• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.1
• /
• pp.15-20
• /
• 2006

The water and $40\%$ ethanol extracts from mulberry fruits were tested for their antimicrobial activities against Helicobacter pylori and antioxidant. Kangwon III (Morus albba L.) was higher phenolic content (2.90 mg/g) than other water extracts. The phenolic contents of $40\%$ ethanol extracts from Kangwon III and Hihak were 3.02 mg/g and 2.46 mg/g, respectively . The ABTS [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfornic acid)] radical decolorization, electron donating ability (EDA), thiobarbituric acid reactive substance (TBARS) and antioxidant protection factor (PF) were determined for water extracts and $40\%$ ethanol extracts from mulberry fruits. EDA was higher in water extracts than ethanol extract. EDA of water extract from Kangwon III was determined as $99.54\%$ while the activity of ethanol extracts was $89.61\%$ in Daechoukmyeun. The water extracts from Cheongilppong showed higher antioxidative activity than another mulberry fruits extract when evaluated by ABTS [2,2'-azinobis(3-ethylbenzothiaznoline-6-sulfornic acid)] radical decolorization, TBARS and antioxidant PF by water extracts. Kangwon III was higher phenolic content (2.90 mg/g) than other that of water extracts. $40\%$ ethanol extracts were determined that phenolic contents of Kangwon III, Hihak were 3.02 mg/g, 2.46 mg/g for each other. Antimicrobial activity showed the high value in water extracts of Cheongilppong, Kuksang 20. The result will be useful nature microbial medicine for mulberry fruits.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.9
• /
• pp.1370-1377
• /
• 2013

Rice is widely grown in Asia and is one of the major dietary staples in the world. Also, rice contains antioxidants which can prevent from oxidative stress related diseases, including cancer, atherosclerosis, and diabetes. Because the rice is consumed cooked, the effect of the cooking process on the antioxidative and antigenotoxic properties of rice is lacking. The aim of this study was to determine the effects of cooking on the antioxidant and antigenotoxic effects of white rice (WR), brown rice (BR), and germinated brown rice (GBR). The antioxidant activities were measured for total phenolic content (TPC), DPPH radical scavenging activity (DPPH RSA), total antioxidant capacity (TRAP), and oxygen radical absorbance capacity (ORAC). The highest TPC was found in uncooked BR (18.4 mg gallic acid equivalent/100 g). After cooking, the TPC of WR significantly increased, while the TPC of BR and GBR were reduced by 47.7% and 36.7%, respectively. The $IC_{50}$ for DPPH RSA was not significantly different in uncooked rice, while the DPPH RSA of WR and GBR decreased after cooking and the DPPH RSA of BR significantly increased. TRAP values in BR and GBR increased after cooking, while the value of WR decreased. The ORAC values of uncooked WR, BR, and GBR were 5.3, 4.3, and $3.9{\mu}M$ trolox equivalent at the concentration of $50{\mu}g/mL$. After cooking, the ORAC value of BR remained unchanged, while the value of GBR increased and the value of WR decreased. The antigenotoxic activities of WR, BR, and GBR were determined by measuring the inhibitory effects of $H_2O_2$-induced DNA damage on human leukocytes using the comet assay. The results showed that all rice tested showed a significant antigenotoxic effect against oxidative stress, except for the cooked white rice. Overall, our results indicate the addition of brown rice and/or germinated brown rice to cooked white rice is a good option for improving the benefits of rice.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.1
• /
• pp.61-71
• /
• 2000

When irradiate the power ultrasound into the aqueous solutions, water vapor is decomposed by the heat of very high temperature in the cavitation bubble to produce OH (hydroxyl radical) and H (hydrogen radical), and these radicals play a role in decomposing the substances in aqueous solution by oxidation and/or reduction, and in producing the hydrogen peroxide. Accordingly it is possible to predict that the quantity of hydrogen peroxide produced may correlate with the sonolysis mechanism of the substance in aqueous solution. Thus to confirm this prediction, the quantities of hydrogen peroxide produced from each of the air saturated distilled water and three aqueous solutions of TCE, benzene, and 2,4-DCP that are prepared by dissolving them into distilled water are measured. As a result, it showed that the quantity of hydrogen peroxide produced from the distilled water and three aqueous solutions are increased in order of distilled water>TCE solution>2,4-DCP solution>benzene solution, and decrease with decrease in concentration of organic substance, which coincide with the sonolysis mechanisms reported that TCE in aqueous solution is decomposed directly by the pyrolysis in and around the cavitation bubbles when its concentration is high and by the radical reaction when low, however, benzene and 2,4-DCP are decomposed not only by the pyrolysis but also by the radical reactions. Effects of such experimental parameters as the acoustic frequency and power and as the concentration showed that the higher the acoustic frequency and the lower the acoustic power, the less the quantity of hydrogen peroxide was produced. This result coincide with the theory of ultrasound for the relation between the cavitation that is the energy source of the power ultrasound in aqueous solution and these experimental parameters.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.23 no.2
• /
• pp.76-90
• /
• 2018

To determine the distribution of mercury (Hg) in the coastal surface sediments around the Korean peninsula, the baseline concentration of Hg was estimated, the extent of contamination was assessed, and the factors controlling the distribution were discussed. The concentrations of Hg in surface sediments were significantly high in Jinhae-Masan Bay in the South Sea, Ulsan-Onsan Bay and Yeongil Bay in the East Sea, but Hg in other sediments showed a similar distribution to Cs and relatively very low concentration between 0.21 and $39.5{\mu}g/kg$ ($13.6{\pm}7.80{\mu}g/kg$). Compared to the sediment quality guidelines in Korea, 8 % of the surface sediments (n=282) analyzed in this study exceeded the values of the threshold effects level (TEL), and six sediments collected around Onsan Port were higher than the value of the probable effects level (PEL). The contamination levels of Hg were assessed by the enrichment factors using the baseline concentration (2.06Cs+1.75) based on the residual analysis from the linear regression line for Cs, and further, factors controlling the distribution of Hg were discussed by the comparison with geochemical substances depending upon the Hg enrichment level. Hg concentrations were correlated well with Cs concentration in the range of less than 1.69 of EF implying grain size control, while in the range of 1.69 and 4.03 Hg concentrations were correlated well with Fe oxyhyroxide and organic carbon contents, which indicates Hg was enriched by superior sorption capability. On the meanwhile, samples with higher EFs (4.03 to 74.9) showed fairly positive correlations with other metals (Cu, Zn, Pb) rather than geochemical substances. For samples in Youngil Bay and Ulsan-Onsan Bay (n=30), Hg concentrations were correlated only with other metals rather than geochemical substances implying simultaneous supply of metal particles from metal refineries. But samples at Gosung, Sokcho and Uljin coast were correlated well with organic carbon even though they had high EFs. In addition, samples in Jinhae-Masan Bay with high contents of S were enriched by relatively high sulfide formation.

• Journal of Food Hygiene and Safety
• /
• v.32 no.6
• /
• pp.460-469
• /
• 2017

The aim of this work was to study the comparison of anti-oxidative activity in a single serving size of commercial coffees and teas. Commercial regular coffees and teas, including, brand regular coffees ($BC_A$, $BC_B$, $BC_C$, $BC_D$, and $BC_E$), green tea ($GT_A$, $GT_B$, $GT_C$, and $GT_D$), black tea ($BT_A$, $BT_B$, and $BT_C$), pu-erh tea ($PT_A$, $PT_B$, and $PT_C$), chamomile tea ($CT_A$, $CT_B$, and $CT_C$), peppermint tea ($P_A$, $P_B$, and $P_C$), polygonatum odoratum tea ($POT_A$, $POT_B$, and $POT_C$), and jujube tea ($JT_A$, $JT_B$, and $JT_C$) were assayed for the levels of ascorbic acid, caffeine, total content of polyphenols and flavonoids, and ability to scavenge free radicals, using two in vitro antioxidant assays. The scavenging abilities of $BC_A$ and $BC_C$ were $664.91{\pm}48.87mg$ ascorbic acid equivalent/serving size and $624.36{\pm}16.18mg$ ascorbic acid equivalent/serving size, respectively. The four beverage samples ($BC_A$, $BC_C$, $GT_D$, and $BT_A$) significantly reduced the production of reactive oxygen species (ROS) and intracellular oxidative stress induced by $H_2O_2$. These results suggest that the beverages possess significant radical scavenging ability, which may be due to the presence of antioxidants. Furthermore, the significant reducing level of ROS evidences the potential antioxidant effects of these beverages in human cells.

• Journal of Life Science
• /
• v.28 no.12
• /
• pp.1406-1415
• /
• 2018

Based on the antioxidative effects in organic solvent fractions obtained from the main methanolic extract of Houttuynia cordata Thunb, the cytoprotective effects by oxidative-stress were here analyzed. Regarding the antioxidant activity of organic solvent fractions, the electron-donating ability of DPPH increased in a dose-dependent manner, and $ED_{50}$ exhibited the highest concentration at $175{\mu}g/ml$ in the Hc-EtOAc fraction. The cell viability of Hc-EtOAc fractions on $H_2O_2$-induced HaCaT cell death ($IC_{50}$) increased in a concentration-dependent manner and a visible cell survival rate of 74% was observed at a concentration of $100{\mu}g/ml$. Meanwhile, the gene expression patterns in HaCaT cells treated with $100{\mu}g/ml$ of the Hc-EtOAc fraction for 6 and 24 hr were identified with microarray analysis. The genes involved in signal transduction, cell division, antioxidant activity, and epithelial cell proliferation were found to be 2-fold up-regulated genes in HaCaT cells following the Hc-EtOAc fraction treatment. Especially, proinflammatory cytokines (IL1B, TNF, and IL6) were identified as involved in antioxidant activity based on the expression patterns of the HaCaT cells, and pathway analysis indicated that TLR4 might be considered an upstream regulator of these genes. In order to verify the activity of IL1B, TNF, and IL6, qRT-PCR showed that the expression increased more than 2 times in HaCaT cells treated with at least $100{\mu}g/ml$ of the Hc-EtOAc fraction. The activity of the upstream regulator TLR4 protein was also increased by the Hc-EtOAc fraction. As a result, the antioxidative activity of the Hc-EtOAc fraction is predicted to pass from TLR4 through cytokines such as IL1B, TNF, and IL6.

• Economic and Environmental Geology
• /
• v.52 no.3
• /
• pp.223-230
• /
• 2019

The calcination of oyster shells have been studied as the possible substitute for the limestone used as an absorbent of $SO_2$ gas. However, since pure shells can not be used in calcination process, some impurities are contained and the changes in the characteristics of the calcination products are expected. In this study, the surface characteristics of the calcination products are investigated by mineralogical analysis according to the contents of NaCl, which can be derived from sea water, and sediments on the surface of the shell as impurities. The marine sediments on the shells were mainly composed of quartz, albite, calcite, small amounts of amphibole and clay minerals such as ilite, chlorite and smectite. After calcination of oyster shells mixed with 0.2-4.0 wt% sediments at $900^{\circ}C$ for 2 hours, regardless of the dehydration, dehydroxylation, and phase change of these minerals at the lower temperature than this experiment, no noticeable changes were observed on the specific surface area of the calcined product. However, when mixed with 0.1 to 2.0 wt% NaCl, the specific surface area generally increases as compared with the shell sample before calcination. The specific surface area increases with increasing amount of salt, and then decreases again. This is closely related to the changes of surface morphology. As the amount of NaCl increases, the morphology of the surface is similar to that of gel. It changes into a slightly angular, smaller particle and again looks like gel with increasing amount of NaCl. Our results show that NaCl affects morphological changes probably caused by melting of some oyster shells, but may have different effects on the specific surface area of calcination product depending on the NaCl contents.

• Economic and Environmental Geology
• /
• v.54 no.6
• /
• pp.671-687
• /
• 2021

This study investigated the firing temperature and thermal deformation process of roof tiles excavated from the connected stone-mound tomb in Seokchon-dong, Seoul, based on mineralogical and physical properties. A large number of roof tiles were excavated from the tomb site and some roof tiles were deformed by heat and were fired in uneven conditions. The colors of original roof tiles and their cores are mostly yellowish-brown, with high water absorption over 12%, containing fine-grained textures and some minerals such as quartz, feldspars, amphibole, and mica. It is estimated that the original roof tiles were fired below 900℃ in oxidation condition, showing loose matrices and mica layers by scanning electron microscopy. However, deformed roof tiles have the uneven surface color of reddish-brown and bluish-gray, and those cross-sections have sandwich structures in which dense reddish-brown surface and porous grey core coexist. They contained mullite and hercynite, so it was estimated to have been fired over 1,000℃, with 0.81~11% water absorption. In some samples, bloating pores by overfiring were observed, which means that they were fired at more than 1,200℃. In addition, the refirng experiments that the original roof tile was fired between 800℃ and 1,200℃ were carried out to investigate the physical and mineralogical properties of roof tiles compared to deformed ones. As a result, the water absorption decreased rapidly and the mineral phase started to change over 1,000℃. As the temperature gradually rises, the matrices are partially melted and recrystallized, resulting in similar thermal characteristics of deformed roof tiles. Therefore, the roof tiles from ancient tombs in Seokchon-dong seem to experience the secondary high temperature of 1,000 to 1,200℃ under uneven firing conditions, resulting in deformation characteristics such as shape transformation and mineral phase transition. It is considered to have been related to cremation rituals at the tombs of Seockchon-dong during the Baekje period.

• Korean Journal of Mineralogy and Petrology
• /
• v.35 no.3
• /
• pp.355-365
• /
• 2022

Precipitation and phase transition of iron minerals in mine drainage greatly affect the behavior of trace elements. However, the precipitation of ferrihydrite, one of the major iron minerals precipitated in drainage, and the related behavior of trace elements have hardly been studied. In this study, the effects of pH change and time on mineral precipitation characteristics in mine drainage from the Munkyeong coal mine were investigated, and the behavioral changes of trace elements related to the precipitation of these minerals were studied. In the case of precipitated mineral phases, goethite was observed at pH 4, and 2-line ferrihydrite mixed with small amount of 6-line ferrihydrite was mainly identified at pH 6 or higher. In addition, it was observed that the precipitation of calcite additionally increased as the pH increased in the samples at pH 6 or higher. The occurrence of goethite was probably due to the phase change of initially precipitated ferrihydrite within a short time under the influence of low pH. Our results showed that the concentration of trace elements was strongly influenced by pH and time. With increasing time, Fe concentration in the drainage showed a abrupt decrease due to the precipitation of iron minerals, and the concentration of As existing as oxyanions in the drainage, also decreased rapidly like Fe regardless of the pH values. This decrease in As concentration was mainly due to co-precipitation with ferrihydrite, and also partly to surface adsorption on goethite at low pH in drainage. Contrary to this observation, the concentration of other trace elements, such as Cd, Co, Zn, and Ni was greatly affected by the pH regardless of the mineral species. The lower the pH value, the higher the concentration of these trace elements were observed in the drainage, and vice versa at higher pH. These results indicate that the behavior of trace elements present as cations is more greatly affected by the mineral surface charge influenced by the pH values than the type of the precipitated mineral.

• Applied Chemistry for Engineering
• /
• v.34 no.3
• /
• pp.258-263
• /
• 2023

In this study, conductive polymers and the enzyme tyrosinase (Tyr) were deposited on the surface of a screen printed carbon electrode (SPCE), which can be fabricated as a disposable sensor chip, and applied to the detection of bisphenol F (BPF), an endocrine disruptor with proven links to male diseases and thyroid disorders, using electrochemical methods. On the surface of the SPCE working electrode, which was negatively charged by oxygen plasma treatment, a positively charged conductive polymer, poly(diallyldimethyl ammonium chloride) (PDDA), a negatively charged polymer compound, poly(sodium 4-styrenesulfonate) (PSS), and another layer of PDDA were layered by electrostatic attraction in the order of PDDA, PSS, and finally PDDA. Then, a layer of Tyr, which was negatively charged due to pH adjustment to 7.0, was added to create a PDDA-PSS-PDDA-Tyr sensor for BPF. When the electrode sensor is exposed to a BPF solution, which is the substrate and target analyte, 4,4'-methylenebis(cyclohexa-3,5-diene-1,2-dione) is generated by an oxidation reaction with the Tyr enzyme on the electrode surface. The reduction process of the product at 0.1 V (vs. Ag/AgCl) generating 4,4'-methylenebis(benzene-1,2-diol) was measured using cyclic and differential pulse voltammetries, resulting in a change in the peak current with respect to the concentration of BPF. In addition, we compared the detection performance of BPF using an ionic liquid electrolyte as an alternative to phosphate-buffered saline, which has been used in many previous sensing studies. Furthermore, the selectivity of bisphenol S, which acts as an interfering substance with a similar structure to BPF, was investigated. Finally, we demonstrated the practical applicability of the sensor by applying it to analyze the concentration of BPF in real samples prepared in the laboratory.