• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1591-1595
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• 2012

Styela clava (Korean name: miduduk) tunic was produced as a byproduct after processing of S. clava. To utilize S. clava tunic, fish paste containing tunic powder was prepared, and quality characteristics were evaluated for color, textural properties, and sensory attributes. Increasing the amount of S. clava tunic in fish paste tended to decrease lightness (L), redness (a), and yellowness (b) values of the surface part of fish paste. Strength and hardness of fish paste increased with increasing amount of tunic. All test samples with 3 mm thickness showed good flexibility and did not break even after folding in half four times. For overall acceptance in the sensory evaluation, fish paste containing 1% S. clava tunic acquired a relatively higher score. These results suggest that S. clava tunic can be applied to fish paste products to improve quality and functionality.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.79-84
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• 1993

This paper describes the development of lithium rechargeable cell. $LiCoO_2$ is recently recognized as a suitable cathode active material of a high voltage, high energy lithium rechargeable batteries because $Li^+$ ion can be electrochemically deintercalated/intercalated from/to $Li_xCoO_2$. The transition metal oxide of $LiCoO_2$ was investigated for using as a cathode active material of 4V class Li rechargeable cell. $LiCoO_2$ cathode was prepared by using a active material of 85 wt%, graphite powder of 12 wt% as a conductor and poly-vinylidene fluoride of 3 wt% as a binder. The electrochemical and charge/discharge properties of $LiCoO_2$ were investigated by cyclic voltammetry and galvanostatic charge/discharge. The open circuit voltage of prepared $LiCoO_2$ electrode exhibited approximately. potential range between 3.32V and 3.42V. During the galvanostatic charge/discharge, $LiCoO_2/Li$ cell showed stable cycling behavior at scan rate of 1mV/sec and potential range between 3.6V and 4.2V. Also its coulombic efficiency as function of cycling was 81%~102%. In this study the $LiCoO_2/Li$ cell showed the available discharge capacity of 90.1 mAh/g at current density of $1mA/cm^2$ and cell discharge voltage range between 3.6V~4.2V.

• Journal of The Korean Association For Science Education
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• v.38 no.4
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• pp.519-526
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• 2018

The purpose of this study is to analyze the Korean high-school physics teachers' difficulties in teaching textbook physics inquiries. For this purpose, 63 high school physics teachers completed a questionnaire. We asked teachers to evaluate the degree of difficulty in teaching textbook physics inquiries. Additionally, we asked physics teachers to select the two most difficult inquiries to teach and to express their reasons for these selections. The main results are as follows: First, the degree of difficulty for all the inquiry is 2.79, indicating a little easy level of difficulty. The two most difficult inquiries are 'Meissner effect experiment' and 'Investigation of diode characteristics using $Cu_2O$ plate and ZnO powder.' Second, the difficulty reasons to teach physics inquiry was presented in the order of 'environment domain,' 'textbook domain,' 'student domain,' and 'teacher domain.' In particular, the biggest reasons for difficulty for teachers are 'preparation of experimental apparatus' and 'safety.' There are many opinions related to 'problem of the experiment itself' in 'textbook domain' and 'lack of ability to manipulate' in 'student domain.' Based on the results of this study, we added a discussion to activate the high school physics textbook inquiries.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1284-1288
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• 2009

Identification of various inorganic compound crystals contained in solar salts, which are produced from 12 areas of Jeonnam, was firstly made by the X-ray diffraction (XRD) technique. The analysis of the XRD spectra was carried out on the basis of Joint Committee on Powder Diffraction Standards (JCPDS) data and the results of Energy Dispersive X-ray Spectrometer (EDX) measurements. In particular, the analysis of the XRD spectra supported that each solar salt contains $Na_2S$ (Shinan Jeungdo and Sinui), $KMgCl_3$ (Shinan Bigeum), $Ca(ClO_3)_2$ (Shinan Docho), $CaAl_4O_7$ (Haenam Songji), $CaSiO_3$ and $CaCl_2$ (Goheung) as inorganic compound crystals, which have not been reported for the solar salts. Also, the XRD results indicated that the solar salts maintain a cubic NaCl crystal structure without any change of lattice parameters etc. However, it was shown in the Field Emission Scanning Electron Microscope (FE-SEM) images that an external form of the solar salts has a lamination layer shape of a cubic structure, which is different from a simple cubic form for the purified salts and the reagent NaCl.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1215-1221
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• 2009

The purpose of this work was to improve the quality of Jeungpyun made with rice sourdough, which was prepared using a mixed culture of Saccharomyces cerevisiae (S. cerevisiae) and Leuconostoc mesenteroides (L. mesenteroides) strains, and to also develop a new process for Jeungpyun preparation using the rice sourdough. The Jeungpyun was manufactured through proofing for 3 hr at $30^{\circ}C$ and steaming steps after mixing the ingredients, including pre-fermented rice sourdough, rice powder and water. After proofing, the expansion ratio of the Jeungpyun dough ranged from 109 to 135% and the pH was decreased to pH 3.80$\sim$4.09. The volumes of the Jeungpyun samples prepared with rice sourdough were 18$\sim$45% greater than that of the control. In particular, the Jeungpyun made with rice sourdough containing 10% brown rice (CM-10) had a significantly greater volume (266 mL). Also the rice sourdough Jeungpyun samples had well developed dense porous structures compared to the control. According to sensory evaluations, the sample prepared with rice sourdough containing 10% brown rice was preferred. Finally, the physical quality (texture properties) and microbiological shelf-life of the Jeungpyun was improved by using the rice sourdough.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2009.09a
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• pp.95-95
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• 2009

우리나라를 비롯한 동양문화권에서는 천연 약용식물자원의 이용을 통하여 전통적으로 지역 보건향상을 도모해 왔으며 최근 성인병과 난치병 해결을 위한 대체의학에 대한 관심이 증가하면서 약용식물자원을 이용한 건강기능식품 분야가 주목되고 있다. 약용식물자원은 민간에서 약선음식 등에 널리 활용되고 있지만 원료 농산물을 그대로 이용하는 수준으로 광범위한 적용성을 가지는 약선식품용 소재화 기술개발은 약용식물자원의 소비촉진에 크게 기여할 것으로 기대된다. 본 연구에서는 약선식품용 식품소재 개발의 일환으로 약용식물자원의 배합비와 추출물의 제형이 품질특성에 미치는 영향을 조사하였다. 스트레스 경감기능을 보유하는 약용식물자원은 고문헌에 기초하여 선정하였으며 약선원리에 따라 소정의 조건으로 3종(CLP 1, CLP 2, CLP 3) 배합비를 설정하였다. 추출물은 온도를 달리한 열수에 추출하고 유동Ext, 분무건조분말 및 과립으로 제형화 하였고 품질특성은 폴리페놀함량, 용해도, 투과도 및 색도특성을 분석하였다. 약용식물자원 혼합 추출물의 수율은 CLP 2가 65%로 가장 많았으며 1차 추출에서 76%의 수율을 보였고 추출시간대비 수율은 상업적 추출의 경우가 가장 높았다. 유동 Ext의 폴리페놀함량은 CLP 2가 g 당 11~13 mg을 함유하여 가장 많았고 CLP1과 CLP 2는 동등한 수준을 나타냈다. 유동 Ext는 99%의 용해도를 보였으며 투과도는 CLP 3가 52~68%로 가장 낮았으며 추출조건에 따라 색도가 차이가 있었다. 분말형태의 경우 폴리페놀 함량은 분무건조로 제조한 CLIP 2가 15.40mg/g으로 가장 많았다. 부형제로 과립화한 CLP 3가 g당 1.7 mg으로 가장 적었다. 분무건조분말은 98~99%의 용해도를 보였으며 부형제를 사용하여 분무건조하거나 과립화한 시료는 투과도와 명도가 높았으며 적색도와 황색도 및 갈색도가 낮았다. 이상의 결과는 약용식물자원 혼합 추출물은 원료의 조합비와 추출물의 제형은 식품소재화에 따른 품질특성의 영향인자로 작용함을 나타낸다.

• Food Science of Animal Resources
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• v.23 no.1
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• pp.70-74
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• 2003

Cheese consumption in Korea has continuously increased far the last decades by industrialization and globalization. In addition, import of fresh cheese has increased from 2 tons, and 30 thousand dollars in 1991 to 20 thousand tons, and 49 million dollars in 2001. However, Korea standard for cheese differs from CODEX, and is not consistent. To investigate more proper standards for cheese, 20 natural cheeses and 17 process cheeses were obtained from market and analysed. All the cheeses except 1 soft cheese met the standard, but 'unripened cheese' was not different from 'soft cheese' in milk solid content. Natural cheese firmness showed exponential inverse relationship(R=0.8226) to moisture on a fat-free basis(MFFB) which is used for the natural cheese standard in CODEX. Therefore, it was thought appropriate to refer to CODEX standard for using textural terminology in Korea standard for natural cheese. For process cheese, milk solid cant be estimated by the analysis, and there are no merits and penalties by the classification. It was thought proper to classify the process cheese by types, such as 'Powder', 'Slice', 'Spread', and 'Portion'. Rule for 15∼34% milk solid content of products should be prepared in standard for animal products as 'Process cheese products' for the promotion of development and consumption of cheese.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.769-774
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• 1993

Defatted rice bran was microparticulated using fluidized bed opposed jet mill and air-classified at different air classifying wheel speed (ACWS) in Turboplex classifier. The median particle size and the standard deviation decreased, and concomitantly the specific surface area increased generally with increasing ACWS. The protein, fat and ash contents of the recovered rice bran increased with ACWS. The contents of minerals; magnesium, zinc, iron and manganese; increased positively with ACWS. The phytic acid content, however, was slightly higher at middle ACWS. The dietary fiber content was highest in the ACWS 15,000 rpm fraction showing 31.47%. Higher ACWS resulted in lighter colored powder. The water holding capacity (WHC) showed the maximum value at ACWS 12,000 rpm and decreased with increasing ACWS, while the oil holding capacity (OHC) increased with ACWS. The rheological property of the microparticulated rice bran/water suspension fitted to the linear model. The yield stress and viscosity of the suspension increased with ACWS. The shape of microparticulated rice bran at ACWS 21,000 rpm was spherical, and the median particle size was $3.7{\mu}m$. When cake was prepared with substitution of microparticulated rice bran at 5%, the cake height and volume increased remarkably.

• Korean Journal of Agricultural Science
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• v.21 no.2
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• pp.142-147
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• 1994

Characteristics of TNP-cellulose which prepared from carboxymethyl cellulose powder, CM32, as substrate for cellulase activity assay were investigated. Enzymatic hydrolysis of TNP-cellulose occured on the cellulose moiety but not on amide bonds, following Michaelis-Menten kinetics. Three cellulase preparations from Trichoderma viride, Aspergillus niger, and Cellulomonas sp. were tested for their pH and temperature dependences and compared with the method determining the increase in reducing power. The enzyme activity was found to have the same temperature range in both methods, however the pH range was broadened in the case of using TNP-cellulose as substrate. The colorimetric method for cellulase assay using TNP-cellulose as substrate was compared with the other methods: one based on determination of the increase in reducing power; and the other based on determining the decrease in viscosity of Na-CM-cellulose solution. The activities measured by the colorimetric method showed a linear correlation with the enzyme concentration of certain range in all three enzymes tested, and the activity values were proportional to those obtained from the other methods. Depending on the enzyme, however, the activity values from this method were not always in proportion to those from the viscometric method. suggesting that this method was not specific for determination of the endo-type cellulase.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.721-726
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• 2013

In this study, a yogurt containing skim milk powder and whole barley flour was fermented with lactic acid bacteria, and its quality and properties were estimated. The yogurts with 1% and 3% barley flour had lower pH values, higher titratable acidity, and higher Brix values than the control. In addition, the viable cell counts were lower and viscosity was higher. The value of L was low, and the values of a and b were high. The yogurt with 3% barley flour had more lactic acid than the control and showed a substantial increase in the amount of acetic acid. ${\beta}$-Glucan content and antioxidant activity increased with the amount of barley flour added. In sensory evaluation, there was a similar preference for the yogurt with 3% barley flour and the control, and as the barley flour content increased, the preference decreased. Moreover, the preference for the yogurt was higher among old people.