influence of thermal processing on the allergenicity of peanut proteins
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Influence of Thermal Processing on the Allergenicity of Peanut Proteins. Mondoulet, E. Paty, M.F. Drumare, S. Ah-Leung, P. Scheinmann From the Journal of Argricultural and Food Chemistry. Premise. Peanut allergies most common and severe IgE mediated response

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influence of thermal processing on the allergenicity of peanut proteins

Influence of Thermal Processing on the Allergenicity of Peanut Proteins

Mondoulet, E. Paty, M.F. Drumare, S. Ah-Leung, P. Scheinmann

From the Journal of Argricultural and Food Chemistry

premise
Premise
  • Peanut allergies most common and severe IgE mediated response
  • Prevalence btw .6%-1% of US and EU populations
  • Far less prevalent in China
  • Most likely due to cooking method in the two populations
  • Why?
the known effects of thermal processing
The known effects of thermal processing
  • Heat can can have varying effects on allergy
  • Inc. by roasting
  • Dec. by boiling
  • Results from modification of structure and reactivity
    • No effect on hazelnut at 100 C but dec. btw 100 and 185 C
    • Roast at 140 C dec. effect of allergen Cor a
      • Inc. allergen LTP Cor a 8
slide4
Aims
  • Assess effect of thermal processing on IgE-binding capacity of whole peanut extract and peanut allergens Ara h 1 and Ara h 2
  • Whole Peanut Extract differentiated by preparation
    • Raw
    • Roasted
    • Boiled
methods
Methods
  • Human Sera – obtaining Ig-E
    • 37 children with allergy history
    • Mean age 8
  • Preparation of peanut protein extract
    • Raw and commericially roasted VA peanuts
    • Boiled for 30 min in water
    • Kernels ground, defatted with ether
    • Extraction buffer at 4 C
    • Centrifugation and dialysed with buffer
ara h 1 and ara h 2 preparation
Ara h 1 and Ara h 2 Preparation
  • Purified from raw, roasted, boiled PE
  • Ara h1 separated with affinity chromatography column
    • on Con A Sepharose Column
  • Ara h 2 isolated from unbound fraction Con A
  • Both purified on reverse phase chromatography column
methods1
Methods
  • Gel electrophoresis (SDS-Page)
  • Western blotting
  • Determination of IgE response
    • Enzyme allergosorbent test (EAST)
    • Raw PE incubated with IgE for 24 h
    • Anti-human IgE labeled with ACHe used as tracer
  • Analysis of immunoreactivity
    • EAST
    • Prelim step: sera pre-incubated with PE for 4 hours in 1:1 ratio and dispensed per well
ige response to whole peanut extract
IgE Response to Whole Peanut Extract

2 fold response dec

In boiled PE

inhibition of ige binding to ara h 1 and 2
Inhibition of IgE binding to Ara h 1 and 2
  • Lower IC50 with Roasted
  • Higher with Boiled
discussion
Discussion
  • Heat formation of stable tetramers in Ara h 1, structural modifications of Ara h 2 could contribute to inc. allergenicity
  • Higher inhibitory capacity than raw and boiled
  • Ara h 2 protects Ara h 1 from degredation and enhanced by roasting
    • Ara h 2 is LTP like, heat stable
  • Dec. in allergenicity by boiling
    • Due to loss of low MW proteins in water
problems
Problems
  • Already established that roasting inc allergy and boiling decreases
  • Disussion contained ill placed literature and notes
  • Lack of specification of inhibitor serum
  • No IC50 values listed
  • Exact comparison of Ara h 1 and 2 complicated
    • Preparation of tracers not fully controlled in terms of concen of activated intermediary derivatives
    • Apparent affinity of IgE for Ara h 1
  • Results underline the importance of food product labeling?
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