significantly higher than 45 per/sq m and 60 per/sq m. Therefore, it was that the 15 per/sq m is optimized stocking density in marine net cages about the 3-year-old pacific abalone over 70 mm size. The result shown that total cross-sectional area under the shelter is based on 15 per/sq m ($2.4{\times}2.4m$, 354 number in a net cage) is suitable for fast growth and survival. But if the economy consider, optimized stocking density would be appropriate to accept 30 per/sq m ($2.4{\times}2.4m$, 710 number in a net cage).