粉末生薬の水分収着特性とそれに及ぼす含有澱粉の役割 Water Sorption Properties of Powdered Crude Drugs and Hydrophilic Function of Their Starches

Access this Article

Author(s)

Abstract

加水比の異なる米飯を冷蔵保存した試料を用いて、米飯の初期老化を評価する方法について比較検討し、次のような結果を得た。1)色彩色差計で測定したL*値で初期の老化程度を判断することは可能であったが、精確さに問題があった。2)DSC測定はX線回折に比べ、保存時間のより短い試料の老化を捉えていた。 3)BAP法による糊化度では保存12時間以降に、DSC測定では9時間後に、水分量の異なる試料間の老化程度の差が現れた。 4)DSC曲線から算出されたエンタルピー変化量には、米飯試料における8%の水分差の影響が現れなかった。一方、米飯試料中の4%の水分減少は吸熱ピークを有意に高温側に移動させた。以上より、冷蔵のより早期に試料の差を検出でき、直接測定が可能である簡便さから考えて、米飯の初期老化の評価にはDSC測定が適していると考察された。

Water sorption isotherms of powdered crude drugs and their starches were measured by a gravimetric method. The powder and the starch were prepared from the roots of Panax ginseng C.A. Meyer (PG) and Panax notoginseng (Burk.) F.H. Chen (PN), the rhizomes of Pinellia ternata (Thunb.) Breitenbach (PT) and Alisma orientale Juzepczuk (AU), and the seed of Coix lacrymajobi Linne var. ma-yuen Stapf (CL). The Guggenheim-Anderson-de Boer equation was well applicable to the water sorption isotherms. The optimum amount of water added to knead and to granulate the powders was approximately 25-28 (w/w)%. The water contents of granules or globules have to be determined on the basis of the isotherms at storage temperature and depend on the species of powders. The water sorption capacity of starch is high at water activity less than approximately 0.5 and it is higher at lower temperatures. The results of Gibbs free energy indicate the change in free energy of a water-starch solution formed by the water sorption was larger than that of the water-powder solution; that is, starch is more hydrophilic than powder. The enthalpy suggests water was sorbed endothermically on powders and exothermically on starches. The entropy suggests freedom of water was decreased in the solution and that those of powder and starch were reversed.

Journal

  • Journal of Applied Glycoscience

    Journal of Applied Glycoscience 49(1), 19-27, 2002-01-01

    The Japanese Society of Applied Glycoscience

References:  14

Codes

  • NII Article ID (NAID)
    10008253249
  • NII NACSIS-CAT ID (NCID)
    AN10453916
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    13403494
  • NDL Article ID
    6053766
  • NDL Source Classification
    ZP24(科学技術--化学・化学工業--糖・澱粉)
  • NDL Call No.
    Z17-15
  • Data Source
    CJP  NDL  J-STAGE  JASI 
Page Top