Korean Journal of Food Science and Technology (한국식품과학회지)

Korean Society of Food Science and Technology (한국식품과학회)
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Physical Properties of Freeze-Dried Powder of Aloe Vera Gel with Respect to the Concentrating Degree as Pre-Treatment

전처리 농축 정도에 따른 Aloe Vera gel의 동결건조분말의 물성

  • Lee, Nam-Jae (Department of Food Science and Technology, Dongguk University) ;
  • Lee, Seung-Ju (Department of Food Science and Technology, Dongguk University)
  • Published : 2009.02.28
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Abstract

The physical properties of freeze-dried Aloe vera gel powders were examined according to the influence of the concentration degrees of the gel solutions as raw materials during freeze-drying. As a pre-treatment prior to freeze-drying, the gel solutions were vacuum-concentrated at three concentration levels (g water/g solids): high (H), 76; medium (M), 119; and low (L), 159. The water contents of the three powder samples were almost the same. For their viscosity measurements, non-Newtonian fluid behavior with shear thinning was observed in samples H and M, whereas Newtonian liquid behavior was found in sample L. In electrical conductivity measurements, sample H showed the highest conductivity upon dissolving the powder in water. For their water sorption isotherms, sample H was analyzed to have the least amount of bound water. Finally, it was determined that the degree of concentration caused only slight differences in the physical properties of freeze-dried Aloe gel powders.

농축시킨 Aloe vera gel을 동결건조하였을 때 그 농축도 차이에 의한 최종 건조분말의 물성 변화를 비교분석하였다. 분말의 최종 수분함량은 거의 차이가 없었으며. 점성 측정에서는 높은 농축 조건의 경우 전형적인 shear thinning 현상과 non-Newtonian 유체의 속성을 나타냈다. 이에 비하여 낮은 농축 조건의 경우 Newtonian 액체의 성질과 고형분이 입자가 아닌 풀린 형태로 존재할 때 나타나는 현상을 보였다. 분말이 물에 용해되는 동안 전기전도도의 변화를 실시간으로 측정한 결과 평형상태에 도달하였을 때, 가장 높은 농축 조건에서 전기전도도가 가장 낮게 나타나, 비전해질성 물질의 용해도가 가장 큰 것으로 해석되었다. 분말의 등온흡습성에서는 농축이 증가할수록 수분 흡착과 결합수의 양이 작아지는 것으로 분석되었다. 결과적으로 Aloe vera gel을 농축하여 동결건조할 때는 그 농축도에 따라 점성, 현탁시 전기전도도에 따른 용해성, 등온흡습성이 변하는 것으로 나타나, 특정 품질의 동결건조제품을 얻기 위해서는 그에 대한 농축의 최적화가 필요한 것으로 생각된다.

Keywords

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