• 제목/요약/키워드: water activity and temperature

검색결과 971건 처리시간 0.035초

A Study on the Sulfur-Resistant Catalysts for Water Gas Shift Reaction III. Modification of $Mo/γ-Al_2O_3$ Catalyst with Iron Group Metals

  • 박진남;김재현;이호인
    • Bulletin of the Korean Chemical Society
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    • 제21권12호
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    • pp.1233-1238
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    • 2000
  • $Mo/{\gamma}-Al_2O_3catalysts$ modified with Fe, Co, and Ni were prepared by impregnation method and catalytic activity for water gas shift reaction was examined. The optimum amount of Mo loaded for the reaction was 10 wt% $MoO_3$ to ${\gamma}-Al_2O_3.$ The catalytic activity of $MoO_3/{\gamma}-Al_2O_3was$ increased by modifying with Fe, Co, and Ni in the order of Co${\thickapprox}$ Ni > Fe. The optimum amounts of Co and Ni added were 3 wt% based on CoO and NiO to 10 wt% $MoO_3/{\gamma}-Al_2O_3$, restectively. The TPR (temperature-programmed reduction) analysis revealed that the addition of Co and Ni enganced the reducibility of the catalysts. The results of both catalytic activity and TPR experiments strongly suggest that the redox property of the catalyst is an important factor in water gas shift reaction on the sulfided Mo catalysts, which could be an evidence of oxy-sulfide redox mechanism.

건조 방법에 따른 계피 Extract의 품질 변화 (Quality Change of Cinnamon Extract Prepared with Various Drying Methods)

  • 김나미;김동희
    • 한국식품영양학회지
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    • 제13권2호
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    • pp.152-157
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    • 2000
  • In order to select the optimum drying method for the production of cinnamon extract, water extract and 70% ethanol extract of cinnamon were prepared. And then several drying method of oven drying, vacuum evaporation, spray drying and freeze drying were performed. Content of cinnamic acid, cinnamic aldehyde, eugenol, tannin and free sugar, and antioxidant activity, degree of browning, pH, color value, turbity and solubility were compared. In water extract, contents of cinnamic acid, cinnamic aldehyde, eugenol were 29.45mg/100g, 94.86mg/100g, 120.75mg/100g and decreased to 4.76%∼44.21%, 5.30%∼48.05%, 3.66%∼21.83% by oven dyring, vaccum drying, spray drying respectively, but freeze drying showed a little decrease of those components. In 70% ethanol extract, effectual components decreased to 76.05%∼88.38% and 26.86%∼78.76% by freeze drying and vacuum evaporation respectively. Antioxidant activity decreased by drying and decreasing rate in 70% ethanol extract was lower than water extract. Degree of browning increased as the drying temperature increased. Tannin and free sugars were little affected by drying temperature. Solubility decreased in oven drying and 70% ethanol extract. Overall data suggested that optimum drying methods of cinnamon extract were freeze drying in case of water extract and freeze drying and vaccum drying in case of 70% ethanol extract.

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생강 페이스트 모형액의 비효소적 갈색화 억제인자 및 반응속도 (Inhibiting Factors and Kinetics of Nonenzymatic Browning in Ginger(Zingiber officinale Roscoe) Paste Model System)

  • 조길석;장영상;신효선
    • 한국식품영양과학회지
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    • 제26권6호
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    • pp.1135-1139
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    • 1997
  • Major factors inhibiting nonenzymatic browning in stored ginger paste were investigated using aqueous model systems with temperature, water activity, pH and sulfur compounds. Browning index and total gingerols were measured during storage. The rate of nonenzymatic browning reactions showed a strong depencence on temperature and pH and a negligible influence on water activity. It was also reduced by the addition of 0.04% N-actyl-L-cysteine(NAcCys), effectively. Activation energies for aqueous ginger model systems with and without 0.04% NAcCys were 29.0 and 25.8kcal/mole, respectively.

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추출 조건에 따른 오미자 추출물의 항산화 및 혈당 강하에 관한 연구 (A Study of Antioxidative and Hypoglycemic Activities of Omija(Schizandra chinensis Baillon) Extract under Variable Extract Conditions)

  • 김순임;심기현;주신윤;한영실
    • 한국식품영양학회지
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    • 제22권1호
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    • pp.41-47
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    • 2009
  • 오미자의 전통식품소재로의 활용성을 높이기 위해 물과 에탄올, 그리고 추출온도와 시간을 달리하여 추출하여 얻은 추출물로부터 항산화능과 혈당 강하능을 살펴보았다. 총 페놀함량은 추출온도에 따른 차이를 크게 나타내었다. 60$^{\circ}C$에서 추출하였을 때 실온에서 추출한 것보다 51${\sim}$68% 더 높은 함량을 나타내었고, 또한 물 추출보다는 60% 에탄올로 추출하였을 때 더 높은 페놀을 함유한 것으로 나타났다. DPPH 유리 라디칼 소거능을 비롯한 $ABTS^+$ 라디칼, Nitrite 소거능 또한 60$^{\circ}C$에서 60% 에탄올로 추출하였을 때 유의적으로 가장 높았으며, 환원력도 60% 에탄올 추출물이 가장 높은 환원력을 나타내었다. 오미자 추출물의 인슐린 비의존형인 제2형 당뇨환자들의 식후 혈당을 저하시키는 효능을 검토하기 위해 ${\alpha}$-glucosidase 의 활성 저해력을 살펴본 결과, 5가지 추출 조건중 60$^{\circ}C$에서 60% 에탄올로 추출한 추출물이 유의적으로 가장 높은 저해력을 보이는 것으로 나타났다. 이상의 결과로 볼 때 오미자로부터 유용성분 용출 및 기능성 증대를 위해 60$^{\circ}C$에서 60% 에탄올로 추출하는 것이 바람직하다고 생각된다.

Changes in Antioxidant Activity with Temperature and Time in Chrysanthemum indicum L. (Gamguk) Teas During Elution Processes in Hot Water

  • Eom, Seok-Hyon;Park, Hyung-Jae;Jin, Cheng-Wu;Kim, Dae-Ok;Seo, Dong-Wan;Jeong, Yeon-Ho;Cho, Dong-Ha
    • Food Science and Biotechnology
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    • 제17권2호
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    • pp.408-412
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    • 2008
  • Determining the elution of water-soluble substances from herbal teas is an important factor in their efficient use in terms of taste, perfume, and content of health-related components. The antioxidant activity and content of catechins in commercial Chrysanthemum indicum (gamguk) teas were determined for optimum elution conditions. The water extract of gamguk teas did not differ significantly in yield compared to methanol extracts and showed stronger antioxidant activity. Catechin contents in gamguk teas were 8-18% of the extracts when individual peaks in high-performance liquid chromatography analysis were compared to standard catechin peaks. Gamguk teas exhibited faster release of antioxidants, and the antioxidant activity was positively correlated with the thermal treatments. Gukhwacha (GC) was the best tea for rapid release (30 sec) of antioxidants with the $50^{\circ}C$ treatment, whereas antioxidants in other teas were relatively slower released.

키토산과 콜라겐의 혼합물로 처리한 폴리에스테르 직물의 항균성 및 물성 (Antimicrobial Activity and Physical Properties of Polyester Fabric Treated with Mixture of Chitosan and Collagen)

  • 박수미;오수민;송화순
    • 한국염색가공학회지
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    • 제11권4호
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    • pp.31-38
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    • 1999
  • The purpose of this study is to develop multifunctional fabric that has improved antimicrobial activity and reduction rate of gas by treatment of mixture of chito colla and crosslinking material for polyester. The surface morphology of treated PET fabric was studied by scanning electron microscopy(SEM). The properties of the PET fabric, such as antimicrobial activity, whiteness, moisture regain, water absorption and static voltage, and handle were investigated. Antimicrobial activity of treated PET fabric was proved 99%. The surface of treated PET fabric showed harshness and irregularity. The whiteness of treated PET fabric on the baking condition was decreased as time and temperature was increased. The moisure regain of treated PET fabric equally was maintained. Water absorption and static voltage of treated PET fabric were improved. KOSHI of treated PET fabric was increased compared with the untreated PET fabric H/W of treated PET fabric was improved compared with the untreated PET fabric and 2HB/B of treated PET fabric were reduced.

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소화효소 활성으로 본 rotifer Brachionus rotundiformis의 적정 영양강화 조건 (The Optimal Enrichment Condition of Rotifer Brachionus rotundiformis)

  • 권오남;박흠기
    • 한국양식학회지
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    • 제21권1호
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    • pp.41-46
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    • 2008
  • 본 연구의 목적은 rotifer Brachionus rotundiformis의 수온과 염분농도의 변화에 따른 이들의 소화효소 활성을 파악하고, 소화효소 활성을 기초로 적정 영양강화 조건을 찾는 것이다. 다른 온도에서 24시간 배양된 rotifer 밀도는 $32^{\circ}C$에서 1,453 개체/mL로 가장 높았다(P<0.05). 그리고 배양온도 $28^{\circ}C$에서 염분농도에 따른 rotifer 밀도는 15 에서 2,147 개체/mL로 가장 높게 나타났다(P<0.05). 배양환경에 따른 rotifer의 소화효소 활성에서 TAP 개체당 활성은 $24-32^{\circ}C$에서 유의적으로 높게 나타났으며(P<0.05), 단백질 비활성은 $32-36^{\circ}C$에서 높게 조사되었다(P<0.05). 그리고 TG-lipase 활성에서는 개체당 활성과 단백질 비활성 모두 $20^{\circ}C$에서 가장 높은 활성을 보였다(P<0.05). 또한 염분별 실험에서 TAP와 TG-lipase 활성은 32 psu에서 가장 높은 활성을 보였다(P<0.05). 32 psu에서 온도별 영양강화한 rotifer의 methionine 함량(% in protein), 지질 함량과 지방산 불포화도이 $20^{\circ}C$에서 유의적으로 높게 나타났다. 특히, DHA와 DHA/EPA 비가 $20^{\circ}C$ 실험구에서 12.6%와 12.5의 비로 각각 높았다(P<0.05). 따라서 rotifer B. rotundiformis의 지질 영양강화는 특히 TGlipase 활성을 높여 줄 수 있는 32 psu, $20^{\circ}C$에서 실시하는 것이 지방산 불포화도, DHA 및 DHA/EPA 비를 높여 줄 수 있는 효과적인 방법이라고 판단된다.

Anticancer and Antioxidant Activity of Allergen-Removed Extract in Rhus verniciflua Stokes

  • Kim, Myong-Jo;Choi, Won-Cheol;Barshinikov, A. M.;Kobayashi, A.
    • 한국약용작물학회지
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    • 제10권4호
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    • pp.288-293
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    • 2002
  • Allergen-removed-extract was produced from Rush verniciflua by two phase methods. Phase one was high temperature treatment of Rush verniciflua tree to get allergen-removed-extract. Phase two was extraction of solution from phase one product using water or organic solvents. The solutions from above method show high antioxidant activity, anticancer activity, and improvement in lung function, but did not contain urushiol family compounds.

건조김의 품질 안정성에 미치는 저장 조건의 영향 (Effect of Storage Conditions on Quality Stability of Dried Laver(Porphyra tenera))

  • 조길석
    • 한국식품저장유통학회지
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    • 제10권1호
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    • pp.32-36
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    • 2003
  • 건조김의 저장 중 품질 안정성에 미치는 저장조건에 관한 기초자료를 조사하기 위해 몇가지 광원, a$_{w}$ , 포장 및 온도의 영향을 시험하였다. 건조김의 주요 지방산 조성은 16:0(13.6%) 및 20:5(45.7%) 이었다. 건조김의 품질 안정성을 지방질 산화 및 chlorophyll 함량의 변화로 판단할 때, 건조김의 품질은 형광등 하에서 가장 악화되었고, 다음이 백열등, 암소저장 순 이었으며, 또한 a$_{w}$ 가 증가할수록, 저장온도가 높을수록 급격히 나빠지는 경향을 보였고 기체 및 광 차단 효과가 적은 포장지에 포장한 시료일수록 품질 안정성은 악화되었다.