• Korean Journal of Food Science and Technology
• /
• v.41 no.6
• /
• pp.628-635
• /
• 2009

Autoxidative stability of wheat bran and germ oil extracted from Keumkang wheat (WBG-K) or Dark Northern Spring wheat (WBG-DNS) at $50^{\circ}C$ in the dark was compared by peroxide values (POV) and fatty acid composition by gas chromatography. Changes of minor compounds were monitored by HPLC. WBG-K showed significantly higher linoleic but lower oleic acid content than WBG-DNS. WBG-DNS contained more phospholipids but less tocopherols and carotenoids than WBG-K. POV of oils was increased during storage, with no significant difference in the oxidation rates between two oils. Tocopherols, carotenoids, and phospholipids in both oils were degraded during the autoxidation. Total phospholipids content showed the highest correlation with the degree of oxidation in WBG oils. The results clearly showed that both fatty acid composition and contents of tocopherols, carotenoids, and phospholipids co-affected the autoxidation of WBG oil.

• Korean journal of food and cookery science
• /
• v.29 no.6
• /
• pp.805-814
• /
• 2013

Lotus root, dried laver, and perilla leaf bugak, Korean traditional fried cuisine, were prepared with fermented glutinous rice batter and unroasted sesame oil or wheat flour batter and soybean oil and their physicochemical characteristics was evaluated. Bugak with fermented glutinous rice batter and unroasted sesame oil showed higher hardness, possibly brittleness than bugak with wheat flour batter and soybean oil. Oil absorption was higher in bugak with fermented glutinous rice batter and unroasted sesame oil than bugak with wheat flour batter and soybean oil, however, the lipid oxidation, evaluated by conjugated dienoic acid and p-anisidine values, was significantly lower in bugak with fermented glutinous rice batter and unroasted sesame oil. Frying oil strongly influenced the degree of lipid oxidation and fatty acid composition of bugak lipid. Different preparation of bugak did not show great effects on the contents of chlorophylls and carotenoids of dried laver and perilla leaf bugak, possibly due to protection by rice or wheat flour batter coating.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.3
• /
• pp.224-231
• /
• 2012

We investigated the effects of various washing methods on the quality of semi-dried Pacific saury Cololabis saira, known in Korea as Guamegi. We immersed samples for 5 min in seawater, tap water, chlorinated water (100 mg/kg), ammonia water (100 mg/kg), citric acid (0.1 M), butylated hydroxyanisole (BHA, 0.2 g/kg), or sesame oil (5 g/100 g), and then dried them in the sun for 3 days. The moisture and crude lipid contents after drying were 26.62-32.49 g/100 g and 26.40-33.01 g/100 g, respectively. The moisture content significantly decreased while the crude lipid content increased during drying. The different washing methods did not have a significant effect on the acidity, peroxide values, or levels of thiobarbituric acid or biogenic amine in Guamegi. The lightness of Guamegi during drying significantly decreased, but this decrease was not significantly different among washing methods. The degree of acceptance in a sensory evaluation was higher for Guamegi treated with sesame oil. Our results suggest that these washing methods should not be used to inhibit lipid oxidation, biogenic amine formation, or color changes in semi-dried Pacific saury, because effective components are extracted by the lipids during drying.

• Applied Chemistry for Engineering
• /
• v.28 no.2
• /
• pp.221-229
• /
• 2017

In this study, a wet impregnation method was applied to catalysts based on the active metal Pt in order to confirm the oxidation characteristics of various commercial alumina supports at room temperature. The catalysts were characterized using XPS, CO-chemisorption, and BET. Various $Pt/Al_2O_3$ catalysts controlled the oxygen species of Pt by the electronegativity of electrons and charges when the catalyst was prepared according to the heat treatment conditions. The reason that the dispersion degree decreases with increasing Pt loading seems to be attributed to HT (Huttig Temperature) of Pt. In addition, the minimum hydrogen concentration that can be controlled at room temperature can control hydrogen from metallic Pt up to 1.0 vol% at over 70.09% in the catalyst.

• Korean journal of food and cookery science
• /
• v.5 no.2
• /
• pp.1-8
• /
• 1989

The physicochemical properties and gel forming properties of mungbean and buckwheat crude starches were investigated. The results were as follows; 1. The granule size and shape of mungbean crude starch were $11~32\mu\textrm{m}$ and oval, and those of buckwheat crude starch were $3~10 \mu\textrm{m}$ and polygonal. 2. The amylose conteut of mungbean crude starch and buckwheat crude starch were 78.0% and 26.4% respectively. 3. The blue value of mungbean crude starch and buckwheat crude starch were 1.030 and 0.409, respectively. 4. Periodate oxidation of mungbean crude starch resulted that amylose had the average molecular weight of 95, 648, degree of polymerization of 590 and amylopectin had the degree of branching of 5.4, glucose unit per segment of 18.6, and periodate oxidation of buckwheat crude starch resulted that amylose had the average molecular weight of 133, 690, degree of polymerization of 825 and amylopectin had the degree of branching of 5.2, glucose unit per segment of 19.2 5. Water binding capacity of mungbean crude starch was 185.1% and that of buckwheat was 209.9% 6. The pattern of change in swelling power of mungbean crude starch for increasing temperature started to increase at $60^{\circ}C$ and increased rapidly from $70^{\circ}C$, and that of buckwheat increased slowly from $60^{\circ}C$ to $90^{\circ}C$ without rapid increase. 7 The ranges of gelatinization temp. of mungbean and buckwheat crude starches were 63. 9-$109^{\circ}C$ and 52.5-84.$2^{\circ}C$, respectively. 8. The gelatinization patterns for 6% munbean crude starch and 8% buckwheat crude starch were investigated by Brabender amglograph. Mungbean crude starch showed the initial pasting temperature of 77.6$^{\circ}C$ without peak height, and buckwheat crude starch showed that of $62.5^{\circ}C$ without peak height. In addition, sensory evaluation for sample starch gels (mungbean, buckwheat, cowpea) was done. 1. The difference of sensory characteristics for each starch gel was significant. 2. The sample starch gels were regarded as 'Mook' by pannels. 3. 74.44% of the degree of Mooklike was explained by hardness.

• Clean Technology
• /
• v.13 no.1 s.36
• /
• pp.54-63
• /
• 2007

Even traces of CO in the hydrogen-rich feed gas to proton exchange membrane fuel cells (PEMFC) poison the platinum anode electrode and dramatically decrease the power output. In this work, a variety of catalytic materials consisting of $Cu/Ce_xZr_{1-x}O_2$, (x = 0.0-1.0) were synthesised, characterized and tested for CO oxidation and preferential oxidation of CO (PROX). These catalysts prepared by hydrothermal and deposition-precipitation methods. The catalysts were characterized by XRD, XRF, SEM, BET, $N_2O$ titration and oxygen storage capacity (OSC) measurement. The effects of composition of the support and degree of excess oxygen were investigated fur activity and $CO_2$ selectivity with different temperatures. The composition of the support markedly influenced the PROX activity. Among the various $Cu/Ce_xZr_{1-x}O_2$ catalysts having different composition, $Cu/Ce_{0.9}Zr_{0.1}O_2$ and $Cu/Ce_{0.7}Zr_{0.3}O_2$ showed the highest activities (>99%) and selectivities (ca.50%) in the temperature range of $150{\sim}160^{\circ}C$. It was found that by using of $Ce_xZr_{1-x}O_2$ mixed oxide support which possesses a high oxygen storage capacity, oxidation-reduction activity of Cu-based catalyst was improved, which resulted in the increase of catalytic activity and selectivity of CO oxidation in excess $H_2$ environments.

• Korean Journal of Food Science and Technology
• /
• v.40 no.6
• /
• pp.707-711
• /
• 2008

The principal objective of the current study was to isolate a purpurogallin derivative as an oxidation product from gallic acid, in an effort to assess the anti-inflammatory effects of this compound. Purpurogallin derivative is known to be the one of the oxidation products of gallic acid. This compound has been identified as a minor chemical component in fermented tea products. It has been previously demonstrated that theaflavins, the oxidation products of catechins found in fermented tea products, exert profound antioxidant and anti-inflammatory effects. However, the biological activities of a minor chemical component in fermented teas have yet to be evaluated. Purpurogallin carboxylic acid (PCA) was identified as a major oxidation product of gallic acid from a peroxidase/hydrogen peroxide oxidation model system. The identity of the PCA was verified by $^{1}H$ NMR, $^{13}C$ NMR and MS techniques. PCA treatment significantly suppressed the generation of pro-inflammatory mediators including nitric oxide and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages. According to the nitrite assay, PCA 100, 75, and $50{\mu}g/mL$ treatment dose-dependently inhibited NO production by 57.6, 41.5, and 21.8%, respectively, in LPS-stimulated RAW264.7 murine macrophage cells. Moreover, IL-6 production was inhibited to a significant degree with PCA treatment of 100 and $75{\mu}g/mL$ at 43.1 and 23.9%, respectively. PCA treatment also significantly suppressed $PGE_2$ production at levels of 100 and $75{\mu}g/mL$. These results showed that PCA exerts inhibitory effects on the production of inflammatory mediators.

• Restorative Dentistry and Endodontics
• /
• v.13 no.2
• /
• pp.221-235
• /
• 1988

The purpose of this study was to observe characteristic properties through the polarization curves and EMPA images from 4 different types of amalgam obtained by using the potentiostats (EG & G PARC) & EPMA (Jeol JSM-35), to investigate the degree of corrosion of each phase of amalgam on the oxidation peak, and to identify corrosion products from the corroded amalgam by use of X-ray diffractometer(Rigaku). After each amlgam alloy and Hg were triturated as the direction of the manufacturer by means of the mechanical amalgamator(Shofu), the triturated mass was inserted into the cylindrical metal mold which was 12mm in diameter and 10mm in height and was condensed by means of routine manner. The specimen was removed from the mold and stored at room temperature for about 7 days. The standard surface preparation was routinely carried out. Anodic polarization measurement was employed to compare the corrosion behaviours of the amalgams in 0.9% saline solution(pH6.8~7.0) and artificial saliva (pH6.8~7.0) at $37^{\circ}C$. The open circuit potential was determined after 30 minutes' immersion of specimen in electrolyte and the potential scan was begun at the potential of 100mV cathodic from the corrosion potential. The scan rate was 1mV/sec and the surface area of amalgam exposed to the solution was 0.64$cm^2$ for each specimen. All the potentials reported are with respect to a saturated calomel electrode (SCE). EPMA images on the determined oxidation peaks of each amalgam in artificial saliva were observed. X-ray diffraction patterns of each sample were recorded before and after polarization in artificial saliva (Aristaloy, Caulk Spherical, Dispersalloy and Tytin: at +770mV, +585mV, +8.10m V and +680m V respectively) by use of a recording diffractometer. Nickel filtered Cu $K_{{\alpha}_1}$ radiation was used and sample was scanned at $4^{\circ}(2{\theta})/min.$ from $25^{\circ}$ to $80^{\circ}$. The following results were obtained. 1. Oxidation peak potential in artificial saliva shifted to more anodic direction than that in saline solution. 2. The corrosion potential of high copper amalgam was more anodic than the potential of low copper amalgam. 3. The current density was lower in artificial saliva than in saline solution. 4. One of the corrosion products, AgCl was identified by X-ray diffraction analysis. 5. ${\gamma}_2$ phase was the most susceptible to corrosion and e phase was stable in low copper amalgam and ${\eta}$' phase and Ag-Cu eutectic were susceptible to corrosion in high copper amalgam.

• Journal of Wetlands Research
• /
• v.23 no.1
• /
• pp.60-66
• /
• 2021

As the concentration of nitrogen in the sewage flowing into the sewage treatment plant increases due to urbanization and industrialization, the degree of adverse effects such as eutrophication and toxicity to the aquatic ecosystem is also increasing. In order to treat sewage containing high concentration of nitrogen, various studies on the biological nitrogen removal process are being conducted. Existing biological nitrogen removal processes require significant costs for supplying oxygen and supplementing external carbon sources. In this respect, as a high-level nitrogen removal process with economic improvement is required, an anaerobic ammonium oxidation process (ANAMMOX), which is more efficient and economical than the existing nitrification and denitrification processes, has been proposed. The purpose of this study is to confirm the stability of the ANAMMOX process in the water treatment process and to derive the ratio of ammonia nitrogen (NH4+) to nitrite nitrogen (NO2-) for the implementation of the mainstream ANAMMOX process. A laboratory-scale Mainstream ANAMMOX reactor was operated by applying the ratio calculated based on the substrate ratio suggested in the previous study. In the initial range, the removal efficiency of NH4+ was 58~86%, and the average removal efficiency was 70%. In the advanced range, the removal efficiency of NH4+ was 94~99%, and the average removal efficiency was 95%. As a result of the study, as the NH4+/NO2- ratio increased, the stability of the mainstream ANAMMOX process was secured, and it was confirmed that the NH4+ removal efficiency and the total nitrogen (TN) removal efficiency increased. As a result, the results of this study are expected to be used as basic data in the application of the ANAMMOX process in the mainstream.

• Korean Journal of Plant Resources
• /
• v.24 no.2
• /
• pp.236-242
• /
• 2011

In this present study, we investigated the anti-oxidant activity, the inhibition ability of lipid peroxidation, and the protective effect of cow pulmonary epithelium (CPAE) cells under oxidative stress using green tea and 3 types of fermented teas of Jeju Island. To compare the physiological activity of non-fermented and 3 types of fermented teas, the fermented time was controlled with 0 hr. (non fermented tea, G), 12 hrs. (20% fermented tea, F20), 17 hrs. (50% fermented tea, F50) and 24 hrs. (80% fermented tea, F80), respectively. Scavenging ability on DPPH radicals of 80 ${\mu}g/mL$ concentration of F20 was similar to that of 50 ${\mu}M$ epigallocatechin gallate (EGCG) but it was stronger than those of G, F50 and F80. All extracts tested inhibited LDL oxidation but G and F20 inhibited LDL oxidation 25~30% more than F50 and F80 at 40 ${\mu}g/mL$ concentration which was similar to that of 50 ${\mu}M$ EGCG. We observed that the CPAE cells treated with the tea extracts had a significant increase in cell viability, especially the cells under oxidative stress with 1 mM $H_2O_2$ as compared with the control group (no treatment with tea extracts). These findings suggested that all tea extracts containing fermented tea had a protective effect on oxidative stressed CPAE cells through their free radical scavenging activity. It can be concluded that F20 extracted from 20% fermented tea has the most significant antioxidative effects that inhibit lipid peroxidation and protect the CPAE cells under oxidative stress.