Food Engineering Progress (산업식품공학)

Korean Society for Industrial Food Engineering (한국산업식품공학회)
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Concentration of Rice Bran Lipid Soluble Bioactive Substances Using Supercritical Carbon Dioxide

초임계 이산화탄소를 이용한 미강유 생리활성물질 농축

  • Kim, Inhwan (Department of Food and Nutrition, Korea University) ;
  • Yoon, Sung Won (Department of Food and Nutrition, Korea University) ;
  • Lee, Junsoo (Department of Food Science and Technology, Chungbuk National University) ;
  • Lee, Jeom-Sig (National Institute of Crop Science, Rural Development Administration) ;
  • Kim, In-Hwan (Department of Food and Nutrition, Korea University)
  • Received : 2013.10.10
  • Accepted : 2013.11.15
  • Published : 2013.11.30
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Abstract

The aim of the present study was to examine the effects of different pressure and temperature combinations on the concentrations of tocols homologues, policosanol, phytosterol, and ${\gamma}$-oryzanol in crude rice bran oil (RBO) using supercritical carbon dioxide (SC-$CO_2$). To effectively separate oily substances from bioactive substances, fatty acid ethyl esterification was performed by sulfuric acid or the lipase catalytic method. In sulfuric acid esterification, ${\gamma}$-tocotrienol content was decreased by ca. 50%, whereas in lipase esterification, ${\gamma}$-tocotrienol content was not decreased. Therefore, lipase catalytic esterification was performed for the fatty acid alkyl esterification of RBO. The fractional extraction of RBO ethyl esters was performed using SC-$CO_2$ in the condition of 9.62 Mpa, 10.34 MPa, or 11.03 MPa and $45^{\circ}C$, $50^{\circ}C$, or $55^{\circ}C$. During the fractionation of RBO using SC-$CO_2$, a little tocols content was extracted with fatty acid ethyl esters, but policosanol and phytosterol were not extracted. Especially, there is a high correlation ($R^2$=0.9306) between the density of $CO_2$ and tocols contents extracted to the fractions. The concentration rates of tocols and phytosterol were the highest in the condition of $55^{\circ}C$ and 9.62 MPa. Therefore, the lower $CO_2$ density applied, the more efficient the concentrations of tocols and phytosterol were in this study.

쌀 도정시 발생하는 미강의 부가가치를 높이기 위하여, 미강내 생리기능성 물질를 고농도로 농축하기 위한 전처리 방법 및 농축조건을 확립하고자 하였다. 미강으로부터 추출한 조미강유중 지방산을 분리하기 위하여 산 또는 효소 촉매를 이용하여 지방산 에틸 에스터를 제조하였다. 산 촉매 에스터 반응시 tocopherol류의 함량은 크게 영향을 받지 않았으나, tocotrienol류의 함량은 크게 감소하였고, 특히 ${\gamma}$-tocotrienol은 52% 감소하였다. 효소 촉매 에스터반응시 tocopherol류와 tocotrienol류 모두 크게 변화가 없었으므로 효소촉매를 이용한 에틸 에스터 반응이 생리활성물질 농축에는 더 적합하였다. 효소 촉매 반응을 이용하여 생산한 미강유 에틸 에스터를 초임계 이산화탄소를 이용하여 분리하고, 생리활성물질을 농축하였다. 온도 조건은 $45^{\circ}C$, $50^{\circ}C$, $55^{\circ}C$, 압력조건은 9.62 MPa, 10.34MPa, 11.03MPa 이었다. Tocols는 소량이지만, 1-5번 추출 분획에서 모두 검출되었으며, 5번 분획에 가까워질수록 더 많은 양의 tocols이 추출되었다. ${\gamma}$-Oryzanol도 매우 소량이기는 하나 1-5번 분획에서 추출되었다. Policosanol과 phytosterol은 1-5번 분획에서 전혀 추출되지 않았다. 특히 초임계 이산화탄소의 밀도와 지방산 에스터와 함께 추출되는 tocols 및 ${\gamma}$-oryzanol의 양은 높은 상관관계를 가지고 있었다($R^2{_{tocols}}$= 0.9306, $R^2{_{oryzanol}}$= 0.7934). Tocols와 phytosterol은 $55^{\circ}C$, 9.62MPa에서 농축시 농축률이 가장 높았으며, ${\gamma}$-oryzanol과 policosanol은 각 조건별로 농축률에 변화가 없었다. 또한 초임계 이산화탄소의 밀도가 클수록 농축속도는 매우 빨랐으나 농축물질의 선택성은 낮았다. 따라서 생리활성물질을 농축하는데에는 상대적으로 낮은 밀도의 초임계 이산화탄소를 적용하는 것이 더 효과적이었으며, 이러한 결과는 건강기능식품등에 이용하는 생리활성물질의 농축 및 정제 공정에 효율적으로 적용될 수 있을 것이다.

Keywords

Acknowledgement

Supported by : 농촌진흥청

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