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Dielectric properties of sweet potato purees at 915 MHZ as affected by temperature and chemical composition

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A process for rapid sterilization and aseptic packaging of sweet potato puree using a continuous flow microwave system operating at 915 MHz has been successfully developed. In microwave processing, dielectric properties have a major role in determining the interaction between purees and the electromagnetic energy. The objective of this research was to determine how dielectric properties are affected by temperature and chemical composition of purees derived from thirteen sweet potato cultivars with varying flesh colors. Results indicated that temperature, moisture, sugar and starch content had a pronounced effect (p < 0.001) on dielectric properties measured from 15°C to 145°C at 915 MHz. Dielectric constant decreased with increasing temperature, while dielectric loss factor increased quadratically. Power penetration depth of all cultivars decreased with increasing temperature. Predictive equations were developed for dielectric constant (R2 = 0.82) and dielectric loss factor (R2 = 0.90) as a function of temperature, moisture, sugar, and starch. The predictive equations would be useful in determining the dielectric properties of sweet potato purees for the microwave processing technology.
Brinley, T.A. , Truong, V.D. , Coronel, P. , Simunovic, J. , Sandeep, K.P.
sweet potatoes , colored varieties , pureed foods , nutrient content , chemical composition , moisture content , water activity , sugar content , lipid content , crude protein , ash content , amylose , dietary fiber , phytochemicals , vitamin content , mineral content , food packaging , sterilizing , continuous systems , microwave treatment , microwave radiation , dielectric properties , electric field , temperature , linear models , equations
p. 158-172.
Includes references
International journal of food properties 2008 Jan., v. 11, issue 1
Journal Articles, USDA Authors, Peer-Reviewed
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