Bound water

Experimental investigation of bound and free water transport process during drying of hygroscopic food material

Hygroscopic food materials contain free (FW) and bound (BW) water in different cellular environments. In-depth understanding of the mechanisms of moisture migration from different cellular environments during drying is crucial for optimising heat and mass transfer as well as for obtaining better quality dried foods. Therefore, the main aim of the present work is to investigate the transportation mechanisms of FW and BW during drying. Experiments were performed on the potato tissue using 1H-NMR T2 relaxometry to uncover the mechanisms involved in FW and BW transportation. The results have confirmed the view that BW migrates after the rupture of the cell membranes. It is interesting to highlight that the cell membranes rupture at different stages of drying rather than collapsing at one time. The membrane collapse depends predominantly on the penetration rate of heat energy and the pressure gradient between intracellular and intercellular environments.

This study also identified the timing of the ruptures of the cell membranes. Understanding of the periods when cell membranes are ruptured are crucial as this knowledge can be used for designing more efficient drying system. The findings of this study will enhance the understanding of heat and mass transfer during drying of plant-based food material and will also contribute to the development of accurate heat and mass transfer models and the prediction of deformation.

Related Publications:

  1. Md Imran H. Khan, Mark Wellard, M. Mahiuddin, M. A. Karim, (2016): Cellular Level Water Distribution and Its Investigation Techniques in Intermittent and Nonstationary Drying Technologies: Principles and Applications. CRC Press (In press).
  2. Md Imran H. Khan, R. Mark Wellard, S. A. Nagy, M.U.H. Joardder, M. A. Karim, (2017): Experimental Investigation of Bound and Free Water Transport Process during Drying of Hygroscopic Food Material. International Journal of Thermal Sciences, 117: 266-273.
  3. Md Imran H. Khan, C. Kumar, M.U.H. Joardder and M. A. Karim, (2017): Determination of appropriate effective diffusivity for different food materials. Drying Technology, 35 (3): 335-346.
  4. Md Imran H. Khan, R. Mark Wellard, A. Nagy, M.U.H. Joardder, M. A. Karim, (2016): Investigation of Bound and Free Water in Plant-Based Food Material Using NMR T2 Relaxometry. Innovative Food Science and Emerging Technologies, 38: 252-261.
  5. Imran H. Khan, M.U.H. Joardder, C. Kumar, M. A. Karim, (2016): Multiphase Porous Media Modelling: A novel approach to predicting food processing performance. Critical Reviews in Food Science and Nutrition, doi:org/10.1080/10408398.2016.1197881.
  6. Imran H. Khan, M.A. Karim, (2017): Cellular Water Distribution, Transport, and Its Investigation Methods for Plant-Based Food Material. Food Research International, (accepted).
  7. Md Imran H. Khan, Kumar, M. A. Karim, (2017): Mechanistic Understanding of Cellular Level of Water in Plant-Based Food Material. Proceedings of American Institute of Physics, (USA).
  8. Md Imran H. Khan, Mark Wellard, Nghia Duc Pham, M.A. Karim, (2016): Investigation of cellular level of water in plant-based food material. The 20th International Drying Symposium (IDS, August, 2016), Gifu, Japan.
  9. Md Imran H. Khan, C. Kumar, M. A. Karim, (2016): Cellular level of water in the hygroscopic food material. The 7th BSME International Conference on Thermal Engineering, 22–24 December 2016, by Bangladesh Society of Mechanical Engineers, Dhaka, Bangladesh.
  10. Nghia Duc Pham, C. Kumar, M.U.H Joardder, Md Imran H. Khan, Martens, M.A. Karim (2016): Effect of different power ratio mode of intermittent microwave-convective drying on quality attributes of kiwi fruit slices. International Drying Symposium (IDS, August, 2016), Gifu, Japan.