Journal article
Dielectric properties of almond kernels associated with radio frequency and microwave pasteurization
Scientific reports, Vol.7(1), pp.42452-42452
02/10/2017
Handle:
https://hdl.handle.net/2376/108189
PMCID: PMC5301201
PMID: 28186149
Abstract
To develop advanced pasteurization treatments based on radio frequency (RF) or microwave (MW) energy, dielectric properties of almond kernels were measured by using an open-ended coaxial-line probe and impedance analyzer at frequencies between 10 and 3000 MHz, moisture contents between 4.2% to 19.6% w.b. and temperatures between 20 and 90 °C. The results showed that both dielectric constant and loss factor of the almond kernels decreased sharply with increasing frequency over the RF range (10-300 MHz), but gradually over the measured MW range (300-3000 MHz). Both dielectric constant and loss factor of almond kernels increased with increasing temperature and moisture content, and largely enhanced at higher temperature and moisture levels. Quadratic polynomial equations were developed to best fit the relationship between dielectric constant or loss factor at 27, 40, 915 or 2450 MHz and sample temperature/moisture content with R
greater than 0.967. Penetration depth of electromagnetic wave into samples decreased with increasing frequency (27-2450 MHz), moisture content (4.2-19.6% w.b.) and temperature (20-90 °C). The temperature profiles of RF heated almond kernels under three moisture levels were made using experiment and computer simulation based on measured dielectric properties. Based on the result of this study, RF treatment has potential to be practically used for pasteurization of almond kernels with acceptable heating uniformity.
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Details
- Title
- Dielectric properties of almond kernels associated with radio frequency and microwave pasteurization
- Creators
- Rui Li - College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, ChinaShuang Zhang - College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, ChinaXiaoxi Kou - College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, ChinaBo Ling - College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, ChinaShaojin Wang - Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120, USA
- Publication Details
- Scientific reports, Vol.7(1), pp.42452-42452
- Academic Unit
- Biological Systems Engineering, Department of
- Publisher
- England
- Identifiers
- 99900547272501842
- Language
- English
- Resource Type
- Journal article