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 Proteins

  • 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 Peanut Proteins

  • 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


Aims Peanut Proteins

  • 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 Peanut Proteins

  • 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 Peanut Proteins

  • 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 Peanut Proteins

  • 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 Peanut Proteins

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 Peanut Proteins

  • Lower IC50 with Roasted

  • Higher with Boiled


Discussion
Discussion Peanut Proteins

  • 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 Peanut Proteins

  • 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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