• Bulletin of the Korean Chemical Society
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• 제15권8호
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• pp.644-649
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• 1994

The approximate rates and stoichiometry of reaction of excess dipyrrolinoaluminum hydride (DPAH) with selected organic compounds containing representative functional groups under standardized conditions (tetrahydrofuran, 0, reagent : compound=4 : 1) were examined in order to define the characteristics of the reagent for selective reductions. The reducing ability of DPAH was also compared with that of bis(diethylamino)aluminum hydride (BEAH). The reagent appears to be stronger than BEAH, but weaker than the parent reagent in reducing strength. DPAH shows a unique reducing characteristics. Thus, the reagent reduces aldehydes, ketones, esters, acid chlorides, epoxides, and nitriles readily. In addition to that, ${\alpha},\;{\beta}$-unsaturated aldehyde is reduced to the saturated alcohol. Quinone are reduced cleanly to the corresponding 1,4-reduction products. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Both primary and tertiary aromatic carboxamides are converted to aldehydes with a limiting amount of DPAH. Finally, disulfides and sulfoxides are readily reduced to thiols and sulfides, respectively.

• Journal of Dairy Science and Biotechnology
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• 제36권4호
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• pp.187-195
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• 2018

Nano-delivery systems, such as nanoparticles, nanoemulsions, and nanoliposomes, are carriers that have been used to enhance the chemical as well as physical stability and bioavailability of bioactive compound. Food-grade nano-delivery system can be produced with edible biopolymers including proteins and carbohydrates. In addition to the low-toxicity, biocompatibility, and biodegradability of these biopolymers, their functional characteristics, such as their ability to bind hydrophobic bioactive compounds and form a gel, make them potential and ideal candidates for the fortification of bioactive compounds in functional dairy foods. This review focuses on different types of nano-delivery systems and edible biopolymers as delivery materials. In addition, the applications of food-grade nano-delivery systems to dairy foods are also described.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.243-249
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• 1998

The reaction of alcohol with a solution of thexylborane (ThxBH2) in tetrahydrofuran (THF) provides a new class of mild and selective reducing agents, thexylalkoxyboranes (ThxBHOR: R=Et, i-Pr, i-Bu, s-Bu, t-Bu, Ph). In order to elucidate the effect of the alkoxy group in reduction reactions, the reducing power of ThxBHOR toward selected organic compounds containing representative functional groups under practical conditions (THF, 25°, the quantitative amount of reagent to compound) has been investigated. Generally, the reactivity of ThxBHOR is largely dependent upon the alkoxy substituent. ThxBHOR can be synthesized from a variety of alcohols, thus allowing control of the steric and electronic environment of these reagents.

• Bulletin of the Korean Chemical Society
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• 제8권4호
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• pp.304-310
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• 1987

The approximate rate and stoichiometry of the reaction of excess di-s-butoxyborane with selected organic compounds containing representative functional groups under standardized conditions (tetrahydrofuran, $25^{\circ}C)$ were examined in order to define the characteristics of the reagent for selective reductions. And the catalytic effect of lithium tetra-s-butoxyborate on the reaction of di-s-butoxyborane was also studied in order to increase the utility of this reducing system. Di-s-butoxyborane reacts only with simple aldehydes. However the addition of 2.5 mole % of lithium tetra-s-butoxyborate shows the tremendous rate enhancement of reaction for aldehydes, ketones, anhydrides, acid chlorides, lactones, and epoxides. This catalytic effect is assumed to in situ formation of lithium trialkoxyborohydride.

• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.162-165
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• 1987

The reduction rate of borohydride exchange resin (BER) was greatly enhanced in the presence of lithium salts. Thus 2-heptanone was reduced completely with BER-LiCl in 1 h at room temperature. However, no reduction was observed with BER alone under the same conditions. With this system, organic compounds containing various fuctional groups were examined in ethanol at room temperature. This study revealed that BER-LiCl system exhibits an excellent chemoselectivity for carbonyl group in the presence of other functional groups. Keto esters and epoxy ketones were reduced with BER-LiCl to give the corresponding hydroxy esters and epoxy alcohols with excellent yields. Selective reductions of carbonyl groups were also possible in the presence of other organic compounds containing functional groups such as 1-idooctane, 1-bromooctane, caproamide, hexanenitrile, nitrobenzene, n-butyl disulfide, dimethyl sulfoxide and 1-dodecene.

• Journal of Dairy Science and Biotechnology
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• 제38권4호
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• pp.189-196
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• 2020

Milk proteins, such as casein and whey protein, exhibit significant potential as natural emulsifiers for the preparation and stabilization of emulsion-based delivery systems. This can be attributed to their unique functional properties, such as the amphiphilic nature, GRAS (generally recognized as safe) status, high nutritional value, and viscoelastic film-forming ability around oil droplets. In addition, milk protein has been used as a coating material in emulsion-based delivery systems to protect bioactive compounds during food processing and storage owing to its unique functional properties. These properties include the ability to bind lipophilic bioactive compounds and antioxidant activity. In this review, we present the use of milk proteins as emulsifiers for the formation of emulsions and food applications of milk protein-stabilized emulsion delivery systems.

• 한국자원식물학회지
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• 제22권4호
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• pp.323-329
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• 2009

기능성 옥수수 수염을 가지는 옥수수 계통을 선발하기 위해 다양한 자식계통과 F1을 대상으로 옥수수 수염의 항산화 성분과 항산화능을 측정하였다. 측정결과, 총 페놀 함량, 총 플라보노이드 함량의 경우 각각 980${\sim}$2,420 mg 100 $g^{-1}$, 1,532${\sim}$3,274 mg 100 $g^{-1}$의 범위를 나타내었다. 안토시아닌의 고유영역인 517 nm에서의 흡광도는 0.05에서 0.76까지의 범위를 보였다. 옥수수 수염의 항산화 성분과 DPPH, ABTS, FRAP assay에서 얻어진 항산화능간의 상관관계를 분석한 결과, ABTS와 FRAP assay에서 옥수수 수염의 항산화 활성과 페놀성물질 및 안토시아닌간의 상관계수가 유의하게 높았다. 옥수수 수염의 안토시아닌을 추출하는 용매가 산성이라는 점과 안토시아닌의 DPPH 용액과의 가시영역 파장에서의 간섭을 고려할 때, DPPH 보다는 ABTS assay나 FRAP assay가 더 적합한 항산화능 측정 방법이 될 것이다. 이들 중 특히 ABTS assay는 옥수수 수염의 주요한 기능성 성분인 안토시아닌과 플라보노이드 및 페놀성 물질과 모두 높은 상관성을 보여 옥수수 수염의 종합적인 항산화능을 평가하고 우수 계통을 선발하는데 적합한 측정 방법이 될 것으로 사료된다. 본 실험에서 안토시아닌 함량과 페놀 함량이 높고 ABTS assay와 FRAP assay에서 모두 높은 항산화능을 보여준 S15은 고 기능성 품종 육종 및 옥수수 수염을 이용한 기능성 소재 개발에 이용될 수 있을 것이다. 또한 옥수수 수염의 항산화능 측정에 대한 항산화 실험의 적합성 연구는 우수한 옥수수 수염을 선발하는데 도움이 될 것이다.

• Biomolecules & Therapeutics
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• 제18권1호
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• pp.39-47
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• 2010

Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor involved in neuronal differentiation, plasticity, survival and regeneration. BDNF draws massive attention mainly due to the potential as a therapeutic target in neurological diseases such as depression and Alzheimer's disease. In a primary screening for the natural compounds enhancing BDNF release from cultured rat primary cortical neuron, we found that compounds such as baicalein, tanshinone IIa, cinnamic acid, epiberberine, genistein and wogonin among many others increased BDNF release. All the compounds at $0.1{\mu}M$ of concentration barely showed stimulatory effect on BDNF induction, however, their combination (mixture 1; baicalein, tanshinone IIa and cinnamic acid, mixture 2; epiberberine, genistein and wogonin) showed synergistic increase in BDNF release as well as mRNA and protein expression. The level of BDNF expression was comparable to the maximum BDNF stimulation attainable by a positive control oroxylin A ($20{\mu}M$) without cell toxicity as determined by MTT analysis. Both mixtures synergistically increased the phosphorylation of extracellular signal-regulated kinase (ERK) as well as cAMP response element binding protein (CREB), an immediate and essential regulator of BDNF expression. Similar to these results, mixture of these compounds synergistically inhibited the up-regulation of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide treatments in rat primary astrocytes. These results suggest that the combinatorial treatment of natural compounds in lower concentration might be a useful strategy to obtain sufficient BDNF stimulation in neurological disease condition such as depression, while minimizing potential side effects and toxicity of higher concentration of a single compound.

• Korean Chemical Engineering Research
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• 제51권2호
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• pp.233-239
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• 2013

Poly(isobutylene), polystyrene 및 poly(methyl methacrylate)로 코팅된 quartz crystal microbalance(QCM) 시스템을 구성하여, 매우 낮은 압력에서 benzene, toluene, p-xylene의 흡착량을 측정하였다. 모든 흡착실험에서 QCM 시스템의 공진 주파수 변화는 압력의 증가에 비례하였다. 실험결과로부터 각각의 고분자 필름에 대한 흡착물질의 Henry 상수를 구하였으며 고분자 필름과 흡착물질 사이의 최소 흡착 포텐셜 에너지와 비교하였다. 전체적으로 흡착량과 최소 흡착 포텐셜 에너지는 명백한 상관관계가 있었다.

• 한국세라믹학회지
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• 제49권1호
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• pp.56-65
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• 2012

Functional materials are often exposed to high temperatures and inherent temperature gradients. These temperature gradients act as thermodynamic driving forces for the diffusion of mobile components. The detailed consequences of thermodiffusion depend on the boundary conditions of the non-isothermal sample: Once the boundaries of the sample are inert and closed for exchange of the mobile components, thermodiffusion leads to their pile-up in the stationary state (the so called Soret effect). Once the system is open for an exchange of the mobile component, chemical diffusion adds to the Soret effect, and stationary non-zero component fluxes are additionally observed in the stationary state. In this review, the essential aspects of thermodiffusion and Soret effect in inorganic functional materials are briefly summarized and our current practical knowledge is reviewed. Major examples include nonstoichiometric binary compounds (oxides and other chalcogenides) and ternary solid solutions. The potential influence of the Soret effect on the long term stability of high temperature thermoelectrics is briefly discussed. Typical Soret coefficients for nonstoichiometric compounds are found to be of the order of (d${\delta}$/dT) ${\approx}$ 1%/K.