• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.2
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• pp.59-68
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• 2023

Sweet corn is widely consumed due to its high nutritional content and diverse phytochemical composition, including carotenoids and phenolic compounds, which have several benefits for human health. This study aims to identify breeding materials for developing high-functional sweet corn varieties by evaluating the phytochemical and antioxidant activities of 37 Korean sweet corn inbred lines. The results revealed genetic variation in various components, such as carotenoid content (range of 120.7~1239.3 mg 100 g^-1), polyphenol content (490.5~740.6 mg gallic acid equivalent 100 g^-1), and flavonoid content (7.3~68.6 mg catechin equivalent 100 g^-1). In addition, the free radical scavenging capacity, measured using 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), also varied among the inbred lines. Therefore, in this study, we identified Korean sweet corn inbred lines with high phytochemical content and excellent antioxidant activity. The development of sweet corn varieties with improved functionality is expected to further expand the role of sweet corn as a source of antioxidants in the Korean diet.

• Journal of the Korean Applied Science and Technology
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• v.41 no.3
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• pp.613-622
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• 2024

This study aims to evaluate the antioxidant and anti-inflammatory effects of pomegranate (Punica granatum) leaves and to explore the potential of pomegranate leaf extract as an anti-aging cosmetic ingredient. The ethyl acetate fraction of ethanolic extract of pomegranate leaf (EFP) was assessed for its total polyphenol and flavonoid contents, as well as its antioxidant and anti-inflammatory activities. The beneficial components and skin improvement potential of pomegranate leaves were investigated. The results showed that the total polyphenol content of EFP was 871.6±16.3 mg gallic acid/g, and the flavonoid content was 36.6±0.3 mg quercetin/g. In the ABTS radical scavenging assay, EFP exhibited a dose-dependent antioxidant activity with an EC50 value of 24.62±0.48 ㎍/mL. In the skin cell cytotoxicity assay, EFP demonstrated high cell viability at concentrations below 50 ㎍/mL, indicating minimal cytotoxicity. In the nitric oxide (NO) production inhibition assay, EFP effectively inhibited NO production even at low concentrations, with near-complete inhibition at 6 ㎍/mL. These results suggest that EFP has the potential to be utilized as a natural cosmetic ingredient with antioxidant and anti-inflammatory properties.

• International Journal of Highway Engineering
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• v.2 no.3
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• pp.129-144
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• 2000

This paper presents the characteristics of viscoelastic properties and fatigue performance of SBS modified asphalt mixtures depending on the aggregate gradation. Dynamic shear rheometer (DSR) and uniaxial tensile creep tests are performed to analyze the thermomechanical behavior of asphalt binders and mixtures, respectively. Uniaxial tensile fatigue tests for seven different asphalt mixtures are conducted to evaluate the effects of aggregate gradations and SBS modifier on the fatigue performance of the mixtures. DSR and uniaxial tensile creep tests results show that the SBS modified asphalt mixtures have better rutting resistance than the unmodified mixtures at high temperatures regardless of the aggregate gradations used. Fatigue factor $G^*sin\delta$ in Superpave binder specification may not be adequate for evaluating the fatigue Performance of asphalt mixtures. It is observed from uniaxial tensile fatigue tests that SBS modified asphalt mixtures compared to unmodified mixtures have ten times longer fatigue lives regardless of the aggregate gradations(dense, SMA, and Superpave gradations) used in the mixtures. The better fatigue performance of the SBS modified mixtures is observed even after long-term aging process. The effect of aggregate gradations on the fatigue performance is not as significant as the SBS modifier. The cellulose fiber added in the SMA mixture has negligible effects on the viscoelastic Properties and fatigue performance of the mixture, but is effective in reducing draindown. Although the SBS modified asphalt binder is used, it may be necessary to add the cellulose fiber into the SMA mixture to prevent the draindown.

• Applied Biological Chemistry
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• v.25 no.2
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• pp.67-74
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• 1982

Morphology, physicochemical properties, pasting properties in the presence of various anionic ions and aging of gels of Akibare (Japoica type) and Milyang 23 (Indica type) rice starch were studied, Both starches. were polygonal with length in the range of $3{\sim}6{\mu}m$. Starch granules of Akibare were somewhat smaller than those of Milyang 23. X-ray diffraction study demonstrated that peak shape and intensity were significantly different between the two starches. Akibare and Milyang 23 rice starch had amylose content of 18.5 and 19.5% and water binding capacity of 106 and 100%, respectively. Milyang 23 rice starch had a higher swelling power than Akibare starch. A relationship between percent solubility and swelling power implied that bonding forces within the granules of the both starches were different. The optical transmittance of 0.1% suspension of the two starches increased rapidly from $60^{\circ}C$. In the range of $60{\sim}90^{\circ}C$, the two starches showed a single gelatinization pattern. Amylograms of the two starches in the presence of various anionic ions showed that pasting temperature and peak temperature were progressively increased in the order of SCN-${SO_4}^=$. SCN- and I- ions increased the peak height of Akibare rice starch while only SCN- ion was effective for Milyang 23 rice starch. There were no differences in the rates of retrogradation of 45% gels of the two starches stored at $21^{\circ}C$.

• Food Science and Preservation
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• v.23 no.4
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• pp.495-501
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• 2016

Seok-jang is one of traditional seasonings prepared by solidification of the mixture of say sauce and salt for long period of aging time. In this study, the physiochemical properties of Seok-jang were investigated for the substitution of solar salt. Seok-jang exhibited highest mineral (P, Na, Fe, Mn, and Al) contents than those of solar salt and soy sauce, while showed lower soluble solids content than that of soy sauce. Seok-jang also exerted the highest pH value 7.70 compared to solar salt and soy sauce. Whereas magnesium and calcium contents of solar salts were 2.90 and 0.26 ppm, which were significantly higher than those of Seok-jang. In color values, $L^*$ value was highest in solar salt and lowest in say sauce, While the highest $a^*$ and $b^*$value were 6.19 and 18.2 observed in Seok-jang followed by a solar salt and soy sauce. On the other hand, less amount of insoluble solid and sand powder content were 0.03 and 0.07% found in Seok-jang, respectively. In conclusion, Seok-jang was suitable for the potentional substitution of natural salt ingredient.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.262-262
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• 2017

Brown rice contains a variety of nutritional and bio-functional components compared to milled rice. However, low consumer preference for steamed brown rice and short shelf life has been implicated as deterrents to the direct consumption of brown rice. This study was undertaken to determine the effect of degree of milling (DOM) on pasting and aging properties of brown rice cultivar. Short-grain (Japonica type) brown rice cv. Boseogchal (BSC), Baegjinju (BJJ), and Hiami (HIAM) were evaluated every month during 4 months storage. Rice cultivar were categorized into waxy (BSC), medium-waxy (BJJ), and non-waxy (HIAM) of which amylose contents were 6.81%, 10.06%, and 16.69~16.72%, respectively. Peak viscosity was the highest in BJJ followed by HIAM, and BSC, showing peak viscosity was lower at low temperature storage. At storage at room temperature from 60 to 120 days, the FFA content significantly increased in the rice samples with DOM1% followed by 3% and 5%, while not significant increase in DOM0% brown rice: at 120 days, the FFA ranged in 28.35~41.48, 111.99~130.06, 76.87~91.99, and 47.13~62.37 mg KOH/100g for DOM 0%, 1%, 3% and 5%, respectively. It indicated that the fat rancidity was the least in the order of DOM 0%, 5%, 3% and 1%. Storage at low temperature could reduce fat hydrolysis with lower FFA release, but rice grain with 1% MD also released more FFA compared to the other samples. It could be assumed that the most outer bran layer, approximately 1~3%, could provide a strong protection from fat rancidity. Pasting viscosity of rice samples also increased with increasing DOM rate. Results indicated that DOM was the most significant factor for lipid rancidity during storage, resulting in high FFA formation. It suggested that brown rice with DOM 0% and/or more than DOM 5% could provide the best shelf life.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.23-30
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• 2007

Round piles of Korean larch were excavated from the foundation of ex-Chosunchongdokbu (ex-Chosun Governer-General Building), which was constructed in 1916 and dismantled later in 1996. By the record (Huh, 1996), the Korean larch logs were logged from the Yalu river area near Mt. Baekdu in North Korea. At present, however, Korean larch is not so popular in South Korea. The latewood ratio profiles and strength properties (longitudinal compression, shear, longitudinal tensile, and bending) were obtained. The ratio of latewood from pith to bark increased up to 25 years, and then it showed constant tendency at 40% with some variances. From the microscopic observation, however, the latewood ratio decreased from the heartwood to the sapwood. Compression strength was greater and bending strength was a little lower than the previous reports (references 13~15), which might be attributed to the strength reduction of old structural members by aging or damage in the compression specimens than the bending ones. The flat-grained specimens for the shear and tension test showed higher coefficient of variation (COV) than the edge-grained ones. For the better comparison of results, in case of shear and tensile strength tests, the strength values of the edge-grained specimens were thought to be adopted rather than those of flat-grained ones.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.7
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• pp.511-523
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• 1989

This paper investigates physical properties, the electrical and mechanical characteristics of the epoxy resin with different curing methods and postcuring conditions at room temperature or cryogenic temperature (LN2). According to the results in this paper, first, it is found that the physical properties, electrical and mechanical characteristics of the epoxy resin are largely affected by the interior reaction temperature on the curing. Thus, in the fabrication of the sample, several excellent characteristics of the sample are obtained by controlling the interior reaction temperature of the epoxy resin. Second, the sample having optimal electrical and mechanical characteristics is obtained for the repetitive post-curing method at 100c in view point of the post-curing conditions of the epoxy resin. Third, it appears that tan and characteristics at LN2 temperature are about half of those at room temperature. Fourth, it appears that the dielectric strength of the epoxy resin at LN2 temperature is higher by about 0.6-1.0 MV/cm than that at room temperature. The heat-aging of the epoxy resin due to the micro-defect and excess fever-movement have been noticed to affect dielectric strength at LN2 temperature more significantly than at room temperature.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.357-363
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• 2015

The development of the environment-friendly tire that meets the standard requirements according to tire labeling system can be improved through using highly homogeneous silica immobilized zinc oxide nanoparticles. In this study, a considerable amount of nanoporous silica was essentially added into nano zinc oxide to improve the physiochemical properties of the formed composite. The introduction of nanoporous silica materials in the composite facilitates the improvement of the wear-resistance and increases the elasticity of the tread. Therefore, the introduction of nanoporous silica can replace carbon black as filler in the formation of composites with desirable properties for conventional green tire. Herein, mesoporous silica immobilized zinc oxide nanoparticle with desirable properties for rubber compounds was investigated. Composites with homogeneous dispersion were obtained in the absence of dispersants. The dispersion stability was controlled through varying the molar ratio, ageing time and mixing order of the reactants. A superior dispersion was achieved in the sample obtained using 0.03 mol of zinc precursor as it had the smallest grain size (50.5 nm) and then immobilized in silica aged for 10 days. Moreover, the specific surface area of this sample was the highest ($649m^2/g$).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.167-172
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• 2004

In the human skin, vitamin C (L -ascorbic acid) that is well known as the activated materials has effects that is skin anti-aging and wrinkle repair by giving impetus to collagen biosynthesis and anti-oxidation, and that is the sun screen, a wound recovering, inhibition melanogenesis and so on. In spite of its effects, vitamin C has the defects of the skin stimulation and easily oxidized instability by water, air, heat and light. For solving their matters, many investigation is advanced and its results are synthesized the various vitamin C derivatives. And yet they have not solved the unstable property of vitamin C and were still insufficient for the comparing with the effect of the pure vitamin C itself. In this study, in order to prepare vitamin C derivative of being improved the stability and to apply vitamin C effect in the skin, we prepared new vitamin C derivative, phytosphingosine ascorbate, by using phytosphingosine, one of sphingolipids, which have a distinguished skin affinity. Phytosphingosine ascorbate can be prepared as the ionic bond between amine group (-NH$_2$) of phytosphingosine and hydroxy group (-OH) of vitamin C by way of the relatively simple reaction. So the structure and properties of the synthesized phytosphingosine ascorbate was confirmed the use of elemental analysis (C 58.3 : H 9.3 : N 2.8 : O 29.5), MALDI TOF-MS (Mw=492.58), Ultraviolet spectra (268.5nm), lH NMR, FT-IR spectra, thermal analysis (m.p=l54$^{\circ}C$), HPLC and so on. And we could confirm the anti-bacterial and anti-oxidation effects. Based on these results, we could confirm to prepare a new material that was expected of both effects of vitamin C and phytosphingosine and that is improved properties of vitamin C.