• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1025-1029
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• 2008

Fresh green tea leaf extracts were prepared by different enzyme treatment conditions, such as concentration, treating time and treating temperature using complex enzyme, Rapidase TF, and then extracted for 30 min at $80^{\circ}C$ to investigate their physicochemical properties. The results showed that free sugar content in every sample tended to increase, especially glucose content was increased up to 7.25 times compared to the control. Total amino acid was barely affected by the enzyme treatment and caffeine content was increased with reaction temperature. Total polyphenol and total catechin content was increased according to the amount of enzyme added and reaction temperature. Regardless of enzyme treatment conditions, composition of catechins were epigallocatechin, epicatechin, epicatechin gallate and epigallocatechin gallate by descending order of the content. Gallic acid content increased up to 0.04% and $45^{\circ}C$ with no further significant changes thereafter. From the results above, we could conclude that a simple and new method to extract green tea materials directly from fresh green tea leaves with improved extract ratio may be introduced by adding $0.08{\sim}0.1%$ of Rapidase TF to heat treated fresh green tea leaves and keeping temperature at $37{\sim}45^{\circ}C$ for $180{\sim}240\;min$ in order to skip existing complicated procedures.

• Journal of Life Science
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• v.7 no.3
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• pp.192-197
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• 1997

Italian ryegrass, red clover, sorghum, and alfalfa were used for leaf protein preparation. Fresh leaves were pulped in the presence or absence of a reducing agent(sodium ascorbate or NaHSO$_{4}$) and green juice was heated and washed with acetone. The biological evaluation of leaf proteins was carried out by the growth method with male rats weighing about 45g. Italian ryegrass, red clover, and sorghum were brown when leaves were pulped in the absence of a reducing agent. On the other hand, alfalfa had neither o-diphenolics nor polyphenolase, and hence the alfalfa leaf protein did not brown during pulping ever in the absence of a reducing agent. The brown leaf protein from Italian ryegrass hd lower digestibility than the leaf protein protected from browning, although there were no difference in growth-promoting effect and protein efficiency ratio(PER)between the two leaf protein. The feeding of brown leaf protein from red clover resulted in the lowering of weight gain, digestibility, and PER, and all the measurement including diet intake were lowered by feeding the brown leaf protein from sorghum. In the case of alfalfa leaf protein, there were no difference in nutritional quality between the two leaf protein made with and without an attempt to prevent browning. The results mentioned above indicate that the occurrence of phenolics and polyphemolase in a crop in responsible for the browning of leaf protein and that the browning of leaf protein caused its nutritional impairment.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.59-65
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• 2012

This study evaluated the baby-leaf growth, leaf red color intensity, and phytochemical compounds, such as total phenols and total flavonoids using domestic Amaranthus accessions, to select promising germplasm for the use of baby-leaf vegetable. The 39 accessions, upper 15% of 262 Amaranthus germplasm collection showing high red color intensity in baby-leaf, measured as Hunter's a value, were primarily selected. The eleven accessions including IT199970, showing stable red color intensity in baby-leaf both in high-temperature and low temperature cultivation, were finally selected as promising germplasm for the use of baby-leaf vegetable Amaranthus. The leaf red color intensities when they were cultivated at low temperature period were generally higher than those at low temperature period, and all the eleven selected germplasm, including four Amaranthus sub-species and five unknown species, showed stable red color expression in baby-leaf. The total phenol and total flavonoid contents were also presented for finally selected germplasm including their baby-leaf fresh weights. These finally selected germplasm could be potentially used as baby-leaf vegetable resources, through fortifying the color balance of salad vegetable.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.134-138
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• 1997

The objective of this study was to examine the effect of phosphorus deficiency on nitrogen fixation and photosynthesis of nitrogen fixing soybean plant under $CO_2$ enrichment condition. The soybean plants(Glycine max [L.] Merr.) inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed(0.05 mM-P) and control(1 mM-P) treatment under control$(400\;{\mu}l/L\;CO_2)$ and enrichment$(800\;{\mu}l/L\;CO_2)$ enviromental condition in the phytotron equipped with high density lamp$(1000\;{\mu}Em^{-2}S^{-1})$ and $28/22^{\circ}C$ temperature cycle for 35 days after transplanting(DAT). At 35 DAT, phosphorus deficiency decreased total dry mass by 64% in $CO_2$ enrichment condition, and 51% in control $CO_2$ condition. Total leaf area was reduced significantly by phosphorus deficiency in control and enriched $CO_2$ condition but specific leaf weight was increased by P deficiency. Phosphorus deficiency significantly reduced photosynthetic rate(carbon exchange rate) and internal $CO_2$ concentration in leaf in both $CO_2$ treatments, but the degree of stress was more severe under $CO_2$ enrichment condition than under control $CO_2$ environmental condition. In phosphorus sufficient plants, $CO_2$ enrichment increased nodule fresh weight and total nitrogenase activity(acetylene reduction) of nodule by 30% and 41% respectively, but specific nitrogenase activity of nodule and nodule fresh weight was not affected by $CO_2$ enrichment in phosphorus deficient plant at 35 DAT. Total nitrogen concentrations in stem, root and nodule tissue were significantly higher in phosphorus sufficient plant grown under $CO_2$ enrichment, but nitrogen concentration in leaf was reduced by 30% under $CO_2$ enrichment. These results indicate that increasing $CO_2$ concentration does not affect plant growth under phosphorus deficient condition and phosphorus stress might inhibit carbohydrate utilization in whole plant and that $CO_2$ enrichment could not increase nodule formation and functioning under phosphorus deficient conditions and phosphorus has more important roles in nodule growth and functioning under $CO_2$ enrichment environments than under ambient condition.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.128-138
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• 1985

This study was conducted to elucidate the shelf-life and quality changes in relation to biochemical components in leaf lettuce (Lactuca sativa L.). The shelf-life of leaf lettuce at room temperature was 2 to 3 days. But it was extended to 3 weeks by packaging in a 0.01 mm thick polyethylene film sack when stored at $3^{\circ}C$. The ascorbic acid contents of fresh leaf lettuce was 25 mg per 100 gram fresh weight. The acid at room temperature was almost destroyed after 4 days storage. But the contents of ascorbic acid at $3^{\circ}C$ maintained about 50 to 60% of the initial level in packaging of polyethylene film sack after 8 days storage. The content of chlorophyll was greatly decreased at room temperature but no significant changes were found at $3^{\circ}C$. The changes of total sugar and reducing sugar contents during storage were not very different between treatments. The contents of alkali soluble protein and free amino acid gradually increased in the treatments of polyethylene film sack packaging during storage in general, but the contents decreased after the increase in control treatment. Nucleic acid content, peroxidase and polyphenoloxidase activities were measured and discussed in relation to the leaf senescence.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.163-175
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• 2007

This study was initiated to investigate the effect of chitosan on Kentucky bluegrass growth. Chitosan was applied rates of 300, 500, and 800 times dilution at ten-day intervals after transplanting. We observed such growth characteristics asleaf length, root length, numbers of leaves, fresh weight and dry weight, and chlorophyll content. Treatment of 300 X diluted chitosan resulted in the longest leaf length of 26.2cm comparing with the 17.1cm average leaf length of control. Leaf numbers were 21.4 and 31.7 for the control and the 500 X dilution treatment. The root length in control was 16.8cm while the treatment of 500 X diluted chitosan increased root length to 27.4cm. Chlorophyll content resulted 19.9mg/$100cm^2$ for the control and 25.5mg/$100cm^2$ for the treatment of 300 X diluted chitosan. In general, we found that the treatment of 500 X diluted chitosan resulted higher leaf number, chlorophyll content, fresh and dry weight.

• Journal of People, Plants, and Environment
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• v.23 no.4
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• pp.445-453
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• 2020

Background and objective: Calcium chloride (CaCl₂) and sodium chloride (NaCl) are commonly used as a deicing agent in South Korea and penetrate the soil on the roadside, causing damage to plants. This study was conducted to investigate the salinity reduction effect of Pennisetum alopecuroides and the chemical characteristics of soil leachate. Methods: The plants were treated with five different concentrations of CaCl₂ (0, 1, 2, 5, and 10g·L^-1) and were grouped into the Cont., C1, C2, C5, and C10 groups. CaCl₂ of 200 m·L^-1 was sprayed to each plant once every two weeks. The growth of P. alopecuroides (plant height, leaf length, leaf width and the number of leaves) was measured. The level of EC and pH, and exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) in the leachate of soil was monitored. Results: The pH of soil leachate decreased as the CaCl₂ concentration increased, and the EC increased significantly. The content of K⁺ did not change significantly until the concentration of CaCl₂ reached 5 g·L^-1, but the content of Ca²⁺, Na⁺, and Mg²⁺ significantly increased. The plant height, leaf length, and leaf width of P. alopecuroides showed the highest value in CaCl₂ 1 g·L^-1 followed by CaCl₂ 2 g·L^-1 and the control group. Root fresh weight was the highest in CaCl₂ 2 g·L^-1. On the other hand, there was no change in the shoot fresh weight, dry weight and root dry weight, and P. alopecuroides growth inhibition at the concentration of 5 g·L^-1 or higher in the plant height and leaf length. Conclusion: P. alopecuroides is relatively highly salt-tolerant and can improve the salt damaged soil by lowering the content of the salt-based exchangeable K⁺ ions.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.91-97
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• 2011

This study was performed to assess the microbiological quality and potential health risk of fresh-cut produce and organic vegetables sampled from supermarkets and department stores in Korea. A total of 96 samples comprised three types of fresh-cut produce (sprouts, mixed-vegetables, fruit) and three types of organic vegetables (lettuce, perilla leaf, green pepper). The samples were analyzed for total viable cell counts, coliforms, Enterobacteriaceae, Escherichia coli, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Bacillus cereus, and Staphylococcus aureus. The microbiological counts of fruit were very low. Sprouts were highly contaminated by total viable cell counts ($8.3{\pm}0.57$ log CFU/g), Enterobacteriaceae ($7.1{\pm}0.76$ log CFU/g), and coliforms ($4.9{\pm}0.40$ log MPN/g), and showed a high incidence level of B. cereus ($2.9{\pm}0.48$ log CFU/g). Of the fresh-cut produce analyzed, six (13.6%) mixed-vegetable salads were E. coli positive. S. aureus was detected in only one sprout sample and one mixed-vegetable salad, and its contamination levels were under 2 log CFU/g, which is appropriate for Korean standards (<3 log CFU/g) of fresh-cut produce. Of the organic vegetables, lettuces were highly contaminated by total viable cell counts ($6.4{\pm}0.74$ log CFU/g), Enterobacteriaceae ($5.7{\pm}0.98$ log CFU/g), and coliforms ($3.7{\pm}1.72$ log MPN/g). Two (13.6%) organic lettuce and one (7.1%) perillar leaf sample were E. coli positive, and S. aureus was detected in one lettuce and two perilla leaf samples. Salmonella spp., Vibrio parahaemolyticus, and Listeria monocytogenes were not detected in any of the fresh-cut produce or organic vegetables analyzed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.3
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• pp.217-222
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• 1998

This experiment was carried out to investigate effects of herbicide application method on Calysteria jcqoonica control and corn yield at the forage experimental field, grassland and forage crops division, National Livestock Research Institute, RDA, Suwon from 1996 to 1997. The experiment was arranged in a randomized block design with three replication. The herbicide application consisted of control, 2~3 leaf stage(Dicamba), 5~6 leaf stage(Dicamba) and soil treatment (Pendimethalin). The hybrid of corn used in this experiment was P 3352. The results obtained are summarized as follow; 1. The plant height was the lowest at control and the highest at Dicamba treatment in 5~6 leaf stage, but no significant difference was found among herbicide application method at ear height. Tasseling and silking date were delayed 2~3 day at control. The length and weight of ear were highest at Dicamba treatment in 2~3 leaf stage. 2. The herbicide injury of corn was very slightly after 10-20 day, but corn was recovered soon. The weed control value was 94.2~67.5% at herbicide application plot. 3. The fresh and dry matter yield of Dicamba treatment in 2-3 leaf stage was highest as 42,878 and 16,033kg/ha, respectively. The application of Dicamba increased the DM yield of corn by 13~30%. 4. Herbicide application time had little effect on the ADF, NDF and CP contents, but the forage quality of ear was higher than that of stover. The result of this experiment indicate that the application of Dicamba in 2~6 leaf stage of corn will remove almost all of Calysreria jqonica and increase DM yield of com.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.1-6
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• 2007

This experiment was conducted to possibility for leaf production of wasabi using hydroponics system. When they were grown in aeroponics and soiless culture such as saprolite and Coir, photosynthesis and transpiration rate were high and marketable yield $(leaf\;width\;11{\sim}13cm)$ showed $11.2{\sim}11.7$ of leaf number per plant and $52{\sim}53.8g$ fresh weight. In spring periods, the highest yield was 25.7 of leaf number per plant in nutrient solution of Yamasaki's solution developed in Japan in deep culture during 130 days. It showed be possibility that marketable leaves harvested one leaf every $2{\sim}4$ days though spring and fall culture periods using hydroponics controlled in environmental culture.