• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1471-1476
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• 2005

The optimization of ethanol treatment was carried out by response surface methodology (RSM) which was expressed through change of ${\Delta}$E value for improvement of color of dried large anchovy. The optimum condition was shown as treatment with 7 volumes (v/m) of ethanol at $50^{\circ}C$ for 9 hrs. At this condition, the removal rates of trimethylamine (TMA) and fat considered as fishy odor-causing materials were 81.1 and $77.4\%$, respectively, when analyzed by solid phase microextraction (SPME)/gas chromatography and soxhlet method, respectively The effect of citric acid on the removal rate of TMA was the highest one among organic acid treatments. The removal rate of TMA was affected greatly by the concentration of organic acid rather than the temperature and time of treatment. $73\%$ of TMA was removed by treatment of $1\%$ of citric acid at $20^{\circ}C$ for 20 min. Specially, above $90\%$ of TMA could be removed by the combination of alcohol and citric acid treatment. In vitro absorption rate of calcium was also increased to $12.3\%$ by the combination of alcohol and citric acid treatment compared with $2.9\%$ of control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.689-695
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• 2007

Antioxidative activity and polyphenol contents of heated licorice in Korea extracted by ethyl.acetate (EtOAc) and ethyl.alcohol (EtOH) were evaluated at various heating temperatures (110, 120, 130, 140, and $150^{\circ}C$), times (1, 2, 3, 4, and 5 hr), and moisture contents (10, 20, 30, 40, and 50%). Maximum extraction yields of EtOAc extract was 10.9% at $130^{\circ}C$, 3 hr, and 50% moisture content and that of EtOH extract was 25.0% at $120^{\circ}C$, 2 hr, and 20% moisture content, whereas those of control were 0.8 and 15.8%, respectively. The highest total polyphenol content was 845.67 mg/100 g in EtOH extract at $120^{\circ}C$, 2 hr, and 20% moisture content (control: 277.00 mg/100 g). The antioxidative activity ($IC_{50}$) was the highest value of 0.53 mg/mL in EtOAc extract at $120^{\circ}C$, 2 hr, and 20% moisture content (control: 12.34 mg/mL). The highest ascorbic acid equivalent antioxidant activity value of 1,584 mg ascorbic acid (AA) eq was obtained from EtOAc extract at $120^{\circ}C$, 2hr, and 40% moisture content (control: 1,263 mg AA eq). Optimum heating conditions for the improvement of antioxidative activity of licorice in Korea was $120^{\circ}C$, 2 hr, and $20{\sim}40%$ moisture content.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.253-262
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• 2016

Yeonsan Ogae has been known as supporting health and high efficacy of treatment. In recent days, as the efficacy of functional peptides has known, the optimization of oligo peptides production and its characteristics from Ogae viscera has been performed. Response surface method was used to perform the optimizaion of enzyme hydrolysis. The range of processes was temperature (40, 50 and $60^{\circ}C$), pH(6.0, 7.0 and 8.0), and enzyme(1, 2 and 3%). The degree of hydrolysis, amono acids, molecular weight of products were analyzed. The optimum process of enzyme hydrolysis were determined as temperature $58^{\circ}C$, pH 7.5, and enzyme concetration 3%. At optimum conditions, the degree of hydrolysis after 2 h reaction was 75-80%. The total amino acids of amino acid and were 386.15 mg/100 g and 155.26 mg/100 g, respectively. The molecular weight of products by using Maldi-TOF was ranged from 300 to 1,000 Da.

• Food Science and Preservation
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• v.22 no.1
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• pp.1-11
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• 2015

Raspberries are a good resource of polyphenols and have a powerful antioxidant activity, but shelf life for raspberries is short which brings a lot of economic losses. In this study, we try to use cool-air ($20{\sim}40^{\circ}C$) or hot-air ($60{\sim}100^{\circ}C$) to produce semi-dried raspberries with extended shelf life, and to determine the best method for improving fruit quality by minimizing nutrient losses during drying processes. The effects of process variables (drying temperature and processing time) on the quality of final dried raspberries were investigated. Response surface methodology was employed to establish statistical models for simulating the drying processes, and the moisture residue content and the loss ratios of total phenolic content (TPC), vitamin C (VC), and ellagic acid (EA) that result from the drying processes of raspberries using either hot or cool-air were predicted. Superimposed contour plots have been successfully used in the determination of the optimum zone within the experimental region. Optimal conditions determined for achieving minimal losses of TPC, VC, and EA, and a final moisture residue of 45% using the hot-air drying process were a drying temperature of $65.75^{\circ}C$ and a processing time of 4.3 hr. While for the cool-air process, the optimal conditions predicted were $21.3^{\circ}C$ and 28.2 hr. Successful application of response surface methodology provided scientific reference for optimal conditions of semi-drying raspberries, minimizing nutrient losses and improving product quality.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.283-283
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• 2010

17~18% 대역의 고효율 결정질실리콘 태양전지를 양산하기 위하여 국내외에서 다양한 연구개발이 수행되고 있으며 국내 다결정실리콘 태양전지 양산에서도 새로운 구조와 개념에 입각한 공정기술과 관련 장비의 국산화에 집중적인 투자를 진행하고 있다. 주지하는 바와 같이, 태양전지의 광전효율은 표면에 입사되는 태양광의 반사를 제외하면 흡수된 광자에 의해 생성되는 전자-정공쌍의 상대적인 비율인 내부양자효율에 의존하게 된다. 실제 생성된 전자-정공쌍은 기판재료의 결정상태와 전기광학적 물성 등에 의해 일부가 재결합되어 2차적인 광자의 생성이나 열로서 작용하고 최종적으로 전자와 정공이 완전히 분리되고 전극에 포집되어 실질적인 유효전류로 작용한다. 16% 이상의 고효율 결정질 실리콘 태양전지 양산이 요구되고 있는 현실에서 광전효율 개선 위해 가장 우선적으로 고려되어야 할 변수는 입력 태양광스펙트럼에 대한 결정질 실리콘 표면반사율을 최소화하여 광흡수를 극대화하는 것이라 할 수 있다. 현재까지 다결정 실리콘 표면을 화학적으로 혹은 플라즈마이온으로 50-100nm 직경의 바늘형 피라미드형상으로 texturing 함으로 단파장대역에서 광반사율의 감소를 기대할 수 있기 때문에 결정질실리콘 태양전지효율 개선에 긍정적인 영향을 미치는 것으로 알려져 있다. 고효율 다결정실리콘 태양전지 양산공정에 적용하기 위해 마스크를 사용하지 않는, RIE기반 건식 저반사율 결정질실리콘 표면 texturing 패턴연구를 수행하였다. 마스크없이 표면 texturing이 완료된 시료들에 대하여 A1.5G 표준태양광스펙트럼의 300-1100nm 파장대역에서 반사율과 minority carrier들의 life time 분포를 측정하고 검토하여 공정조건을 최적화 하였다. 저반사율의 건식 결정질실리콘 표면 texturing에 가장 적합한 플라즈마파워는 100W 내외로 낮았고 $SF_6/O_2$ 혼합비율은 0.8~0.9 범위엿다. 본 연구에서 확인된 최적의 texturing을 위한 플라즈마공정 조건은 이온에 의한 Si표면원자들의 스퍼터링과 화학반응에 의한 증착이 교차하는 상태로서 확인된 최저 평균반사율은 ~14% 내외였고 p-형 결정질실리콘 표면 texturing 패턴과 minority carrier의 life time 상관는 단결정이 16uS대역에서 14uS대역으로 감소하는 반면에서 다결정은 1.6uS대역에서 1.7uS대역으로 오히려 미세한 증가를 보여 다결정 웨이퍼생산과정에서 발생하는 saw-damage 제거의 긍정적 효과와 texturing공정의 표면 결함발생에 의한 부정적 효과가 상쇄되어 큰 변화를 보이지 않는 것으로 해석된다.

• Analytical Science and Technology
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• v.31 no.6
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• pp.225-231
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• 2018

Benzoic acid, methyl paraben, and butyl paraben are preservatives that have been used in pharmaceutical, cosmetic, and food products. However, as their toxicities for human have been reported, many nations and organizations including Korea have established a regulation limit for thier usage of these preservatives in food products. The present study developed the isotope dilution liquid chromatography mass spectrometry method for accurate determination of three target preseratives in soysauce. In this study, the isotope dilution liquid chromatography mass spectrometry method was developed for accurate determination of three target preservatives in soy sauce. LC separation was optimized considering the pKa of benzoic acid which is lower than those of methyl and butyl parabens. A C18 column was used with 5 mM ammonium acetate and methanol as mobile phases. Mass spectrometry was operated in negative mode and selected reaction monitoring mode (SRM). Soy sauce sample was cleaned-up with C18 SPE cartridge for removing matrix inferences and color material. Optimized conditions and the method were validated with soy sauce reference materials for the analysis of food preservatives from Health Science Authority in Singapore. The measured values of benzoic acid, methyl and butyl paraben agreed well with reference values within their uncertainties.

• Clean Technology
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• v.27 no.2
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• pp.115-123
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• 2021

This study demonstrates a new method for the synthesis of organic-inorganic hybrid particles composed of an inorganic silica shell and organic core particles. The organic core particles are prepared with a uniform size using droplet-based microfluidic technology. In the process of preparing the organic core particles, uniform droplets are generated by independently controlling the flow rates of the dispersed phase containing photocurable resins and the continuous phase. After the generation of droplets in a microfluidic device, the droplets are photo-polymerized as particles by ultraviolet irradiation at the ends of microfluidic channels. The core particle is coated with a nano complex composed of polyallylamine hydrochloride (PAH) and phosphate ion (Pi) through strong non-covalent interactions such as hydrogen bonding and electrostatic interaction under optimized pH conditions. The polyamine nano complex rapidly induces the condensation reaction of silicic acid through the arranged amine groups of the main chain of PAH. Therefore, this method enabled the preparation of organic-inorganic hybrid particles coated with inorganic silica nanoparticles on the organic core. Finally, we demonstrated the synthesis of organic-inorganic hybrid particles in a short time under ambient and environmentally friendly conditions, and this is applicable to the production of organic-inorganic hybrid particles having various sizes and shapes.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.47-54
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• 2021

In this study, the performance of a honeycomb-type hydrogen oxidation catalyst to remove hydrogen in a hydrogen economy society to secure leaking hydrogen. The Pd/TiO₂ catalyst was prepared based on a liquid phase reduction method that is not exposed to a heat source, and it was showed through H₂-chemisorption analysis that it existed as very small active particles of 2~4 nm. In addition, it was found that the metal dispersion decreased and the active particle size increased as the reduction reaction temperature increased. It was meant that the active metal particle size and the hydrogen oxidation performance were in a proportional correlation, so that it was consistent with the hydrogen oxidation performance reduction result. The prepared catalyst was coated on a support in the form of a honeycomb so that it could be applied to the hydrogen industrial process. When 20 wt% or more of the AS-40 binder was coated, oxidation performance of 90% or more was observed under low-concentration hydrogen conditions. It was showed through SEM analysis that long-term catalytic activity can be expected by enhancing the adhesion strength of the catalyst and preventing catalyst desorption. It is a basic research that can secure safety in a hydrogen society such as gasification, organic resource, and it can be utilized as a system that can respond to unexpected safety accidents in the future.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.404-411
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• 2023

For the direct reforming of biogas, a three-phase gliding arc plasma reformer was designed to expand the plasma discharge region, and the operation conditions of the plasma reformer, such as the S/C ratio, the gas flow rate, and the plasma input power, were optimized. The H₂ production efficiency is increased at a lower specific plasma input energy density, but byproducts such as C_XH_Y and carbon soot are generated along with the increase in H₂ production efficiency. The formation of byproducts is decreased at higher specific plasma input energy densities and S/C ratios. The optimized operation conditions are 5.5 ~ 6.0 kJ/L for the specific plasma input energy density and 3 for the S/C ratio, considering the conversion efficiency, H₂ production, and byproduct formation. It is expected that the H₂ production efficiency will improve with the decrease in fuel consumption in biogas burners because the heat generated from plasma discharge heats up the feed gas to over 500 ℃.

• Food Science and Preservation
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• v.15 no.1
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• pp.58-65
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• 2008

The Acorn (Quercus acutissima CARRUTHERS), which contains a large quantity of tannin, should be developed as a processed food as the acorn is rich in natural antioxidants and other valuable components. Accordingly, acorn extraction conditions for polyphenol and gallic acid (both antioxidants) were investigated by response surface methodology. The content of polyphenols were determined under 16 different extraction conditions based upon a central composite design. The parameters varied over $30-70^{\circ}C$ of extraction temperature, 1-5 h of extraction time, and 5-25 mL/g of solvent ratio, Gallic acid extraction was optimal at $60-100^{\circ}C$ extraction temperature, 1-5 h of extraction time, and 5-25 mL/g of solvent ratio, Epicatechin content was highest at $56.77^{\circ}C$, 4.16 hand 22.38 mL/g. Catechin content was highest at $52.37^{\circ}C$, 2h and 23.59 mL/g. The maximum catechin content was $91.30{\mu}g/mL$. Epigallocatechin content was influenced by extraction temperature and time. The maximum epigallocatechin content was $1,066.56{\mu}g/mL$ at $61.42^{\circ}C$, 4.17h, and 9.25 mL/g. The maximum value of epicatechingallate content was $125.39{\mu}g/mL$ at $47.72^{\circ}C$, 3.04h, and 24.93mL/g. Epigallocatechingallate content was influenced principally by solvent ratio and the maximum content was $61.38{\mu}g/mL$ at $48.11^{\circ}C$, 2.96h, and 24.95mL/g. The total polyphenol content was maximal at $1,332.75{\mu}g/mL$, after extraction at $61.50^{\circ}C$, 4.24h, at 9.71mL/g. The higher the extraction temperature and the longer the extraction time, the greater the polyphenol content. Gallic acid content was highest, the maximal level was $30.51{\mu}g/mL$ after $65.84^{\circ}C$, 1.65h at 17.17 mL/g, and this was influenced principally by extraction time and solvent ratio.