Proceedings of the Korean Society for Agricultural Machinery Conference (한국농업기계학회:학술대회논문집)

Korean Society for Agricultural Machinery (한국농업기계학회)
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EFFECT OF CONTINUOUS AND STEPWISE CHANGE IN DRYING TEMPERATURE ON DRYING CHARACTERISTICS AND PRODUCT QUALITY

  • Chua, K.J. (Department of Mechanical and Production Engineering, National University of Singapore) ;
  • Mujumdar, A.S. (Department of Mechanical and Production Engineering, National University of Singapor) ;
  • A Hawlader, M.N. (Department of Mechanical and Production Engineering, National University of Singapor) ;
  • Chou, S.K. (Department of Mechanical and Production Engineering, National University of Singapor) ;
  • Ho, J.C. (Department of Mechanical and Production Engineering, National University of Singapore)
  • Published : 2000.11.01
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Abstract

Samples of banana were dried in a two-stage heat pump dryer capable of producing stepwise control of the inlet drying air temperature while keeping absolute humidity constant. Two stepwise air temperature profiles were tested. The incremental temperature step change in temperature of the drying air about the mean air temperature of 30 $^{\circ}C$ was 5 $^{\circ}C$. The total drying time for each temperature-time profile was about 300 minutes. The drying kinetics and color change of the products dried under these stepwise variation of the inlet air temperature were measured and compared with constant air temperature drying. The stepwise air temperature variation was found to yield better quality product in terms of color of the dried product. Further, it was found that by employing a step-down temperature profile, it was possible to reduce the drying time to reach the desired moisture content.

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