Transport Properties of Foods

Saravacos, G.D. and Maroulis, Z.B. Transport Properties of Foods, Marcel Dekker, New York, 2001. 

Transport Properties of Foods, George D. Saravacos and Zacharias B. Maroulis... 

The transport properties of foods received much attention in the literature [184-188]. The main results presented by Saravacos and Maroulis [188] are summarized in this section. The results refer to moisture diffusivity and thermal condnc-tivity. Recently published values of moisture diffusivity and thermal conductivity in various foods were retrieved from the literature and were classified and analyzed statistically to reveal the influence of material moisture content and tempera-tnre. Empirical models relating moisture diffusivity and thermal conductivity to material moisture content and temperature were fitted to all examined data for each material. The data were screened carefully using residual analysis techniques. A promising model was proposed based on an Arrhenius-type effect of temperature, which uses a parallel structural model to take into account the effect of material moisture content. 

Rheology is the science of deformation and flow of matter. In food rheology, the matter of interest is food, and the importance of its deformation and flow relate to several important properties. Of these, texture is the most important. Texture is one of four quality factors of foods the others are flavor, appearance, and nutrition. In the food industry, there are other properties and processes in which rheology has an important role. They include formulation, manufacturing, transportation, and shelf stability. The measurement of the rheological properties of foods provides the food scientist and engineer with critical information necessary for the successful development and delivery of formulated foods to the consumer. 

Araki, T., Sagara, Y., Abdullah, K., Tam-bunan, A.H. Transport properties of cellular food materials undergoing freeze-drying. Drying Technol. 19, 297-312, 2001... 

The use and design of polymers in the food packaging industry requires an understanding of the water transport properties of the... 

Howsmon, G.J., andN.A. Peppas, "Mathematical Analysis of Transport Properties of Polymer Films for Food Packaging. VI Coupling of Moisture and Oxygen Transport Using Langmuir Sorption Isotherms", J Appl Poly Sci 1986, 31, pp 2071-2082. 

Regier, M., Hardy, E. H., Knoerzer, K., Leeb, C. V., Schuchmann, H. P., 2007. Determination of stmctural and transport properties of cereal products by optical scanning, magnetic resonance imaging and Monte Carlo simulations./. Food Eng. 81 485-91. 

Hernandez, R.J., Effect of Water Vapor on the Transport Properties of Oxygen through Polyamides Packaging Materials, J. Food Eng., 22, 495, 1994. 

Transport properties of small molecules in amorphous polymer matrices play an important role in many industrial applications such as gas separation of mixtures, packaging applications ranging from food conservation to controlled drug and cosmetics release, to special coatings for protecting specific substrates from gases. 

By varying the counter-ion type the FAMI technology [20,21] has enabled significantly enhanced gas permeability for oxygen, carbon dioxide, or alternatively water vapor. Certain FAMI compositions have achieved novel smart vapor barrier capability where FAMI self-regulates transitions from a moisture barrier to a moisture transmitter and vice versa, upon change of the relative humidity of the environment. The novel gas transport properties of FAMFs have enabled selective gas breathability enhancement and atmosphere controls to facilitate various applications, like food packaging, protective apparel, smart vapor barrier house and roof liners, etc. 

Supercritical Extraction. The use of a supercritical fluid such as carbon dioxide as extractant is growing in industrial importance, particularly in the food-related industries. The advantages of supercritical fluids (qv) as extractants include favorable solubiHty and transport properties, and the abiHty to complete an extraction rapidly at moderate temperature. Whereas most of the supercritical extraction processes are soHd—Hquid extractions, some Hquid—Hquid extractions are of commercial interest also. For example, the removal of ethanol from dilute aqueous solutions using Hquid carbon dioxide... 

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