UNESCO - EOLSS SAMPLE CHAPTER FOOD ENGINEERING – Engineering Properties of Foods - Barbosa-Cánovas G.V., Juliano P. and Peleg M. ENGINEERING PROPERTIES OF FOODS Barbosa-Cánovas G.V. and Juliano P. Washington State University, USA Peleg M. University of Massachusetts, USA Keywords: Food engineering, engineering property, physical, thermal, heat, electrical, foods, density, porosity, shrinkage, particulates, powders, compressibility, flowability, conductivity, permittivity, dielectric, color, gloss, translucency, microstructure, microscopy, diffusivity, texture Contents 1. Introduction 2. Thermal Properties 3. Optical Properties 4. Electrical Properties 5. Mechanical Properties 6. Properties of Food Powders 7. Role of Food Microstructure in Engineering Properties Glossary Bibliography Biographical Sketches To cite this chapter Summary The engineering properties of foods are important, if not essential, in the process design and manufacture of food products. They can be classified as thermal (specific heat, thermal conductivity, and diffusivity), optical (color, gloss, and translucency), electrical (conductivity and permittivity), mechanical (structural, geometrical, and strength), and food powder (primary and secondary) properties. Most of these properties indicate changes in the chemical composition and structural organization of foods ranging from the molecular to the macroscopic level. Both modern and more conventional measurement methods allow computation of these properties, which can provide information about the macrostructural effects of processing conditions in fresh and manufactured foods. Mathematical models have been fitted to data as a function of one or several experimental parameters, such as temperature, water content, porosity, or other food characteristics. Most engineering properties are significantly altered by the structural differences between foods. Several microscopy, scanning, and spectrometric technologies permit close visualization of changes in structure at different levels without intrusion. Microstructure studies have increased understanding of several changes detected in foods resulting from treatment in emerging and conventional unit operations, by relating these changes to engineering property characterization data and models. In the future, structure–property modeling could lead to the synthetic production of natural materials with improved characteristics, provided advances in genetic engineering and biotechnology are incorporated into the food engineering field. ©Encyclopedia of Life Support Systems (EOLSS)