• Journal of Dairy Science and Biotechnology
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• v.34 no.4
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• pp.263-270
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• 2016

This study was carried out to evaluate the antioxidant activity and total polyphnol content of Greek-style yogurt in 12% solid content with added stevia leaf extracts. Stevia leaf extracts used as sweetener in preparing Greek-style yogurt were prepared in hot water ($100^{\circ}C$ for 6 h 3 times, and by 70% fermented ethanol for 24 h at room temperature 3 times). The antioxidant activities were measured by assessing the radical scavenging effect through DPPH, ABTS, and FRAP assays. To identify the compounds present, total polyphenol content was evaluated using a Folin-Dennis assay. The capability to scavenge free radicals and total polyphenolic content were the highest in Greek-style yogurt containing 1% stevia extract and fermented in 70% ethanol. According to the results, antioxidant activities significantly increased when high concentration of stevia extracts were added to the yogurt (p<0.05). Therefore, these results suggest that stevia leaf extracts can be used as a source of functional compounds in Greek-style yogurt. We also suggest that fermented ethanol extraction can be used to obtain stevia leaf extracts.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.199-205
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• 1998

In human intestine, more than 100 species of bacteria reside and dietary factors may alter the bacterial flora which produce bacterial enzymatic activities. Especially ${\beta}-glucuronidase$ and tryptophanase activities in colon are closely associated with occurrence of colon cancer. Therefore, the inhibitory effect of traditional herbal food extracts on these intestinal bacterial enzymes are measured. The results of this study showed that Zizyphi fructus and Glycyrrhiziae radix decreased not only ${\beta}-glucuronidase$ and tryptophanase productions of human intestinal bacteria but also inhibited potently ${\beta}-glucuronidase$ and tryptophanase. Among solvent-extracted fraction of tested herbal foods, ether fraction of Glycyrrhiziae radix and ethylacetate fraction of Zizyphi fructus inhibited potently ${\beta}-glucuronidase$ and tryptophanse. Thus, ethylacetate fraction of Zizyphi fructus separated six components by silica gel column chromatography. The component having Rf=0.34 and Rf=0.43 $(developing\;solvent,\;CHCl_3/MeOH\;(3:1))$ shwed the highest inhibitory effect of ${\beta}-glucuronidase$ and tryptophanase among them.

• Journal of the Korean Electrochemical Society
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• v.2 no.1
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• pp.5-12
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• 1999

By the PVA-precursor method, polycrystalline powder of $Li_xNi_{1-y}Co_yO_2$, cathode material for lithium battery, was synthesized. Using the powder as the cathode material, lithium ion batteries were fabricated, whose electrochemical properties were measured. The effect of changing synthetic conditions, such as PvA/metal mole ratio, concentration of PVA, degree of polymerization of PVA, pyrolysis condition, and metal stoichiometry, on the battery performance was investigated. Considering the initial performance of the cell, the optimum stoichiometry of the $Li_xNi_{1-y}Co_yO_2$, synthesized by the PVA-precursor method was observed to be x: 1.0 and y=0.26. A minor phase of $Li_2CO_3$, which was generated by the residual carbon in the powder precursor, deteriorated the performance of the cell. In order to eliminate the minor phase, the precursor had to be pyrolyzed under the flow of dry air. Annealing the powder at $500^{\circ}C$ under the flow of dry air also eliminated the minor phase, and the performance of the cell was largely improved by the treatment.

• The Korean Journal of Mycology
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• v.35 no.2
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• pp.101-108
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• 2007

Armillaria tabescens, one of edible and medicinal mushrooms belonging to Agaricales of Basidiomycota, has been known to have outstanding curative effects on chronic hepatitis and cholecystitis and inhibitory effects on the sarcoma 180 and Erhrlich carcinoma of mice. Neutral saline soluble (0.9% NaCl), hot water soluble and methanol soluble substances (hereinafter referred to Fr, NaCl, Fr. HW and Fr, MeOH, respectively) were extracted from fruiting body of the mushroom. In vitro cytotoxicity tests showed that crude polysaccharides were not cytotoxic against cancer cell lines such as NIH3T3 and Sarcoma 180 at the concentration of $2000\;{\mu}g/ml$. Intraperitoneal injection with crude polysaccharides exhibited life prolongation effect of $28.8{\sim}46.5%$ in mice inoculated with Sarcoma 180, respectively. Fr. NaCl improved the immunopotentiation activity of B lymphocyte by increasing the alkaline phosphatase activity by $1.8{\sim}2.1$ folds, respectively. In case of Fr, NaCl, the numbers of peritoneal exudate cells and circulating leukocytes were increased by 9 and 1.9 folds, respectively.

• Polymer(Korea)
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• v.37 no.2
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• pp.141-147
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• 2013

Poly(lactide-co-glycolic acid) (PLGA) has been widely used in the drug delivery and tissue engineering applications because of its good mechanical strength and biodegradation profile. However, cell attachment to the scaffold is low compared with that on fibrin although cells can be attached to the polymer surface. In this study, PLGA scaffolds were soaked in cells-fibrin suspension and polymerized with dropping fibrinogen-thrombin solution. Cellular proliferation activity was observed in PLGA/fibrin-seeded costal cartilage cells (CC) on 1, 3, and 7 days using the MTT assay and SEM. The effects of fibrin on the extracellular matrix (ECM) formation were evaluated using CC cell-seeded PLGA/fibrin scaffolds. The PLGA/fibrin scaffolds elicited more production of glycosaminoglycan (GAG) and collagen than the PLGA scaffold. In this study, fibrin incorporated PLGA scaffolds were prepared to evaluate the effects of fibrin on the cell attachment and proliferation in vitro and in vivo. In this result, we confirmed that proliferation of cells in PLGA/fibrin scaffolds were better than in PLGA scaffolds. The PLGA/fibrin scaffolds provide suitable environment for growth and proliferation of costal cartilage cells.

• Food Science and Preservation
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• v.19 no.5
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• pp.751-756
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• 2012

Antioxidant capacity and acetylcholinesterase (AChE) inhibitory activity of the aqueous methanolic extract of Rhus javanica were investigated in vitro. The antioxidant properties was measured by radical scavenging assays using DPPH and $ABTS^+$ radicals. The AChE inhibitory efficacy of R. javanica was tested by Ellman's assay and the total phenolic content was determined using a spectrophotometric method. All tested samples showed a dose-dependent AChE inhibitory and radical scavenging activities. In particularly, ethyl acetate (EtOAc)-soluble portion from the methanolic extract of R. javanica showed significantly higher inhibitory activity than other organic solvent soluble-portions in an AChE and radical scavenging assay systems. These results suggest that R. javanica may be possess potential benefits which might be useful in development of antioxidant and anti-alzheimer's disease ingredient.

• Food Science and Preservation
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• v.23 no.1
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• pp.89-96
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• 2016

The purpose of this study was to investigate the chemical composition of the freeze-dried stems and fruit of the cactus Cheonnyuncho. The analysis showed that powdered stems have the highest fat content (1.91%) and the powdered fruits have he highest protein content (2.62%). The K content of the fruits higher than that of the stems, while the Ca, Mg, Na and P contents of the stems were higher than those of the fruits. Both the stems and fruits powders contained high levels of the amino acids glutamic acid and aspartic acid. The free sugars such as sucrose, fructose, and glucose were detected in both the stems and fruits. The 75% ethanol (EtOH) extract showed a relatively high antioxidative activity compared to those of the water and 75% methanol (MeOH) extracts. Furthermore, the 75% EtOH extract of the stem powder exhibited a total polyphenol content of 3.60 g/100 g, and a total flavonoid content of 2.00 g/100 g. The antioxidant activities of the stem and fruit powder extracts, measured in DPPH radical scavenging experiments, were higher than that of the control group.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.277-282
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• 2012

When wind speed exceeds a certain threshold, daily minimum temperature does not drop as predicted by the geospatial model in a cold pooling catchment. A linear regression equation was derived to explain the warming effect of wind speed on daily minimum temperature by analyzing observations at a low lying location within an enclosed catchment. The equation, Y=2X+0.4 ($R^2$=0.76) where Y stands for the warming ($^{\circ}C$) and X for the mean horizontal wind speed (m/s) at 2m height, was combined to an existing model to predict daily minimum temperature across an enclosed catchment on cold pooling days. The adjusted model was applied to 3 locations submerged in a cold air pool to predict daily minimum temperature on 25 cold pooling days with the input of simulated wind speed at each location. Results showed that bias (mean error) was reduced from -1.33 to -0.37 and estimation error (RMSE) from 1.72 to 1.20, respectively, in comparison with those from the unadjusted model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.151-156
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• 1985

In order to develop a sanitary and economic storage method for chicken carcass by gamma-irradiation, the samples irradiated with 5 to 10 kGy were stored at 3 to $4^{\circ}C$ for 41 days, and the changes in ordour, appearance and the cooking guality of stored samples were determined. The nonirradiated samples which stored for more than 7 days were not tested because of microbial spoilage on the chicken carcasses. However, the quality of irradiated groups of 5 to 10 kGy was similar to that of fresh chicken for about 15 days though it deteriorated slightly after 20 days, however, they were still acceptable to eat each after 27 days of storage. The overall acceptability, flavor and texture was not significantly different in the samples of nonirradiated those of irradiated immediately and those of irradiated and then stored for 15 days when they were prepared for Sam Gei Tang arid steamed chicken. The acceptibility of Sam Gei Tang prepared with chickens after 15 days of the storage, the irradiated groups of 8 and 10 kGy showed a similarity to the chickens prepared immediately after slaughter. In steamed chickens prepared with the samples stored for 15 days texture of the irradiated group was superior to that of the nonirradiated fresh chicken, and there were no statistical differences in the flavors between each group.

• Journal of the Korean Chemical Society
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• v.60 no.1
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• pp.16-20
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• 2016

The solvolysis rate constants of biphenyl-4-carbonyl chloride (C₆H₅C₆H₅COCl, 1) in 19 different solvents are well correlated with the extended Grunwald-Winstein equation, using the N_T solvent nucleophilicity scale, Y_Cl solvent ionizing scale, and I aromatic ring parameter with sensitivity values of 0.31±0.10, 0.46±0.05, and 0.96±0.20 for l, m, and h, respectively. These l, m, and h values can be considered to support a dissciative S_N2 reaction pathway. This interpretation is further supported by the activation parameters, i.e., relatively small positive ΔH^‡ (15.3~16.1 kcal/mol) values and large negative ΔS^‡ (−17.2~−20.0 cal/mol·K) values.