Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518884
Title: Application of microwave sensors to potato products
Author: Mohamad Noh, Badaruzzaman Bin
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2010
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Abstract:
The first microwave measurement techniques uses an open ended coaxial probe with a purposely built sample holder to measure the dielectric properties of potato products from 500 MHz to 1 GHz. The second system utilises a waveguide cell with a purposely built sample holder to characterise potato products from 2.4 to 3.5 GHz. Common British varieties of raw potatoes such as Estima, King Edward and Maris Piper are used in this study. The two microwave measurement techniques are also used to measure the dielectric properties of potato products at elevated temperatures for these frequency ranges. Both measurement techniques are also used to study the effect of storage temperature on the dielectric properties of Saturna raw potato. For this part of the study, it is concluded that the microwave measurement techniques are unable to discriminate between potatoes that had a storage history of different temperature profiles. On the other hand, waveguide cells and open ended coaxial probes are able to measure the dielectric properties of raw potato, partial cooked fried potato and fried potato at the 500 MHz to 1 GHz and 2.4 GHz to 3.5 GHz frequency range. The measurement results show that both dielectric constant and loss values of fried potatoes decreased with frying time, due to the reduced moisture content during the frying process. Furthermore, the dielectric loss behaviour of raw and fried potatoes is dominated by the effect of the ionic conductivity at frequencies lower than 1 GHz. An apparatus has been designed and built in order to measure the dielectric properties of potato for both frequency ranges as a function of temperature. In the subsequent measurements it is found that the dielectric properties of potato products at elevated temperatures also depend on frequency and moisture content. For high moisture content potato (~> 70 %), at 2.45 GHz both the dielectric constant and loss are found to decrease with temperature, whereas at 915 MHz the dielectric constant decreases but the loss increases for the moisture content above 30%. For the intermediate moisture content (10%
Supervisor: Gibson, Andrew Sponsor: MARDI
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.518884  DOI: Not available
Keywords: Fried potato ; Estima ; King Edward ; Maris Piper ; Dielectric ; Microwave heating ; 915 MHz ; 2.45 GHz
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