Combined effect of temperature and pulsed electric fields on apple juice peroxidase and polyphenoloxidase inactivation.

Food chemistry · 2008 · Benefit · Low evidence

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BenefitLow evidencePaper 3383

Study snapshot

PublicationFood chemistry · 2008

Study typeengineering

Reported directionBenefit

Evidence ratingLow

Abstract

Pulsed electric fields (PEF) were applied to freshly prepared apple juice using a laboratory scale continuous PEF system to study the feasibility of inactivating peroxidase (POD) and polyphenoloxidase (PPO). Square wave PEF using different combinations of electric field strength, pre-treatment temperature and treatment time were evaluated in this study and compared to conventional pasteurisation (72°C; 26s). Inactivation curves for the enzyme were plotted for each parameter and inactivation kinetics were calculated. Results showed the highest level of decrease in the enzymatic activity of 71% and 68%, for PPO and POD, respectively, were obtained by using a combination of preheating to 50°C, and a PEF treatment time of 100μs at 40kV/cm. This level of inactivation was significantly higher (P<0.05) than that recorded in juice processed by conventional mild pasteurisation where the activity of PPO and POD decreased by 46% and 48%, respectively. The kinetic data for the inactivation of both enzymes could be described using a 1st-order model (P<0.001).

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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 typeengineering

Effect directionbenefit

PopulationNot supplied

Sample sizeNot supplied

Exposuretreatment time up to 100 μs (example condition reported)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In freshly prepared apple juice, a combination of preheating to 50°C and PEF treatment at 40 kV/cm for 100 μs produced the highest reported decreases in enzymatic activity (71% for PPO and 68% for POD). These decreases were significantly greater (P<0.05) than those achieved by conventional mild pasteurisation (72°C for 26 s), which reduced PPO and POD activity by 46% and 48%, respectively. Inactivation kinetics for both enzymes were described by a 1st-order model (P<0.001).

Outcomes measured

Peroxidase (POD) activity inactivation in apple juice
Polyphenoloxidase (PPO) activity inactivation in apple juice
Comparison with conventional pasteurisation (72°C; 26 s)
Inactivation kinetics model fit (1st-order)

Limitations

No sample size reported in the abstract
No detailed PEF parameters beyond field strength, waveform type (square), pre-treatment temperature, and treatment time are provided in the abstract
Outcomes are limited to enzyme activity in apple juice; no broader health or exposure implications are addressed

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": null,
    "source": "pulsed electric fields (PEF) food processing system",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "treatment time up to 100 μs (example condition reported)"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Peroxidase (POD) activity inactivation in apple juice",
    "Polyphenoloxidase (PPO) activity inactivation in apple juice",
    "Comparison with conventional pasteurisation (72°C; 26 s)",
    "Inactivation kinetics model fit (1st-order)"
  ],
  "main_findings": "In freshly prepared apple juice, a combination of preheating to 50°C and PEF treatment at 40 kV/cm for 100 μs produced the highest reported decreases in enzymatic activity (71% for PPO and 68% for POD). These decreases were significantly greater (P<0.05) than those achieved by conventional mild pasteurisation (72°C for 26 s), which reduced PPO and POD activity by 46% and 48%, respectively. Inactivation kinetics for both enzymes were described by a 1st-order model (P<0.001).",
  "effect_direction": "benefit",
  "limitations": [
    "No sample size reported in the abstract",
    "No detailed PEF parameters beyond field strength, waveform type (square), pre-treatment temperature, and treatment time are provided in the abstract",
    "Outcomes are limited to enzyme activity in apple juice; no broader health or exposure implications are addressed"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "pulsed electric fields",
    "PEF",
    "apple juice",
    "peroxidase",
    "polyphenoloxidase",
    "enzyme inactivation",
    "pasteurisation",
    "temperature",
    "kinetics"
  ],
  "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: 10.1016/j.foodchem.2007.12.059
PubMed: 26003364

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