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RESEARCH PRODUCT

Dielectric properties of pineapple as function of temperature and water content

subject

description

Microwave assisted processing is a new and growing field of interest for food industry (Tang et al., 2002; Schubert & Regier, 2005). Many advantages (fast treatments, selective heating and so on) are obtainable by microwave heating due to its peculiar energy transfer that derives from a direct interaction between electromagnetic field and matter (Metaxas & Meredith, 1983). As foods are poor heat conductors, endogenous heat generation allows to overcome some difficulties that characterise conventional heating methods based on convective/conductive heat transfer phenomena (Barba, 2005; Botha et al., 2012). The key-role in design, modelling and management of microwave assisted processes is played by the dielectric properties (or permittivity), which describe how microwaves interact with the irradiated matter. The dielectric behaviour of a substance is fully depicted by the single complex function known as permittivity and reported as relative entity: er 1⁄4 e e0 1⁄4 e 0 ie00ð1Þ