High pressure, thermal and pulsed electric-field-induced structural changes in selected food allergens.
METHODS
The effects of high-pressure/temperature treatment and pulsed electric field treatment on native peanut Ara h 2, 6 and apple Mal d 3 and Mal d 1b prepared by heterologous expression were examined.


RESULTS
Changes in secondary structure and aggregation state of the treated proteins were characterized by circular dichroism spectroscopy and gel-filtration chromatography. Pulsed electric field treatment did not induce any significant changes in the structure of any of the allergens. High-pressure/temperature at 20 °C did not change the structure of the Ara h 2, 6 or Mal d 3 and resulted in only minor changes in structure of Mal d 1b. Ara h 2, 6 was stable to HPP at 80 °C, whereas changes in circular dichroism spectra were observed for both apple allergens. However, these changes were attributable to aggregation and adiabatic heating during HPP. An ELISA assay of temperature treated Mal d 3 showed the antibody reactivity correlated well with the loss of structure.


CONCLUSIONS
In conclusion, novel-processing techniques had little effect on purified allergen structure. Further studies will demonstrate if these stability properties are retained in foodmatrices.
Johnson
Phil E
PE
Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney, UK.
Van der Plancken
Iesel
I
Balasa
Ana
A
Husband
Fiona A
FA
Grauwet
Tara
T
Hendrickx
Marc
M
Knorr
Dietrich
D
Mills
E N Clare
EN
Mackie
Alan R
AR
D000485:Allergens / Q000737:chemistry*; D010367:Arachis / Q000737:chemistry* / Q000276:immunology; D002942:Circular Dichroism; D004560:Electricity; D005511:Food Handling / Q000379:methods*; D005512:Food Hypersensitivity / Q000276:immunology / Q000378:metabolism*; D006358:Hot Temperature; D027845:Malus / Q000737:chemistry* / Q000276:immunology; D010940:Plant Proteins / Q000737:chemistry; D011312:Pressure; D017433:Protein Structure, Secondary
D000485:Allergens; D010940:Plant Proteins