Liquid impregnation and delivery of functionality in a food matrix are strongly dependent on liquid transport mechanisms that occur at nano- and micro-scale. Liquid distribution of a given pore structure depends on the morphology and topology of the porous matrix. Transparent micromodels can be defined as transparent networks of pores and constrictions that simulate some of the complexities of natural porous media: they are a useful tool to observe liquid distribution at pore scale. 2D micromodels have traditionally been built of glass and resin and have been very useful tools to observe and quantify liquid distribution and transport mechanisms involved in processes such as drying and vacuum impregnation (1), (2), (3). Since they are built with rigid materials, phenomena such as shrinkage and matrix deformation can only be indirectly studied. A new method based on the traditional photolithographic technique has been developed to build deformable micromodels, which is an elastomeric material called polydimethylsiloxane (PDMS). According to McDonald et al. (4), “PDMS is an excellent material for the fabrication of microchannel systems for use with biological samples in aqueous solutions”. This study reports the protocol to build 3D deformable transparent PDMS micromodels with a Log-Normal pore size distribution and pore values ranging between 160 and 500 mm (mean value of 200 mm and standard deviation of 60 mm). Micromodels in PDMS are a useful tool to determine the liquid transport mechanism involved in impregnation and delivery of functionality in porous structures that simulate a food matrix.
Principal investigator: Prof. Luis A. Segura lsegura@ubiobio.cl
ACKNOWLEDGEMENTS
This study was financed by FONDECYT Grant 1120347.
References:
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- C. A. Oyarzún & L.A. Segura, 2009, Drying Technology, 27, 14-29.
- G.M. Badillo, L.A. Segura & J.B, 2011, Int. Journal of Multiphase Flow, 37,1219-1266
- J.C. Mcdonald, D.C. Duffy, J.R. Anderson, D.T. Chiu, H. Wu, O.J. Schueller, & G.M. Whitesides, 2000, Electrophoresis, 21, 27- 40.
