• Journal of the Korean Applied Science and Technology
• /
• v.34 no.1
• /
• pp.163-172
• /
• 2017

The purpose of this study was to measure the bioactivity and antioxidant activity of peel from Gardenia jasminoides Ellis fructus (GJE). GJE have been known to contain functional materials such as crocin, crocetin, geniposide, gardenosid, geniposidic acid, iridoid glycosides etc. We were separated into GJE peel. After that, we determined proanthocyanidin. GJE peel were extracted by 70% methanol, ethyl acetate (EA) and distilled water (DW) of three solvents. To investigate by the solvent extract of flavonoid content and value as a functional food ingredient of GJE peel through antioxidant activities (DPPH radical scavenging activity, ABTS radical scavenging activity, superoxide dismutase like ability, hydroxyl radical scavenging activity, ferrous ion-chelating capacity) were performed. Solvent extract antioxidant activity of increasing concentrations (0.2, 0.4, 0.6 mg/mL) were significantly increased (p<0.05). GJE peel extracts showed lower activity than positive control (ascorbic acid, BHA, EDTA). These results, by a solvent of peel were found that the relationship with the increase of flavonoid content increased physiological activity. The antioxidant activity of the extract from the other except for the EA extract on peel was observed at a high level. The results suggest that GJE peel can be used as nutraceutical foods and natural antioxidant.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.3
• /
• pp.343-349
• /
• 2017

The study was conducted to compare quality characteristics and antioxidant activities of aged black chestnut inner shells (ACI) and raw chestnut inner shells (RCI). RCI were aged for 15 days at high humidity and temperature. As storage time progressed, the pH level decreased while acidity increased. The sugar concentration ($^{\circ}Brix$) and reducing sugar concentration (%) increased during storage, whereas L (lightness) decreased. Compared with RCI, L value of ACI was darker than that of RCI after 9 days of storage. In the Hunter color system, L and a (redness) values of ACI were higher than those of RCI, whereas there was no visible difference in degree of aging. Although total phenol contents increased with degree of aging, phenol contents of ACI increased more than those of RCI after 9 days of aging. $IC_{50}$ values for 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging activities decreased with degree of aging. Based on these results, it is suggested that aged black chestnut inner shells were appropriate in terms of both physicochemical and antioxidative activities.

• Polymer(Korea)
• /
• v.27 no.3
• /
• pp.210-216
• /
• 2003

4-Vinyl-1-cyclohexene diepoxide (VCE)/diglycidyl ether of bisphenol-A (DGEBA) epoxy blends with benzylquinoxalinium hexafluoroanti-monate were cured using an electron-beam technique. The effect of DGEBA content to VCE on cure behavior, thermal stabilities, and mechanical properties was investigated. The composition of VCE/DGEBA blend system vaned within 100:0, 80:20, 60:40, 40:60, 20:80, and 0:100 wt%. The cure behavior and thermal stability of the cured specimens was monited by near-infrared spectroscopy and thermogravimetric analysis, respectively. Also, the critical stress intensity factor ($_{4}$) test of the cured specimens was performed to study the mechanical interfacial properties. As a result, the decreases of short side-chain structure and chain scission were observed in NIR measurements as the DGEBA content increases, resulting in varying the hydroxyl and carbonyl groups. And, the initial decomposition temperature (IDT), temperature of maximum weight loss (T$\_$max/), and decomposition activation energy (E$\_$d/) as thermal stability factors were increased with increasing the DGEBA content. These results could be explained by mean of decreasing viscosity, stable aromatic ring structure, and grafted interpenetrating polymer network with increasing of DGEBA content. Also, the maximum $_{4}$ value showed at mixing ratio of 40:60 wt% in this blend system. in this blend system.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.2
• /
• pp.158-164
• /
• 1998

Crystal structural analyses of the API-TLCK complex revealed that the ${\epsilon}$-amino group (NZ) of the lysyl part of TLCK forms hydrogen bonds with OD1 of $Asp^225$ which is a substrate specificity determinant of API, OG of $Ser^214$, O of $Ser^214$, OG1 of $Thr^189$, and O of $Thr^189$ l89/. The ${\beta}$-carboxyl oxygen of $Asp^225$ forms hydrogen bonds with the NE1 of $Trp^182$. From these observations, it is thought that besides $Asp^225$, $Thr^189$, $Ser^214$, and $Trp^182$ may also contribute to the steric specificity for lysine and high proteolytic activity of API. The side-chain hydroxyl groups of $Thr^189$ and $Ser^214$ were removed to elucidate the role of these hydrogen bonds in the $S_1$-pocket. The $k_{cat}$/$K_m$ of T189V, S214A, and T189V.S214A were decreased to 1/4, 1/3, and 1/46, respectively, of the value for native API. The decreased activities were mainly due to the increase of $K_m$. The CD and fluoroscence spectra of the three mutants were similar to those of wild-type API. With regards to the kinetic parameters ($K_i\;and\;k_2$) of mutants for the reaction involving TLCK and DFP, $k_2$decreased by increase of $K_1$ only. These results suggest that the decreased catalytic activity of these mutants is caused by the partial loss of the hydrogen bond network in the $S_1$-pocket. On the other hand, the similarity of enzymatic properties between W182F and the native enzyme suggests that the hydrogen bond between OD2 of $Asp^225$ and NE1 of $Trp^182$ is not directly related to the reaction of $Asp^225$ with the substrate.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.6
• /
• pp.567-572
• /
• 2005

In this study, a lab-scale test was performed to apply the ozone process in drinking water treatment plant using dissolved ai, flotation(DAF). The kinetic study on the ozone decay and hydroxyl(OH) radical formation was investigated by several parameters, such as I.D(Instantaneous ozone demand), $k_c$(ozone decomposition rate), ozone-Ct and OH radical-Ct. Ozonation of several target waters, such as raw water, DAF treated water and filtrate, was conducted to select the optimum position and dosage of ozone process. The highest value of Ozone-Ct and OH radical-Ct was observed at DAF treated water at initial run time($0{\sim}30\;min$). From the results of ozonation, the intermediate ozonation was proposed as the optimum position and the effective dose of ozone was determined to be $1{\sim}2\;mg/L$.

• Journal of the Korea Concrete Institute
• /
• v.19 no.3
• /
• pp.367-375
• /
• 2007

Critical chloride content for corrosion initiation is a crucial parameter in determining the durability and integrity of reinforced concrete structures, however, the value is still ambiguous. Most of the studies reporting critical threshold chloride content have involved the experimental measurement of the average amount of the total chloride content at arbitrary time. The majority of these researches have not dealt with this issue combined with carbonation of concrete, although carbonation can significantly impact on critical threshold chloride content. Furthermore, the studies have tried to define the critical chloride content within the scope of their experimental concrete mix proportion at arbitrary time. However, critical chloride content for corrosion initiation is known to be affected by a lot of factors including cement content, type of binder, chloride binding, concentration of hydroxyl ions, and so on. It is necessary to define the unified formulation to express the critical chloride content for various mix proportions of concrete. The purpose of this study is to establish an analytical formulation of the critical chloride content of concrete. In this formulation, affecting factors, such as mix proportion, environment, chemical evolution of pore solution with elapsed time, carbonation of concrete and so on are taken into account. Based on the Gouda's experimental results, critical chloride content is defined as a function of $[Cl^-]$ vs. $[OH^-]$ in pore solution. This is expressed as free chloride content with mass unit to consider time evolution of $[OH^-]$ content in pore solution using the numerical simulation programme of cementitious materials, HYMOSTRUC. The result was compared with other experimental studies and various codes. It is believed that the approach suggested in this study can provide a good solution to determine the reasonable critical chloride content with original source of chloride ions, for example, marine sand at initial time, and sea water penetration later on.

• ALGAE
• /
• v.21 no.1
• /
• pp.141-148
• /
• 2006

Benthic diatoms are known as a good food for shellfish in nature and in commercial hatchery of Jeju Island, Korea. Grammatophora marina is commonly found as dominant benthic micro-algae in Jeju coastal waters throughout the year. To know the best growth conditions of this species, culture was done in terms of three parameters; water temperature, salinity and nutrients. Each parameter was controlled by temperature of 15, 20 and 25°C; salinity of 25, 30 and 35 psu; and nutrient concentrations of 50, 100 and 200%. F/2 media was used with artificial seawater for the culture, which was continued for two weeks with L:D cycle 12:12 by using fluorescent light. Maximum specific growth rate was recorded 1.68 d–1 at temperature of 25°C with salinity of 35 psu and nutrient concentration of 200% on 6th day during the culture period. Maximum biomass was also observed 4.9 × 105 cells mL–1 in the same condition. This species may belong to the euryhaline and eutrophic habitat with warm condition. For nutritional aspects of this species, protein, lipid and carbohydrate were measured. The value of protein, lipid and carbohydrate was 4.96%, 15.82% and 5.65%, respectively. The antioxidant activities of 80% methanolic extract were 46.7%, 23.7% and 23.8% on DPPH (1,1-Diphenyl-2-picrylydrazy) radical, superoxide anion radical and hydrogen peroxide scavenging, respectively. Percentage metal chelating activity was 81.2%. Enzymatic extracts of Alcalase and Ultraflow showed remarkable scavenging activities on DPPH radical (86.5% and 57.2%, respectively), and superoxide anion scavenging activities were 45.3% and 41.4% from Kojizyme and Viscozyme extracts, respectively. Extract of Protomex revealed 24.8% activity on hydrogen peroxide and Neutase showed 30.8% on hydroxyl radical scavenging effects. Celluclast and Viscozyme extracts showed 33.2% and 32.1% activities on nitric oxide scavenging, respectively, while Alcalase showed 61.5% on metal chelating. This species contains higher lipids among the biochemical compounds and higher metal chelating activities from both 80% methanolic and enzymatic extracts.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.20 no.3
• /
• pp.213-218
• /
• 1987

The DNA damage mechanism by fish oil peroxidation was investigated through the model system of a DNA-mackerel lipid at $37^{\circ}C$. Mackerel lipid peroxidation products induced a great DNA damage with the increment of its concentration, and such DNA damage in all systems examined occurred below $100millieq{\cdot}/kg$ in POV (peroxide value) Singlet oxygen $(^1O_2)$ and superoxide anion${\cdot}O_2^-$ greatly participated in the DNA damage during peroxidation of mackerel lipid, while hydrogen peroxide$(H_2O_2)$ and hydroxyl radical $({\cdot}OH)$ did little show the DNA damage. From the results of the addition of several active oxygen scavengers to the DNA-lipid systems, singlet oxygen ana superoxide anion greatly affected to the increase of POV ana to the DNA damage by mackerel lipid peroxidation, respectively. It indicates that there was a close relationship between the effects of active oxygens in the mackerel lipid peroxidation and its DNA damage mechanism.

• Journal of the Korean Chemical Society
• /
• v.21 no.5
• /
• pp.307-319
• /
• 1977

The crystal structure of $N-({\alpha}-dimethyl\;{\beta}-hydroxy)ethyl\;N'-cyclohexyl\;thiourea,\;C_{ll}H_{22}N_2OS)$, has been determined by X-ray diffraction method. The compound crystallizes in the orthorhombic space group Pbca with a = 10.33(3), b = 11.82(3), c = 22.57(4)${\AA}$ and Z = 8. A total of 1414 observed reflections collected by the Weissenberg photographs and was solved by heavy atom method and refined by block diagonal least-squares methods to the R value of 0.13. The cyclohexane ring has a normal chair conformation and the thiourea unit is planar. The primary alcoholic group O-H bonded to C(l) makes an intramolecular hydrogen bond with N(2), which leads to stablize the molecule. There are two independent hydrogen bonds in the structure. One of them is of the type N-H${\cdot}{\cdot}{\cdot}$O intramolecular hydrogen bond with the length 2.71${\AA}$, another is of the type O-H${\cdot}{\cdot}{\cdot}$S intermolecular hydrogen bond with the length 3.21${\AA}$ parallel to the b axis. Apart from the hydrogen bonding system the molecules are held together by van der Waals forces in the crystal.

• Journal of the Korean Chemical Society
• /
• v.47 no.3
• /
• pp.250-256
• /
• 2003

In this work, the effect of cationic initiator content on the electron-beam (EB) curing process of diglycidylether of bisphenol-A (DGEBA) resin was studied using near-infrared spectroscopy (NIRS), thermogravimetric analysis (TGA), and critical stress intensity factor $(K_{IC})$. Benzylquinoxalinium hexafluoroantimonate (BQH) were used as an initiator and its content was varied from 0.5 to 3 phr. NIRS measurements showed that the hydroxyl group of EB-cured epoxy resin was increased with increasing the BQH content. Thermal stability and $K_{IC}$ value of EB-cured epoxy resin were increased with increasing the BQH content but were decreased above 2 phr content. These results could be attributed to the decrease of the conversion and degree of crosslinking. In another word, the conversion and degree of crosslinking were restricted by the incomplete network structure from high reactivity at the BQH content above 2 phr, resulting in decreasings of thermal stability and $K_{IC}$.