• Food Science and Biotechnology
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• 제17권1호
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• pp.151-155
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• 2008

Oxidation of low density lipoprotein (LDL) is regarded to play an important role in the development of atherosclerosis. In the present study, salad vegetables with a remarkable DPPH radical-scavenging activity were extracted with methanol, and the methanol extracts were evaluated for the inhibition of $Cu^{2+}$-induced oxidation of human LDL. Separately, the amount of total phenolics was determined colorimetrically using Folin-Ciocalteu reagent. The vegetable extracts, expressing a strong inhibition of LDL oxidation ($IC_{50}$ values, <$100\;{\mu}g/mL$), were from angelica, dandelion, mustard leaf, and water spinach, which contained relatively high level of polyphenol content. Noteworthy, a highly positive correlation was observed between inhibition of LDL oxidation and amount of total polyphenol (p<0.01). Based on these results, it is suggested that salad vegetables, especially angelica, dandelion, and mustard leaf, may be used as easily accessible sources of natural antioxidants, especially in anti-atherosclerosis.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.94-94
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• 2010

As a new plasma source for the plasma enhanced chemical vapor deposition (PCVD) of ${\mu}c$-Si deposition, we have demonstrated a microwave-excited plasma source, which can produce high density (${\sim}10^{12}\;cm^{-3}$) plasma with low electron temperature (~1 eV) and low plasma potential (~10 V). In this plasma source, microwave power radiated from slot antenna is distributed along the plasma-dielectric interface in large area and this enables us to produce uniform high-density plasma in large area. To optimize deposition conditions, deep understanding of gas phase chemistry is indispensable. In this presentation, we will discuss on the gas phase diagnostics of microwave $SiH_4/H_2$ plasma such as $SiH_4$ dissociation or $SiH_3$ radical profile as well as deposited film properties.

• Bulletin of the Korean Chemical Society
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• 제20권10호
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• pp.1177-1180
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• 1999

The ab initio SCF MO and density functional theory (DFT) studies are carried out on the electrophilic (1a) and electron transfer (1b) addition reactions to the vinyl double bond of aryl vinyl sulfides and ethers. In the electrophilic addition processes, a double bond shift from C3 = C4 to X = C3 occurs with occupation number (1.97) close to the normal two. Due to this shift direct conjugation between the cationic center, X = S or O, and the para electron-donor substituent becomes impossible so that the reaction energies (or log K) are correlated with σ rather than σ+. By contrast, radical cation formation leads to delocalization of the SOMO, a lone-pair πorbital on X, with four major resonance structures in which cationic charge as well as spin density is delocalized over C4 , X and C7 atoms. As a result, partial πbonds are formed over C1 -X and C3 - C4 with occupation numbers (0.82) lower than one. In two of the cannonical structures, III(Ⅹ) and III(X+), direct conjugation between the cationic center, X, and the para substituent is achieved so that a better correlation with σ+ rather than σis obtained. The SCF MO energies at the HF/3-21G* and HF/6-31G* levels lead to very much inferior Hammett correlations in the σ/ σ+ diagnostic criterion. In contrast, the ρvalues evaluated with the DFT energies can give reliable diagnostic distinction between the two addition mechanisms.

• 한국약용작물학회지
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• 제12권3호
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• pp.237-242
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• 2004

인삼 식물체의 식품 첨가물로의 이용성을 타진하기 위해 각 부위별 항산화 활성 및 총 페놀 함량을 분석, 비교하였으며 그 결과는 다음과 같다. 인간 LDL의 산화에 대한 저해활성은 뿌리 $(45.2{\sim}54.3%)$에서 높은 활성을 나타내었으며, linoleic acid에 대한 자동산화에 대해서는 잎이 $90.1{\sim}96.5%$의 매우 높은 저해활성을 나타내었다. Superoxide anion 라디칼에 대해서 줄기 $(35.6{\sim}76.1%)$, 잎 $(60.1{\sim}69.3%)$, 뿌리 $(-5.6{\sim}20.1%)$의 순으로 높은 활성을 나타내었다. DPPH 라디칼 소거능은 대체적으로 낮은 활성을 나타내었으며 총 페놀 화합물은 인삼 잎 $(147{\sim}200\;mg%)$, 줄기 $(110{\sim}153\;mg%) $, 뿌리 $(61{\sim}86\;mg%)$의 순으로 높게 나타났다.

• 대한의생명과학회지
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• 제11권4호
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• pp.533-538
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• 2005

This investigation was performed to study the antioxidant activities of Hovenia dulcis THUNBER var. koreana Nakai fruits extracts and the effect of Hovenia dulcis fruits extracts on glucose, lipid metabolism in diabetic rats. DPPH free radical scavanging activitiy and superoxide anion radical Scavenging of Hovenia dulcis fruits $80\%$ methanol extracts were $0.06\pm0.002mg$ polyphrnol/ml and $0.l2\pm0.00lmg$ polyphmol/ml, respectively. Hovenia dulcis fruits $80\%$ methanol extracts were partitioned into hexan, dichloro methane, ethyl acetate and butanol, successively. Ethyl acetate fraction were good antioxidant activity. Streptozotocin (45 mg/kg body weight, i.p.) induced diabetic rats showed a significant increases of plasma glucose, triglyceride and total cholesterol. Concomitantly significant decrease of plasma high density lipoprotein. Glutathione level were decrease in cytosol of liver. Lipid peroxide were increase in microsome of liver. Group 1 and 2 were treated with Hovenia dulcis fruits ethyl acetate extracts 50 mg/kg body weight and 20mg/kg body weight for 24 days, individually. Group land 2 rats showed decreased plasma glucose, triglyceride, total cholesterol and lipide peroxide in microsome of liver tissue of rats, and increased plasma high density lipoprotein and glutathione in cytosol of liver tissue rats. The result suggest that Hovenia dulcis THUNBER var. koreana Nakai fruits extracts may effectively normalize the impaired antioxiants status in streptozotocin induced diabetic rats. Hovenia dulcis fruits ethyl acetate extracts were used to improve the imbalance between free radicals and antioxidant system due to the diabetes.

• Asian Journal of Atmospheric Environment
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• 제9권2호
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• pp.158-164
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• 2015

The estimation of the concentration of hydroxyl radical (OH) in the atmosphere is essential to build atmospheric models and to understand the mechanisms of the reactions involved in OH. Although water vapor is one of the most abundant species in the troposphere, only a few studies have been performed for the reaction of OH and water vapor. Here I demonstrate an ab initio study on the complex forming reation of OH with $H_2O$ in the gas phase performed based on density functional theory to calculate the reaction rate and the energy states of the reactant and the OH-$H_2O$ complex. The structure of the complex, which belongs to the Cs point group, was optimized at global minima. The transition state was not found at the B3LYP and MP2 levels of theory. Rate constants of the forward and the reverse reactions were calculated as $1.1{\times}10^{-16}cm^3\;molecule^{-1}\;s^{-1}$ and $5.3{\times}10^9\;s^{-1}$, respectively. The extremely slow rates of complex forming reaction and the resulting hydrogen atom exchange reaction of OH and $H_2O$, which are consistent with experimentally determined values, imply a negligible possibility of a change in OH reactivity through the title reaction.

• 한국식생활문화학회지
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• 제28권1호
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• pp.70-77
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• 2013

This study was conducted to evaluate the effects of chestnut powder on antioxidant activity and quality characteristics of cookies. Cookies were prepared using different amounts of chestnut powder (0, 5, 10, 15 and 20% to the flour quantity). The antioxidant activity was estimated by measuring DPPH free radical scavenging activity and the total phenolic content in chestnut powder and cookies. In addition, the quality characteristics of the chestnut cookies were estimated based on: the bulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations. The spread ratio, a values, total polyphenol contents, and DPPH free radical scavenging activity of cookies significantly increased with increasing chestnut powder (p<0.001), while the leavening rate, L values, b values and hardness of the cookies significantly decreased with increasing chestnut powder (p<0.05). The sensory evaluation scores for the 15% chestnut powder cookie groups ranked significantly higher (p<0.05) than the other groups in overall preference, appearance, taste, color, chestnut taste, oily flavor, and aftertaste. Taken together, the results of this study suggest that chestnut powder is a good ingredient for increasing the consumer acceptability and functionality of cookies.

• 한국식품조리과학회지
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• 제28권6호
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• pp.665-673
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• 2012

The purpose of this study was to propose optimal mixing proportion by adding stevia in powder form, which are low caloric and high intensity sweetener to cookies, and to determine the characteristic of product. It reduced the average sugar content of cookies to 50%, processed stevia powder, add them in 2, 4, 6, and 8% to make cookies and measured various product characteristics, including anti-oxidant activity. The antioxidant activity was highly correlated with the total phenolic composition of stevia cookies (r=0.967). Total phenolic contents and DPPH free radical scavenging activity of cookies significantly increased with increasing stevia powder. The bulk density of the dough, spread factor and the hardness, total polyphenol contents and DPPH free radical scavenging activity of cookies significantly increased with increasing stevia powder, while the pH of the dough, and L values of the cookies decreased with increasing stevia powder content (p<0.001). Additionally, the consumer acceptability scores for the 4% stevia cookie groups ranked significantly (p<0.001) higher than those of the other groups in color, taste, flavor, sweetness and overall preference. All the take together, the results of this study suggest that stevia powder is a good ingredient for increasing the consumer acceptability and the functionality of cookies.

• 한국식생활문화학회지
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• 제27권2호
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• pp.225-232
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• 2012

This study was conducted to investigate the effects of acorn ($Quercus$ autissima carruther) powder on the antioxidant activity and quality characteristics of cookies. Cookies were prepared with different amounts of acorn powder (at ratios of 0, 0.5, 1, 3 and 5% to total flour quantity). Antioxidant activity was estimated based on DPPH free radical scavenging activity and total phenol content in acorn powder and cookies. To analyze quality characteristics, bulk density, pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations were measured. Loss rate, a values, total polyphenol contents and DPPH free radical scavenging activity of cookies significantly increased with increasing acorn powder content (p<0.01), whereas pH of the dough, L values and b values of the cookies significantly decreased with increasing acorn powder content (p<0.01). The results of sensory evaluation (appearance, taste, flavor, texture and overall preference) demonstrate that the 3% acorn cookie group showed the highest degree of preference among all items of added acorn powder. From these results, we suggest that acorn is a good ingredient for increasing the consumer acceptability and functionality of cookies.

• 한국식품영양학회지
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• 제25권2호
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• pp.224-232
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• 2012

This study was conducted to investigate the effect of chestnut inner shell powder on antioxidant activity and the quality characteristics of cookies. Cookies were prepared with different amounts of chestnut inner shell powder(in ratios of 0, 0.5, 1, 3 and 5% to the flour quantity). The antioxidant activity was estimated by DPPH free radical scavenging activity and the total phenol content in chestnut inner shell powder and cookies. For analyzing quality characteristics, bulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations were measured. The spread ratio, a values, total phenol contents and DPPH free radical scavenging activity of cookies significantly increased with increasing chestnut inner shell powder(p<0.001), while the pH of the dough, L values and b values of the cookies significantly decreased with increasing chestnut inner shell powder content(p<0.001). The consumer acceptability score for the 3% chestnut inner shell cookie groups ranked significantly higher(p<0.01) than those of the other groups in overall preference, flavor, taste and color. From these results, we suggest that chestnut inner shell is a good ingredient for increasing the consumer acceptability and the functionality of cookies.