Principios De La Calidad

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 citethis chapter

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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, andstrength), 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 conditionsin 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 visualizationof 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 naturalmaterials with improved characteristics, provided advances in genetic engineering and biotechnology are incorporated into the food engineering field.

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FOOD ENGINEERING – Engineering Properties of Foods - Barbosa-Cánovas G.V., Juliano P. and Peleg M.

1. Introduction The word engine, derived fromthe words engineer and engineering, comes from the Latin word for talent, ingenium. From the onset of the Industrial Revolution to the beginning of the twentieth century, the term was used almost exclusively to describe power machines. Those who designed, built, and operated these machines became known as engineers, and their profession, or expertise, as engineering. In today’s technological world,the meaning of the term has expanded to include not only such disciplines or activities as chemical, medical, polymer, or food engineering, but also genetic engineering and social engineering. Although these disciplines have little to do with engines, they heavily rely on the ingenuity from which the term was originally conceived. It is difficult to define what exactly constitutes an engineeringproperty of a certain food. In general, however, any attribute affecting the processing or handling of a food can be defined as an engineering property. Since many properties are related, there is usually an arbitrary element in their classification. Traditionally, they are divided into the following categories:

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Food materials or biological materials in general can...