• Title/Summary/Keyword: 동결온도

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생약재 추출물의 수율 및 항고혈압 활성

  • 도정룡;김기주
    • 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.137.2-138
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    • 2003
  • 본 실험에 사용한 생약재는 금산 약초시장에서 2003년 6월에 구입하여 추출수율을 조사하였다. 그 결과, 생약재의 물 추출물의 동결건조 중량(%)이 30~40%에 달하는 생약재는 가자, 갈근, 맥문동, 산수유가 있고, 20~30%에 달하는 생약재는 감초, 구기자, 당귀, 오미자, 천궁, 황기가 이에 속했으며, 중량(%)이 10~20%에 달하는 생약재는 복분자, 오수유, 애엽, 작약, 진피, 지유, 파고지, 황련이 이에 속했다. 마지막으로 10%이하의 추출 수율을 나타낸 생약재들은 가시오가피, 강황, 계피, 석곡, 소목, 영지, 오약, 육두구, 정향, 죽엽, 필발, 초두구, 호장근이 이에 속했다. 생약재의 70% Ethanol 추출물의 동결건조중량을 살펴본 결과, 동결건조 중량(%)이 30~40%에 달하는 생약재는 가자, 당귀, 산수유가 이에 속하였고, 20~30%에 달하는 생약재는 감초, 맥문동, 구기자, 오미자, 오수유, 천궁, 황기가 속하였으며, 동결건조 중량(%)이 10~20%에 달하는 생약재는 복분자, 육두구, 애엽, 작약, 정향, 지유, 파고지, 호장근, 황련이 이에 속했다. 또한 10% 이하의 수율을 나타내는 생약재는 가시오가피, 강황, 갈근, 계피, 석곡, 소목, 영지, 오약, 익지인, 죽엽, 필발, 초두구가 이에 속하였다. 생약재의 추출 시간 및 온도에 따른 수율을 조사한 결과, 추출 시간이 경과함에 따라서 수율이 점차 증가하는 경향을 보였으며, 가자, 갈근, 황련, 복분자, 지유, 정향, 계피, 소목 순으로 높은 수율을 얻을 수 있었다. 생약재에 여러가지 효소를 이용한 가수분해 결과, 대부분의 생약재에 대해 95$^{\circ}C$에서 2시간동안 추출한 수율과 그다지 큰 차이는 보이지 않았지만 대부분의 생약재가 Termamyl 효소를 사용하여 가수분해하였을 때 가장 높은 수율을 나타내었다. 또한 지유의 경우는 Viscozyme 효소를 처리하였을 경우 가장 좋은 수율을 나타내었다. 또한, 효소의 최적 온도로 조정한 Water bath에서 0, 30, 60, 120, 210분간 효소 반응 시켜, 420nm에서 갈변도를 시간별로 측정해본 결과, Viscozyme 효소를 처리한 생약재에서 시간이 흐름에 따라 흡광도 수치의 변화가 크게 나타났다. 32종의 생약재 물 추출물의 항고혈압 활성을 측정한 결과, 파고지, 소목, 죽엽의 항고혈압 활성이 높은 것으로 나타났으며, 파고지의 효과가 가장 우수한 것으로 나타났다. 10%에탄을 추출물의 경우에는 오미자, 오수유, 소목에서 항고혈압 활성이 높은 것으로 나타났으며, 오미자의 효과가 가장 우수한 것으로 나타났다. 파고지 물 추출물을 칼럼(Sephacryl S-300, High Resolution)으로 분획하여 3개의 Peak를 얻었으며, 2번째 Peak의 항고혈압 활성이 매우 높은 것으로 나타났다.

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Estimating the freezing and supercooling points of Korean agricultural products from experimental and quality characteristics (국내산 농산물의 과냉각 및 동결점 분석)

  • Park, Jong Woo;Kim, Jinse;Park, Seok Ho;Choi, Dong Soo;Choi, Seung Ryul;Kim, Yong Hoon;Lee, Soo Jang;Park, Chun Wan;Han, Gui Jeung
    • Food Science and Preservation
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    • v.23 no.3
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    • pp.438-444
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    • 2016
  • This study was performed to determine the optimal freezing point for the reliable cold storage of Korean agricultural products, and to provide basic data for determining the storage temperature based on the quality characteristics. Additional supercooling temperature analysis was conducted to explore the possibility of supercooling storage. To determine the effects of quality characteristics on the freezing point, the hardness, acidity, moisture and sugar content were analyzed. The crops were frozen using customized cooling unit and their freezing and supercooling points were determined based on their heat release points. The freezing temperatures of garlic, leek, cucumber, hot pepper, grape, oriental melon, netted melon, peach, cherry tomato, plum, daikon, sweet persimmon, apple, sweet potato, mandarin, pear, and strawberry were -1.6, -0.5, -0.5, -0.7, -1.6, -1.6, -1.3, -0.8, -0.3, -1.1, -0.3, -1.7, -1.5, -1.5, -0.8, -1.5, and -$0.9^{\circ}C$, respectively; otherwise, supercooling points were -7.8, -3.7, -3.3, -4.9, -5.7, -4.6, -2.8, -3.3, -5.9, -4.2, -0.8, -4.7, -3.2, -3.7, -4.7, -4.2, and -$3.4^{\circ}C$, respectively. These results suggest that the ideal freezing temperature of crops could be estimated through freezing point depression because of their sugar content, and this technique should be used to maintain an optimum storage temperature. However, cold storage is complicated and further study is required because of the effects of long-term cold storage on the crops.

진공동결건조 후 두부의 수분활성 및 품질변화에 관한 연구

  • 김진성;이준호;하영선
    • 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.163.1-163
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    • 2003
  • 식품의 건조는 저장성을 향상시키고 수송을 간편하게 하나 특별한 경우는 건조과정에서 일어나는 성분변화에 의해 풍미, 색깔, 조직 등이 향성되게 하는 경우도 있다. 그러나 일반적으로 건조에 의해 풍미의 저하, 색깔의 퇴조, 영양성분의 손실 및 조직과 형태의 손상 등 품질을 저하시키므로 가능한 저온에서 단시간에 수분을 제거해야 한다. 건조식품의 저장성은 수분활성도, 제품의 종류, 저장온도등 다양한 요인들에 영향을 받으며, 특히 수분 활성도에 따라 비효소 갈색화 반응, 지방의 산패, 미생물의 발생정도가 달라진다. 따라서 건조식품 저장시 변질을 방지하기 위해서는 식품의 수분함량을 측정할 수 있는 등온흡습곡선을 작성하는 것이 중요하다. 또한 식품의 단분자층 수분함량을 결정하고, 흡습에 필요한 에너지를 구함으로서 건조식품의 저장조건 및 포장조건의 선택시 유용한 자료가 된다. 특히 식품분말의 흡습특성은 분말입자의 크기, 형태, 화학성분 등과 밀접한 관련이 있다. 위의 사실로 미루어 볼 때 본 연구에서는 시판 유통되고 있는 두부를 진공동결 시킴으로써 위생화와 장기저장 가능성을 연구하면서 진공동결 건조 후 시료의 수분활성, 재수화 및 일반성분 변화를 검토하고자 한다.

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Freezing and Bearing Capacity Characteristics of Road Foundations under Temperature Condition (온도조건에 의한 도로하부 지반의 동결 및 지지력 특성)

  • Shin, Eun-Chul;Kim, Sung-Hwan;Park, Jeong-Jun
    • Journal of the Korean Geotechnical Society
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    • v.28 no.3
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    • pp.5-14
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    • 2012
  • In the current design codes for anti-freezing layer, the thickness of anti-freezing layer is calculated by freezing depth against the temperature condition. Therefore, they have a tendency of over-design and uniform thickness without the considerations of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential for studying the appropriateness and bearing capacity of road foundation materials as well as their seasonal and mechanical properties to take an appropriate and reasonable design of the road structure system. In this paper, the freezing and bearing capacity characteristics of typical road foundation materials were evaluated in the large scale laboratory test. LFWD (light falling weight deflectometer) was used to determine the change of elastic modulus ($E_{LFWD}$) caused by to the frost heave and thaw. Furthermore, the influence of crushed natural aggregate on the freezing of the subgrade soil was studied to verify the function and effectiveness of the anti-freezing layer.

Effects of Sucrose Immersion on the Rehydration Characteristics of Freeze Dried Mooks (전처리가 동결건조묵의 재수화 특성에 미치는 영향)

  • Youn, Kwang-Sup;Hwang, Jung-Shub
    • Korean Journal of Food Science and Technology
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    • v.33 no.4
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    • pp.395-400
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    • 2001
  • The objectives of this study are to establish efficient pretreatment concentration and rehydration process for the production of the high quality of freeze-dried Mook, a traditional gel food in Korea, as an instant food. Effect of immersion in sucrose solution as pretreatment before freeze-drying on the rehydration efficiency and quality characteristics was studied. The rehydration efficiency of non-treated Mook was the highest. The rehydration efficiency increased as the concentration of sucrose increased. The texture of rehydrated Mook treated in sucrose solution was decreased with increase in rehydration temperature. The Mook treated at 60% sucrose solution was somewhat similar to the market selling Mook in the quality and the treatment prevented color and texture degradation.

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Effect of Glycerol Concentration, Freezing Rate and Thawing Rate on Semen Characteristics in PoongSan-dog (풍산개 정자의 동결보존에 있어서 Glycerol 농도, 동결 및 융해속도가 정자성상에 미치는 영향)

  • Ji, D.Y.;Yoon, T.C.;Rho, J.R.;Cho, S.R.;Kim, C.K.;Pang, M.G.;Kim, Bo-Sook
    • Journal of Animal Science and Technology
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    • v.49 no.5
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    • pp.585-592
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    • 2007
  • This research was carried out in order to establish the production technique for Poong-san dog’s frozen semen, by examining the semen characteristic and the volume of glycerol added to the dilution solution, thawing temperature and sperm motility and viability as well as the motility using CASA according to time variation. Average semen volume was 5.9ml, sperm concentration 116.3×106 sperm/ml, total sperm number 789.3×106 sperm, motility 88.7±1.7% and viability 87.6±7.8%. When it was cryopreservation and thawed at different glycerol concentrated extender, it showed 52.7% motility and 57.7±10.3% viability at 7% glycerol, compared to other treatments. For semen cryogeny, at conditions of 5, 7cm and a height of 10cm for pre-cryogeny and maintaining the semen at 7cm from the surface of liquid nitrogen resulted in profitable motility and viability.

A Study on Boiling Characteristics of Direct Contact LNG Evaporator (직접접촉식 액화천연가스 기화기의 비등특성 연구)

  • 김남진;김종보
    • Journal of Energy Engineering
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    • v.4 no.3
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    • pp.420-428
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    • 1995
  • 현재 사용하고 있는 액화천연가스 기화기는 관내부로 -162$^{\circ}C$의 액화가스가 흐르고, 관외부로 발전소 증기응축기 출구에서 배출된 20~3$0^{\circ}C$의 해수를 흐르도록 하여, 두 유체사이의 온도차로 기화시키는 간접접촉방식 열교환기가 사용되고 있다. 그러나 간접접촉방식 열교환기는 두 유체사이의 큰 온도차로 인한 금속재료의 피로현상과 해수의 염분에 의한 재질의 부식 및 미생물 부착 등의 원인으로 열전달효율이 저하되고 있다. 따라서 본 연구는 관을 중간매체로 하는 간접접촉식 열교환기대신 액화천연가스와 기화용수인 물을 직접접촉시키는 방법으로 이용하여, 위와 같은 문제점들을 근본적으로 해결하려 한다. 본 실험에서는 기화기내의 수위 500 mm와 물의 유량 10 l/min을 일정하게 고정시키고, 액화천연가스의 유량 0.12 ㅣ/min, 0.36 l/min, 0.6 l/min, 기화기내의 압력을 100 kPa, 300 kPa, 500kPa로 변화시키면서 기화기내의 기포, 온도분포, 급팽창현상, 동결현상 및 기화후 수분함유량등의 비등특성을 규명하였다. 실험결과 기화기내의 압력이 증가할수록 기포는 작고 균일한 분포를 이루고, 폭발적인 급팽창현상은 일어나지 않았다. 또한 동결현상은 액화천연가스의 기화를 방지하지 못하였으며, 기화된 천연가스내의 수분함유량 몰%는 압력과 유량이 증가함에 따라 감소하는 경향을 보이고 있다.

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Changes in the Viable Counts and Microflora of Oyster and Weakfish during Cold Storage (굴과 Weakfish의 저온저장중 생균수 및 Microflora의 변화)

  • 박찬성
    • Korean journal of food and cookery science
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    • v.12 no.3
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    • pp.312-319
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    • 1996
  • Oyster (Crassostrea virginica) and Weakfish (Cynoscion regalis) were stored at 6, 0, -4 and -20$^{\circ}C$ for up to 45 days and examined for changes in microflora. Aerobic plate counts (incubated at 21$^{\circ}C$) were performed at selected times during storage and 495 isolates (255 isolates from oyster and 240 isolates from Weakfish) were randomly selected from the plates during the storage. Before the storage of the fishes, viable counts of oyster were 4.9${\times}$10$\^$5/ CFU/g of meat and those of Weakfish were 1.5${\times}$10$^4$ CFU/cm$^2$of skin. Microflora of oyster before storage, the major isolates identified as Pseudomonas spp. (67%) and Vibrio spp. (20%). Pseudomonas ll1/1V-H and Flavobacterium/Cytophaga were predominant genus in the microflora of oyster during cold storage at 6, 0, -4 and -20$^{\circ}C$. The composition of the microflora of Weakfish before storage, Acinetobacter (40%) and Moraxella (33%) were the major species, with Pseudomonas and Vibrio constituting a small percentage of the total isolates. The microflora shifted to predominantly Pseudomonas spp. during storage at 6. 0 and -4$^{\circ}C$, making up from 60 to 100% of isolated strains. During frozen storage, the percentage of isolates identified as Mnraxella increased to 40-60% of the total isolates. During cold storage, halophilic bacteria (Pseudomonas lII/IV-H and Vibrio) were predominant in oyster while nonhalophilic bacteria (Pseudomonas III/IV-NH and Moraxella) were predominant in Weakfish. Vibrio spp. were higher in oyster than in Weak fish. Listeria spp. were not isolated but unidentified ${\beta}$-hemolytic bacteria were islolated from both of the fishes during cold storage.

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Variations of Geotechnical Characteristics Following Freeze-Thaw of Terra Nova Bay Rocks, Antarctica (남극 테라노바 만 편마암의 동결-융해에 따른 지반공학적 특성 변화)

  • Kim, YoungSeok;Kim, Kiju;Jang, Hyun-Shic;Jang, Bo-An
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.4
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    • pp.1499-1508
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    • 2013
  • Freeze-thaw tests were performed on gneiss samples collected from Terra Nova Bay, Antarctica in order to examine the engineering properties of rocks with slightly weathered (SW) and moderately weathered (MW). The tests were conducted under temperature ranging from $20{\pm}2^{\circ}C$ to $-20{\pm}2^{\circ}C$. A cycle of test consisted of 5 hours of freezing followed by another 5 hours of thawing under full saturation. In this paper, total 200 cycles of freeze-thaw test were performed with measurements of porosity, absorption, ultrasonic velocity, and shore hardness per each 20 cycle and that of uniaxial compressive strength (UCS) per each 50 cycle. The UCS of the SW rocks approximately decreased 0.07 MPa per a single cycle, while that of MW rocks decreased around 0.2 MPa per a single cycle. During the 200 cycles of SW rocks, the absorption increased from 0.23% to 0.39%, the P-wave velocity decreased from 4,054 m/s to 3,227 m/s and S-wave velocity decreased from 2,519 m/s to 2,079 m/s. Similarly, those of MW rocks changed from 0.65% to 1.6%, 3,207 m/s to 2,133 m/s and 2,028 m/s to 1,357 m/s. In conclusion, it was inferred that the properties of SW rocks experienced approximately 200-300 cycles of freeze-thaw process become close to those of MW rocks.

Ideal Body Modeling of Rock Frost-thawing (이상물체를 이용한 암반의 동결융해 Modeling)

  • Han, Heuisoo
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.12
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    • pp.5-11
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    • 2010
  • If the groundwater in rock joint is changed into ice, it induces the stress increment by volume increase. Also, if the ice is changed into groundwater again, the stress in joint decreases by volume decrease. The accumulated displacement and fatigues of joints are increased by the stress-hysterisis, induced from the continuous frost-thawing. Also the shear strength is decreased by them continuously. The stress-hysterisis is affected by the atmospheric temperature changes, whose behavior is visco-elasticity, usually. Therefore, Kelvin model could be used to analyze the frost-thawing behavior in winter. The measured data of total 5 points are examined, which are composed of 3 points of shallow joints and 2 points of deep joints. Because shallow weathered rocks have many joints, a lot of Kelvin model are connected and the behaviors are complicated. In case of deep joints, simple Kelvin model is applied and the behaviors are also simple.