8. コーヒーの凍結乾燥プロセスにおける乾燥層の移動係数測定について(昭和57年度第28回凍結および乾燥研究会特別講演および研究報告)

DOI

書誌事項

タイトル別名
  • 8. Measurements of Dried Layer Transport Properties During Freeze-Drying of Coffee Solutions(Synopsis paper presented at the 28th Annual Meeting)

抄録

Experiments were conducted to determine the transport properties of the dried layer using a radiant heating upon the sample surface. The samples of 6-30% coffee solution were freeze-dried in a dish of 70.5mm in diameter and 25 mm in height at constant surface temperatures ranging from 20 to 55℃ under about 10-95 Pa total pressure range, the usual operating condition of commercial freeze-dryer. Thermal conductivities and permeabilities of the dried layer were determined by applying the drying data to a model based on heat and mass transport in the sample. Thermal conductivities had a tendency to decrease as the sample concentration was increassed, and there was no definite effect of the dried layer temperature on thermal conductivity. Permeability decresced with increasing the sample concentration and it increased as the dried layer temperature increased. These transport properties were not affected by the pressure of water vapor in the dried layer under experimental conditions. From these results it may be concluded that transport properties depend mainly on concentration of sample tested and the concentration was one of the most important factors which affected the structure as well as transport properties of the dried layer. The relationships between transport properties and controlling factors were discussed in connection with the freezing and freeze-drying operations of the sample.

収録刊行物

詳細情報 詳細情報について

  • CRID
    1390001205085752576
  • NII論文ID
    110007368274
  • DOI
    10.20585/touketsukansokaishi.28.0_30
  • ISSN
    24329916
    02888297
  • 本文言語コード
    ja
  • データソース種別
    • JaLC
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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