Journal of Food Science and Technology

, Volume 55, Issue 8, pp 3119–3126 | Cite as

Dielectric characterization of raw and packed soy milks from 0.5 to 20 GHz at temperatures from 20 to 70 ºC

  • Tejinder Kaur Kataria
  • Alonso Corona-Chávez
  • José Luis Olvera-Cervantes
  • Roberto Rojas-Laguna
  • María Elena Sosa-MoralesEmail author
Original Article


For microwave heating pasteurization processes, knowledge of the dielectric characteristics of foods are very important. In this paper, we present the dielectric properties of raw soy milk and commercial packed soy milk of four different flavors (light, natural, chocolate and pecan) from 500 MHz to 20 GHz, covering most of the assigned frequencies by the Federal Communications Commission for heating purposes. Experiments were performed using an open-ended-coaxial probe and a vector network analyzer. This characterization was carried out for temperatures ranging from 20 to 70 °C in steps of 10 °C. The dielectric constant of soy milks decreased with increasing frequency, while increasing temperature resulted in decreasing of the values. The dielectric loss factor presents a U shape behavior, where the loss started decreasing from 500 MHz to about 3 GHz and then, it increased again up to 20 GHz. In addition, higher temperatures decreased the dielectric loss. Applying the higher order Debye´s equation, two relaxation times were calculated for the soymilks, with good agreement with the measured properties. Deeper penetration of microwaves were obtained for raw soy milk at 915 MHz, making it suitable for microwave pasteurization.


Dielectric properties Soy milk Penetration depth Open ended coaxial probe Debye´s equation 



Authors would like to thank CONACYT (Consejo Nacional de Ciencia y Tecnología, México) for financial support through the Project 180061, and PRODEP-NPTC UGTO 543/2016.


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Copyright information

© Association of Food Scientists & Technologists (India) 2018

Authors and Affiliations

  • Tejinder Kaur Kataria
    • 1
  • Alonso Corona-Chávez
    • 1
    • 2
  • José Luis Olvera-Cervantes
    • 2
  • Roberto Rojas-Laguna
    • 1
  • María Elena Sosa-Morales
    • 3
    Email author
  1. 1.Departamento de ElectrónicaUniversidad de GuanajuatoSalamanca, GuanajuatoMexico
  2. 2.Instituto Nacional de Astrofísica, Óptica y ElectrónicaTonanzintla, PueblaMexico
  3. 3.Departamento de AlimentosUniversidad de GuanajuatoIrapuato, GuanajuatoMexico

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