High-pressure treatment reduces the immunoreactivity of the major allergens in apple and celeriac

Scope: The impact of thermal and high pressure (HP) processing on the immunoreactivity of the allergens Mal d 1, Mal d 3 and Api g 1 has been investigated in apple and celeriac tissue, respectively. Methods and results: The extracted proteins were assessed using SDS-PAGE and Western blot. The results showed that Mal d 1 was subject to loss of immunoreactivity as soon as the apple tissue was disrupted although it was remarkably resistant to both thermal and HP processing. This is in contrast to the Mal d 1 structural homolog from celeriac, Api g 1, that was susceptible to thermal processing. The other major allergen in apple, Mal d 3, was found to be resistant to chemical modification and thermal processing in apple, which is in contrast to behavior in solution. However, the combination of pressure and temperature significantly reduced its immunoreactivity. Pectin was found to protect Mal d 3 from thermal denaturation in solution and is a possible candidate for the protective effect of the fruit. Conclusion: The conclusion to be drawn from these results is that the combination of HP and thermal processing is an effective method to reduce the allergenicity of both apple and celeriac.