• Food Science and Preservation
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• v.13 no.2
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• pp.252-258
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• 2006

To find the optimum extraction condition of dried omija, central composite experimental design having three independent variable (extraction temperature, extraction time and water ratio) with five levels was conducted for response surface analysis. The maximum of soluble solid was predicted to the extraction conditions of over 25 fold water ratio, $7{\sim}8hr$ and $75^{\circ}C$. Total acid, total phenol, reducing sugar and vitamin C were predicted to respectively 30 fold water ratio, 6 hr, $70^{\circ}C$, 30 fold water ratio, $6{\sim}7\;hrs,\;80^{\circ}C$ and 30 fold water ratio, $6{\sim}8\;hr,\;80^{\circ}C$, 25 fold water ratio, $5{\sim}6hr,\;80^{\circ}C$ extraction condition. Turbidity of extraction condition. Turbidity of extraction condition was 7 over 25 ford water ratio and over $60^{\circ}C$. From the superimposing results of response variables, the optimum extraction condition was predicted 25 folds water ratio, 6 hr and $65{\sim}70^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.65-72
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• 2002

This study was to determine the optimum conditions of malt extracting temperature, extracting time of malt in water, ratio of malt to water, and rice volume of malt extract water on saccharification in producing sikhe (sweet rice drink) using central composite design of response surface methodology. Glucose and maltose were analyzed by a biosensor having dual cathode system. The optimum temperatures of malt extracting for glucose and maltose were 60 and $55^{\circ}C$. The saccharification power for the two sugars was highest when malt powder soaked for 6.5 and 5.75 hour, respectively. And ratios of malt to water for optimum saccharification were 1 : 6.3 to 1 : 8.8, respectively. The optimum volumes of malt extracting to rice for the two sugars were 0.48% and 0.6%, respectively. The application of response surface methodology to sikhe processing showed a good correlation with high significance.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.123-128
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• 2012

Computer simulation of buildings and solar energy systems is being used increasingly in energy assessments and design. The purpose of our work is to predict the surface temperature on inclined surfaces based on ISO-TRY typical weather data. To reach this goal, three studies were performed. They consisted of quantifying the accuracy of various well-known three models. The first type of models calculated diffuse horizontal irradiations from global ones and the second type models computed global irradiations on inclined planes from diffuse and global components on a horizontal surface. The third type of model calculated long-wave radiation and surface temperature from ISO-TRY typical weather data. The proposed model can provide an alternative to building designers in estimating the surface temperature and solar irradiation on inclined surfaces where only the typical meteorological data are available.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.433-438
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• 2004

This study was conducted to develop a sweet pumpkin to intermediate materials for various processed foods and dried food having high quality. Factorial experiment design with three variables having three levels was adapted and response surface methodology was used to determine optimum conditions for osmotic dehydration of sweet pumpkin. The moisture content, weight reduction, moisture loss and solid gain after osmotic dehydration increased according to increasement of immersion temperature, concentration and time. The effect of concentration was more significant than that of temperature and time at given conditions. Sugar concentration and vitamin C content increased in accordance with increasement of immersion temperature, concentration and time during osmotic dehydration. Hardness was increased by increasing immersion time. The regression models showed very significant values and high correlation coefficients (R2) above 0.91, excepting hardness. The optimum condition for osmotic dehydration was 23$^{\circ}C$, 52$^{\circ}C$Brix and 80 min at the constricted conditions such as 60∼70% moisture content, above 3 mg/100 g vitamin C and more than 10 kg/$\textrm{cm}^2$ hardness.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.177-183
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• 2014

Recently, many biofuels and chemicals converted from renewable resources have been introduced into chemical industries. Sargassum fulvellum is a brown macro-algae, which is found on the seashores of Korea and Japan. In this work, the production of total reducing sugar and levulinic acid from S. fulvellum, using dilute-acid catalyzed hydrothermal hydrolysis and statistical methodology, was investigated. As a result, 15.28 g/l total reducing sugar was obtained under the optimized conditions of $160.1^{\circ}C$, 1.0% sulfuric acid, in 20.2 min. Furthermore, 2.65 g/l levulinic acid was obtained at $189.5^{\circ}C$, 2.93% sulfuric acid, in 48.8 min.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.3
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• pp.131-135
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• 2004

This study was carried out for the analysis of temperature characteristics on soil surface using soil heat flux which is one of the important parameters forming soil temperature. Soil surface temperature was estimated by using the soil temperature measured at 10 cm soil depth and the soil heat flux measured by flux plate at 5 cm soil depth. There was time lag of two hours between soil temperature and soil heat flux. Temperature changes over time showed a positive correlation with soil heat flux. Soil surface temperature was estimated by the equation using variable separation method for soil surface temperature. Arithmetic mean using temperatures measured at soil surface and 10 cm depth, and soil temperature measured at 5 cm depth were compared for accuracy of the value. To validate the regression model through this comparison, F-validation was used. Usefulness of deductive regression model was admitted because intended F-value was smaller than 0.001 and the determination coefficient was 0.968. It can be concluded that the estimated surface soil temperatures obtained by variable separation method were almost equal to the measured surface soil temperature.

• Food Science and Preservation
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• v.20 no.2
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• pp.257-264
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• 2013

Central composite design along with response surface methodology (RSM) was applied to improve the fermentation process in onion (Allium cepa) wine production. The effects of different fermentation parameters (time, temperature, and initial sugar content) were found to be significant with respect to the physicochemical and sensory properties of wine. The maximum score for the alcoholic content was obtained at $29.27^{\circ}C$ fermentation temperature, 103.43 h fermentation time, and $27.52^{\circ}Brix$ initial sugar content. The maximum score for overall palatability was obtained at $39.27^{\circ}C$ fermentation temperature, 57.28 h fermentation time, and $22.14^{\circ}Brix$ initial sugar content. The coefficients of determination ($R^2$) were 0.9620 and 0.9060 for alcoholic content and overall palatability, respectively. The ranges of the optimum fermentation conditions ($28{\sim}32^{\circ}C$, 80~90 hr, and $20{\sim}25^{\circ}Brix$) were obtained by superimposing the response surfaces with regard to the alcoholic content and overall palatability of onion wine.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.137.2-138
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• 2003

농산물의 효율적인 가공.저장은 농산물의 안정된 공급과 물가안정에 크게 기여하며, 부가가치 향상과 식품관련산업의 국제경쟁력 강화에도 필수적인 요건이라 할 수 있다. 호박은 전국 각지의 유휴지에서 별다른 시비나 농약의 사용없이 재배가능한 농산물로 vitamin C 및 vitamin A의 전구체인 carotene과 무기질, 식이섬유, 전분, 자당, 포도당 등이 풍부하다. 호박은 이뇨작용과 산후부종에 효과가 인정되어 널리 이용되고 있으며, 당뇨병, 야맹증, 각막건조증 등에도 효과가 있다. 국민의 생활수준이 향상되고 사회구조가 변화함에 따라 식품소비의 양상도 크게 변화하여 편의식과 건강 지향적인 가공식품의 수요가 급격히 증가하고 있으며, 이에 부응하여 건강식품에 관한 다각적인 연구가 많이 행해지고 있으나 미비한 실정이다. 호박은 특히 수분함량이 많고 조직의 연화현상 등으로 저장성이 낮아서 경제성이 떨어지므로 호박을 이용한 다양한 가공제품의 개발이 요구된다. 호박의 이용성을 검토하고, 나아가 호박의 부가가치 향상 및 경쟁력을 가진 지역특산물화를 위하여 기능성을 갖춘 건강음료개발을 시도하였으며, 이러한 음료의 유통중 품질변화를 모니터링하였다. 호박음료의 유통중 품질변화는 저장온도(20, 30, 40, 50, 6$0^{\circ}C$) 및 저장기간(0, 2, 4, 6, 8 week)에 따른 중심합성실험계획으로 실험을 행하여, 저장에 따른 당, 산, pH, 갈색도 및 관능적 특성에 대하여 반응표면분석을 하였다. 당도, 산도, pH 및 갈색도의 경우 저장시간에 영향을 많이 받는 것으로 나타났으며, 관능적 특성 중 전반적인 기호도에 있어서는 저장온도 및 저장시간에 영향을 많이 받는 것으로 나타났다. 당도, 산도, pH의 경우 저장온도 및 저장기간에 따라 큰 차이를 보이지 않았다. 갈색도의 경우 저장온도 51.1$0^{\circ}C$ 및 저장기간 7.33 week일 때 최대의 갈색도로 나타났다. 전반적인 기호도 있어서는 저장온도 32.52$^{\circ}C$ 및 저장기간 0.30 week일 때 우수한 것으로 나타났다.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.181-188
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• 1999

재료의 표면을 pulsed laser로 가열할 때, 유한한 두께를 가지는 반무한 평판의 온도분포를 해석하여 열확산계수, 재료의 두께, 열원의 주기, 그리고 열원의 반경이 온도분포에 미치는 영향을 알아보았다. Pulsed laser에 의하여 가열되는 불투명 고체의 시간에 따른 온도는 전체적으로 증가하지만 열원의 주기와 동일한 주기를 가지고 일정한 온도차를 가지는 전체온도와 평균온도의 차, Tac가 존재한다. 열확산계수가 증가하면 재료 내부로 에너지의 확산이 활발하기 때문에 Tac는 커진다. 재료의 두께가 열확산길이보다 얇은 경우에는 두께변화에 따라서 온도가 민감하게 변하지만, 열확산길이보다 재료의 두께가 두꺼울 때는 두께의 변화에 관계없이 거의 일정한 온도가 나타난다. 열원의 단속주파수가 증가하면 한 주기당 에너지가 작아지므로 Tac의 크기는 작아진다. 열원의 반경이 커지면 단위면적당 에너지가 감소하므로 Tac의 크기는 삼각파, 싸인파, 사각파 순으로 크게 나타난다. 따라서 열원의 파형을 측정하여 이를 적용하는 것이 바람직하다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.142.2-142
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• 2003

손바닥 선인장(Opuntia ficus indica)은 중심자목 선인장과에 속하는 다년생 초본으로 열매는 서양배 모양이며 많은 종자가 들어있고 다량의 점질물을 함유하고 있다. 손바닥 선인장 열매(prickly pear pulp)는 14.5%의 고형분 함량을 가지고 있으며, 0.21%의 단백질, 0.12%의 지방, 0.44%의 회분, 0.19%의 pectin 이외에 미량의 비타민 A와 C 그리고 여러 종류의 무기질을 포함하고 있다. 주요 당류로서 sucrose(68.7%), fructose(18.0%) 및 glucose(12.8%)를 함유하고 있으며, 점질다당류의 구성분인 mannose 가 0.5% 포함되어 있다. 손바닥 선인장 열매는 높은 혈중 콜레스테롤, 염증 및 비만 등의 치료에 유용한 것으로 알려져 있다. 본 연구에서는 손바닥 선인장 열매 추출물의 기능적 특성을 반응표면분석에 의해 모니터링 하였다. 그 결과 환원당 함량은 최대값이 33.39 mg%로 추출온도 69.87$^{\circ}C$, 추출시간 68.84 min및 시료에 대한 용매비 16.29 ml/g일 때였다. 총 플라보노이드 함량은 추출온도 89.7$0^{\circ}C$, 추출시간 170 min 및 시료에 대한 용매비 17.07 ml/g일 때 2,03 mg%로 최대값을 나타내었다. 펙틴 함량은 추출온도 96.54$^{\circ}C$, 추출시간 135.28 min및 시료에 대한 용매비 20.02 nWg일 때 최대값 82.04 mg%를 나타내었으며, 비타민 C 함량은 추출온도 61.8$0^{\circ}C$, 추출시간 101.98 min 및 시료에 대한 용매비 12.14 ml/g일 때 최대값이 3.76 mg%였다.