RF Safe

Effect of temperature (-5 to 130 degrees C) and fiber direction on the dielectric properties of beef Semitendinosus at radio frequency and microwave frequencies.

Journal of food science · 2008 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 2798

Dielectric properties of beef Semitendinosus measured at 27, 915, and 1800 MHz varied with frequency, temperature (-5 to 130 °C), and muscle fiber orientation. Dielectric constant and dielectric loss factors were often higher when muscle fibers were oriented …

Study snapshot

PublicationJournal of food science · 2008
Study typeexposure_assessment
Reported directionUnclear
Evidence ratingInsufficient

Abstract

The dielectric properties must be defined to design efficient radio frequency (RF) and microwave (MW) processes by the food manufacturers. The objective of this study was to understand how frequency, temperature, and muscle fiber orientation influence the dielectric properties. The eye of round (Semitendinosus) muscle was selected because it contains large, relatively uniform muscle cells with similar muscle fiber orientation and relatively uniform chemical composition throughout the tissue. Dielectric properties were measured using an open-ended coaxial probe technique at 27, 915, and 1800 MHz and temperatures between -5 and 130 degrees C. Power penetration depth was calculated. Since many commercially prepared, thermally processed, ready-to-eat entrees are made with frozen meat, dielectric property measurements were started from -5 degrees C. The dielectric constant and dielectric loss factors were often higher for muscle with the muscle fiber measured in a parallel orientation to the probe compared to samples of the same treatment (for example, fresh or frozen) in a perpendicular tissue orientation at the same frequency and temperature. Dielectric constant and loss values for frozen beef tended to be higher than fresh beef at the same temperature and frequency. Tissue orientation appeared to have a greater effect on dielectric loss values at lower frequencies. Penetration depth tended to be greater when the direction of propagation was perpendicular to the muscle fiber.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeexposure_assessment
Effect directionunclear
PopulationNot supplied
Sample sizeNot supplied
ExposureRF
Evidence strengthInsufficientConfidence: 78% · Peer reviewed: yes

Main findings

Dielectric properties of beef Semitendinosus measured at 27, 915, and 1800 MHz varied with frequency, temperature (-5 to 130 °C), and muscle fiber orientation. Dielectric constant and dielectric loss factors were often higher when muscle fibers were oriented parallel to the probe versus perpendicular at the same frequency and temperature; frozen beef tended to show higher dielectric constant and loss values than fresh beef at the same temperature and frequency. Penetration depth tended to be greater when propagation was perpendicular to the muscle fiber.

Outcomes measured

  • Dielectric constant
  • Dielectric loss factor
  • Power penetration depth

Limitations

  • Sample size not reported in abstract.
  • Study is on beef tissue (food processing context), not human/animal health outcomes.
  • No dosimetry metrics such as SAR reported in abstract.
View raw extracted JSON
{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "RF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Dielectric constant",
    "Dielectric loss factor",
    "Power penetration depth"
  ],
  "main_findings": "Dielectric properties of beef Semitendinosus measured at 27, 915, and 1800 MHz varied with frequency, temperature (-5 to 130 °C), and muscle fiber orientation. Dielectric constant and dielectric loss factors were often higher when muscle fibers were oriented parallel to the probe versus perpendicular at the same frequency and temperature; frozen beef tended to show higher dielectric constant and loss values than fresh beef at the same temperature and frequency. Penetration depth tended to be greater when propagation was perpendicular to the muscle fiber.",
  "effect_direction": "unclear",
  "limitations": [
    "Sample size not reported in abstract.",
    "Study is on beef tissue (food processing context), not human/animal health outcomes.",
    "No dosimetry metrics such as SAR reported in abstract."
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "dielectric properties",
    "beef",
    "Semitendinosus",
    "radio frequency",
    "microwave",
    "temperature",
    "muscle fiber orientation",
    "open-ended coaxial probe",
    "penetration depth",
    "27 MHz",
    "915 MHz",
    "1800 MHz"
  ],
  "suggested_hubs": []
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1111/j.1750-3841.2008.00835.x
PubMed: 19241544

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