Mathematical modelling of dielectric properties of food with respect to moisture content using adapted water activity equations

Renshaw, Ryan C.; Dimitrakis, Georgios A.; Robinson, John P.

Abstract

There is currently no recognised equation, or set of equations, that can be used to adequately describe moisture dependant dielectrics. This study addresses this issue so that moisture dependant dielectric properties can be directly input into drying models, where the microwave or radio frequency source is always limited to a single frequency. This was achieved by adapting water activity equations to describe the moisture dependant behaviour of the loss factor and the dielectric constant of hygroscopic inhomogeneous materials at microwave and radio frequencies. These equations were fitted to thirty moisture dependant loss factor and dielectric constant data sets. The adapted water activity equations proved to be very effective at describing dielectric behaviour, with the best equation fits to the thirty moisture dependant dielectric data sets having an average Mean Relative Error of 2.99%. The suitability of the equations are discussed, and specific equations are recommended for fitting to different types of moisture dependant dielectric response.

Citation

Renshaw, R. C., Dimitrakis, G. A., & Robinson, J. P. (2021). Mathematical modelling of dielectric properties of food with respect to moisture content using adapted water activity equations. Journal of Food Engineering, 300, Article 110538. https://doi.org/10.1016/j.jfoodeng.2021.110538

• Journal Article Type: Article
• Acceptance Date: Feb 10, 2021
• Online Publication Date: Feb 13, 2021
• Publication Date: 2021-07
• Deposit Date: Feb 22, 2021
• Publicly Available Date: Feb 14, 2022
• Journal: Journal of Food Engineering
• Print ISSN: 0260-8774
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 300
• Article Number: 110538
• DOI: https://doi.org/10.1016/j.jfoodeng.2021.110538
• Keywords: Food Science
• Public URL: https://nottingham-repository.worktribe.com/output/5335755
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S0260877421000637